@property --glow-alpha {
    syntax: '<number>';
    inherits: true;
    initial-value: 1;
}

@keyframes flood-pulse-glow {
    from {
        --glow-alpha: 0.2;
    }
    to {
        --glow-alpha: 0.6;
    }
}

:root {
    /* Modern Color Palette - Light Mode - Low Glare / Grey Theme */
    /* Background is lighter (Slate 50/100) */
    --bg-gradient-1: #f1f5f9; /* Slate 100 */
    --bg-gradient-2: #f8fafc; /* Slate 50 */
    --bg-pattern: none;
    --bg-opacity: 1;

    --primary-bg: #f8fafc;

    /* Panels are DARKER than background (Slate 200) to reduce glare */
    --secondary-bg: #e2e8f0; /* Slate 200 */
    --panel-bg: rgba(226, 232, 240, 0.98); /* Slate 200 */

    --text-color: #0f172a; /* Slate 900 */
    --text-muted: #475569; /* Slate 600 */
    --border-color: #cbd5e1; /* Slate 300 */
    --shadow-color: rgba(71, 85, 105, 0.1);
    --shadow-elevation-low: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-elevation-medium: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-elevation-high: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);

    --heading-color: #020617; /* Slate 950 */

    /* Brand Colors */
    --primary-color: #2563eb; /* Blue 600 */
    --primary-hover: #1d4ed8; /* Blue 700 */
    --success-color: #059669; /* Emerald 600 */
    --success-hover: #047857; /* Emerald 700 */
    --warning-color: #d97706; /* Amber 600 */
    --warning-hover: #b45309; /* Amber 700 */
    --danger-color: #dc2626; /* Red 600 */
    --danger-hover: #b91c1c; /* Red 700 */
    --info-color: #0284c7; /* Sky 600 */

    /* Button Mappings */
    --button-primary-bg: var(--primary-color);
    --button-primary-text: #ffffff;
    --button-primary-hover-bg: var(--primary-hover);

    /* Secondary Buttons - Darker than panels (Slate 300) */
    --button-secondary-bg: #cbd5e1; /* Slate 300 */
    --button-secondary-text: #0f172a; /* Slate 900 */
    --button-secondary-hover-bg: #94a3b8; /* Slate 400 */

    --button-success-bg: var(--success-color);
    --button-success-hover-bg: var(--success-hover);

    --button-warning-bg: var(--warning-color);
    --button-warning-hover-bg: var(--warning-hover);

    --button-google-bg: #4285f4;
    --button-google-hover-bg: #3367d6;

    --button-active-bg: var(--warning-color);
    --button-active-text: #ffffff;

    --input-bg: #f8fafc; /* Light inputs for contrast against grey panels */
    --input-text-color: #0f172a;
    --input-border-color: #94a3b8;

    --gold-text: #b45309;
    --win-message-color: #059669;
    --loss-message-color: #dc2626;
    --logged-in-color: #059669;

    --modal-overlay-bg: rgba(15, 23, 42, 0.6);
    --modal-content-bg: #f1f5f9; /* Slate 100 */
    --modal-content-border: #cbd5e1;
    --modal-heading-color: var(--primary-color);

    --palette-border: #94a3b8;
    --palette-active-border: #0f172a;

    --face-bg-color: rgba(203, 213, 225, 0.9); /* Slate 300 */
    --cell-border-color: rgba(148, 163, 184, 0.2); /* Subtle gray, mostly transparent */

    --edge-highlight-color: #2563eb;
    --edge-highlight-rgb: 37, 99, 235;
    --start-cell-highlight-outline: #2563eb;
    --edge-highlight-thickness: 1px; /* Reduced to 1px for thinner edges */

    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;

    --tutorial-card-bg: #e2e8f0;

    /* Retro Mode Pattern Color - Slate 200 (Darker than bg-gradient-1) */
    --retro-pattern-color: #e2e8f0;
}

.guest-btn {
    background-color: transparent;
    color: var(--text-muted);
    border: 1px solid var(--border-color);
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1rem;
}

.guest-btn:hover {
    background-color: var(--secondary-bg);
    color: var(--text-color);
    border-color: var(--text-muted);
}

html[data-theme='dark'] {
    /* Modern Color Palette - Dark Mode */
    --bg-gradient-1: #102a43;
    --bg-gradient-2: #243b53;
    --bg-pattern: none;
    --bg-opacity: 1;

    --primary-bg: #102a43;
    --secondary-bg: #243b53;
    --panel-bg: rgba(36, 59, 83, 0.9);
    --text-color: #f0f4f8;
    --text-muted: #9fb3c8;
    --border-color: #334e68;
    --shadow-color: rgba(0, 0, 0, 0.4);
    --shadow-elevation-low: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-elevation-medium: 0 4px 8px rgba(0, 0, 0, 0.4);
    --shadow-elevation-high: 0 8px 16px rgba(0, 0, 0, 0.5);

    --heading-color: #ff6b6b;

    /* Brand Colors - Adjusted for Dark Mode */
    --primary-color: #339af0;
    --primary-hover: #74c0fc;
    --success-color: #51cf66;
    --success-hover: #69db7c;
    --warning-color: #fcc419;
    --warning-hover: #ffd43b;
    --danger-color: #ff6b6b;
    --danger-hover: #ff8787;

    --button-primary-bg: var(--primary-color);
    --button-primary-hover-bg: var(--primary-hover);

    --button-secondary-bg: #486581;
    --button-secondary-text: #f0f4f8;
    --button-secondary-hover-bg: #627d98;

    --button-success-bg: var(--success-color);
    --button-success-hover-bg: var(--success-hover);

    --button-warning-bg: var(--warning-color);
    --button-warning-hover-bg: var(--warning-hover);

    --button-google-bg: #4285f4;
    --button-google-hover-bg: #5b96f7;

    --button-active-bg: var(--warning-color);

    --input-bg: #102a43;
    --input-text-color: #f0f4f8;
    --input-border-color: #486581;

    --gold-text: #fcc419;
    --win-message-color: #51cf66;
    --loss-message-color: #ff6b6b;

    --modal-overlay-bg: rgba(0, 0, 0, 0.7);
    --modal-content-bg: #243b53;
    --modal-content-border: #334e68;
    --modal-heading-color: #74c0fc;

    --palette-border: #486581;
    --palette-active-border: #f0f4f8;

    --face-bg-color: rgba(30, 58, 138, 0.6); /* Lighter blue for defined corners */
    --cell-border-color: rgba(51, 78, 104, 0.25); /* Subtle dark gray, mostly transparent */

    --edge-highlight-color: #f0f4f8; /* Brighter Silver */
    --edge-highlight-rgb: 240, 244, 248;
    --start-cell-highlight-outline: #f0f4f8;

    --tutorial-card-bg: rgba(0, 0, 0, 0.2);

    /* Retro Mode Pattern Color - Darker than bg-gradient-1 */
    --retro-pattern-color: #081624;
}

html[data-theme='premium-purple'] {
    /* Premium Purple Palette - Refined */
    --bg-gradient-1: #120136; /* Very Dark Deep Purple */
    --bg-gradient-2: #320b86; /* Rich Indigo */
    --bg-pattern: none;
    --bg-opacity: 1;

    --primary-bg: #120136;
    --secondary-bg: #240046; /* Dark Violet */
    --panel-bg: rgba(36, 0, 70, 0.95); /* Deep Purple Panel */
    --text-color: #e0aaff; /* Soft Lavender */
    --text-muted: #9d4edd; /* Vivid Violet for muted text */
    --border-color: #7b2cbf; /* Medium Purple */
    --shadow-color: rgba(0, 0, 0, 0.6);
    --shadow-elevation-low: 0 2px 4px rgba(0, 0, 0, 0.5);
    --shadow-elevation-medium: 0 4px 8px rgba(0, 0, 0, 0.6);
    --shadow-elevation-high: 0 8px 16px rgba(0, 0, 0, 0.7);

    --heading-color: #ffcc00; /* Rich Gold */

    /* Brand Colors - Adjusted for Purple Theme */
    --primary-color: #c77dff; /* Light Purple */
    --primary-hover: #e0aaff;
    --success-color: #00e676; /* Keep Vibrant Green */
    --success-hover: #69f0ae;
    --warning-color: #ffab00; /* Keep Amber */
    --warning-hover: #ffd740;
    --danger-color: #ff1744;
    --danger-hover: #ff5252;

    --button-primary-bg: #6200ea; /* Deep Electric Purple */
    --button-primary-text: #ffffff;
    --button-primary-hover-bg: #7c4dff;

    --button-secondary-bg: #3c096c; /* Dark Violet */
    --button-secondary-text: #ffffff;
    --button-secondary-hover-bg: #5a189a;

    --button-success-bg: var(--success-color);
    --button-success-hover-bg: var(--success-hover);

    --button-warning-bg: var(--warning-color);
    --button-warning-hover-bg: var(--warning-hover);

    --button-google-bg: #4285f4;
    --button-google-hover-bg: #5b96f7;

    --button-active-bg: var(--warning-color);
    --button-active-text: #ffffff;

    --input-bg: #240046;
    --input-text-color: #e0aaff;
    --input-border-color: #7b2cbf;

    --gold-text: #ffcc00;
    --win-message-color: #00e676;
    --loss-message-color: #ff1744;

    --modal-overlay-bg: rgba(5, 0, 15, 0.9);
    --modal-content-bg: #240046; /* Dark Violet */
    --modal-content-border: #7b2cbf;
    --modal-heading-color: #ffcc00;

    --palette-border: #7b2cbf;
    --palette-active-border: #ffcc00;

    --face-bg-color: rgba(60, 9, 108, 0.8); /* Lighter purple for defined corners */
    --cell-border-color: rgba(90, 24, 154, 0.15); /* Subtle purple, mostly transparent */

    --edge-highlight-color: #f0f4f8; /* Brighter Silver */
    --edge-highlight-rgb: 240, 244, 248;
    --start-cell-highlight-outline: #f0f4f8;

    --tutorial-card-bg: rgba(0, 0, 0, 0.4);

    /* Retro Mode Pattern Color - Darker than bg-gradient-1 */
    --retro-pattern-color: #0a001f;
}

html[data-theme='premium-purple'] .achievement-item {
    background-color: rgba(60, 9, 108, 0.4);
    border-color: #9d4edd;
}

html[data-theme='premium-purple'] .achievement-item.unlocked {
    background-color: rgba(60, 9, 108, 0.8);
    border-color: #ffcc00;
    box-shadow: 0 0 10px rgba(255, 204, 0, 0.2);
}

* {
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
        Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    box-sizing: border-box;
}

html,
body {
    height: 100%;
    width: 100%;
    margin: 0;
    overflow: hidden;
    background: linear-gradient(135deg, var(--bg-gradient-1) 0%, var(--bg-gradient-2) 100%);
    background-attachment: fixed;
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    touch-action: manipulation;
    position: relative;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: var(--bg-pattern);
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    opacity: var(--bg-opacity);
    pointer-events: none;
    z-index: -1;
}
#main-layout {
    display: flex;
    flex-direction: row;
    width: 100%;
    height: 100%;
    flex-grow: 1;
    overflow: hidden;
}
#game-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex-grow: 1;
    padding: 2px 10px 10px 10px; /* Reduced top padding to minimum */
    box-sizing: border-box;
    min-height: 0;
    position: relative;
    z-index: 1;
    overflow-y: auto;
}
h1 {
    margin-top: 5px;
    margin-bottom: 5px;
    font-size: clamp(1.4em, 3.5vw, 2em);
    color: var(--heading-color);
    text-shadow: 1px 1px 2px var(--shadow-color);
    position: relative;
    z-index: 10;
}
#game-mode-heading {
    margin-top: -2px;
    margin-bottom: 5px;
    font-size: clamp(0.9em, 2.5vw, 1.1em);
    font-weight: 500;
    color: var(--gold-text);
    text-shadow: 1px 1px 2px var(--shadow-color);
}
#scores-panel {
    width: 250px;
    min-width: 200px;
    max-width: 30%;
    padding: 15px;
    box-sizing: border-box;
    background-color: var(--panel-bg);
    border-left: 2px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 15px;
    overflow-y: auto;
    position: relative;
    z-index: 20;
}
#scores-panel h2 {
    margin-top: 0;
    margin-bottom: 5px;
    color: var(--heading-color);
    font-size: clamp(1.2em, 3vw, 1.5em);
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 5px;
}
.stats-group p {
    margin: 4px 0;
    font-size: clamp(0.8em, 2.2vw, 0.95em);
}
.stats-group strong {
    color: var(--gold-text);
}
#top-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
    justify-content: center;
    margin-bottom: 15px;
    padding: 8px;
    background-color: var(--secondary-bg);
    border-radius: 8px;
    box-shadow: 0 2px 5px var(--shadow-color);
    position: relative;
    z-index: 20;
    overflow: visible;
}

#modes-dropdown button {
    font-size: 0.85em;
    padding: 10px 12px;
    min-width: 0;
    width: 100%;
}
/* Ensure infinite button maintains consistent font size */
#modes-dropdown button.infinite-btn {
    font-size: 0.85em;
}
#modes-dropdown {
    width: 180px;
}
#top-bar {
    position: relative;
}
#top-bar-status {
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
}
#settings-dropdown-container {
    position: relative;
}
#view-results-btn {
    display: none;
}
#scene-container {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    flex-grow: 1;
    min-height: 150px;
    margin-bottom: 8px;
    position: relative;
}
#scene {
    cursor: grab;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    touch-action: none;
    overscroll-behavior: contain;
    transition: filter 0.3s ease;
}
#scene:active {
    cursor: grabbing;
}
#cube-container {
    width: 100%;
    height: 100%;
    position: relative;
    transform-style: preserve-3d;
    transform: scale(var(--cube-zoom, 1));
    transform-origin: center center;
    will-change: transform;
}
#scene-container.win-celebration #cube-container {
    animation: win-full-spin 4s ease-in-out infinite;
}

.start-cell-highlight::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 0;
    pointer-events: none;
    animation: pulse-start-highlight 3s ease-in-out infinite alternate;
}
#controls {
    /* Handled by ad-layout.css */
    /* display: flex; */
    /* flex-direction: column; */
    /* align-items: center; */
    /* background-color: var(--secondary-bg); */
    /* padding: 12px 8px 4px 8px; */
    /* border-radius: var(--radius-lg); */
    /* box-shadow: var(--shadow-elevation-medium); */
    /* width: 95%; */
    /* max-width: 550px; */
    /* box-sizing: border-box; */
    /* position: relative; */
    /* z-index: 10; */
    /* border: 1px solid var(--border-color); */
}
#controls > p {
    display: none;
}
.attempts-display {
    position: absolute;
    left: 0;
    bottom: 100%;
    margin-bottom: 8px;
    z-index: 100;
    display: flex;
    justify-content: center;
    gap: 5px;
    min-height: 32px;
    padding-left: 8px; /* Align with container padding */
}
.attempt-icon {
    font-size: 1.8em;
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.2));
    transition: transform 0.2s ease, opacity 0.2s ease;
}
.attempt-icon.lost {
    opacity: 0.3;
    filter: grayscale(1);
    transform: scale(0.8);
}
#moves-display-main {
    font-size: clamp(1.2em, 3.8vw, 1.8em);
    font-weight: 700;
    margin-bottom: 12px;
    padding: 5px 0;
    color: var(--text-color);
    letter-spacing: -0.02em;
}
.moves-count {
    font-size: 1.2em;
    color: var(--success-color);
    transition: color 0.3s ease;
    font-variant-numeric: tabular-nums;
}
.low-moves-warning {
    color: var(--loss-message-color) !important;
    animation: pulse-danger 1s infinite alternate;
}

/* Fade-in animation for the login modal benefits box */
@keyframes authBenefitsFadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#auth-benefits {
    animation: authBenefitsFadeIn 360ms cubic-bezier(0.2, 0.9, 0.25, 1) both;
}

@media (prefers-reduced-motion: reduce) {
    #auth-benefits {
        animation: none !important;
    }
}
#palette {
    /* Handled by ad-layout.css */
    /* display: flex; */
    /* gap: 4px; */
    /* margin-bottom: 4px; */
    /* flex-wrap: nowrap; */
    /* justify-content: center; */
    /* padding: 4px 2px; */
    /* width: 100%; */
    /* overflow-x: visible; */
    /* touch-action: none; */
}
#palette::before,
#palette::after {
    content: none; /* Remove spacers */
}
#palette::-webkit-scrollbar {
    display: none;
}
.palette-color {
    /* Handled by ad-layout.css */
    /* flex: 1 1 auto; */
    /* width: auto; */
    /* max-width: 75px; */
    /* min-width: 0; */
    /* height: clamp(35px, 8vw, 45px); */
    /* border: 2px solid var(--palette-border); */
    /* cursor: pointer; */
    /* border-radius: var(--radius-md); */
    /* transition: transform 0.1s ease, box-shadow 0.2s ease; */
    /* position: relative; */
    /* overflow: hidden; */
    /* will-change: transform; */
}

/* Glassy Gemstone Effect for Palette Buttons - ONLY when gem-mode active */
body.gem-mode .palette-color::after {
    content: '';
    position: absolute;
    inset: 0;
    pointer-events: none;
    border-radius: inherit;
}

.palette-color:hover {
    /* Removed scale transform to prevent layout shift */
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
    z-index: 1;
    border-color: var(--text-muted);
}
.palette-color.active {
    box-shadow: 0 0 10px 2px var(--hover-shadow-color, currentColor),
        0 0 15px 2px var(--palette-active-border);
    /* Removed scale transform */
    border-color: transparent;
    z-index: 2;
    pointer-events: none;
    /* Removed margin */
}

/* --- Texture Modes --- */

/* Textured (Plastic/Glossy) Mode - Now Gem Mode */

body.gem-mode .palette-color {
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.15), inset 2px 2px 4px rgba(255, 255, 255, 0.25),
        inset -2px -2px 4px rgba(0, 0, 0, 0.1);
    background-image: linear-gradient(
            135deg,
            rgba(255, 255, 255, 0.3) 0%,
            rgba(255, 255, 255, 0) 50%,
            rgba(0, 0, 0, 0.05) 100%
        ),
        radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.6) 0%, transparent 25%);
    border: none; /* Remove base border to prevent double-line artifact */
}

body.gem-mode .palette-color.active {
    box-shadow: 0 0 10px 2px var(--hover-shadow-color, currentColor),
        0 0 0 4px var(--palette-active-border), inset 0 0 8px rgba(0, 0, 0, 0.15),
        inset 2px 2px 4px rgba(255, 255, 255, 0.25), inset -2px -2px 4px rgba(0, 0, 0, 0.1);
}

/* 16-bit Retro Mode */
body.retro-16bit-mode {
    /* Pixelated/Dithered Background - Uses theme colors */
    background-image: linear-gradient(
            45deg,
            var(--retro-pattern-color) 25%,
            transparent 25%,
            transparent 75%,
            var(--retro-pattern-color) 75%,
            var(--retro-pattern-color)
        ),
        linear-gradient(
            45deg,
            var(--retro-pattern-color) 25%,
            transparent 25%,
            transparent 75%,
            var(--retro-pattern-color) 75%,
            var(--retro-pattern-color)
        ),
        linear-gradient(135deg, var(--bg-gradient-1) 0%, var(--bg-gradient-2) 100%);
    background-size: 20px 20px, 20px 20px, 100% 100%;
    background-position: 0 0, 10px 10px, 0 0;
    background-attachment: fixed;
    background-color: var(--bg-gradient-2);

    /* Set edge highlight color to white for Retro mode, so standard logic picks it up */
    --edge-highlight-color: #ffffff;
    --edge-highlight-rgb: 255, 255, 255;
}

body.retro-16bit-mode .palette-color {
    border-width: 4px; /* Match cells */
    border-radius: 4px; /* Slightly rounded for 16-bit feel */
    box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.4); /* Hard shadow like cells */
    transition: none; /* Instant feedback */
    background-image: none; /* Remove glossy gradient */
    border-style: solid;
    /* Simulate bevel with borders - match cells exactly */
    border-top-color: rgba(255, 255, 255, 0.4);
    border-left-color: rgba(255, 255, 255, 0.4);
    border-right-color: rgba(0, 0, 0, 0.2);
    border-bottom-color: rgba(0, 0, 0, 0.2);
    image-rendering: pixelated;
}

body.retro-16bit-mode .palette-color:active,
body.retro-16bit-mode .palette-color.clicked {
    transform: translate(4px, 4px); /* Match shadow offset */
    box-shadow: none;
}

body.retro-16bit-mode .palette-color.active {
    /* Keep same 4px bezel, just make it white for visibility */
    border-top-color: #ffffff;
    border-left-color: #ffffff;
    border-right-color: #ffffff;
    border-bottom-color: #ffffff;
    box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.4); /* Keep original shadow */
    transform: translate(0, 0); /* No offset for active state */
}

/* Retro mode: Make flood edge highlighting visible by turning bezel white */
/* Restore specific overrides to ensure highlight works on top of bevel */

.palette-color.clicked {
    animation: palette-click-pulse 0.4s ease-out;
}

@keyframes palette-click-pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(0.95);
    }
    100% {
        transform: scale(1);
    }
}

/* Low Power Mode: Disable all texture theming for performance */
body.low-power .cell,
body.low-power .palette-color {
    box-shadow: none !important;
    background-image: none !important;
    border-width: 2px !important;
    border-style: solid !important;
    border-color: var(--cell-border-color) !important;
    image-rendering: auto !important;
    animation: none !important; /* Disable pulse animation */
}

body.low-power .palette-color.active {
    box-shadow: 0 0 0 2px var(--palette-active-border) !important;
    border-color: var(--palette-active-border) !important;
}

#message {
    font-size: clamp(0.9em, 3vw, 1.1em);
    font-weight: 600;
    min-height: 1.5em;
    text-align: center;
    margin-top: 4px;
    margin-bottom: 0;
    color: var(--text-muted);
}

#message:empty {
    display: none;
    min-height: 0;
    margin: 0;
}

/* Generic Modal Title Styling */
.modal-content h2 {
    margin-bottom: 24px;
    text-align: center;
    color: var(--heading-color);
    padding-bottom: 10px;
}

/* Common button base styles */
button,
.primary,
.secondary,
.success,
.warning,
.google,
.danger,
.infinite-btn {
    border: none;
    border-radius: var(--radius-md);
    padding: clamp(10px, 2.5vw, 12px) clamp(16px, 3.5vw, 24px);
    font-size: clamp(0.9em, 2.3vw, 1em);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-elevation-low);
    letter-spacing: 0.01em;
}

button:hover,
.primary:hover,
.secondary:hover,
.success:hover,
.warning:hover,
.google:hover,
.danger:hover,
.infinite-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-elevation-medium);
}

button:active,
.primary:active,
.secondary:active,
.success:active,
.warning:active,
.google:active,
.danger:active,
.infinite-btn:active {
    transform: translateY(0);
    box-shadow: var(--shadow-elevation-low);
}

/* Button variants */
button.primary,
.primary {
    background-color: var(--button-primary-bg);
    color: var(--button-primary-text);
}
button.primary:hover,
.primary:hover {
    background-color: var(--button-primary-hover-bg);
}

button.secondary,
.secondary {
    background-color: var(--button-secondary-bg);
    color: var(--button-secondary-text);
}
button.secondary:hover,
.secondary:hover {
    background-color: var(--button-secondary-hover-bg);
}

button.success,
.success {
    background-color: var(--button-success-bg);
    color: #fff;
}
button.success:hover,
.success:hover {
    background-color: var(--button-success-hover-bg);
}

button.warning,
.warning {
    background-color: var(--button-warning-bg);
    color: #fff;
}
button.warning:hover,
.warning:hover {
    background-color: var(--button-warning-hover-bg);
}

button.google,
.google {
    background-color: var(--button-google-bg);
    color: var(--button-primary-text);
}
button.google:hover,
.google:hover {
    background-color: var(--button-google-hover-bg);
}

button.danger,
.danger {
    background-color: var(--loss-message-color);
    color: #fff;
}

/* Login Button Variant - Brighter Orange from Palette */
button.login-action,
.login-action {
    background-color: #f88436;
    color: #ffffff;
}
button.login-action:hover,
.login-action:hover {
    background-color: #e0702b;
}

.infinite-btn {
    background-color: #8e44ad;
    color: #ffffff;
}
.infinite-btn:hover {
    background-color: #7a379b;
}

.power-mode-btn {
    background-color: #ffd700;
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
}
.power-mode-btn:hover {
    background-color: #e6c200;
}

.time-attack-btn:not(.secondary) {
    background-color: var(--danger-color);
    color: #ffffff;
}
.time-attack-btn:not(.secondary):hover {
    background-color: var(--danger-hover);
}

.mode-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    min-height: 90px;
    padding: 16px 20px;
    margin: 0;
    position: relative;
    border: 1px solid transparent; /* Reserve space for border */
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 2px 4px rgba(0, 0, 0, 0.06);
}

.mode-btn strong {
    font-size: 1.2em;
    font-weight: 700;
    letter-spacing: 0.02em;
}

.mode-btn:disabled {
    background-color: var(--button-secondary-bg) !important;
    color: var(--text-muted) !important;
    opacity: 0.7;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
    border-color: transparent;
}

.mode-btn-desc {
    display: block;
    font-size: 0.9em;
    opacity: 0.9;
    font-weight: 500;
    margin-top: 4px;
    line-height: 1.3;
}

.mode-btn-header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 4px;
}

.mode-btn-icon {
    font-size: 1.4em;
    vertical-align: middle;
    line-height: 1;
}

button:disabled {
    opacity: 0.65;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

/* Keyboard focus indicators for accessibility */
button:focus-visible,
.palette-color:focus-visible,
input:focus-visible,
select:focus-visible,
#scene:focus-visible {
    outline: 3px solid var(--button-primary-bg);
    outline-offset: 2px;
}

/* Enhanced focus for buttons */
button.primary:focus-visible {
    outline-color: var(--button-primary-bg);
}
button.success:focus-visible {
    outline-color: var(--button-success-bg);
}
button.warning:focus-visible {
    outline-color: var(--button-warning-bg);
}
button.danger:focus-visible {
    outline-color: var(--loss-message-color);
}

/* Skip to main content link (for screen readers) */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--button-primary-bg);
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    z-index: 100;
    border-radius: 0 0 8px 0;
}

.skip-link:focus {
    top: 0;
}

/* Power button sizing */
.intro-content .primary,
.intro-content .secondary,
.auth-actions .primary,
.auth-actions .success,
.intro-content button,
.auth-actions button {
    display: block;
    width: 100%;
    max-width: 100%;
    padding: 14px 20px;
    font-size: 1.05em;
    min-height: 52px;
    font-weight: 600;
}

.mini-btn {
    padding: 6px 12px !important;
    min-height: 36px !important;
    font-size: 0.85em !important;
}

#undo-btn {
    position: absolute;
    right: 0;
    bottom: 100%; /* Align bottom of button to top of container */
    margin-bottom: 8px; /* Add some spacing */
    z-index: 100;
    font-size: 0.9em;
    padding: 8px 16px;
    white-space: nowrap;
    border-radius: 20px;
    background-color: var(--button-secondary-bg);
    color: var(--button-secondary-text);
    box-shadow: var(--shadow-elevation-low);
}

#tutorial-start,
#mode-info-play-btn,
.back-button {
    min-width: 140px;
    max-width: 160px;
    padding: 12px 18px;
    font-size: 1rem;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.modal-actions-info {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    align-items: center;
}
.modal-actions-info .back-button {
    margin-top: 0;
}

/* Modals */
.modal,
#intro-screen {
    position: fixed;
    z-index: 1000;
    inset: 0;
    overflow: auto;
    touch-action: pan-y;
    background-color: var(--modal-overlay-bg);
    -webkit-backdrop-filter: blur(5px);
    backdrop-filter: blur(5px);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px 0;
    padding-bottom: calc(20px + env(safe-area-inset-bottom));
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1), visibility 0s linear 0.3s;
}
.modal.visible,
#intro-screen.visible {
    opacity: 1;
    visibility: visible;
    transition-delay: 0s;
}

.modal.visible .modal-content,
#intro-screen.visible .intro-content {
    transform: scale(1) translateY(0);
    opacity: 1;
}

.modal-content,
.intro-content {
    background-color: var(--modal-content-bg);
    padding: 30px;
    border: 1px solid var(--modal-content-border);
    border-radius: var(--radius-lg);
    width: 95%;
    max-width: 700px;
    box-shadow: var(--shadow-elevation-high);

    color: var(--text-color);
    text-align: center;
    position: relative;
    margin: auto;
    touch-action: auto;

    /* Modern Transition */
    transform: scale(0.95) translateY(10px);
    opacity: 0;
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.3s ease;
}

.modal-close-x {
    position: absolute;
    top: 15px;
    right: 15px;
    background: rgba(0, 0, 0, 0.05);
    border-radius: 50%;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    font-size: 20px;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0;
    line-height: 1;
    font-weight: bold;
    transition: all 0.2s ease;
}
.modal-close-x:hover {
    transform: rotate(90deg);
    background: rgba(0, 0, 0, 0.1);
    color: var(--danger-color);
}

.back-button {
    background-color: var(--button-secondary-bg);
    color: var(--button-secondary-text);
    font-size: 0.95em;
    padding: 10px 16px;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    width: auto;
    min-width: 110px;
    max-width: 160px;
    min-height: 42px;
    display: inline-block;
    box-sizing: border-box;
}
.back-button:hover {
    background-color: var(--button-secondary-hover-bg);
    transform: translateY(-2px);
}

.modal .modal-content .modal-actions,
.modal .modal-content .modal-actions button,
.modal .modal-content .modal-actions .back-button {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    align-items: center;
}

.modal .modal-content .modal-actions button,
.modal .modal-content .modal-actions .back-button {
    min-width: 120px;
    max-width: 200px;
    padding: 10px 16px;
    font-size: 0.95em;
    height: 42px;
    flex: 0 0 auto;
    margin-top: 0;
    display: inline-flex;
}

.modal-content > .back-button {
    margin-top: 15px;
}

/* Share button sizing */
.summary-row + div button.share-btn,
#daily-double-summary-stats .share-btn,
#win-overlay-stats-challenge .share-btn,
#win-overlay-stats-timeattack .share-btn {
    min-width: 120px;
    padding: 8px 14px;
    font-size: 0.95rem;
}

.prominent-share-btn {
    width: 80%;
    max-width: 300px;
    height: 42px;
    margin: 10px auto 8px auto !important;
    display: flex !important;
    align-items: center;
    justify-content: center;
    font-size: 1em;
    font-weight: 600;
    padding: 0 20px !important;
}

/* Modal animations */
@keyframes win-full-spin {
    0% {
        transform: scale(var(--cube-zoom, 1)) rotateX(var(--current-x-angle, -25deg))
            rotateY(var(--current-y-angle, 30deg));
    }
    100% {
        transform: scale(var(--cube-zoom, 1)) rotateX(var(--current-x-angle, -25deg))
            rotateY(calc(var(--current-y-angle, 30deg) + 360deg));
    }
}

@keyframes pulse-start-highlight {
    from {
        box-shadow: inset 0 0 2px 1px var(--start-cell-highlight-outline);
        opacity: 0;
    }
    to {
        box-shadow: inset 0 0 8px 2px var(--start-cell-highlight-outline);
        opacity: 0.6;
    }
}

@keyframes pulse-danger {
    from {
        opacity: 1;
    }
    to {
        opacity: 0.6;
    }
}

@keyframes palette-click-pulse {
    0% {
        transform: scale(1);
        box-shadow: 0 0 0 0 var(--hover-shadow-color, #fff);
    }
    50% {
        transform: scale(1.25);
        box-shadow: 0 0 20px 4px var(--hover-shadow-color, #fff);
    }
    100% {
        transform: scale(1.1);
        box-shadow: 0 0 10px 2px var(--hover-shadow-color, #fff);
    }
}

@keyframes floodPulse {
    0% {
        box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.4);
    }
    60% {
        box-shadow: 0 0 10px 6px rgba(255, 255, 255, 0.2);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(255, 255, 255, 0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Animation classes */
.cell.flood-animate {
    animation: floodPulse 0.3s cubic-bezier(0.4, 0, 0.2, 1) 1;
    z-index: 2;
}

.animate-fade-in-up {
    animation: fadeInUp 0.5s cubic-bezier(0.2, 0.9, 0.2, 1) forwards;
}
.animate-fade-in {
    animation: fadeIn 0.4s ease-out forwards;
}

/* Tutorial Overlay Styles */
.tutorial-content {
    padding: 10px 5px;
}

.tutorial-content h2 {
    font-size: 1.6em;
    margin-bottom: 25px;
    color: var(--heading-color);
    text-align: center;
}

.tutorial-step {
    background-color: var(--tutorial-card-bg);
    border-radius: var(--radius-md);
    padding: 16px;
    margin-bottom: 16px;
    border: 1px solid var(--border-color);
    text-align: left;
    box-shadow: var(--shadow-elevation-low);
}

.tutorial-step h3 {
    margin-top: 0;
    margin-bottom: 10px;
    color: var(--primary-color);
    font-size: 1.1em;
    display: flex;
    align-items: center;
    gap: 8px;
}

.tutorial-step p {
    margin: 0;
    line-height: 1.5;
    font-size: 0.95em;
    color: var(--text-color);
}

.tutorial-step ol {
    margin: 0;
    padding-left: 24px;
    color: var(--text-color);
}

.tutorial-step li {
    margin-bottom: 6px;
    line-height: 1.4;
    font-size: 0.95em;
}

.tutorial-step li:last-child {
    margin-bottom: 0;
}

.tutorial-navigation {
    display: flex;
    gap: 12px;
    margin-top: 25px;
    justify-content: center;
}

.tutorial-navigation button {
    flex: 1;
    max-width: 180px;
    padding: 12px;
    font-size: 1em;
    border-radius: var(--radius-md);
    font-weight: 600;
}

/* Benefits Box Style (for login/signup screens only) */
.benefits-box,
#intro-screen .benefits-box {
    background-color: rgba(76, 175, 80, 0.1);
    border: 2px solid var(--win-message-color);
    border-radius: 8px;
    padding: 16px;
    margin: 15px 0;
    text-align: left;
    width: 100%;
    box-sizing: border-box;
}

html[data-theme='dark'] .benefits-box,
html[data-theme='dark'] #intro-screen .benefits-box {
    background-color: rgba(76, 175, 80, 0.15);
}

.benefits-box h3,
.benefits-box h4 {
    margin: 12px 0 8px 0;
    color: var(--win-message-color);
    font-size: 1.1em;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 700;
}

.benefits-box h3:first-child,
.benefits-box h4:first-child {
    margin-top: 0;
}

.benefits-box ul,
.benefits-box ol {
    margin: 0 0 12px 0;
    padding-left: 24px;
    font-size: 0.95em;
    line-height: 1.6;
}

.benefits-box li {
    margin-bottom: 6px;
}

.benefits-box p {
    margin: 0 0 8px 0;
    font-size: 0.95em;
    line-height: 1.6;
}

/* Tutorial and How-to-Play Modals - Simple Left-Aligned Styling */
#tutorial-overlay .modal-content,
#how-to-play-modal .modal-content {
    text-align: left;
    padding: 30px;
}

#tutorial-overlay .modal-content h2,
#how-to-play-modal .modal-content h2 {
    text-align: center;
    margin-bottom: 20px;
}

#tutorial-overlay .modal-content h3,
#how-to-play-modal .modal-content h3 {
    margin: 20px 0 10px 0;
    font-size: 1.1em;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 8px;
}

#tutorial-overlay .modal-content h3:first-of-type,
#how-to-play-modal .modal-content h3:first-of-type {
    margin-top: 0;
}

#tutorial-overlay .modal-content p,
#how-to-play-modal .modal-content p {
    margin: 0 0 10px 0;
    line-height: 1.6;
}

#tutorial-overlay .modal-content ol,
#tutorial-overlay .modal-content ul,
#how-to-play-modal .modal-content ol,
#how-to-play-modal .modal-content ul {
    margin: 0 0 15px 0;
    padding-left: 24px;
    line-height: 1.6;
}

#tutorial-overlay .modal-content li,
#how-to-play-modal .modal-content li {
    margin-bottom: 8px;
}

/* Toggle Switch Styles */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 26px;
    flex-shrink: 0;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: 0.4s;
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: '';
    height: 18px;
    width: 18px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: 0.4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--primary-color);
}

input:focus + .slider {
    box-shadow: 0 0 1px var(--primary-color);
}

input:checked + .slider:before {
    transform: translateX(24px);
}

/* Adjust toggle label container for better alignment */
.toggle-label {
    justify-content: space-between;
}

/* Powerup Icons */
.active-powerups-container {
    display: flex;
    justify-content: flex-end; /* Align to right */
    gap: 10px;
    margin: 0;
    padding-right: 20px;
    width: 100%;
    height: 0; /* Take no vertical space */
    overflow: visible;
    z-index: 10;
    transform: translateY(10px); /* Push down slightly */
    transition: opacity 0.3s ease;
    pointer-events: none; /* Allow clicks to pass through container */
}

.active-powerups-container.hidden {
    display: none;
}

.powerup-icon {
    pointer-events: auto; /* Re-enable clicks on icons */
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background-color: var(--panel-bg);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2em;
    box-shadow: var(--shadow-elevation-low);
    position: relative;
    cursor: help;
}

.powerup-icon .powerup-badge {
    position: absolute;
    bottom: -5px;
    right: -5px;
    background-color: var(--primary-color);
    color: white;
    font-size: 0.7em;
    padding: 2px 5px;
    border-radius: 10px;
    font-weight: bold;
}

.powerup-label {
    position: absolute;
    bottom: -20px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 0.6em;
    color: var(--text-color);
    white-space: nowrap;
    font-weight: bold;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.starter-icon {
    border-color: #00ffff;
    background-color: rgba(0, 255, 255, 0.1);
}

.scatter-icon {
    border-color: #ffaa00;
    background-color: rgba(255, 170, 0, 0.1);
}

.rewind-icon {
    border-color: #ff00ff;
    background-color: rgba(255, 0, 255, 0.1);
}

/* Media Queries - consolidated for better performance */
/* Increased breakpoint to 1200px to force mobile layout on tablets and foldables */
@media (max-width: 1200px) {
    #main-layout {
        flex-direction: column;
    }
    #scores-panel {
        width: 100%;
        max-width: 100%;
        border-left: none;
        border-top: 1px solid var(--border-color);
        order: 2;
        flex-direction: row;
        justify-content: space-around;
        flex-wrap: wrap;
        gap: 10px;
        padding-top: 10px;
    }
    #scores-panel .stats-group {
        flex-basis: 150px;
        flex-grow: 1;
        text-align: center;
    }
    #scores-panel .stats-group h2 {
        padding-bottom: 4px;
        margin-bottom: 4px;
    }
    #game-wrapper {
        order: 1;
        padding: 8px;
    }
    #top-bar {
        flex-direction: row;
        justify-content: space-around;
        padding: 8px;
        margin-bottom: 12px;
    }
    button {
        padding: 8px 12px;
        font-size: 0.85em;
    }
}

@media (orientation: portrait), (max-width: 1200px) {
    #scores-panel {
        display: none !important;
    }
    #game-wrapper {
        height: 100%;
        padding: 2px; /* Minimal padding */
    }
    #controls {
    }
    #mobile-game-stats {
        display: flex !important;
        font-size: clamp(0.85em, 4vw, 1.1em) !important;
        font-weight: 600;
        font-variant-numeric: tabular-nums;
        background: rgba(0, 0, 0, 0.2);
        padding: 8px 12px;
        border-radius: var(--radius-md);
        box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.2);
        margin-bottom: 10px;
        flex-wrap: nowrap !important;
        white-space: nowrap;
        width: 100%;
        justify-content: space-evenly !important;
    }
    #mobile-game-stats strong {
        font-size: 1.2em;
        color: var(--success-color);
    }
    #moves-display-main {
        display: none !important;
    }
    #palette {
    }
    .modal-close-x {
        display: none !important;
    }
    .modal-content {
        padding-top: 24px;
    }
}

@media (max-width: 480px) {
    #top-bar button {
        padding: 6px 10px;
        font-size: 0.8em;
    }
    #settings-panel {
        padding: 16px;
        gap: 16px;
        min-width: 280px;
    }
    #settings-panel label {
        font-size: 0.9em;
    }
    #settings-panel input[type='color'] {
        width: 60px;
        padding: 4px;
    }
    .palette-color {
        flex: 1 1 auto;
        width: auto;
        height: auto;
        max-width: 70px; /* Increased from 55px */
        min-width: 28px;
        aspect-ratio: 1;
    }
    .color-input-wrapper input[type='color'] {
        width: clamp(35px, 8vw, 50px);
        height: clamp(28px, 7vw, 40px);
    }

    /* Reduce side padding for all modals on thin devices */
    .modal-content,
    .intro-content {
        padding-left: 12px;
        padding-right: 12px;
    }
}

/* Low Power Mode Optimizations */
body.low-power .modal,
body.low-power #intro-screen {
    -webkit-backdrop-filter: none !important;
    backdrop-filter: none !important;
    background-color: var(
        --modal-overlay-bg
    ); /* Fallback to solid/opaque color if needed, or keep transparent */
}

/* Increase opacity for readability without blur */
body.low-power[data-theme='dark'] .modal,
body.low-power[data-theme='dark'] #intro-screen {
    background-color: rgba(0, 0, 0, 0.85);
}
body.low-power:not([data-theme='dark']) .modal,
body.low-power:not([data-theme='dark']) #intro-screen {
    background-color: rgba(16, 42, 67, 0.85);
}

body.low-power .cell {
    box-shadow: none !important;
    transition: background-color 0.1s linear !important;
}

/* Low Power Mode: Ensure edge highlights are visible but cheap */
body.low-power .cell.highlight-edge-top {
    border-top-color: var(--edge-highlight-color) !important;
}
body.low-power .cell.highlight-edge-bottom {
    border-bottom-color: var(--edge-highlight-color) !important;
}
body.low-power .cell.highlight-edge-left {
    border-left-color: var(--edge-highlight-color) !important;
}
body.low-power .cell.highlight-edge-right {
    border-right-color: var(--edge-highlight-color) !important;
}

body.low-power .cell.highlight-edge-top,
body.low-power .cell.highlight-edge-bottom,
body.low-power .cell.highlight-edge-left,
body.low-power .cell.highlight-edge-right {
    animation: none !important;
    box-shadow: none !important;
}

/* Low Power Mode: Disable start cell pulse */
body.low-power .start-cell-highlight::after {
    animation: none !important;
    box-shadow: none !important;
    border: 2px solid var(--start-cell-highlight-outline);
}

body.low-power .face {
    box-shadow: none !important;
}

body.low-power #scene {
    filter: none !important;
}

body.low-power .palette-color {
    box-shadow: none !important;
    transition: none !important;
}

body.low-power .palette-color.active {
    box-shadow: 0 0 0 4px var(--palette-active-border) !important;
}

body.low-power * {
    text-shadow: none !important;
}

/* Optimize cube rendering */
#cube-container {
    will-change: transform;
    transform-style: preserve-3d;
}

.face {
    /* Hardware acceleration and containment for performance */
    will-change: transform;
    /* contain: layout paint style; REMOVED to prevent clipping of 3D children/effects */
    transform-style: preserve-3d;
    backface-visibility: hidden; /* OPTIMIZATION: Don't render back side of faces */
}

/* PERFORMANCE: Disable interactions during rotation */
body.is-rotating .face {
    pointer-events: none !important;
}

body.is-rotating {
    -webkit-user-select: none;
    user-select: none;
}

/* Jewel Shine Effect (Now using Textured/Plastic Look) */
html[data-theme='premium-purple'] body.gem-mode .palette-color,
html[data-theme='premium-purple'] body.gem-mode .cell {
    /* Fix rendering gaps between cells */
    transform: scale(1.01);
    /* Textured Mode Box Shadow */
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.15), inset 2px 2px 4px rgba(255, 255, 255, 0.25),
        inset -2px -2px 4px rgba(0, 0, 0, 0.1);

    /* Textured Mode Overlay */
    --texture-overlay: linear-gradient(
        135deg,
        rgba(255, 255, 255, 0.3) 0%,
        rgba(255, 255, 255, 0) 50%,
        rgba(0, 0, 0, 0.05) 100%
    );

    position: relative;
    overflow: hidden; /* Required for transform-based shimmer */
}

/* Ensure edge highlights persist in Jewel Shine mode - Use standard border highlight */
html[data-theme='premium-purple'] body.gem-mode .cell.highlight-edge-top {
    border-top-color: var(--edge-highlight-color) !important;
}
html[data-theme='premium-purple'] body.gem-mode .cell.highlight-edge-bottom {
    border-bottom-color: var(--edge-highlight-color) !important;
}
html[data-theme='premium-purple'] body.gem-mode .cell.highlight-edge-left {
    border-left-color: var(--edge-highlight-color) !important;
}
html[data-theme='premium-purple'] body.gem-mode .cell.highlight-edge-right {
    border-right-color: var(--edge-highlight-color) !important;
}

html[data-theme='premium-purple'] body.gem-mode .palette-color::before,
html[data-theme='premium-purple'] body.gem-mode .cell::before {
    content: '';
    position: absolute;
    top: -100%;
    left: -100%;
    width: 300%;
    height: 300%;
    background: linear-gradient(
        135deg,
        rgba(255, 255, 255, 0) 30%,
        rgba(255, 255, 255, 0.1) 45%,
        rgba(255, 255, 255, 0.4) 50%,
        rgba(255, 255, 255, 0.1) 55%,
        rgba(255, 255, 255, 0) 70%
    );
    background-size: 100% 100%;
    background-position: center;
    pointer-events: none;
    z-index: 1;
    border-radius: inherit;
    opacity: 0; /* Hidden by default */
    transition: opacity 0.3s;
}

/* Shimmer effect on rotation - Diagonal Wave Optimization */
html[data-theme='premium-purple'] body.gem-mode.is-rotating .palette-color::before {
    opacity: 0.5;
    animation: shimmer-rotate 1.5s linear infinite;
}

html[data-theme='premium-purple'] body.gem-mode.is-rotating .cell.flood-member::before {
    opacity: 0.5;
    /* Diagonal wave effect using injected grid coordinates */
    animation: shimmer-rotate 2s linear infinite;
    animation-delay: calc((var(--r) + var(--c)) * 0.05s);
    will-change: transform; /* Optimize for performance */
}

@keyframes shimmer-rotate {
    0% {
        transform: translate(-33%, -33%);
        opacity: 0.3;
    }
    50% {
        opacity: 0.6;
    }
    100% {
        transform: translate(33%, 33%);
        opacity: 0.3;
    }
}

/* Add a subtle sparkle animation */
@keyframes sparkle {
    0%,
    100% {
        opacity: 0.5;
    }
    50% {
        opacity: 1;
    }
}

html[data-theme='premium-purple'] body.gem-mode .palette-color::after {
    content: '✦';
    position: absolute;
    top: 30%;
    left: 30%;
    transform: translate(-50%, -50%);
    color: white;
    font-size: 10px;
    opacity: 0.8;
    animation: sparkle 2s infinite;
    pointer-events: none;
    text-shadow: 0 0 2px white;
}

/* Crown Glow Effect - Active whenever Premium Theme is on */
html[data-theme='premium-purple'] #premium-crown-icon {
    opacity: 1;
    cursor: pointer;
    transition: transform 0.3s ease, filter 0.3s ease;
    display: inline-block; /* Ensure transform works */
}

/* Only glow/pulse when Gem Mode is actually active */
html[data-theme='premium-purple'] #premium-crown-icon.active {
    filter: drop-shadow(0 0 4px #ffcc00) drop-shadow(0 0 8px #ffcc00);
    animation: pulse-crown 2s infinite alternate;
}

/* Fix alignment of crown icon next to text */
#premium-theme-container label:first-child {
    flex-grow: 0 !important; /* Prevent label from pushing crown to the right */
    margin-right: 5px;
}

@keyframes crown-pulse {
    from {
        filter: drop-shadow(0 0 4px #ffcc00);
        transform: scale(1);
    }
    to {
        filter: drop-shadow(0 0 8px #ffcc00) drop-shadow(0 0 12px #ffab00);
        transform: scale(1.15);
    }
}

/* Logout button - reduced brightness */
#auth-controls-modal button {
    opacity: 0.7;
    filter: saturate(0.6);
}

#auth-controls-modal button:hover {
    opacity: 0.85;
    filter: saturate(0.8);
}

/* Settings Menu Layout Improvements */
.toggle-label {
    display: flex;
    align-items: center;
    justify-content: space-between; /* Space between label and toggle */
    gap: 10px;
    max-width: 300px;
    width: 100%;
}

.toggle-label label:first-child {
    text-align: left;
    flex-grow: 1;
    font-size: 1rem; /* Consistent font size */
    font-weight: 400; /* Normal weight */
}

/* Disabled toggle styling */
.toggle-label.disabled {
    opacity: 0.5;
    pointer-events: none;
}

.toggle-label .toggle-switch {
    margin-left: auto; /* Push toggle to the right */
}

/* Low Power Mode - Disables animations and complex effects */
body.low-power * {
    animation: none !important;
    transition: none !important;
    box-shadow: none !important;
    text-shadow: none !important;
}

body.low-power .cell::before,
body.low-power .palette-color::before,
body.low-power .palette-color::after {
    display: none !important;
}
/* Friends List Styles */
.friend-item {
    background-color: rgba(0, 0, 0, 0.1);
    border-radius: var(--radius-md);
    padding: 10px;
    margin-bottom: 8px;
    display: flex;
    flex-direction: column;
    gap: 5px;
    border: 1px solid var(--border-color);
}

.friend-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.friend-name {
    font-weight: 600;
    font-size: 1em;
    color: var(--text-color);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.remove-friend-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1.2em;
    padding: 4px 8px;
    line-height: 1;
    border-radius: 4px;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.remove-friend-btn:hover {
    color: var(--danger-color);
    background-color: rgba(255, 0, 0, 0.1);
    transform: scale(1.1);
}

.friend-stats {
    font-size: 0.85em;
    color: var(--text-muted);
    padding-top: 5px;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.friend-stats p {
    margin: 2px 0;
    display: flex;
    justify-content: space-between;
}

.friend-stat-label {
    opacity: 0.8;
}

.friend-stat-value {
    font-weight: 600;
    color: var(--text-color);
}
/* Leaderboard Table Styles */
.leaderboard-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}

.leaderboard-table thead {
    background-color: rgba(0, 0, 0, 0.15);
}

.leaderboard-table th {
    padding: 8px 10px;
    text-align: left;
    font-weight: 700;
    font-size: 0.9em;
    border-bottom: 2px solid var(--border-color);
    color: var(--text-color);
}

.leaderboard-table td {
    padding: 8px 10px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    font-size: 0.9em;
}

.leaderboard-table tr.current-user {
    background-color: rgba(var(--primary-color-rgb, 37, 99, 235), 0.1);
    font-weight: 600;
}

.leaderboard-table tr:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

.leaderboard-table .rank-col {
    width: 60px;
    text-align: center;
    font-weight: 700;
}

.leaderboard-table .player-col {
    width: auto;
    font-weight: 600;
}

.leaderboard-table .moves-col,
.leaderboard-table .time-col {
    width: 80px;
    text-align: right;
    font-variant-numeric: tabular-nums;
}

.leaderboard-table .rank-col.rank-1 {
    font-size: 1.2em;
}

/* Modern Input Styling */
.flood-input {
    width: 100%;
    padding: 12px 16px;
    margin: 8px 0;
    display: inline-block;
    border: 2px solid var(--input-border-color);
    border-radius: var(--radius-md);
    box-sizing: border-box;
    background-color: var(--input-bg);
    color: var(--input-text-color);
    font-size: 1em;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.flood-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(var(--edge-highlight-rgb), 0.3);
}

.flood-input::placeholder {
    color: var(--text-muted);
    opacity: 0.7;
}

/* Refactored Inline Styles */

/* Environment Indicator */
#env-indicator {
    display: none;
    position: fixed;
    top: 10px;
    left: 10px;
    z-index: 9999;
    background: #ff6b6b;
    color: white;
    padding: 8px 12px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: bold;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* Auth Modal */
#auth-status-message {
    margin-bottom: 15px;
}

/* Username Modal */
#username-modal {
    z-index: 1001;
}
.username-modal-description {
    margin-bottom: 15px;
    font-size: 0.95em;
}
#username-modal-close-back {
    display: none;
}

.locked-mode-btn {
    opacity: 0.7;
    cursor: not-allowed;
    position: relative;
}
.locked-mode-btn:hover {
    transform: none !important;
    box-shadow: none !important;
}

/* Remind Me Tomorrow Button */
.remind-me-container {
    text-align: center;
    margin-bottom: 15px;
}
.remind-me-btn {
    font-size: 0.8em;
    padding: 5px 10px;
}

/* Settings Modal */
#settings-modal {
    z-index: 1050;
    align-items: flex-start;
    overflow-y: auto;
}

#settings-modal .modal-content {
    max-height: calc(100vh - 60px);
    overflow-y: auto;
    margin-top: 20px;
}
.settings-content-wrapper {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 20px;
    align-items: center;
}
.settings-btn-full {
    max-width: 300px;
    width: 100%;
}
.settings-btn-hidden {
    display: none;
}
.settings-toggle-container {
    display: flex;
    align-items: center;
    gap: 10px;
    max-width: 300px;
    width: 100%;
}
.settings-toggle-label {
    flex-grow: 1;
}
.settings-section-divider {
    margin-top: 5px;
    padding-top: 5px;
    border-top: 1px solid var(--border-color);
}
.premium-theme-container {
    display: none; /* Hidden by default */
    align-items: center;
    gap: 10px;
    max-width: 300px;
    width: 100%;
}
.premium-label-wrapper {
    flex-grow: 1;
    display: flex;
    align-items: center;
    gap: 5px;
}
.premium-label-text {
    color: #9c27b0;
    font-weight: bold;
    cursor: pointer;
}
.premium-crown-icon {
    cursor: pointer;
    font-size: 1em;
}
.texture-toggles-container {
    display: none; /* Hidden by default */
    flex-direction: column;
    gap: 10px;
    max-width: 300px;
    width: 100%;
    padding-left: 20px; /* Indent sub-options */
}
.retro-label {
    flex-grow: 1;
    font-family: 'Courier New', monospace;
    letter-spacing: -1px;
}
.reminder-time-container {
    display: none;
    flex-direction: row;
    align-items: center;
    justify-content: flex-start;
    gap: 10px;
    max-width: 300px;
    width: 100%;
    margin-top: 5px;
    margin-bottom: 5px;
}
.reminder-time-input {
    padding: 6px 8px;
    border-radius: 6px;
    border: 1px solid #444;
    background: #2a2a2a;
    color: #fff;
    width: 135px;
    text-align: center;
    cursor: pointer;
}
.reminder-time-input-group {
    display: flex;
    align-items: center;
}
#test-notification-btn {
    margin-top: 5px;
    margin-bottom: 5px;
}

.install-app-btn {
    margin-top: 8px;
    display: none;
    max-width: 300px;
    width: 100%;
}
.sfx-toggle-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 0;
    border-top: 1px solid var(--border-color);
}
.sfx-toggle-input {
    width: 40px;
    height: 20px;
    cursor: pointer;
}
.account-info-container {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-width: 300px;
    width: 100%;
    margin-top: 5px;
    padding-top: 10px;
    border-top: 1px solid var(--border-color);
}
.about-panel {
    display: none;
    flex-direction: column;
    gap: 20px;
    text-align: center;
    padding: 10px 0;
}

.about-header {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.version-info {
    font-size: 1.1em;
    color: var(--text-muted);
    margin: 0;
}

.creator-info {
    font-size: 1.2em;
    margin: 0;
}

.credits-section {
    background-color: rgba(0, 0, 0, 0.05);
    padding: 15px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.credits-section h4 {
    margin: 0 0 8px 0;
    color: var(--primary-color);
    font-size: 1em;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.credits-list {
    margin: 0;
    font-size: 0.95em;
    line-height: 1.5;
    color: var(--text-muted);
}

.about-description {
    font-style: italic;
    color: var(--text-muted);
    line-height: 1.6;
    padding: 0 10px;
}

.about-description p {
    margin: 0;
}

.account-management {
    margin-top: 10px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.account-management h4 {
    margin: 0 0 15px 0;
    color: var(--text-color);
}

.account-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.settings-btn-full {
    width: 100%;
}
.about-footer {
    margin: 6px 0;
    font-size: 0.85em;
    opacity: 0.8;
}

/* Intro Screen */
.intro-section {
    margin: 20px 0;
    padding: 15px;
    background-color: var(--panel-bg);
    border-radius: 8px;
    display: none;
}
.intro-section-relative {
    position: relative;
}
.intro-heading {
    margin-top: 20px;
    font-size: 1.2em;
    color: var(--modal-heading-color);
}
.intro-heading-top {
    margin-top: 0;
    font-size: 1.2em;
    color: var(--modal-heading-color);
}
.intro-btn-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.intro-guest-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 15px;
}
.intro-warning {
    margin-top: 10px;
    margin-bottom: 0;
    font-size: 0.9em;
    color: var(--loss-message-color);
    font-weight: bold;
    text-align: center;
}
.intro-form-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 15px;
}
.intro-input {
    padding: 10px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color);
}
.intro-input-full {
    width: 100%;
    box-sizing: border-box;
}
.intro-divider {
    text-align: center;
    margin: 15px 0;
    color: var(--text-color);
    opacity: 0.6;
}
.intro-back-btn {
    margin-top: 15px;
}
.intro-mode-title {
    margin-bottom: 15px;
    margin-top: 25px;
    font-weight: 600;
}
.intro-mode-btn-group {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 15px;
}
.intro-mode-footer {
    margin-top: 20px;
    display: flex;
    gap: 10px;
    justify-content: center;
}
.intro-mode-back-btn {
    margin-top: 15px;
    display: none;
}

/* Tutorial & How to Play */
.tutorial-modal-h2 {
    margin-bottom: 20px;
}
.how-to-play-content {
    max-width: 650px;
}
.text-win-color {
    color: var(--win-message-color);
}
.text-primary-bg {
    color: var(--button-primary-bg);
}
.text-warning-bg {
    color: var(--button-warning-bg);
}
.text-purple {
    color: #8e44ad;
}

/* Top Bar */
.top-bar-status {
    text-align: center;
    font-size: 1em;
    font-weight: 600;
    color: var(--gold-text-color);
    margin: 8px 0 12px 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
}
.username-display {
    font-weight: 400;
    color: var(--text-color);
}
.game-mode-heading {
    display: none;
}
.top-bar-container {
    position: relative;
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: nowrap;
}
/* Dropdown styles removed - replaced by Game Modes Modal */
.view-results-btn {
    white-space: nowrap;
}
.settings-btn {
    display: none;
    white-space: nowrap;
}

/* Game Area */
.scene-container-hidden {
    visibility: hidden;
}
.controls-hidden {
    visibility: hidden;
}
.mobile-game-stats {
    display: none;
    flex-direction: row;
    justify-content: center; /* Center items by default */
    align-items: center;
    gap: 20px; /* Increased gap for better separation */
    margin-bottom: 8px;
    font-size: 0.9em;
    flex-wrap: nowrap;
    white-space: nowrap;
    width: 100%;
}
.mobile-stat-item {
    display: flex;
    align-items: center;
    gap: 5px;
}
.palette-wrapper {
    position: relative;
    width: 100%;
    max-width: 800px;
}

/* Scores Panel */
.scores-panel-hidden {
    visibility: hidden;
}
.user-status-stats-p {
    margin-top: 6px;
    font-size: 0.85em;
}
.challenge-stats-detail {
    font-size: 0.75em;
    margin-top: -6px;
    opacity: 0.75;
}
.leaderboard-btn-container {
    margin-top: 10px;
    text-align: center;
}
.leaderboard-btn-full {
    width: 100%;
}

.leaderboard-btn-full + .leaderboard-btn-full {
    margin-top: 8px;
}

/* Color Picker */
.edge-color-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin: 15px 0;
    padding: 10px;
    background: var(--secondary-bg);
    border-radius: 8px;
}
.edge-color-label {
    font-weight: 500;
}
.edge-color-input {
    cursor: pointer;
}

/* Mode Info */
.mode-info-description {
    line-height: 1.6;
    font-size: 1.1em;
    margin-top: 20px;
}

/* Win Overlay */
.win-overlay-stats-container {
    display: none;
}
.daily-double-summary {
    display: none;
}
.summary-status-row {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-bottom: 8px;
}
.summary-status-final {
    flex: 1;
    text-align: right;
}
.summary-row {
    display: flex;
    justify-content: space-between;
    padding: 4px 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}
.win-actions-column {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    flex-direction: column;
}
.share-btn-bold {
    display: none;
    font-weight: bold;
    margin-bottom: 8px;
}
.next-challenge-btn {
    display: none;
}
.modal-action-btn {
    display: none;
}
.clipboard-helper {
    position: absolute;
    left: -9999px;
}

/* Friends Modal */
.add-friend-description {
    margin-bottom: 15px;
    font-size: 0.95em;
}
.friends-modal-content {
    max-width: 600px;
}
.friends-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}
.friends-tab-btn {
    flex: 1;
}
.requests-tab-btn {
    flex: 1;
    position: relative;
}
.requests-badge {
    display: none;
    position: absolute;
    top: -5px;
    right: -5px;
    background-color: var(--loss-message-color);
    color: white;
    border-radius: 10px;
    padding: 2px 6px;
    font-size: 0.7em;
    min-width: 18px;
    text-align: center;
}
.friends-action-container {
    margin-bottom: 15px;
}
.send-request-btn {
    width: 100%;
}
.requests-content {
    display: none;
}

/* Leaderboard Modal */
.leaderboard-modal-content {
    max-width: 560px;
}
.leaderboard-tabs {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 15px;
    align-items: center;
    flex-wrap: wrap;
}
.leaderboard-tab-btn {
    padding: 8px 20px;
}
.leaderboard-reload-btn {
    padding: 8px 16px;
}

.infinite-toggle {
    display: flex;
    background: var(--button-secondary-bg);
    border-radius: var(--radius-sm);
    padding: 2px;
    gap: 2px;
}

.toggle-btn {
    background: transparent;
    border: none;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    cursor: pointer;
    color: var(--button-secondary-text);
    transition: all 0.2s ease;
}

.toggle-btn.active {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.toggle-btn:hover:not(.active) {
    background: rgba(0, 0, 0, 0.05);
}

.leaderboard-list-container {
    font-size: 0.95em;
}
.leaderboard-loading {
    text-align: center;
    opacity: 0.7;
}
.leaderboard-friends-container {
    display: none;
}
.leaderboard-back-container {
    text-align: center;
    margin-top: 12px;
}

/* Infinite Modal */
.infinite-modal {
    z-index: 1100;
}
.infinite-description {
    margin-bottom: 18px;
    font-size: 0.95em;
}
.infinite-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: center;
}
.infinite-start-btn {
    width: 100%;
    margin: 4px 0;
    background-color: #8e44ad;
    color: #fff;
    border: none;
}
.infinite-back-btn {
    margin-top: 15px;
}

/* Stats Panels - Hidden by default */
.daily-double-stats,
.challenge-cube-stats,
.time-attack-stats,
.friends-stats {
    display: none;
}

/* Win Overlay Stats - Hidden by default */
.win-overlay-stats-hidden {
    display: none;
}

.daily-double-summary-hidden {
    display: none;
}

.win-share-btn {
    display: none;
    font-weight: bold;
    margin-bottom: 8px;
    /* Make it bigger/prominent */
    width: 80%;
    max-width: 300px;
    padding: 12px 20px !important;
    font-size: 1.1em !important;
}

.win-next-btn {
    display: none;
}

.win-leaderboard-btn {
    display: none;
}

.win-overlay-actions {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    flex-direction: column;
}

.daily-double-summary-row {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-bottom: 8px;
}

.add-friend-desc {
    margin-bottom: 15px;
    font-size: 0.95em;
}

.add-friend-container {
    margin-bottom: 15px;
}

.add-friend-full-btn {
    width: 100%;
}

.requests-tab-hidden {
    display: none;
}

.leaderboard-list {
    font-size: 0.95em;
}

.loading-text {
    text-align: center;
    opacity: 0.7;
}

.leaderboard-friends-hidden {
    display: none;
}

.leaderboard-actions {
    text-align: center;
    margin-top: 12px;
}

.infinite-modal-z {
    z-index: 1100;
}

.infinite-desc {
    margin-bottom: 18px;
    font-size: 0.95em;
}

.infinite-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: center;
}

.infinite-start-btn {
    width: 100%;
    margin: 4px 0;
    background-color: #8e44ad;
    color: #fff;
    border: none;
}

.infinite-back-btn {
    margin-top: 15px;
}

/* Toast Notification */
#toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    left: auto;
    transform: none;
    z-index: 11000; /* Higher than modals (1000+) */
    display: flex;
    flex-direction: column;
    gap: 12px;
    pointer-events: none;
    align-items: flex-end;
}

.toast {
    background-color: var(--panel-bg); /* Use theme panel bg */
    color: var(--text-color);
    padding: 16px 20px;
    border-radius: 12px;
    font-size: 0.95em;
    font-weight: 500;
    box-shadow: var(--shadow-elevation-medium);
    opacity: 0;
    transform: translateX(50px); /* Slide in from right */
    transition: opacity 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275),
        transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    pointer-events: auto;
    text-align: left;
    min-width: 260px;
    max-width: 320px;
    border: 1px solid var(--border-color);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
}

.toast strong {
    display: block;
    font-size: 1.1em;
    margin-bottom: 4px;
    color: var(--heading-color);
}

.toast small {
    display: block;
    font-size: 0.9em;
    color: var(--text-muted);
    line-height: 1.4;
}

.toast.show {
    opacity: 1;
    transform: translateX(0);
}

/* Achievements Modal */
#achievements-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
    max-height: 60vh;
    min-height: 100px; /* Ensure it has height even if empty */
    overflow-y: auto;
    padding: 10px;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--input-bg);
}

.achievement-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 12px;
    border-radius: var(--radius-md);
    background-color: var(--panel-bg);
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    flex-shrink: 0; /* Prevent shrinking */
    width: 100%;
}

@media (max-width: 480px) {
    #achievements-list {
        max-height: 50vh;
        padding: 8px;
        gap: 8px;
        display: block; /* Fallback for flex issues */
    }
    .achievement-item {
        display: flex; /* Ensure flex is set */
        padding: 10px;
        gap: 10px;
        width: 100%;
        min-height: 60px;
        margin-bottom: 8px; /* Add margin for block layout */
        box-sizing: border-box; /* Ensure padding doesn't affect width */
    }
    .achievement-icon {
        font-size: 1.5em;
        min-width: 40px;
        flex-shrink: 0; /* Prevent icon from shrinking */
    }
    .achievement-title {
        font-size: 1em;
    }
    .achievement-desc {
        font-size: 0.85em;
    }
}

.achievement-item.locked {
    opacity: 0.6;
    filter: grayscale(1);
}

.achievement-item.unlocked {
    border-color: var(--gold-text);
    box-shadow: 0 2px 8px rgba(255, 215, 0, 0.15);
}

.achievement-icon {
    font-size: 2em;
    min-width: 50px;
    text-align: center;
}

.achievement-content {
    flex-grow: 1;
    text-align: left;
}

.achievement-title {
    font-weight: 700;
    font-size: 1.1em;
    color: var(--heading-color);
    margin-bottom: 4px;
}

.achievement-desc {
    font-size: 0.9em;
    color: var(--text-muted);
}

#achievements-summary {
    font-weight: 600;
    color: var(--gold-text);
    margin-bottom: 15px;
}

/* Color Picker Modal Improvements */
.color-picker-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 10px;
    margin-bottom: 20px;
    max-height: 50vh;
    overflow-y: auto;
    padding: 4px;
}

.color-input-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--secondary-bg);
    padding: 8px 12px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.color-input-wrapper:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-elevation-low);
}

.color-input-wrapper label {
    font-size: 0.9em;
    font-weight: 600;
    color: var(--text-color);
    margin-right: 8px;
}

.color-input-wrapper input[type='color'] {
    width: 40px;
    height: 30px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    padding: 0;
    background: none;
    box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.1);
}

.edge-color-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--secondary-bg);
    padding: 12px 16px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    margin-bottom: 20px;
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
}

.edge-color-label {
    font-weight: 600;
    color: var(--text-color);
}

.edge-color-input {
    width: 50px;
    height: 35px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    padding: 0;
    background: none;
}

/* Click-to-Flood Mode */
body.click-to-flood-mode #palette {
    display: none !important;
}
body.click-to-flood-mode #message {
    display: none !important;
}
body.click-to-flood-mode #moves-display-main {
    margin-bottom: 2px;
}

/* Metal Mode Palette Buttons */
body.metal-mode .palette-color {
    background-image: linear-gradient(
        135deg,
        rgba(255, 255, 255, 0.4) 0%,
        rgba(255, 255, 255, 0) 50%,
        rgba(0, 0, 0, 0.1) 100%
    );
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.3), inset 0 1px 0 rgba(255, 255, 255, 0.6),
        0 2px 4px rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(0, 0, 0, 0.2);
    border-radius: 6px;
    position: relative;
    overflow: hidden;
}

body.metal-mode .palette-color::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(
        to bottom right,
        rgba(255, 255, 255, 0.8) 0%,
        rgba(255, 255, 255, 0) 40%,
        rgba(255, 255, 255, 0) 100%
    );
    transform: rotate(30deg);
    opacity: 0.3;
    pointer-events: none;
}

body.metal-mode .palette-color:active {
    transform: scale(0.95);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.4);
}

.hidden {
    display: none;
}

/* Gold Shiny Button */
.gold-shiny-btn {
    background: linear-gradient(
        110deg,
        #ffd700 0%,
        #fffacd 25%,
        #ffd700 50%,
        #fdb931 75%,
        #ffd700 100%
    );
    background-size: 200% 100%;
    color: #ffffff !important; /* Changed to white for consistency */
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.4); /* Added shadow for readability on yellow */
    border: 1px solid #b8860b;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 0 15px rgba(255, 215, 0, 0.4);
    animation: shine 6s infinite linear;
}

.gold-shiny-btn:hover {
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15), 0 0 20px rgba(255, 215, 0, 0.6);
    transform: translateY(-2px);
}

@keyframes shine {
    to {
        background-position: -200% center;
    }
}

/* Premium Shiny Button (Purple) */
.premium-shiny-btn {
    background: linear-gradient(
        110deg,
        #8e44ad 0%,
        #d2b4de 25%,
        #8e44ad 50%,
        #7a379b 75%,
        #8e44ad 100%
    );
    background-size: 200% 100%;
    color: #ffffff !important;
    border: 1px solid #6c3483;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 0 15px rgba(142, 68, 173, 0.4);
    animation: shine 6s infinite linear;
}

.premium-shiny-btn:hover {
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15), 0 0 20px rgba(142, 68, 173, 0.6);
    transform: translateY(-2px);
}

.premium-shiny-btn:disabled {
    background: var(--button-secondary-bg) !important;
    color: var(--text-muted) !important;
    box-shadow: none;
    animation: none;
    border: none;
}

/* Power Mode Popup Style (Now applied to all win/loss modals) */
.modal.power-mode-popup {
    background-color: transparent !important;
    -webkit-backdrop-filter: none !important;
    backdrop-filter: none !important;
    align-items: center !important; /* Centered */
    justify-content: center !important; /* Centered */
    padding: 20px !important;
    pointer-events: none !important;
}

.modal.power-mode-popup .modal-content {
    pointer-events: auto !important;
    margin: 0 !important; /* Reset margins */
    width: 320px !important;
    max-width: 90vw !important;
    animation: popIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275) !important; /* Bouncy pop */
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.3) !important;
    border: 2px solid var(--border-color) !important;
}

@keyframes popIn {
    from {
        transform: scale(0.8);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.leaderboard-menu-btn {
    white-space: nowrap;
    margin-right: 8px;
}

/* Hide Palette Mode */
body.hide-palette #palette {
    display: none !important;
}
body.hide-palette .palette-wrapper {
    display: none;
}
body.hide-palette #scene-container {
    margin-bottom: 0;
}
body.hide-palette #message {
    margin-top: 0;
}

/* Account Management Styling */
.account-management {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.account-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    align-items: center;
    margin-top: 15px;
}

#auth-controls-modal {
    margin-top: 15px;
    text-align: center;
}

.btn-small-faded {
    background-color: transparent;
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
    opacity: 0.6;
    font-size: 0.85em;
    padding: 6px 12px;
    width: auto;
    display: inline-block;
    margin: 5px auto;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-small-faded:hover {
    opacity: 1;
    background-color: rgba(220, 38, 38, 0.05);
}

/* Account Management Styling */
.account-management {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.account-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    align-items: center;
    margin-top: 15px;
}

#auth-controls-modal {
    margin-top: 15px;
    text-align: center;
}

.btn-small-faded {
    background-color: transparent;
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
    opacity: 0.6;
    font-size: 0.85em;
    padding: 6px 12px;
    width: auto;
    display: inline-block;
    margin: 5px auto;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-small-faded:hover {
    opacity: 1;
    background-color: rgba(220, 38, 38, 0.05);
}

/* Powerup Guide button */
.powerup-info-btn {
    /* Positioned in top-bar now */
    white-space: nowrap;
}

/* Shiny Gold Star for Scatter Icon */
.scatter-icon {
    border-color: #ffd700 !important; /* Gold */
    background-color: rgba(255, 215, 0, 0.15) !important;
    box-shadow: 0 0 10px rgba(255, 215, 0, 0.5); /* Shiny glow */
}

.intro-version-display {
    position: absolute;
    bottom: 5px;
    right: 15px;
    font-size: 0.7rem;
    color: var(--text-muted);
    opacity: 0.6;
    pointer-events: none;
}