/* Sudoku Game Styles - Theme-Aware
 * Uses CSS variables from css/tokens/colors.css
 * Supports: dark-blue, light, dark, midnight, navy themes
 */

/* ======================================
   SITE HEADER (Try Sudoku standalone)
   ====================================== */

.sudoku-site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 1rem;
    background: linear-gradient(135deg, var(--color-nav-start) 0%, var(--color-nav-end) 100%);
    border-bottom: 1px solid var(--color-nav-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.site-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.site-logo {
    font-size: 1.5rem;
    color: var(--color-highlight);
}

.site-logo-img {
    width: 56px;
    height: 56px;
    border-radius: 10px;
    object-fit: contain;
}

.site-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-text-light, #ffffff);
    font-family: 'Poppins', sans-serif;
}

.site-nav {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.site-nav .nav-link {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.4rem 0.7rem;
    color: var(--color-text-light, #ffffff);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    border-radius: 6px;
    transition: all 0.2s ease;
    background: var(--color-btn-secondary-start);
    border: 1px solid transparent;
}

.site-nav .nav-link:hover {
    background: var(--color-btn-primary-start);
    border-color: var(--color-border-accent);
    transform: translateY(-1px);
}

.site-nav .nav-link i {
    font-size: 0.9rem;
}

/* Solitaire link with logo */
.site-nav .nav-link.solitaire-link .solitaire-logo {
    width: 20px;
    height: 20px;
    object-fit: contain;
    border-radius: 3px;
}

.site-nav .nav-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--color-btn-secondary-start);
    border: 1px solid transparent;
    border-radius: 6px;
    color: var(--color-text-light, #ffffff);
    cursor: pointer;
    transition: all 0.2s ease;
}

.site-nav .nav-btn:hover {
    background: var(--color-btn-primary-start);
    border-color: var(--color-border-accent);
    transform: translateY(-1px);
}

/* New Puzzle Dropdown */
.nav-dropdown {
    position: relative;
}

.nav-dropdown .dropdown-toggle {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.8rem;
    background: linear-gradient(135deg, var(--color-btn-primary-start) 0%, var(--color-btn-primary-end) 100%);
    border: 1px solid var(--color-border-accent);
    border-radius: 6px;
    color: var(--color-text-light, #ffffff);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    width: auto;
    height: auto;
}

.nav-dropdown .dropdown-toggle:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* Language dropdown button should match settings button styling */
#language-dropdown .dropdown-toggle {
    width: 36px;
    height: 36px;
    padding: 0;
    background: var(--color-btn-secondary-start);
    border: 1px solid transparent;
}

#language-dropdown .dropdown-toggle:hover {
    background: var(--color-btn-primary-start);
    border-color: var(--color-border-accent);
    box-shadow: none;
}

.nav-dropdown .dropdown-arrow {
    font-size: 0.65rem;
    transition: transform 0.2s ease;
}

.nav-dropdown.open .dropdown-arrow {
    transform: rotate(180deg);
}

.nav-dropdown .dropdown-menu {
    position: absolute;
    top: calc(100% + 4px);
    left: 50%;
    transform: translateX(-50%);
    min-width: 150px;
    background: var(--color-modal-bg, #1a1f2e);
    border: 1px solid var(--color-border-accent);
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateX(-50%) translateY(-10px);
    transition: all 0.2s ease;
    z-index: 200;
    overflow: hidden;
}

.nav-dropdown.open .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.nav-dropdown .dropdown-item {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    width: 100%;
    padding: 0.7rem 1rem;
    background: transparent;
    border: none;
    color: var(--color-text-light, #ffffff);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s ease;
    text-align: left;
}

.nav-dropdown .dropdown-item:hover {
    background: var(--color-btn-primary-start);
}

.nav-dropdown .dropdown-item i {
    width: 18px;
    text-align: center;
    opacity: 0.8;
}

/* Difficulty colors */
.nav-dropdown .dropdown-item[data-difficulty="beginner"] i { color: #4ade80; }
.nav-dropdown .dropdown-item[data-difficulty="easy"] i { color: #60a5fa; }
.nav-dropdown .dropdown-item[data-difficulty="hard"] i { color: #f97316; }
.nav-dropdown .dropdown-item[data-difficulty="xtreme"] i { color: #ef4444; }

/* Language menu styling */
.nav-dropdown .language-option {
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-dropdown .language-option .lang-flag {
    font-size: 1.2em;
    min-width: 24px;
}

.nav-dropdown .language-option.active {
    background: rgba(37, 99, 235, 0.15);
    border-left: 3px solid #2563eb;
    padding-left: 9px;
}

/* Settings Modal */
.sudoku-settings-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
}

.sudoku-settings-content {
    background: var(--sudoku-container-bg, rgba(27, 38, 59, 0.98));
    border-radius: 12px;
    padding: 1.5rem;
    max-width: 400px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
    border: 1px solid var(--color-border-accent, #415a77);
}

.sudoku-settings-content h2 {
    color: var(--color-text-primary, #e0e1dd);
    margin: 0 0 1.5rem;
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.settings-group {
    margin-bottom: 1.5rem;
}

.settings-group label {
    display: block;
    color: var(--color-text-heading, #778da9);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.theme-options {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.theme-btn {
    flex: 1;
    min-width: 80px;
    padding: 0.6rem 0.8rem;
    background: var(--color-bg-primary, #0d1b2a);
    border: 2px solid var(--color-border-accent, #415a77);
    border-radius: 8px;
    color: var(--color-text-primary, #e0e1dd);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.theme-btn:hover {
    border-color: var(--color-stats-highlight, #778da9);
    transform: translateY(-2px);
}

.theme-btn.active {
    background: var(--color-btn-primary-start, #415a77);
    border-color: var(--color-highlight, #fbbf24);
}

/* Difficulty selector (same styles as theme buttons) */
.difficulty-selector {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.difficulty-btn {
    flex: 1;
    min-width: 80px;
    padding: 0.6rem 0.8rem;
    background: var(--color-bg-primary, #0d1b2a);
    border: 2px solid var(--color-border-accent, #415a77);
    border-radius: 8px;
    color: var(--color-text-primary, #e0e1dd);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.3rem;
}

.difficulty-btn:hover {
    border-color: var(--color-stats-highlight, #778da9);
    transform: translateY(-2px);
}

.difficulty-btn.active {
    background: var(--color-btn-primary-start, #415a77);
    border-color: var(--color-highlight, #fbbf24);
}

.toggle-setting {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 0;
    border-bottom: 1px solid rgba(65, 90, 119, 0.3);
}

.toggle-setting:last-child {
    border-bottom: none;
}

.toggle-setting span {
    color: var(--color-text-primary, #e0e1dd);
    font-size: 0.9rem;
}

.toggle-switch {
    position: relative;
    width: 48px;
    height: 26px;
}

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

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg-primary, #0d1b2a);
    border: 2px solid var(--color-border-accent, #415a77);
    border-radius: 26px;
    transition: all 0.3s ease;
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 2px;
    bottom: 2px;
    background: var(--color-text-primary, #e0e1dd);
    border-radius: 50%;
    transition: all 0.3s ease;
}

.toggle-switch input:checked + .toggle-slider {
    background: var(--color-success, #4ade80);
    border-color: var(--color-success, #4ade80);
}

.toggle-switch input:checked + .toggle-slider:before {
    transform: translateX(22px);
}

.settings-close-btn {
    width: 100%;
    padding: 0.8rem;
    background: var(--color-btn-primary-start, #415a77);
    color: var(--color-text-light, #ffffff);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-top: 1rem;
}

.settings-close-btn:hover {
    background: var(--color-btn-primary-hover-start, #778da9);
}

/* Statistics Grid in Settings */
.stats-group label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.stats-group label i {
    color: var(--color-highlight, #60a5fa);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
    margin-top: 0.5rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0.75rem 0.5rem;
    background: var(--color-bg-tertiary, rgba(255, 255, 255, 0.05));
    border-radius: 8px;
    border: 1px solid var(--color-border-accent, rgba(255, 255, 255, 0.1));
}

.stat-value {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-highlight, #60a5fa);
    line-height: 1.2;
}

.stat-label {
    font-size: 0.7rem;
    color: var(--color-text-muted, #94a3b8);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-top: 0.25rem;
    text-align: center;
}

/* Mobile responsive header */
@media (max-width: 480px) {
    .sudoku-site-header {
        padding: 0.5rem 0.75rem;
    }

    .site-name {
        font-size: 1rem;
    }

    .site-logo {
        font-size: 1.3rem;
    }

    .site-nav .nav-link span {
        display: none;
    }

    .site-nav .nav-link {
        padding: 0.4rem;
        width: 36px;
        height: 36px;
        justify-content: center;
    }

    .site-nav .nav-link i {
        font-size: 1rem;
    }

    /* Dropdown mobile adjustments */
    .nav-dropdown .dropdown-toggle span {
        display: none;
    }

    .nav-dropdown .dropdown-toggle {
        padding: 0.4rem 0.6rem;
        gap: 0.3rem;
    }

    .nav-dropdown .dropdown-menu {
        left: 0;
        transform: translateX(0);
        min-width: 140px;
    }

    .nav-dropdown.open .dropdown-menu {
        transform: translateX(0) translateY(0);
    }

    /* Daily Challenge button - match New Puzzle button style on mobile */
    .daily-challenge-btn span {
        display: none;
    }

    .daily-challenge-btn {
        padding: 0.4rem 0.6rem;
        gap: 0.3rem;
    }

    /* Print Puzzles button - match Daily Challenge button style on mobile */
    .print-puzzles-btn span {
        display: none;
    }

    .print-puzzles-btn {
        padding: 0.4rem 0.6rem;
        gap: 0.3rem;
    }

    /* Stats grid 2 columns on mobile */
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ======================================
   END SITE HEADER
   ====================================== */

/* Sudoku Variable Mappings - Maps theme colors to Sudoku-specific aliases */
/* Note: --sudoku-* variables are defined per-theme in css/tokens/colors.css */
body:has(.sudoku-container) {
    /* Map theme colors to Sudoku semantic variables */
    --sudoku-primary: var(--color-btn-primary-start, #415a77);
    --sudoku-primary-dark: var(--color-btn-primary-end, #1b263b);
    --sudoku-primary-light: var(--color-stats-highlight, #778da9);
    --sudoku-primary-lighter: var(--color-text-heading-secondary, #a8b4c4);
    --sudoku-primary-lightest: var(--color-stats-border, rgba(119, 141, 169, 0.5));
    --sudoku-accent: var(--color-highlight, #fbbf24);
    --sudoku-accent-secondary: var(--color-warning, #fbbf24);
    --sudoku-error: var(--color-error, #f87171);
    --sudoku-success: var(--sudoku-success, var(--color-success, #10b981));

    /* Cell colors - lighter and more subtle for better grid visibility */
    --sudoku-cell-selected-bg: var(--sudoku-cell-selected, rgba(61, 90, 128, 0.6));
    --sudoku-cell-highlighted-bg: var(--sudoku-cell-highlighted, rgba(100, 140, 180, 0.15));
    --sudoku-cell-same-bg: var(--sudoku-cell-same-number, rgba(140, 170, 200, 0.25));

    /* Text colors - now read from theme, with fallbacks */
    --sudoku-given-text: var(--sudoku-given-color, #e0e1dd);
    --sudoku-user-text: var(--sudoku-user-color, #60a5fa);
    --sudoku-pencil-text: var(--sudoku-pencil-color, #778da9);

    /* Container colors - now read from theme, with fallbacks */
    --sudoku-container-background: var(--sudoku-container-bg, rgba(27, 38, 59, 0.95));
    --sudoku-grid-border-color: var(--sudoku-grid-border, #5a7a9a);
    --sudoku-box-border-color: var(--sudoku-box-border, #8fa8c8);

    /* Button colors */
    --sudoku-btn-bg: var(--color-bg-primary, #0d1b2a);
    --sudoku-btn-border: var(--color-border-accent, #415a77);
    --sudoku-btn-text: var(--color-text-primary, #e0e1dd);
    --sudoku-btn-hover-bg: var(--color-btn-primary-start, #415a77);
}

/* Fit Sudoku in viewport without scrolling */
#game-area:has(.sudoku-container) {
    overflow: auto;
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding: 0.5rem;
}

/* Light-blue theme: solid white background instead of checkered pattern */
[data-theme="light-blue"] #game-area:has(.sudoku-container) {
    background: #ffffff;
    background-image: none;
}

/* Light-blue theme: Fix validate button visibility */
[data-theme="light-blue"] .validate-btn {
    background: #dcfce7;
    color: #059669;
    border-color: #86efac;
}

[data-theme="light-blue"] .validate-btn:hover:not(:disabled) {
    background: #bbf7d0;
    border-color: #059669;
}

/* Sudoku Game Header - Improved Visual Hierarchy */
.sudoku-game-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    background: var(--sudoku-container-background);
    border-bottom: 1px solid var(--sudoku-cell-border);
    flex-shrink: 0;
    flex-wrap: nowrap;
}

/* Accessibility: Visually hidden but available to screen readers */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Game Mode Info (Left side - Daily badge + Date + Difficulty) */
.game-mode-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-shrink: 0;
}

/* Daily Challenge Badge */
.game-mode-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.game-mode-badge.daily {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: #ffffff;
}

.game-mode-badge .mode-label {
    line-height: 1;
}

/* Challenge Date */
.challenge-date {
    font-size: 0.75rem;
    color: var(--sudoku-given-text);
    font-weight: 500;
    padding: 0.2rem 0.4rem;
    background: var(--sudoku-cell-highlighted-bg, rgba(255,255,255,0.1));
    border-radius: 4px;
    line-height: 1.2;
    white-space: nowrap;
}

/* Difficulty Badge */
.difficulty-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    line-height: 1;
}

.difficulty-badge .difficulty-label {
    line-height: 1;
}

/* Difficulty colors */
.difficulty-badge.difficulty-beginner {
    background: rgba(34, 197, 94, 0.2);
    color: #4ade80;
}

.difficulty-badge.difficulty-easy {
    background: rgba(59, 130, 246, 0.2);
    color: #60a5fa;
}

.difficulty-badge.difficulty-hard {
    background: rgba(249, 115, 22, 0.2);
    color: #fb923c;
}

.difficulty-badge.difficulty-xtreme {
    background: rgba(239, 68, 68, 0.2);
    color: #f87171;
}

/* Game Stats Group (Middle - horizontal layout) */
.game-stats-group {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0.5rem;
}

.game-stats-group .stat-item {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--sudoku-given-text);
    background: none;
    border: none;
    padding: 0;
}

.stat-item .stat-icon {
    font-size: 0.65rem;
    opacity: 0.7;
}

.stat-item.mistakes .stat-icon {
    color: #f87171;
}

.stat-item.hints .stat-icon {
    color: #fbbf24;
}

.stat-item .stat-value {
    min-width: 1ch;
    text-align: center;
}

/* Timer Group (Right side - Most prominent) */
.timer-group {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    margin-left: auto;
}

.timer-btn {
    background: var(--sudoku-primary, #2563eb);
    border: none;
    border-radius: 4px;
    padding: 0.35rem;
    width: 28px;
    height: 28px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s ease;
}

.timer-btn:hover {
    background: var(--sudoku-primary-light, #3b82f6);
    transform: scale(1.05);
}

.timer-btn:focus {
    outline: 2px solid var(--sudoku-primary-light, #3b82f6);
    outline-offset: 2px;
}

.timer-btn .timer-icon {
    font-size: 0.7rem;
    color: #ffffff;
    line-height: 1;
}

.timer-display {
    font-size: 1rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--sudoku-given-text);
    padding: 0.25rem 0.5rem;
    background: var(--sudoku-cell-highlighted-bg, rgba(255,255,255,0.1));
    border-radius: 4px;
    min-width: 3.5rem;
    text-align: center;
    letter-spacing: 0.02em;
}

/* Header Print Button */
.sudoku-header-print-btn {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.7rem;
    background: linear-gradient(135deg, var(--sudoku-primary, #2563eb) 0%, var(--sudoku-primary-light, #3b82f6) 100%);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    color: #ffffff;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
    flex-shrink: 0;
}

.sudoku-header-print-btn:hover {
    background: linear-gradient(135deg, var(--sudoku-primary-light, #3b82f6) 0%, var(--sudoku-primary, #2563eb) 100%);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.sudoku-header-print-btn:active {
    transform: translateY(0);
}

.sudoku-header-print-btn:focus {
    outline: 2px solid var(--sudoku-primary-light, #3b82f6);
    outline-offset: 2px;
}

.sudoku-header-print-btn i {
    font-size: 0.9rem;
    line-height: 1;
}

/* Light theme adjustments */
[data-theme="light-blue"] .game-mode-badge.daily {
    background: linear-gradient(135deg, #f59e0b, #d97706);
}

[data-theme="light-blue"] .difficulty-badge.difficulty-beginner {
    background: rgba(34, 197, 94, 0.15);
    color: #16a34a;
}

[data-theme="light-blue"] .difficulty-badge.difficulty-easy {
    background: rgba(59, 130, 246, 0.15);
    color: #2563eb;
}

[data-theme="light-blue"] .difficulty-badge.difficulty-hard {
    background: rgba(249, 115, 22, 0.15);
    color: #ea580c;
}

[data-theme="light-blue"] .difficulty-badge.difficulty-xtreme {
    background: rgba(239, 68, 68, 0.15);
    color: #dc2626;
}

[data-theme="light-blue"] .stat-item.mistakes .stat-icon {
    color: #dc2626;
}

[data-theme="light-blue"] .stat-item.hints .stat-icon {
    color: #d97706;
}

/* Light theme adjustments for Daily Challenge Calendar Modal */
[data-theme="light-blue"] .daily-challenge-modal {
    background: #f8fafc;
    border: 1px solid #cbd5e1;
}

[data-theme="light-blue"] .daily-modal-header h2 {
    color: #1e293b;
}

[data-theme="light-blue"] .difficulty-tabs {
    background: #e2e8f0;
    border-bottom: 1px solid #cbd5e1;
}

[data-theme="light-blue"] .diff-tab {
    color: #475569;
}

[data-theme="light-blue"] .diff-tab:hover {
    color: #1e293b;
    background: rgba(0, 0, 0, 0.05);
}

[data-theme="light-blue"] .diff-tab.active {
    color: #1e293b;
    background: rgba(37, 99, 235, 0.1);
    border-bottom-color: #2563eb;
}

[data-theme="light-blue"] .diff-tab.active.difficulty-beginner {
    border-bottom-color: #22c55e;
}

[data-theme="light-blue"] .diff-tab.active.difficulty-easy {
    border-bottom-color: #3b82f6;
}

[data-theme="light-blue"] .diff-tab.active.difficulty-hard {
    border-bottom-color: #f97316;
}

[data-theme="light-blue"] .diff-tab.active.difficulty-xtreme {
    border-bottom-color: #ef4444;
}

[data-theme="light-blue"] .calendar-nav-btn {
    color: #475569;
    background: #e2e8f0;
}

[data-theme="light-blue"] .calendar-nav-btn:hover {
    color: #1e293b;
    background: #cbd5e1;
}

[data-theme="light-blue"] .calendar-month-year {
    color: #1e293b;
}

[data-theme="light-blue"] .calendar-weekday {
    color: #64748b;
}

[data-theme="light-blue"] .calendar-day {
    color: #334155;
    background: #f1f5f9;
}

[data-theme="light-blue"] .calendar-day:hover:not(.empty):not(.future) {
    background: #e2e8f0;
}

[data-theme="light-blue"] .calendar-day.today {
    border-color: #2563eb;
}

[data-theme="light-blue"] .calendar-day.completed {
    background: rgba(34, 197, 94, 0.15);
    color: #166534;
}

[data-theme="light-blue"] .calendar-day.future {
    color: #94a3b8;
    background: #f8fafc;
}

.sudoku-container {
    width: 100%;
    max-width: 600px;
    max-height: 100%;
    margin: 0 auto;
    padding: 15px;
    font-family: 'Arial', sans-serif;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    background: var(--sudoku-container-background);
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.sudoku-stats {
    display: flex;
    gap: 0.5rem;
    font-size: 0.75rem;
    color: var(--sudoku-given-text);
    font-weight: 500;
}

/* Default: show text, hide icons */
.mistakes-icon,
.hints-icon {
    display: none;
}

.mistakes-text,
.hints-text {
    display: inline;
}

/* Grid Wrapper */
.sudoku-grid-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 0;
}

/* Sudoku Grid */
.sudoku-grid {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    gap: 0;
    background: var(--sudoku-grid-border, #5a7a9a);
    border: 3px solid var(--sudoku-box-border, #8fa8c8);
    border-radius: 4px;
    padding: 0;
    width: min(80vw, 55vh, 500px);
    height: min(80vw, 55vh, 500px);
    aspect-ratio: 1;
    flex-shrink: 1;
}

/* Sudoku Cell */
.sudoku-cell {
    background: var(--sudoku-cell-bg, #1b263b);
    border: 1px solid var(--sudoku-cell-border, #4a6a8a);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    position: relative;
    font-size: clamp(1.2rem, 4vw, 2rem);
    transition: all 0.15s ease;
    aspect-ratio: 1;
    min-height: 0;
    box-sizing: border-box;
    overflow: hidden;
}

/* Thicker borders for 3x3 boxes */
.sudoku-cell:nth-child(3n) {
    border-right: 2px solid var(--sudoku-box-border, #8fa8c8);
}

.sudoku-cell:nth-child(n+19):nth-child(-n+27),
.sudoku-cell:nth-child(n+46):nth-child(-n+54) {
    border-bottom: 2px solid var(--sudoku-box-border, #8fa8c8);
}

/* Given numbers (clues) */
.sudoku-cell.given .cell-value {
    color: var(--sudoku-given-text);
    font-weight: bold;
    font-family: 'Arial', sans-serif;
}

/* User-filled numbers */
.sudoku-cell:not(.given) .cell-value {
    color: var(--sudoku-user-text);
    font-weight: 600;
    font-family: 'Arial', sans-serif;
}

/* Selected cell */
.sudoku-cell.selected {
    background: var(--sudoku-cell-selected-bg);
    border: 2px solid var(--sudoku-primary-light);
    box-shadow: inset 0 0 0 2px var(--sudoku-primary);
}

/* Highlighted cells (same row/col/box) */
.sudoku-cell.highlighted {
    background: var(--sudoku-cell-highlighted-bg);
    box-shadow: inset 0 0 3px rgba(120, 160, 200, 0.2);
}

/* Same number highlighting */
.sudoku-cell.same-number {
    background: var(--sudoku-cell-same-bg);
    box-shadow: inset 0 0 5px rgba(140, 180, 220, 0.25);
}

/* Error highlight */
.sudoku-cell.error {
    background: var(--sudoku-error-bg, rgba(248, 113, 113, 0.3));
    animation: errorPulse 0.5s ease;
}

@keyframes errorPulse {
    0%, 100% { background: var(--sudoku-error-bg, rgba(248, 113, 113, 0.3)); }
    50% { background: var(--sudoku-error, #f87171); }
}

/* Pencil Marks/Notes */
.pencil-notes {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    width: 100%;
    height: 100%;
    padding: 0;
    gap: 0;
}

.pencil-note {
    font-size: clamp(0.5rem, 1.5vw, 0.7rem);
    color: transparent;
    display: flex;
    align-items: center;
    justify-content: center;
}

.pencil-note.visible {
    color: var(--sudoku-pencil-text);
    font-weight: 500;
}

/* Controls */
.sudoku-controls {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex-shrink: 0;
}

.sudoku-actions {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
    justify-content: center;
}

.sudoku-btn {
    padding: 0.4rem 0.8rem;
    background: var(--sudoku-btn-bg);
    color: var(--sudoku-btn-text);
    border: 2px solid var(--sudoku-btn-border);
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 0.3rem;
    white-space: nowrap;
}

.sudoku-btn:hover:not(:disabled) {
    background: var(--sudoku-btn-hover-bg);
    border-color: var(--sudoku-primary-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(65, 90, 119, 0.3);
}

.sudoku-btn:active:not(:disabled) {
    transform: translateY(0);
}

.sudoku-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.sudoku-btn.active {
    background: var(--sudoku-primary);
    color: var(--color-text-light, #ffffff);
}

.validate-btn {
    background: var(--sudoku-btn-highlight-bg, var(--sudoku-cell-highlighted-bg));
    color: var(--sudoku-success);
    border-color: var(--sudoku-btn-border);
}

.validate-btn:hover:not(:disabled) {
    background: var(--sudoku-btn-hover-bg);
    border-color: var(--sudoku-success);
}

.print-btn {
    background: var(--sudoku-btn-highlight-bg, var(--sudoku-cell-highlighted-bg));
    color: var(--sudoku-btn-text);
    border-color: var(--sudoku-btn-border);
}

.print-btn:hover:not(:disabled) {
    background: var(--sudoku-btn-hover-bg);
    border-color: var(--sudoku-primary-light);
}

/* Number Pad - Compact Single Line */
.sudoku-number-pad {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.4rem;
    max-width: 100%;
    margin: 0 auto 1rem;
    padding: 0 0.5rem;
}

.number-btn {
    width: 36px;
    height: 36px;
    flex-shrink: 0;
    background: var(--sudoku-btn-bg);
    color: var(--sudoku-btn-text);
    border: 2px solid var(--sudoku-btn-border);
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.number-btn:hover {
    background: var(--sudoku-btn-hover-bg);
    border-color: var(--sudoku-primary-light);
    transform: scale(1.1);
}

.number-btn:active {
    transform: scale(0.95);
}

.clear-btn {
    width: auto;
    padding: 0 0.8rem;
    font-size: 0.85rem;
    background: var(--sudoku-error-bg, rgba(248, 113, 113, 0.3));
    color: var(--sudoku-error);
    border-color: var(--sudoku-error);
}

.clear-btn:hover {
    background: var(--sudoku-error);
    color: var(--color-text-light, #ffffff);
    border-color: var(--sudoku-error);
}

/* Sudoku Master Character & Teaching Panel - Side Coach (Non-blocking) */
.sudoku-master-overlay {
    position: fixed;
    bottom: 1rem;
    right: 1rem;
    width: 360px;
    max-width: calc(100vw - 2rem);
    max-height: calc(100vh - 120px);
    z-index: 9999;
    animation: slideInRight 0.4s ease;
    pointer-events: none;
}

@keyframes slideInRight {
    from {
        transform: translateX(420px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.master-teaching-panel {
    background: linear-gradient(135deg, var(--sudoku-primary) 0%, var(--sudoku-primary-dark) 100%);
    border-radius: 16px;
    padding: 1rem;
    box-shadow: 0 10px 40px rgba(65, 90, 119, 0.4), 0 0 0 2px var(--sudoku-primary-light);
    pointer-events: auto;
    overflow-y: auto;
    max-height: calc(100vh - 120px);
}

.master-character {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin-bottom: 1rem;
    padding-bottom: 0.8rem;
    border-bottom: 2px solid var(--sudoku-primary-light);
}

.master-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--sudoku-primary-light) 0%, var(--sudoku-primary) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    box-shadow: 0 4px 15px rgba(65, 90, 119, 0.5);
    flex-shrink: 0;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-4px); }
}

.master-intro {
    flex: 1;
    min-width: 0;
}

.master-name {
    font-size: 1.1rem;
    font-weight: bold;
    color: var(--color-text-light, #ffffff);
    margin: 0 0 0.2rem;
}

.master-title {
    font-size: 0.75rem;
    color: var(--color-text-muted, rgba(255, 255, 255, 0.8));
    margin: 0;
}

.master-message {
    background: var(--sudoku-container-background);
    border-radius: 10px;
    padding: 1rem;
    margin-bottom: 1rem;
    color: var(--sudoku-given-text);
    line-height: 1.5;
}

.master-message h3 {
    margin: 0 0 0.6rem;
    color: var(--sudoku-primary-light);
    font-size: 1rem;
}

.master-message p {
    margin: 0 0 0.6rem;
    font-size: 0.85rem;
}

.master-message p:last-child {
    margin-bottom: 0;
}

.master-message .highlight {
    background: var(--sudoku-cell-highlighted-bg);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
    font-weight: 600;
    color: var(--sudoku-user-text);
}

.reason-list {
    background: var(--sudoku-cell-highlighted-bg);
    border-left: 3px solid var(--sudoku-primary-light);
    padding: 0.6rem 0.8rem;
    margin: 0.6rem 0;
    border-radius: 4px;
    font-size: 0.8rem;
}

.reason-list li {
    margin: 0.3rem 0;
    color: var(--sudoku-given-text);
    font-weight: 500;
}

.master-options {
    display: flex;
    gap: 0.6rem;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 0.8rem;
}

.master-option-btn {
    min-width: 50px;
    height: 50px;
    background: var(--sudoku-btn-bg);
    color: var(--sudoku-btn-text);
    border: 3px solid var(--sudoku-primary-light);
    border-radius: 10px;
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 3px 8px rgba(65, 90, 119, 0.3);
}

.master-option-btn:hover {
    background: var(--sudoku-primary);
    color: var(--color-text-light, #ffffff);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(119, 141, 169, 0.4);
}

.master-option-btn:active {
    transform: translateY(-1px);
}

.master-close-btn {
    width: 100%;
    padding: 0.8rem;
    background: var(--sudoku-cell-highlighted-bg);
    color: var(--color-text-light, #ffffff);
    border: 2px solid var(--sudoku-primary-light);
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.master-close-btn:hover {
    background: var(--sudoku-primary-light);
    color: var(--color-bg-primary, #0d1b2a);
}

/* Original Beginner Mode Coaching (for inline hints) */
.sudoku-coaching {
    background: var(--sudoku-cell-highlighted-bg);
    border: 2px solid var(--sudoku-success);
    border-radius: 8px;
    padding: 0.5rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    flex-shrink: 0;
    max-height: 80px;
    overflow-y: auto;
}

.coaching-message {
    margin: 0;
    color: var(--sudoku-success);
    font-weight: 500;
    text-align: center;
    font-size: 0.8rem;
}

.coaching-success {
    color: var(--sudoku-success);
    font-weight: 600;
    margin: 0;
    font-size: 0.9rem;
}

.coaching-error {
    color: var(--sudoku-error);
    font-weight: 600;
    margin: 0;
    font-size: 0.85rem;
}

.coaching-hint {
    color: var(--sudoku-accent);
    font-style: italic;
    margin: 0.3rem 0 0;
    font-size: 0.75rem;
}

/* Tablet Responsive (481px - 768px) */
@media (max-width: 768px) and (min-width: 481px) {
    .sudoku-game-header {
        padding: 0.5rem 0.6rem;
        gap: 0.6rem;
    }

    .game-mode-info {
        gap: 0.4rem;
    }

    .game-mode-badge {
        font-size: 0.65rem;
        padding: 0.2rem 0.4rem;
    }

    .difficulty-badge {
        font-size: 0.7rem;
    }

    .challenge-date {
        font-size: 0.7rem;
    }

    .stat-item {
        font-size: 0.75rem;
    }

    .timer-display {
        font-size: 0.9rem;
        min-width: 3rem;
    }

    .sudoku-container {
        padding: 1rem;
        max-width: 600px;
    }

    .sudoku-grid {
        width: min(70vw, 500px);
        height: min(70vw, 500px);
    }

    .sudoku-cell {
        font-size: clamp(1.2rem, 4vw, 1.8rem);
    }

    .sudoku-actions {
        gap: 0.5rem;
        flex-wrap: nowrap;
        justify-content: center;
    }

    .sudoku-btn {
        padding: 0.6rem;
        font-size: 0;
        min-width: 48px;
        width: 48px;
        height: 48px;
        justify-content: center;
    }

    .sudoku-btn span {
        font-size: 1.4rem;
        margin: 0;
    }

    .number-btn {
        font-size: 1.4rem;
        min-height: 50px;
    }
}

/* Mobile & Tablet Responsive (up to 768px) */
@media (max-width: 768px) {
    .sudoku-game-header {
        padding: 0.4rem 0.5rem;
        gap: 0.4rem;
        flex-wrap: nowrap;
    }

    .game-mode-info {
        gap: 0.3rem;
        flex-shrink: 1;
        min-width: 0;
        overflow: hidden;
    }

    .game-mode-badge {
        font-size: 0.6rem;
        padding: 0.15rem 0.35rem;
    }

    .game-mode-badge .mode-label {
        display: none;
    }

    .difficulty-badge {
        font-size: 0.65rem;
        padding: 0.2rem 0.4rem;
    }

    .difficulty-badge .difficulty-label {
        display: none;
    }

    .challenge-date {
        font-size: 0.65rem;
        padding: 0.15rem 0.3rem;
    }

    .game-stats-group {
        gap: 0.5rem;
    }

    .stat-item {
        font-size: 0.65rem;
        gap: 0.15rem;
    }

    .stat-item .stat-icon {
        font-size: 0.55rem;
    }

    .timer-group {
        gap: 0.3rem;
    }

    .timer-btn {
        width: 26px;
        height: 26px;
        padding: 0.25rem;
    }

    .timer-btn .timer-icon {
        font-size: 0.6rem;
    }

    .timer-display {
        font-size: 0.85rem;
        padding: 0.2rem 0.4rem;
        min-width: 3rem;
    }

    /* Hide print button text on mobile, show icon only */
    .sudoku-header-print-btn {
        padding: 0.35rem;
        min-width: 32px;
        justify-content: center;
    }

    .sudoku-header-print-btn .btn-text {
        display: none;
    }

    .sudoku-header-print-btn i {
        font-size: 0.85rem;
    }

    /* Legacy classes - keep for backwards compatibility */
    .mistakes-icon,
    .hints-icon {
        display: none;
    }

    .mistakes-counter,
    .hints-counter {
        display: flex;
        align-items: center;
        gap: 0.2rem;
    }

    .timer-btn {
        padding: 0.25rem;
        min-width: 24px;
        height: 24px;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .timer-btn .timer-icon {
        font-size: 0.65rem;
        line-height: 1;
    }

    .sudoku-timer {
        font-size: 0.65rem;
        padding: 0.25rem 0.35rem;
        min-width: 42px;
        text-align: center;
    }

    .sudoku-container {
        padding: 0.3rem;
        padding-bottom: 1rem;
        max-height: 100%;
        overflow-y: visible;
    }

    .sudoku-header {
        flex-direction: column;
        gap: 0.4rem;
        padding: 0.5rem;
        margin-bottom: 0.5rem;
    }

    .sudoku-info,
    .sudoku-stats {
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
    }

    .difficulty-label {
        font-size: 0.95rem;
    }

    .daily-badge {
        font-size: 0.7rem;
        padding: 0.2rem 0.5rem;
    }

    .mistakes-counter,
    .hints-counter {
        font-size: 0.85rem;
    }

    /* Grid optimized for small screens */
    .sudoku-grid-wrapper {
        margin-bottom: 0.5rem;
        flex-shrink: 1;
    }

    .sudoku-grid {
        width: min(85vw, 340px);
        height: min(85vw, 340px);
        border-width: 2px;
        gap: 0;
    }

    .sudoku-cell {
        font-size: clamp(0.9rem, 3.5vw, 1.3rem);
        min-height: unset;
        aspect-ratio: 1;
    }

    .sudoku-cell .cell-value {
        font-size: inherit;
    }

    /* Touch-friendly controls */
    .sudoku-controls {
        gap: 0.5rem;
        margin-bottom: 0.5rem;
    }

    .sudoku-actions {
        gap: 0.4rem;
        flex-wrap: nowrap;
        justify-content: center;
    }

    .sudoku-btn {
        padding: 0.6rem;
        min-width: 44px;
        width: 44px;
        height: 44px;
        justify-content: center;
        flex: 0 0 auto;
    }

    .sudoku-btn .btn-icon {
        font-size: 1.3rem;
        margin: 0;
    }

    .sudoku-btn .btn-text {
        display: none;
    }

    .number-btn .btn-text,
    .clear-btn .btn-text {
        display: none;
    }

    .number-btn .btn-icon,
    .clear-btn .btn-icon {
        display: inline;
    }

    /* Number pad optimization */
    .sudoku-number-pad {
        gap: 0.3rem;
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .number-btn {
        width: 32px;
        height: 32px;
        font-size: 0.9rem;
        flex-shrink: 0;
    }

    .clear-btn {
        padding: 0;
        font-size: 1.1rem;
        width: 32px;
        font-weight: 400;
    }

    /* Pencil marks for mobile */
    .pencil-note {
        font-size: clamp(0.35rem, 1vw, 0.5rem);
    }

    /* Beginner coaching */
    .sudoku-coaching {
        padding: 0.5rem;
        margin-top: 0.5rem;
    }

    .coaching-message {
        font-size: 0.85rem;
    }

    .beginner-options {
        gap: 0.4rem;
    }

    .beginner-option-btn {
        min-width: 44px;
        min-height: 44px;
        font-size: 1.2rem;
    }

    /* Master Sudo Mobile Optimization - Bottom Sheet */
    .sudoku-master-overlay {
        bottom: 0;
        right: 0;
        left: 0;
        width: 100%;
        max-width: 100%;
        border-radius: 0;
        animation: slideUp 0.4s ease;
    }

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

    .master-teaching-panel {
        padding: 1rem;
        border-radius: 16px 16px 0 0;
        max-height: 60vh;
    }

    .master-character {
        gap: 0.6rem;
        margin-bottom: 0.8rem;
        padding-bottom: 0.6rem;
    }

    .master-avatar {
        width: 45px;
        height: 45px;
        font-size: 1.8rem;
    }

    .master-name {
        font-size: 1rem;
    }

    .master-title {
        font-size: 0.7rem;
    }

    .master-message {
        padding: 0.8rem;
    }

    .master-message h3 {
        font-size: 0.95rem;
        margin-bottom: 0.5rem;
    }

    .master-message p {
        font-size: 0.8rem;
        margin-bottom: 0.5rem;
    }

    .master-option-btn {
        min-width: 45px;
        height: 45px;
        font-size: 1.3rem;
    }

    .reason-list {
        padding: 0.5rem 0.7rem;
        font-size: 0.75rem;
    }

    .master-close-btn {
        padding: 0.7rem;
        font-size: 0.9rem;
    }
}

/* Extra small phones (320px - 375px) */
@media (max-width: 375px) {
    .sudoku-container {
        padding: 0.2rem;
    }

    .sudoku-grid {
        width: min(98vw, 340px);
        height: min(98vw, 340px);
    }

    .sudoku-cell {
        font-size: clamp(0.8rem, 3.2vw, 1.1rem);
    }

    .sudoku-btn {
        font-size: 0;
        padding: 0.5rem;
        width: 40px;
        height: 40px;
        min-width: 40px;
    }

    .sudoku-btn span {
        font-size: 1.1rem;
    }

    .number-btn {
        font-size: 1rem;
        min-height: 40px;
    }

    .pencil-note {
        font-size: 0.32rem;
    }
}

/* Landscape mode for phones */
@media (max-height: 500px) and (orientation: landscape) {
    .sudoku-container {
        padding: 0.3rem;
    }

    .sudoku-header {
        flex-direction: row;
        padding: 0.3rem 0.5rem;
        margin-bottom: 0.3rem;
    }

    .sudoku-grid {
        width: min(50vh, 350px);
        height: min(50vh, 350px);
    }

    .sudoku-controls {
        margin-bottom: 0.3rem;
    }

    .sudoku-btn {
        padding: 0.3rem 0.5rem;
        font-size: 0.7rem;
    }

    .number-btn {
        min-height: 35px;
        font-size: 0.9rem;
    }
}

/* Large tablets and small desktops */
@media (min-width: 769px) and (max-width: 1024px) {
    .sudoku-container {
        max-width: 90vw;
        padding: 1rem;
    }

    .sudoku-grid {
        width: min(70vw, 60vh, 450px);
        height: min(70vw, 60vh, 450px);
    }

    .sudoku-controls {
        gap: 0.6rem;
    }

    .sudoku-actions {
        gap: 0.5rem;
    }
}

/* Daily Challenge Modal */
.daily-challenge-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
}

.daily-challenge-content {
    background: var(--sudoku-container-background);
    border-radius: 12px;
    padding: 2rem;
    max-width: 500px;
    width: 90%;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
    border: 1px solid var(--sudoku-cell-border);
}

.daily-challenge-content h2 {
    color: var(--sudoku-primary-light);
    margin: 0 0 0.5rem;
    font-size: 1.8rem;
    text-align: center;
}

.daily-challenge-content p {
    color: var(--sudoku-given-text);
    margin: 0 0 1.5rem;
    text-align: center;
}

.daily-difficulty-buttons {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.daily-diff-btn {
    background: var(--sudoku-btn-bg);
    border: 2px solid var(--sudoku-btn-border);
    border-radius: 8px;
    padding: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    text-align: left;
}

.daily-diff-btn:not(:disabled):hover {
    background: var(--sudoku-btn-hover-bg);
    border-color: var(--sudoku-primary-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(65, 90, 119, 0.3);
}

.daily-diff-btn.completed {
    background: var(--sudoku-cell-highlighted-bg);
    border-color: var(--sudoku-success);
    cursor: not-allowed;
}

.diff-label {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--sudoku-given-text);
}

.completed-badge {
    font-size: 0.9rem;
    color: var(--sudoku-success);
    font-weight: 500;
}

.streak-badge {
    font-size: 0.85rem;
    color: var(--sudoku-accent);
    font-weight: 500;
}

.close-modal-btn {
    width: 100%;
    padding: 0.8rem;
    background: var(--sudoku-primary);
    color: var(--color-text-light, #ffffff);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.close-modal-btn:hover {
    background: var(--sudoku-primary-light);
}

/* Modal Responsive Styles */
@media (max-width: 768px) {
    .daily-challenge-content {
        padding: 1.5rem;
        width: 92%;
        max-width: 450px;
    }

    .daily-difficulty-buttons {
        gap: 0.8rem;
    }

    .daily-diff-btn {
        padding: 0.9rem;
        min-height: 60px;
    }
}

@media (max-width: 480px) {
    .daily-challenge-content {
        padding: 1.2rem;
        width: 95%;
        border-radius: 8px;
    }

    .daily-challenge-content h2 {
        font-size: 1.4rem;
        margin-bottom: 0.4rem;
    }

    .daily-challenge-content p {
        font-size: 0.9rem;
        margin-bottom: 1rem;
    }

    .daily-difficulty-buttons {
        gap: 0.6rem;
        margin-bottom: 1rem;
    }

    .daily-diff-btn {
        padding: 0.8rem;
        min-height: 55px;
    }

    .diff-label {
        font-size: 1.05rem;
    }

    .completed-badge,
    .streak-badge {
        font-size: 0.8rem;
    }

    .close-modal-btn {
        padding: 0.7rem;
        font-size: 0.95rem;
    }
}

@media (max-width: 375px) {
    .daily-challenge-content {
        padding: 1rem;
    }

    .daily-challenge-content h2 {
        font-size: 1.3rem;
    }

    .diff-label {
        font-size: 1rem;
    }
}

/* Sudoku Victory Modal Theming - Override base styles completely */
.sudoku-win-modal {
    align-items: flex-start !important;
    padding-top: 2vh !important;
}

.sudoku-win-modal .win-modal-content,
.sudoku-validation-modal .win-modal-content {
    background: var(--sudoku-container-background) !important;
    max-height: 96vh !important;
    overflow-y: auto !important;
    margin: 0 !important;
    border: 1px solid var(--sudoku-cell-border);
}

.sudoku-win-modal .modal-header.sudoku-modal-header,
.sudoku-validation-modal .modal-header.sudoku-modal-header {
    background: linear-gradient(135deg, var(--sudoku-primary) 0%, var(--sudoku-primary-dark) 100%);
    color: var(--color-text-light, #ffffff);
    padding: 1.25rem 1.5rem !important;
}

.sudoku-win-modal .modal-header h2 {
    font-size: 1.75rem !important;
    margin-bottom: 0.25rem !important;
}

.sudoku-win-modal .win-subtitle {
    color: var(--sudoku-primary-lighter) !important;
    text-shadow: none;
    font-size: 0.95rem !important;
}

.sudoku-win-modal .win-modal-content h2,
.sudoku-validation-modal .win-modal-content h2 {
    color: var(--color-text-light, #ffffff) !important;
}

/* Fix modal body text visibility */
.sudoku-win-modal .modal-body {
    color: var(--sudoku-given-text) !important;
    padding: 1.25rem 1.5rem !important;
}

.sudoku-win-modal .win-stats {
    background: var(--sudoku-cell-highlighted-bg) !important;
    backdrop-filter: none !important;
    padding: 1rem !important;
    margin-bottom: 1.25rem !important;
    border-radius: 8px;
}

.sudoku-win-modal .win-stats p {
    color: var(--sudoku-given-text) !important;
    border-bottom-color: var(--sudoku-cell-border) !important;
    margin: 0.5rem 0 !important;
    padding: 0.5rem 0 !important;
    font-size: 0.9rem !important;
}

.sudoku-win-modal .win-stats p strong {
    color: var(--sudoku-primary-light) !important;
}

.sudoku-win-modal .win-stats p span:last-child {
    color: var(--sudoku-user-text) !important;
    font-weight: 700 !important;
    font-size: 1rem !important;
}

.sudoku-win-modal .win-stats p.highlight {
    background: linear-gradient(135deg, var(--sudoku-cell-highlighted-bg) 0%, var(--sudoku-cell-same-bg) 100%);
    border-left: 4px solid var(--sudoku-primary-light);
    padding-left: 1rem;
}

.sudoku-win-modal .win-stats p.highlight span:last-child {
    color: var(--sudoku-accent) !important;
}

.sudoku-win-modal .share-title {
    color: var(--sudoku-primary-light) !important;
    font-weight: 600 !important;
    font-size: 1rem !important;
    margin-bottom: 0.75rem !important;
}

/* Social Share Button Overrides for Sudoku */
.sudoku-win-modal .share-btn.whatsapp {
    background: var(--sudoku-success);
    color: var(--color-text-on-light, #0d1b2a);
}

.sudoku-win-modal .share-btn.copy {
    background: var(--sudoku-primary);
    color: var(--color-text-light, #ffffff);
    border: 1px solid var(--sudoku-primary-light);
}

.sudoku-win-modal .share-btn.copy:hover {
    background: var(--sudoku-primary-light);
}

/* Validation Modal Specific Styles */
.sudoku-validation-modal .modal-header.validation-success {
    background: linear-gradient(135deg, var(--sudoku-success) 0%, var(--sudoku-success) 100%) !important;
}

.sudoku-validation-modal .modal-header.validation-error {
    background: linear-gradient(135deg, var(--sudoku-error) 0%, var(--sudoku-error) 100%) !important;
}

.sudoku-validation-modal .validation-icon {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    font-weight: bold;
}

.sudoku-validation-modal .validation-message {
    font-size: 1rem;
    color: var(--sudoku-given-text);
    margin: 1.5rem 0;
    line-height: 1.6;
    text-align: center;
}

.sudoku-validation-modal .action-btn.btn-primary {
    background: linear-gradient(135deg, var(--sudoku-primary) 0%, var(--sudoku-primary-dark) 100%);
    border-color: var(--sudoku-primary);
    min-width: 120px;
}

.sudoku-validation-modal .action-btn.btn-primary:hover {
    background: linear-gradient(135deg, var(--sudoku-primary-dark) 0%, var(--sudoku-primary) 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(65, 90, 119, 0.3);
}

.sudoku-win-modal .win-stats.sudoku-win-stats p.highlight {
    background: linear-gradient(135deg, var(--sudoku-cell-highlighted-bg) 0%, var(--sudoku-cell-same-bg) 100%);
    border-left: 4px solid var(--sudoku-primary-light);
}

.sudoku-badges {
    background: var(--sudoku-cell-highlighted-bg);
    border-radius: 8px;
    padding: 0.75rem;
    margin: 0.75rem 0;
    border: 2px solid var(--sudoku-cell-border);
}

.badges-title {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--sudoku-primary-light);
    margin: 0 0 0.5rem;
    text-align: center;
}

.badges-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    justify-content: center;
}

.sudoku-badges .badge-item {
    background: var(--sudoku-btn-bg);
    padding: 0.4rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--sudoku-given-text);
    border: 1px solid var(--sudoku-cell-border);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.sudoku-win-modal .action-btn.btn-primary {
    background: linear-gradient(135deg, var(--sudoku-primary) 0%, var(--sudoku-primary-dark) 100%) !important;
    border-color: var(--sudoku-primary) !important;
    color: var(--color-text-light, #ffffff) !important;
}

.sudoku-win-modal .action-btn.btn-primary:hover {
    background: linear-gradient(135deg, var(--sudoku-primary-light) 0%, var(--sudoku-primary) 100%) !important;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(65, 90, 119, 0.3);
}

/* Victory Modal Responsive Adjustments */
@media (max-width: 768px) {
    .sudoku-win-modal .modal-header h2 {
        font-size: 1.5rem !important;
    }

    .sudoku-win-modal .win-subtitle {
        font-size: 0.85rem !important;
    }

    .sudoku-win-modal .modal-body {
        padding: 1rem !important;
    }

    .sudoku-win-modal .win-stats {
        padding: 0.75rem !important;
    }

    .sudoku-win-modal .win-stats p {
        font-size: 0.85rem !important;
        margin: 0.4rem 0 !important;
        padding: 0.4rem 0 !important;
    }

    .sudoku-win-modal .win-stats p span:last-child {
        font-size: 0.95rem !important;
    }
}

@media (max-width: 480px) {
    .sudoku-win-modal .modal-header.sudoku-modal-header {
        padding: 1rem !important;
    }

    .sudoku-win-modal .modal-header h2 {
        font-size: 1.3rem !important;
    }

    .sudoku-win-modal .win-subtitle {
        font-size: 0.8rem !important;
    }

    .sudoku-win-modal .modal-body {
        padding: 0.75rem !important;
    }

    .sudoku-win-modal .win-stats {
        padding: 0.6rem !important;
        margin-bottom: 1rem !important;
    }

    .sudoku-win-modal .win-stats p {
        font-size: 0.8rem !important;
        margin: 0.3rem 0 !important;
        padding: 0.3rem 0 !important;
    }

    .sudoku-win-modal .win-stats p span:last-child {
        font-size: 0.9rem !important;
    }

    .sudoku-win-modal .share-title {
        font-size: 0.9rem !important;
        margin-bottom: 0.5rem !important;
    }

    .sudoku-badges {
        padding: 0.6rem;
        margin: 0.6rem 0;
    }

    .badges-title {
        font-size: 0.85rem;
    }

    .sudoku-badges .badge-item {
        font-size: 0.75rem;
        padding: 0.3rem 0.6rem;
    }
}

/* Touch and interaction improvements */
@media (hover: none) and (pointer: coarse) {
    /* Better touch targets for touch devices */
    .sudoku-cell {
        cursor: pointer;
        -webkit-tap-highlight-color: rgba(79, 195, 247, 0.3);
    }

    .sudoku-btn,
    .number-btn,
    .beginner-option-btn,
    .daily-diff-btn {
        -webkit-tap-highlight-color: rgba(79, 195, 247, 0.3);
        touch-action: manipulation; /* Prevents double-tap zoom */
    }

    /* Disable hover effects on touch devices */
    .sudoku-btn:hover,
    .number-btn:hover,
    .beginner-option-btn:hover,
    .daily-diff-btn:not(:disabled):hover {
        transform: none;
    }

    /* Better active states for touch */
    .sudoku-btn:active,
    .number-btn:active,
    .beginner-option-btn:active {
        transform: scale(0.95);
        opacity: 0.8;
    }
}

/* ======================================
   HOW TO PLAY CONTENT SECTION
   Uses theme variables from colors.css directly
   ====================================== */

.sudoku-how-to-play {
    display: block;
    max-width: 900px;
    margin: 2rem auto;
    padding: 1.5rem 2rem;
    background: var(--sudoku-container-bg, var(--color-stats-bg-start, rgba(27, 38, 59, 0.98)));
    border-radius: 16px;
    border: 1px solid var(--sudoku-grid-border, var(--color-border-accent, #5a7a9a));
    color: var(--color-text-primary, #e0e1dd);
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    line-height: 1.7;
}

.content-page.sudoku-how-to-play h2,
.sudoku-how-to-play h2 {
    font-size: 1.6rem !important;
    font-weight: 700 !important;
    color: #60a5fa !important;
    margin: 0 0 1.2rem 0 !important;
    font-family: 'Poppins', sans-serif !important;
    border-bottom: 2px solid var(--sudoku-box-border, var(--color-border-accent, #8fa8c8)) !important;
    padding-bottom: 0.5rem !important;
}

.content-page.sudoku-how-to-play h3,
.sudoku-how-to-play h3 {
    font-size: 1.3rem !important;
    font-weight: 600 !important;
    color: var(--color-text-primary, #e0e1dd) !important;
    margin: 1.8rem 0 0.8rem 0 !important;
    font-family: 'Poppins', sans-serif !important;
}

.sudoku-how-to-play h4 {
    font-size: 1.1rem !important;
    font-weight: 600 !important;
    color: #60a5fa !important;
    margin: 1.2rem 0 0.5rem 0 !important;
}

.sudoku-how-to-play p {
    margin: 0.8rem 0;
    color: var(--color-text-primary, #e0e1dd);
    opacity: 0.9;
}

.sudoku-how-to-play strong {
    color: var(--color-text-primary, #e0e1dd);
    font-weight: 600;
    opacity: 1;
}

.sudoku-how-to-play ul {
    margin: 0.6rem 0;
    padding-left: 1.5rem;
}

.sudoku-how-to-play li {
    margin: 0.4rem 0;
    color: var(--color-text-primary, #e0e1dd);
    opacity: 0.9;
}

.sudoku-how-to-play li strong {
    color: var(--color-text-primary, #e0e1dd);
    opacity: 1;
}

.sudoku-how-to-play i.fas,
.sudoku-how-to-play i.far {
    margin-right: 0.3rem;
}

/* Responsive adjustments for How to Play content */
@media (max-width: 768px) {
    .sudoku-how-to-play {
        margin: 1rem;
        padding: 1rem 1.2rem;
        border-radius: 12px;
    }

    .sudoku-how-to-play h2 {
        font-size: 1.3rem;
    }

    .sudoku-how-to-play h3 {
        font-size: 1.15rem;
    }

    .sudoku-how-to-play h4 {
        font-size: 1rem;
    }

    .sudoku-how-to-play p,
    .sudoku-how-to-play li {
        font-size: 0.95rem;
    }
}

@media (max-width: 480px) {
    .sudoku-how-to-play {
        margin: 0.5rem;
        padding: 0.8rem 1rem;
    }

    .sudoku-how-to-play h2 {
        font-size: 1.2rem;
    }

    .sudoku-how-to-play h3 {
        font-size: 1.05rem;
    }
}

/* ======================================
   DAILY CHALLENGE CALENDAR MODAL
   ====================================== */

/* Daily Challenge Button in Header */
.daily-challenge-btn {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.8rem;
    background: linear-gradient(135deg, var(--color-btn-primary-start) 0%, var(--color-btn-primary-end) 100%);
    border: 1px solid var(--color-border-accent);
    border-radius: 6px;
    color: var(--color-text-light, #ffffff);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.daily-challenge-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.daily-challenge-btn i {
    font-size: 0.9rem;
}

/* Print Puzzles Button - Match Daily Challenge button style exactly */
#print-puzzles-btn,
.site-nav .nav-btn.print-puzzles-btn,
.site-nav #print-puzzles-btn,
.print-puzzles-btn {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.8rem;
    background: linear-gradient(135deg, var(--color-btn-primary-start) 0%, var(--color-btn-primary-end) 100%);
    border: 1px solid var(--color-border-accent);
    border-radius: 6px;
    color: var(--color-text-light, #ffffff);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    width: auto;
    height: auto;
}

#print-puzzles-btn:hover,
.site-nav .nav-btn.print-puzzles-btn:hover,
.site-nav #print-puzzles-btn:hover,
.print-puzzles-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.site-nav .nav-btn.print-puzzles-btn i,
.print-puzzles-btn i {
    font-size: 0.9rem;
}

/* Calendar Modal Overlay */
.daily-challenge-calendar-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    padding: 1rem;
}

/* Calendar Content Container */
.daily-calendar-content {
    background: var(--sudoku-container-background, rgba(27, 38, 59, 0.98));
    border-radius: 12px;
    max-width: 400px;
    width: 100%;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
    border: 1px solid var(--color-border-accent, #415a77);
    overflow: hidden;
}

/* Modal Header Bar */
.modal-header-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.25rem;
    background: linear-gradient(135deg, var(--sudoku-primary, #415a77) 0%, var(--sudoku-primary-dark, #1b263b) 100%);
    border-bottom: 1px solid var(--color-border-accent, #415a77);
}

.modal-header-bar h2 {
    margin: 0;
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-text-light, #ffffff);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.modal-header-bar h2 i {
    color: var(--color-highlight, #fbbf24);
}

.modal-close-x {
    background: transparent;
    border: none;
    color: var(--color-text-light, #ffffff);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.25rem;
    opacity: 0.7;
    transition: opacity 0.2s ease;
}

.modal-close-x:hover {
    opacity: 1;
}

/* Modal Body Content */
.modal-body-content {
    padding: 1.25rem;
}

/* Difficulty Tabs */
.difficulty-tabs {
    display: flex;
    gap: 0;
    background: var(--sudoku-btn-bg, #0d1b2a);
    border-bottom: 1px solid var(--color-border-accent, #415a77);
}

.diff-tab {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.75rem 0.5rem;
    background: transparent;
    border: none;
    border-bottom: 3px solid transparent;
    color: var(--sudoku-pencil-text, #778da9);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.diff-tab:hover {
    background: var(--sudoku-cell-highlighted-bg, rgba(61, 90, 128, 0.2));
    color: var(--sudoku-given-text, #e0e1dd);
}

.diff-tab.active {
    color: var(--color-text-light, #ffffff);
    border-bottom-color: var(--color-highlight, #fbbf24);
    background: var(--sudoku-cell-highlighted-bg, rgba(61, 90, 128, 0.3));
}

.diff-tab[data-difficulty="easy"] i { color: #60a5fa; }
.diff-tab[data-difficulty="hard"] i { color: #f97316; }
.diff-tab[data-difficulty="xtreme"] i { color: #ef4444; }

.diff-tab.active[data-difficulty="easy"] { border-bottom-color: #60a5fa; }
.diff-tab.active[data-difficulty="hard"] { border-bottom-color: #f97316; }
.diff-tab.active[data-difficulty="xtreme"] { border-bottom-color: #ef4444; }

/* Calendar Header with Navigation */
.calendar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.calendar-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--sudoku-given-text, #e0e1dd);
}

.calendar-nav-btn {
    background: var(--sudoku-btn-bg, #0d1b2a);
    border: 1px solid var(--sudoku-btn-border, #415a77);
    border-radius: 6px;
    padding: 0.5rem 0.75rem;
    color: var(--sudoku-btn-text, #e0e1dd);
    cursor: pointer;
    transition: all 0.2s ease;
}

.calendar-nav-btn:hover:not(:disabled) {
    background: var(--sudoku-btn-hover-bg, #415a77);
    border-color: var(--sudoku-primary-light, #778da9);
}

.calendar-nav-btn:disabled,
.calendar-nav-btn.disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

/* Calendar Grid */
.calendar-grid {
    margin-bottom: 1rem;
}

.calendar-day-names {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 2px;
    margin-bottom: 0.5rem;
}

.day-name {
    text-align: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--sudoku-pencil-text, #778da9);
    padding: 0.25rem;
    text-transform: uppercase;
}

.calendar-days {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 3px;
}

.calendar-day {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--sudoku-cell-bg, #1b263b);
    border: 1px solid var(--sudoku-cell-border, #4a6a8a);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.15s ease;
    position: relative;
    min-height: 40px;
}

.calendar-day:hover:not(.empty):not(.unavailable) {
    background: var(--sudoku-cell-highlighted-bg, rgba(61, 90, 128, 0.3));
    border-color: var(--sudoku-primary-light, #778da9);
    transform: scale(1.05);
}

.calendar-day.empty {
    background: transparent;
    border: none;
    cursor: default;
}

.calendar-day.unavailable {
    opacity: 0.3;
    cursor: not-allowed;
}

/* Completed day for selected difficulty */
.calendar-day.completed {
    background: linear-gradient(135deg, rgba(74, 222, 128, 0.2) 0%, rgba(52, 211, 153, 0.2) 100%);
    border-color: var(--sudoku-success, #4ade80);
}

.calendar-day.today {
    border: 2px solid var(--color-highlight, #fbbf24);
    background: var(--sudoku-cell-selected-bg, rgba(61, 90, 128, 0.4));
}

.calendar-day.selected {
    background: var(--sudoku-primary, #415a77);
    border-color: var(--sudoku-primary-light, #778da9);
}

.day-number {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--sudoku-given-text, #e0e1dd);
}

.calendar-day.unavailable .day-number {
    color: var(--sudoku-pencil-text, #778da9);
}

.completion-indicator {
    position: absolute;
    bottom: 2px;
    right: 2px;
    font-size: 0.55rem;
    color: var(--sudoku-success, #4ade80);
}

/* Difficulty Selection View */
.difficulty-selection {
    text-align: center;
}

.difficulty-selection h3 {
    margin: 0 0 0.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--sudoku-primary-light, #778da9);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.difficulty-selection h3 i {
    color: var(--color-highlight, #fbbf24);
}

.difficulty-selection p {
    margin: 0 0 1rem;
    font-size: 0.9rem;
    color: var(--sudoku-pencil-text, #778da9);
}

.difficulty-options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 1.25rem;
}

.diff-option-btn {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.25rem;
    background: var(--sudoku-btn-bg, #0d1b2a);
    border: 2px solid var(--sudoku-btn-border, #415a77);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.diff-option-btn:hover:not(.completed) {
    background: var(--sudoku-btn-hover-bg, #415a77);
    border-color: var(--sudoku-primary-light, #778da9);
    transform: translateX(4px);
}

.diff-option-btn.completed {
    background: linear-gradient(135deg, rgba(74, 222, 128, 0.15) 0%, rgba(52, 211, 153, 0.15) 100%);
    border-color: var(--sudoku-success, #4ade80);
}

.diff-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.diff-info i {
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.diff-option-btn[data-difficulty="easy"] .diff-info i {
    color: #60a5fa;
}

.diff-option-btn[data-difficulty="hard"] .diff-info i {
    color: #f97316;
}

.diff-option-btn[data-difficulty="xtreme"] .diff-info i {
    color: #ef4444;
}

.diff-info span {
    font-size: 1rem;
    font-weight: 600;
    color: var(--sudoku-given-text, #e0e1dd);
}

.completed-check {
    font-size: 1.1rem;
    color: var(--sudoku-success, #4ade80);
}

.back-to-calendar-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.75rem;
    background: var(--sudoku-cell-highlighted-bg, rgba(61, 90, 128, 0.3));
    border: 1px solid var(--sudoku-btn-border, #415a77);
    border-radius: 8px;
    color: var(--sudoku-given-text, #e0e1dd);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.back-to-calendar-btn:hover {
    background: var(--sudoku-btn-hover-bg, #415a77);
    border-color: var(--sudoku-primary-light, #778da9);
}

/* Calendar Modal Responsive */
@media (max-width: 480px) {
    .daily-challenge-calendar-modal {
        padding: 0.5rem;
    }

    .daily-calendar-content {
        max-width: 100%;
        border-radius: 10px;
    }

    .modal-header-bar {
        padding: 0.85rem 1rem;
    }

    .modal-header-bar h2 {
        font-size: 1.05rem;
    }

    /* Difficulty tabs mobile */
    .difficulty-tabs {
        gap: 0;
    }

    .diff-tab {
        padding: 0.6rem 0.3rem;
        font-size: 0.75rem;
        gap: 0.25rem;
    }

    .diff-tab i {
        font-size: 0.9rem;
    }

    .modal-body-content {
        padding: 1rem;
    }

    .calendar-day {
        min-height: 36px;
        border-radius: 4px;
    }

    .day-number {
        font-size: 0.8rem;
    }

    .completion-indicator {
        font-size: 0.5rem;
    }

    .diff-option-btn {
        padding: 0.85rem 1rem;
    }

    .diff-info i {
        font-size: 1rem;
    }

    .diff-info span {
        font-size: 0.9rem;
    }

}

/* ============================================
   Site Footer Styles
   ============================================ */

.sudoku-site-footer {
    width: 100%;
    margin-top: 4rem;
    padding: 2rem 1.5rem 1.5rem;
    background: var(--sudoku-bg-secondary, #1e293b);
    border-top: 1px solid var(--sudoku-cell-border, #415a77);
}

.footer-content {
    max-width: 1000px;
    margin: 0 auto;
}

.footer-section {
    margin-bottom: 2rem;
}

.footer-section-title {
    color: var(--sudoku-primary-light, #60a5fa);
    font-size: 1rem;
    font-weight: 600;
    margin: 0 0 1rem 0;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.footer-section-title i {
    font-size: 1rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.footer-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--sudoku-primary-light, #60a5fa);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.footer-link:hover {
    color: var(--sudoku-primary-hover, #3b82f6);
    transform: translateY(-2px);
}

.footer-link i {
    font-size: 0.9rem;
}

.footer-copyright {
    margin: 0;
    padding-top: 1.5rem;
    color: var(--sudoku-text-muted, #94a3b8);
    font-size: 0.85rem;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

/* Footer responsive */
@media (max-width: 768px) {
    .footer-content {
        display: flex;
        flex-direction: column;
    }

    .footer-section {
        margin-bottom: 1.5rem;
    }

    .footer-links {
        gap: 1.5rem;
    }

    .footer-link {
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .sudoku-site-footer {
        margin-top: 2rem;
        padding: 1.5rem 1rem 1rem;
    }

    .footer-section-title {
        font-size: 0.9rem;
    }

    .footer-links {
        gap: 1rem;
    }

    .footer-link {
        font-size: 0.85rem;
        flex-direction: column;
        gap: 0.25rem;
    }

    .footer-link span {
        font-size: 0.75rem;
    }

    .footer-link i {
        font-size: 1rem;
    }

    .footer-copyright {
        font-size: 0.8rem;
    }
}