/* ===== CSS Variables & Themes ===== */
:root {
    /* Dark Theme (Default) */
    --bg-primary: #0a0a1a;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #252540;
    --text-primary: #ffffff;
    --text-secondary: #b8b8d1;
    --text-muted: #6c6c8a;
    --accent-primary: #00f5ff;
    --accent-secondary: #ff00ff;
    --accent-tertiary: #ffff00;
    --border-color: #3a3a5c;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --success-color: #00ff00;
    --warning-color: #ffa500;
    --danger-color: #ff0000;
    
    /* Game Board */
    --board-bg: #0d0d1a;
    --board-grid: #1a1a2e;
    --ghost-opacity: 0.3;
    
    /* Block Colors */
    --block-i: #00f5ff;
    --block-j: #0000ff;
    --block-l: #ffa500;
    --block-o: #ffff00;
    --block-s: #00ff00;
    --block-t: #800080;
    --block-z: #ff0000;
    
    /* Sizing */
    --cell-size: 30px;
    --board-width: 300px;
    --board-height: 600px;
    --header-height: 60px;
    --panel-width: 180px;
    
    /* Animation */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #f0f0f5;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e8e8f0;
    --text-primary: #1a1a2e;
    --text-secondary: #4a4a6a;
    --text-muted: #8a8aa0;
    --border-color: #d0d0e0;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --board-bg: #e0e0ea;
    --board-grid: #d0d0da;
}

/* Retro Theme */
[data-theme="retro"] {
    --bg-primary: #1a1a00;
    --bg-secondary: #2a2a00;
    --bg-tertiary: #3a3a00;
    --text-primary: #00ff00;
    --text-secondary: #00cc00;
    --text-muted: #009900;
    --accent-primary: #00ff00;
    --accent-secondary: #00cc00;
    --border-color: #00aa00;
    --board-bg: #0a0a00;
    --board-grid: #1a1a00;
}

/* Neon Theme */
[data-theme="neon"] {
    --bg-primary: #0a0010;
    --bg-secondary: #150020;
    --bg-tertiary: #200030;
    --text-primary: #ff00ff;
    --text-secondary: #00ffff;
    --accent-primary: #ff00ff;
    --accent-secondary: #00ffff;
    --border-color: #ff00ff;
    --board-bg: #050008;
    --board-grid: #150020;
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    line-height: 1.6;
    overflow-x: hidden;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 { font-size: 1.75rem; }
h2 { font-size: 1.25rem; }
h3 { font-size: 1rem; }

p {
    color: var(--text-secondary);
}

/* ===== Header ===== */
.game-header {
    background: var(--bg-secondary);
    padding: 0.75rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.game-header h1 {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-icon {
    flex-shrink: 0;
}

.main-nav {
    display: flex;
    gap: 0.5rem;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-secondary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.nav-btn:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

.nav-btn:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.nav-btn svg {
    color: var(--accent-primary);
}

/* ===== Main Game Container ===== */
.game-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    gap: 2rem;
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

/* ===== Side Panels ===== */
.left-panel, .right-panel {
    width: var(--panel-width);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.left-panel section, .right-panel section {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 1rem;
    border: 1px solid var(--border-color);
}

.left-panel h2, .right-panel h2 {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

/* ===== Hold Section ===== */
.hold-display {
    background: var(--board-bg);
    border-radius: 8px;
    display: flex;
    justify-content: center;
    align-items: center;
    aspect-ratio: 1;
    border: 1px solid var(--border-color);
}

.hold-display canvas {
    max-width: 100%;
    max-height: 100%;
}

.hold-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: center;
    margin-top: 0.5rem;
}

.hold-hint kbd {
    background: var(--bg-tertiary);
    padding: 0.125rem 0.375rem;
    border-radius: 4px;
    font-family: inherit;
    font-size: 0.75rem;
    border: 1px solid var(--border-color);
}

/* ===== Stats Section ===== */
.stats-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.stat-item dt {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.stat-item dd {
    font-size: 1.25rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--accent-primary);
}

/* ===== Combo Section ===== */
.combo-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 0.25rem;
}

.combo-display #combo {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-secondary);
    text-shadow: 0 0 20px var(--accent-secondary);
}

.combo-label {
    font-size: 1.5rem;
    color: var(--text-muted);
}

/* ===== Game Board Section ===== */
.game-board-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.game-board-wrapper {
    position: relative;
    background: var(--board-bg);
    border-radius: 12px;
    padding: 10px;
    border: 2px solid var(--border-color);
    box-shadow: 
        0 0 30px var(--shadow-color),
        inset 0 0 20px rgba(0, 0, 0, 0.3);
}

#game-board {
    display: block;
    border-radius: 4px;
}

/* ===== Game Overlay ===== */
.game-overlay {
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    bottom: 10px;
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(4px);
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 4px;
    z-index: 10;
}

.game-overlay.hidden {
    display: none;
}

.overlay-content {
    text-align: center;
    padding: 2rem;
}

.overlay-content h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.overlay-content p {
    margin-bottom: 1.5rem;
}

/* ===== Game Controls ===== */
.game-controls {
    display: flex;
    gap: 0.75rem;
}

.control-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    font-size: 1rem;
    font-weight: 500;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.control-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.control-btn:not(:disabled):hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px var(--shadow-color);
}

.primary-btn {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: #000;
}

.primary-btn:not(:disabled):hover {
    box-shadow: 0 4px 20px rgba(0, 245, 255, 0.4);
}

.secondary-btn {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.control-btn:not(.primary-btn) {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

/* ===== Next Pieces Section ===== */
.next-pieces {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.next-pieces canvas {
    background: var(--board-bg);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    width: 100%;
    height: auto;
}

/* ===== Level Progress ===== */
.progress-bar {
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    transition: width var(--transition-normal);
    border-radius: 4px;
}

.progress-text {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: center;
}

/* ===== Controls Hint ===== */
.controls-list {
    list-style: none;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.controls-list li {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    margin-bottom: 0.375rem;
    flex-wrap: wrap;
}

.controls-list kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 1.5rem;
    padding: 0.125rem 0.375rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-family: inherit;
    font-size: 0.7rem;
}

/* ===== Mobile Controls ===== */
.mobile-controls {
    display: none;
    flex-direction: column;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 50;
}

.mobile-controls-row {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
}

.mobile-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 60px;
    height: 60px;
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

.mobile-btn:active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    transform: scale(0.95);
}

.mobile-btn.small {
    width: 80px;
    height: 50px;
    font-size: 0.625rem;
    gap: 0.125rem;
}

.mobile-btn svg {
    color: var(--accent-primary);
}

.mobile-btn:active svg {
    color: #000;
}

.mobile-extra {
    justify-content: center;
    gap: 1rem;
    margin-top: 0.5rem;
}

/* ===== Modals ===== */
.modal {
    border: none;
    border-radius: 16px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 0;
    max-width: 90vw;
    max-height: 85vh;
    box-shadow: 0 20px 60px var(--shadow-color);
}

.modal::backdrop {
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
}

.modal-content {
    display: flex;
    flex-direction: column;
    max-height: 85vh;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.25rem;
}

.modal-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
}

.modal-body article {
    margin-bottom: 1.5rem;
}

.modal-body article:last-child {
    margin-bottom: 0;
}

.modal-body h3 {
    color: var(--accent-primary);
    margin-bottom: 0.75rem;
}

.modal-body ul {
    padding-left: 1.5rem;
    color: var(--text-secondary);
}

.modal-body li {
    margin-bottom: 0.375rem;
}

/* ===== Tetromino Grid (How to Play) ===== */
.tetromino-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    gap: 1rem;
    margin-top: 0.75rem;
}

.tetromino-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border-radius: 8px;
}

.tetromino-item span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* ===== Scoring Table ===== */
.scoring-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.scoring-table th,
.scoring-table td {
    padding: 0.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.scoring-table th {
    color: var(--text-muted);
    font-weight: 500;
}

.scoring-table td:last-child {
    color: var(--accent-primary);
    font-weight: 600;
}

/* ===== Settings ===== */
.setting-group {
    margin-bottom: 1.5rem;
}

.setting-group h3 {
    color: var(--accent-primary);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--bg-tertiary);
}

.setting-item label {
    color: var(--text-secondary);
}

.setting-item select,
.setting-item input[type="range"] {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.5rem 0.75rem;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.setting-item select {
    min-width: 120px;
}

.setting-item input[type="range"] {
    width: 120px;
    cursor: pointer;
}

.setting-item input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--accent-primary);
}

/* ===== Keybindings ===== */
.keybinding-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.keybinding-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
}

.keybinding-item span {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.keybind-btn {
    min-width: 100px;
    padding: 0.5rem 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 0.75rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.keybind-btn:hover {
    border-color: var(--accent-primary);
}

.setting-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

/* ===== High Scores ===== */
.high-scores-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.tab-btn {
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-secondary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.tab-btn.active,
.tab-btn:hover {
    background: var(--accent-primary);
    color: #000;
    border-color: var(--accent-primary);
}

.high-scores-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.high-scores-table th,
.high-scores-table td {
    padding: 0.75rem 0.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.high-scores-table th {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.high-scores-table tbody tr:hover {
    background: var(--bg-tertiary);
}

.no-scores {
    text-align: center;
    color: var(--text-muted);
    padding: 2rem !important;
}

.high-scores-actions {
    display: flex;
    justify-content: flex-end;
    margin-top: 1.5rem;
}

/* ===== Game Over Modal ===== */
.game-over-content {
    text-align: center;
    min-width: 350px;
}

.final-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.final-stat {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: 8px;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-primary);
}

.new-high-score {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem;
    background: linear-gradient(135deg, rgba(255, 215, 0, 0.2), rgba(255, 165, 0, 0.2));
    border-radius: 8px;
    margin-bottom: 1.5rem;
    animation: pulse 1.5s infinite;
}

.new-high-score span {
    font-size: 1.25rem;
    font-weight: 600;
    color: #ffd700;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

.name-input-section {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.name-input-section label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.name-input-section input {
    padding: 0.75rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    text-align: center;
}

.name-input-section input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.game-over-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.hidden {
    display: none !important;
}

/* ===== Footer ===== */
.game-footer {
    text-align: center;
    padding: 1rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    font-size: 0.75rem;
    color: var(--text-muted);
}

.game-footer p {
    margin-bottom: 0.25rem;
}

/* ===== Animations ===== */
@keyframes lineClear {
    0% { 
        background: #fff;
        transform: scaleY(1);
    }
    50% { 
        background: var(--accent-primary);
        transform: scaleY(1.1);
    }
    100% { 
        background: transparent;
        transform: scaleY(0);
    }
}

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .game-container {
        gap: 1rem;
        padding: 1rem;
    }

    .left-panel, .right-panel {
        width: 150px;
    }
}

@media (max-width: 900px) {
    .game-container {
        flex-wrap: wrap;
    }

    .left-panel, .right-panel {
        width: 100%;
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
    }

    .left-panel section, .right-panel section {
        flex: 1;
        min-width: 150px;
        max-width: 200px;
    }

    .controls-hint-section {
        display: none;
    }
}

@media (max-width: 768px) {
    .game-header {
        flex-direction: column;
        gap: 0.75rem;
        padding: 0.5rem 1rem;
    }

    .game-header h1 {
        font-size: 1.25rem;
    }

    .main-nav {
        width: 100%;
        justify-content: center;
    }

    .nav-btn {
        padding: 0.375rem 0.75rem;
        font-size: 0.75rem;
    }

    .nav-btn span {
        display: none;
    }

    .game-container {
        flex-direction: column;
        align-items: center;
        padding-bottom: 200px;
    }

    .left-panel, .right-panel {
        order: 2;
    }

    .game-board-section {
        order: 1;
    }

    .mobile-controls {
        display: flex;
    }

    .game-board-wrapper {
        padding: 5px;
    }

    #game-board {
        width: 250px;
        height: 500px;
    }

    :root {
        --board-width: 250px;
        --board-height: 500px;
        --cell-size: 25px;
    }
}

@media (max-width: 480px) {
    .left-panel section, .right-panel section {
        min-width: 100%;
    }

    .game-controls {
        flex-wrap: wrap;
        justify-content: center;
    }

    .control-btn {
        flex: 1;
        min-width: 100px;
        justify-content: center;
    }

    .modal {
        max-width: 95vw;
        margin: 0.5rem;
    }

    .final-stats {
        grid-template-columns: 1fr;
    }
}

/* ===== Accessibility ===== */
/* ===== Kakao Left Vertical Ad ===== */
.ad-left-wrapper {
    position: fixed;
    left: 0;
    top: calc(var(--header-height) + 16px);
    width: 160px;
    height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    pointer-events: auto;
}
.ad-left-wrapper .kakao_ad_area {
    display: block !important;
    width: 160px !important;
    height: 600px !important;
}

@media (max-width: 1024px) {
    .ad-left-wrapper { display: none !important; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus visible for keyboard navigation */
:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* Screen reader only content */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ===== Print Styles ===== */
@media print {
    .game-header,
    .game-controls,
    .mobile-controls,
    .modal {
        display: none !important;
    }

    body {
        background: #fff;
        color: #000;
    }
}