/* 2048 Game - Warm Aesthetic */
:root {
    --bg-primary: #0f0f12;
    --bg-secondary: #1a1a20;
    --bg-board: #252530;
    --bg-cell: #33333f;
    --accent-gold: #edc53f;
    --accent-orange: #f67c5f;
    --accent-red: #f65e3b;
    --accent-pink: #f47c97;
    --accent-purple: #a855f7;
    --text-primary: #f9fafb;
    --text-secondary: #a0a9b8;
    --text-dark: #1a1a20;
    --font-family: 'Plus Jakarta Sans', sans-serif;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition-fast: 100ms ease;
    --transition-base: 150ms ease;
    --tile-size: 100px;
    --gap: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { height: 100%; overflow: hidden; touch-action: none; }
body {
    font-family: var(--font-family);
    background: var(--bg-primary);
    background-image: 
        radial-gradient(circle at 30% 20%, rgba(237, 197, 63, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 70% 80%, rgba(246, 124, 95, 0.03) 0%, transparent 50%);
    color: var(--text-primary);
}

/* Navigation */
.game-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: rgba(15, 15, 18, 0.95);
    backdrop-filter: blur(10px);
    z-index: 100;
    border-bottom: 1px solid rgba(237, 197, 63, 0.1);
}

.back-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-fast);
}
.back-link svg { width: 20px; height: 20px; }
.back-link:hover { color: var(--accent-gold); }

.game-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-gold);
}

.nav-spacer { width: 100px; }

/* Container */
.game-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 5rem 1rem 2rem;
}

.game-wrapper {
    max-width: 500px;
    width: 100%;
}

/* Header */
.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.title-section h1 {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent-gold) 0%, var(--accent-orange) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1;
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.scores {
    display: flex;
    gap: 0.75rem;
}

.score-box {
    background: var(--bg-secondary);
    padding: 0.5rem 1.25rem;
    border-radius: var(--radius-md);
    text-align: center;
    min-width: 80px;
}
.score-box.best { background: linear-gradient(135deg, var(--accent-gold), var(--accent-orange)); }
.score-box.best .score-label,
.score-box.best .score-value { color: var(--text-dark); }

.score-label {
    display: block;
    font-size: 0.7rem;
    text-transform: uppercase;
    color: var(--text-muted);
    font-weight: 600;
    letter-spacing: 0.05em;
}

.score-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    line-height: 1.2;
}

/* Controls */
.game-controls-top {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.control-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-weight: 600;
    font-family: inherit;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-base);
}
.control-btn:hover:not(:disabled) { 
    background: var(--bg-board); 
    color: var(--text-primary);
    border-color: var(--accent-gold);
}
.control-btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-icon { font-size: 1rem; }

/* Game Board */
.game-board-container {
    position: relative;
}

.game-board {
    display: grid;
    grid-template-columns: repeat(4, var(--tile-size));
    grid-template-rows: repeat(4, var(--tile-size));
    gap: var(--gap);
    padding: var(--gap);
    background: var(--bg-board);
    border-radius: var(--radius-lg);
    position: relative;
}

/* Background cells */
.cell {
    background: var(--bg-cell);
    border-radius: var(--radius-sm);
}

/* Tiles */
.tile {
    position: absolute;
    display: flex;
    align-items: center;
    justify-content: center;
    width: var(--tile-size);
    height: var(--tile-size);
    border-radius: var(--radius-sm);
    font-weight: 800;
    font-size: 2rem;
    transition: top var(--transition-base), left var(--transition-base);
    z-index: 10;
}

.tile.new {
    animation: tileAppear 0.2s ease;
}
@keyframes tileAppear {
    0% { transform: scale(0); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.tile.merged {
    animation: tileMerge 0.2s ease;
}
@keyframes tileMerge {
    0% { transform: scale(1); }
    50% { transform: scale(1.15); }
    100% { transform: scale(1); }
}

/* Tile colors */
.tile-2 { background: #e8e4db; color: #776e65; }
.tile-4 { background: #e8e1c9; color: #776e65; }
.tile-8 { background: #f2b179; color: #f9f6f2; }
.tile-16 { background: #f59563; color: #f9f6f2; }
.tile-32 { background: #f67c5f; color: #f9f6f2; }
.tile-64 { background: #f65e3b; color: #f9f6f2; }
.tile-128 { background: #edcf72; color: #f9f6f2; font-size: 1.75rem; box-shadow: 0 0 20px rgba(237, 207, 114, 0.3); }
.tile-256 { background: #edcc61; color: #f9f6f2; font-size: 1.75rem; box-shadow: 0 0 25px rgba(237, 204, 97, 0.4); }
.tile-512 { background: #edc850; color: #f9f6f2; font-size: 1.75rem; box-shadow: 0 0 30px rgba(237, 200, 80, 0.5); }
.tile-1024 { background: #edc53f; color: #f9f6f2; font-size: 1.5rem; box-shadow: 0 0 35px rgba(237, 197, 63, 0.6); }
.tile-2048 { background: linear-gradient(135deg, #edc22e 0%, #f9d423 100%); color: #f9f6f2; font-size: 1.5rem; box-shadow: 0 0 40px rgba(237, 194, 46, 0.7); }
.tile-super { background: linear-gradient(135deg, #a855f7 0%, #f47c97 100%); color: #f9f6f2; font-size: 1.25rem; box-shadow: 0 0 45px rgba(168, 85, 247, 0.5); }

/* Overlays */
.game-overlay {
    position: absolute;
    inset: 0;
    background: rgba(15, 15, 18, 0.9);
    display: none;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-lg);
    z-index: 100;
}
.game-overlay.active { display: flex; }

.overlay-content {
    text-align: center;
    padding: 2rem;
}
.overlay-content h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--accent-orange);
}
.overlay-content p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.win-overlay .overlay-content h2 { color: var(--accent-gold); }
.win-icon { font-size: 4rem; margin-bottom: 1rem; animation: bounce 1s ease infinite; }
@keyframes bounce { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

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

/* Buttons */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--accent-gold) 0%, var(--accent-orange) 100%);
    color: var(--text-dark);
    border: none;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 9999px;
    cursor: pointer;
    transition: var(--transition-base);
    font-family: inherit;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 5px 20px rgba(237, 197, 63, 0.3); }

.btn-secondary {
    padding: 0.875rem 2rem;
    background: transparent;
    border: 2px solid var(--text-muted);
    color: var(--text-secondary);
    border-radius: 9999px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-base);
    font-family: inherit;
}
.btn-secondary:hover { border-color: var(--accent-gold); color: var(--accent-gold); }

/* Instructions */
.instructions {
    margin-top: 1.5rem;
    padding: 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    text-align: center;
}
.instructions p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
}
.instructions strong { color: var(--text-primary); }

/* Responsive */
@media (max-width: 520px) {
    :root {
        --tile-size: 70px;
        --gap: 8px;
    }
    
    .game-nav { padding: 0.75rem 1rem; }
    .game-title { font-size: 1rem; }
    .nav-spacer { display: none; }
    
    .game-container { padding: 4.5rem 0.75rem 1rem; }
    
    .game-header { flex-direction: column; gap: 1rem; text-align: center; }
    .title-section h1 { font-size: 2.5rem; }
    
    .score-box { padding: 0.5rem 1rem; min-width: 70px; }
    .score-value { font-size: 1.25rem; }
    
    .tile { font-size: 1.5rem; }
    .tile-128, .tile-256, .tile-512 { font-size: 1.25rem; }
    .tile-1024, .tile-2048 { font-size: 1rem; }
    .tile-super { font-size: 0.9rem; }
}

@media (max-width: 380px) {
    :root {
        --tile-size: 60px;
        --gap: 6px;
    }
    
    .tile { font-size: 1.25rem; }
    .tile-128, .tile-256, .tile-512 { font-size: 1rem; }
    .tile-1024, .tile-2048, .tile-super { font-size: 0.85rem; }
}