/* Memory Match Game - PostHog Inspired */
:root {
    --bg-primary: #0d0f14;
    --bg-secondary: #151822;
    --bg-tertiary: #1d2130;
    --bg-card: rgba(29, 33, 48, 0.8);
    --accent-primary: #f7a600;
    --accent-secondary: #f54e00;
    --accent-green: #22c55e;
    --accent-red: #ef4444;
    --accent-blue: #3b82f6;
    --accent-purple: #a855f7;
    --text-primary: #f9fafb;
    --text-secondary: #a0a9b8;
    --text-muted: #6b7280;
    --gradient-primary: linear-gradient(135deg, var(--accent-primary) 0%, var(--accent-secondary) 100%);
    --font-family: 'Plus Jakarta Sans', sans-serif;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 32px;
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { height: 100%; overflow-x: hidden; }
body {
    font-family: var(--font-family);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
}

/* 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(13, 15, 20, 0.9);
    backdrop-filter: blur(10px);
    z-index: 100;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.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-primary); }

.game-title {
    font-size: 1.25rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-spacer { width: 100px; }

/* Container */
.game-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 5rem 1.5rem 2rem;
}

/* Screens */
.screen { display: none; width: 100%; max-width: 600px; animation: fadeIn 0.4s ease; }
.screen.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: scale(0.95); } to { opacity: 1; transform: scale(1); } }

.screen-content {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    padding: 2.5rem;
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

/* Intro Screen */
.game-icon { font-size: 4rem; margin-bottom: 1rem; animation: bounce 2s ease-in-out infinite; }
@keyframes bounce { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

.intro-screen h1 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.tagline { color: var(--text-secondary); margin-bottom: 2rem; }

/* Difficulty Selector */
.difficulty-selector, .theme-selector { margin-bottom: 1.5rem; }
.difficulty-selector h3, .theme-selector h3 {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
}

.difficulty-options { display: flex; gap: 0.75rem; justify-content: center; }
.diff-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem 1.5rem;
    background: var(--bg-tertiary);
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-base);
    font-family: inherit;
}
.diff-btn:hover { border-color: var(--accent-primary); }
.diff-btn.active { border-color: var(--accent-primary); background: rgba(247, 166, 0, 0.1); }
.diff-grid { font-size: 1.25rem; font-weight: 700; color: var(--text-primary); }
.diff-label { font-size: 0.8rem; color: var(--accent-primary); font-weight: 600; }
.diff-pairs { font-size: 0.75rem; color: var(--text-muted); }

.theme-options { display: flex; gap: 0.5rem; justify-content: center; flex-wrap: wrap; }
.theme-btn {
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition-base);
    font-family: inherit;
    font-size: 0.9rem;
}
.theme-btn:hover { border-color: var(--accent-primary); }
.theme-btn.active { border-color: var(--accent-primary); background: rgba(247, 166, 0, 0.1); color: var(--text-primary); }

/* Buttons */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    background: var(--gradient-primary);
    color: var(--bg-primary);
    border: none;
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
    font-weight: 700;
    border-radius: 9999px;
    cursor: pointer;
    transition: var(--transition-base);
    font-family: inherit;
}
.btn-primary svg { width: 20px; height: 20px; }
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 10px 40px rgba(247, 166, 0, 0.4); }

.btn-secondary {
    padding: 0.75rem 1.5rem;
    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-primary); color: var(--accent-primary); }

.best-score {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}
.best-score .label { display: block; font-size: 0.85rem; color: var(--text-muted); }
.best-score .value { font-size: 1.5rem; font-weight: 700; color: var(--accent-primary); }

/* Game Screen */
.game-screen { max-width: 800px; }

.game-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 1.5rem;
}
.stat-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--bg-card);
    padding: 1rem 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.05);
}
.stat-icon { font-size: 1.25rem; margin-bottom: 0.25rem; }
.stat-value { font-size: 1.5rem; font-weight: 700; color: var(--accent-primary); }
.stat-label { font-size: 0.75rem; color: var(--text-muted); text-transform: uppercase; }

/* Game Board */
.game-board {
    display: grid;
    gap: 0.75rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.05);
    margin-bottom: 1.5rem;
}

.game-board.size-4 { grid-template-columns: repeat(4, 1fr); }
.game-board.size-6 { grid-template-columns: repeat(6, 1fr); }
.game-board.size-8 { grid-template-columns: repeat(8, 1fr); }

/* Cards */
.card {
    aspect-ratio: 1;
    perspective: 1000px;
    cursor: pointer;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.5s;
    transform-style: preserve-3d;
}

.card.flipped .card-inner { transform: rotateY(180deg); }
.card.matched .card-inner { transform: rotateY(180deg); }

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
}

.card-front {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    box-shadow: 0 4px 15px rgba(247, 166, 0, 0.2);
}
.card-front::after {
    content: '?';
    font-weight: 800;
    color: var(--bg-primary);
    font-size: 1.5rem;
}

.card-back {
    background: var(--bg-tertiary);
    border: 2px solid rgba(255, 255, 255, 0.1);
    transform: rotateY(180deg);
}

.card.matched .card-back {
    border-color: var(--accent-green);
    box-shadow: 0 0 20px rgba(34, 197, 94, 0.3);
}

.card:hover:not(.flipped):not(.matched) .card-inner {
    transform: scale(1.05);
}

/* Game Controls */
.game-controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Victory Screen */
.victory-icon { font-size: 5rem; margin-bottom: 1rem; animation: victoryBounce 0.6s ease; }
@keyframes victoryBounce { 0% { transform: scale(0); } 50% { transform: scale(1.2); } 100% { transform: scale(1); } }

.victory-screen h2 {
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.victory-message { color: var(--text-secondary); margin-bottom: 1.5rem; }

.victory-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    padding: 1.5rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-lg);
    margin-bottom: 1.5rem;
}
.stat-item { text-align: center; }
.stat-item .stat-value { display: block; font-size: 1.75rem; font-weight: 700; color: var(--accent-primary); }
.stat-item .stat-label { font-size: 0.8rem; color: var(--text-muted); text-transform: uppercase; }

.new-record {
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid var(--accent-green);
    color: var(--accent-green);
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    margin-bottom: 1.5rem;
    animation: pulse 2s infinite;
}
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.7; } }

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

/* Responsive */
@media (max-width: 768px) {
    .game-nav { padding: 1rem; }
    .game-title { display: none; }
    .nav-spacer { display: none; }
    .screen-content { padding: 1.5rem; }
    .difficulty-options { flex-direction: column; }
    .diff-btn { flex-direction: row; gap: 1rem; justify-content: center; }
    .game-stats { gap: 1rem; }
    .stat-box { padding: 0.75rem 1rem; }
    .stat-value { font-size: 1.25rem; }
    .game-board { padding: 1rem; gap: 0.5rem; }
    .card-front::after { font-size: 1rem; }
    .card-back { font-size: 1.5rem; }
    .victory-stats { flex-direction: column; gap: 1rem; }
}

@media (max-width: 480px) {
    .game-board.size-6 { grid-template-columns: repeat(4, 1fr); }
    .game-board.size-8 { grid-template-columns: repeat(4, 1fr); }
}