/* UE5 Animation Deep Dive - Common Styles */
:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: #1a1a25;
    --bg-card-hover: #222230;
    --text-primary: #f0f0f5;
    --text-secondary: #8888a0;
    --text-muted: #555566;
    --accent-cyan: #00d4ff;
    --accent-magenta: #ff006e;
    --accent-gold: #ffd700;
    --accent-green: #00ff88;
    --accent-purple: #8b5cf6;
    --accent-orange: #ff9500;
    --accent-red: #ff4757;
    --accent-blue: #4d7cff;
    --gradient-primary: linear-gradient(135deg, #ff6b35 0%, #f7931e 50%, #ffd700 100%);
    --gradient-subtle: linear-gradient(135deg, rgba(255,107,53,0.1) 0%, rgba(255,215,0,0.1) 100%);
    --border-subtle: rgba(255,255,255,0.06);
    --shadow-glow: 0 0 60px rgba(255,107,53,0.15);
    --radius-sm: 8px; --radius-md: 16px; --radius-lg: 24px; --radius-xl: 32px;
}
[data-theme="light"] {
    --bg-primary: #f8f9fc; --bg-secondary: #ffffff; --bg-card: #ffffff;
    --bg-card-hover: #f0f2f8; --text-primary: #0a0a0f; --text-secondary: #555566;
    --text-muted: #999999; --border-subtle: rgba(0,0,0,0.08);
    --shadow-glow: 0 4px 40px rgba(0,0,0,0.08);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: 'Noto Sans KR', -apple-system, sans-serif; background: var(--bg-primary); color: var(--text-primary); line-height: 1.7; overflow-x: hidden; }
.bg-grid { position: fixed; inset: 0; background-image: linear-gradient(rgba(255,255,255,0.02) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,0.02) 1px, transparent 1px); background-size: 60px 60px; pointer-events: none; z-index: 0; }
.bg-glow { position: fixed; width: 600px; height: 600px; border-radius: 50%; filter: blur(120px); opacity: 0.3; pointer-events: none; z-index: 0; }
.bg-glow-1 { top: -200px; right: -100px; background: #ff6b35; }
.bg-glow-2 { bottom: -200px; left: -100px; background: #ffd700; }
header { position: fixed; top: 0; left: 0; right: 0; z-index: 100; padding: 20px 40px; display: flex; justify-content: space-between; align-items: center; background: linear-gradient(to bottom, var(--bg-primary), transparent); backdrop-filter: blur(20px); }
.logo { font-family: 'Playfair Display', serif; font-size: 1.5rem; font-weight: 900; background: var(--gradient-primary); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; text-decoration: none; }
.nav-controls { display: flex; align-items: center; gap: 16px; }
.nav-btn { padding: 10px 20px; border-radius: var(--radius-sm); border: 1px solid var(--border-subtle); background: var(--bg-card); color: var(--text-secondary); font-size: 0.9rem; cursor: pointer; transition: all 0.3s ease; text-decoration: none; }
.nav-btn:hover { background: var(--bg-card-hover); color: var(--text-primary); }
.theme-toggle { width: 48px; height: 48px; border-radius: 50%; border: 1px solid var(--border-subtle); background: var(--bg-card); color: var(--text-primary); cursor: pointer; display: flex; align-items: center; justify-content: center; font-size: 1.2rem; transition: all 0.3s ease; }
.theme-toggle:hover { transform: rotate(180deg); }
main { position: relative; z-index: 1; max-width: 1200px; margin: 0 auto; padding: 120px 40px 80px; }
.hero { text-align: center; margin-bottom: 80px; animation: fadeInUp 0.8s ease-out; }
@keyframes fadeInUp { from { opacity: 0; transform: translateY(40px); } to { opacity: 1; transform: translateY(0); } }
.hero-badge { display: inline-block; padding: 8px 20px; border-radius: 100px; background: var(--gradient-subtle); border: 1px solid var(--border-subtle); font-size: 0.85rem; color: #ff6b35; font-weight: 500; margin-bottom: 24px; }
.hero h1 { font-family: 'Playfair Display', serif; font-size: clamp(2.5rem, 6vw, 4rem); font-weight: 900; line-height: 1.2; margin-bottom: 24px; }
.hero h1 span { background: var(--gradient-primary); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero p { font-size: 1.2rem; color: var(--text-secondary); max-width: 600px; margin: 0 auto; }
.section { margin-bottom: 80px; animation: fadeInUp 0.8s ease-out; }
.section-header { margin-bottom: 40px; }
.section-number { font-family: 'JetBrains Mono', monospace; font-size: 0.85rem; color: #ff6b35; margin-bottom: 8px; letter-spacing: 2px; }
.section-title { font-size: 1.8rem; font-weight: 700; margin-bottom: 12px; }
.section-desc { color: var(--text-secondary); font-size: 1.05rem; }
.content-box { background: var(--bg-secondary); border-radius: var(--radius-xl); border: 1px solid var(--border-subtle); padding: 48px; position: relative; overflow: hidden; }
.content-box::before { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 4px; background: var(--gradient-primary); }
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 24px; }
.card { background: var(--bg-card); border-radius: var(--radius-lg); border: 1px solid var(--border-subtle); padding: 32px; transition: all 0.4s ease; }
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-glow); }
.info-box { padding: 24px; border-radius: var(--radius-md); margin: 24px 0; }
.info-box.tip { background: rgba(0,255,136,0.1); border: 1px solid rgba(0,255,136,0.3); }
.info-box.warning { background: rgba(255,149,0,0.1); border: 1px solid rgba(255,149,0,0.3); }
.info-box.important { background: rgba(255,0,110,0.1); border: 1px solid rgba(255,0,110,0.3); }
.info-box.note { background: rgba(0,212,255,0.1); border: 1px solid rgba(0,212,255,0.3); }
.info-box-title { font-weight: 600; margin-bottom: 8px; }
.code-block { background: #1e1e2e; border-radius: var(--radius-md); padding: 24px; overflow-x: auto; font-family: 'JetBrains Mono', monospace; font-size: 0.9rem; line-height: 1.6; margin: 24px 0; position: relative; }
.code-block code { color: #cdd6f4; white-space: pre-wrap; display: block; }
.code-label { position: absolute; top: 8px; right: 12px; font-size: 0.75rem; color: var(--text-muted); background: rgba(0,0,0,0.3); padding: 2px 8px; border-radius: 4px; }
.table-container { overflow-x: auto; margin: 24px 0; }
table { width: 100%; border-collapse: collapse; }
th, td { padding: 16px; text-align: left; border-bottom: 1px solid var(--border-subtle); }
th { background: var(--bg-card); font-weight: 600; }
td { color: var(--text-secondary); }
.key-points { background: var(--bg-card); border-radius: var(--radius-lg); padding: 32px; margin: 32px 0; }
.key-points ul { list-style: none; }
.key-points li { padding: 12px 0; padding-left: 28px; position: relative; color: var(--text-secondary); border-bottom: 1px solid var(--border-subtle); }
.key-points li:last-child { border-bottom: none; }
.lecture-nav { display: flex; justify-content: space-between; align-items: center; margin-top: 80px; padding-top: 40px; border-top: 1px solid var(--border-subtle); }
.lecture-nav-btn { display: flex; align-items: center; gap: 12px; padding: 16px 24px; background: var(--bg-card); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); color: var(--text-secondary); text-decoration: none; transition: all 0.3s ease; }
.lecture-nav-btn:hover { background: var(--bg-card-hover); color: var(--text-primary); }
.lecture-nav-btn.next { margin-left: auto; }
footer { text-align: center; padding: 60px 40px; color: var(--text-muted); font-size: 0.9rem; }
.text-cyan { color: var(--accent-cyan); } .text-green { color: var(--accent-green); } .text-purple { color: var(--accent-purple); } .text-orange { color: var(--accent-orange); } .text-red { color: var(--accent-red); }
.stat-comparison { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 20px; margin: 24px 0; }
.stat-item { background: var(--bg-card); padding: 20px; border-radius: var(--radius-md); text-align: center; border: 1px solid var(--border-subtle); }
.stat-value { font-family: 'JetBrains Mono', monospace; font-size: 2rem; font-weight: 700; color: #ff6b35; }
.stat-label { font-size: 0.85rem; color: var(--text-secondary); margin-top: 8px; }
.render-pipeline { background: var(--bg-card); border-radius: var(--radius-lg); padding: 24px; margin: 24px 0; border-left: 4px solid #ff6b35; }
.render-pipeline-title { font-family: 'JetBrains Mono', monospace; font-size: 0.9rem; color: #ff6b35; margin-bottom: 16px; font-weight: 600; }
.pipeline-flow { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; font-family: 'JetBrains Mono', monospace; font-size: 0.85rem; }
.pipeline-step { background: var(--bg-secondary); padding: 8px 16px; border-radius: var(--radius-sm); border: 1px solid var(--border-subtle); }
.pipeline-arrow { color: #ff6b35; }
.architecture-diagram { background: var(--bg-card); border-radius: var(--radius-lg); padding: 32px; margin: 24px 0; font-family: 'JetBrains Mono', monospace; font-size: 0.85rem; line-height: 1.8; overflow-x: auto; }
.diagram-title { font-size: 1rem; font-weight: 600; color: var(--text-primary); margin-bottom: 16px; }
.diagram-content { color: var(--text-secondary); white-space: pre-wrap; }
@media (max-width: 768px) { header { padding: 16px 20px; } main { padding: 100px 20px 60px; } .content-box { padding: 24px; } .hero h1 { font-size: 2rem; } .lecture-nav { flex-direction: column; gap: 16px; } .lecture-nav-btn { width: 100%; justify-content: center; } }