:root {
  --bg-color: #0d1117;
  --card-bg: #161b22;
  --card-border: #30363d;
  --text-main: #e6edf3;
  --text-muted: #8b949e;
  --accent-blue: #58a6ff;
  --accent-cyan: #39c5cf;
  --accent-purple: #bc8cff;
  --accent-green: #3fb950;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { background-color: var(--bg-color); color: var(--text-main); font-family: var(--font-main); line-height: 1.7; -webkit-font-smoothing: antialiased; }
a { color: var(--accent-blue); text-decoration: none; transition: 0.2s; }
a:hover { opacity: 0.8; }

.container { max-width: 1100px; margin: 0 auto; padding: 2rem 1.5rem; }
.site-header { border-bottom: 1px solid var(--card-border); background: rgba(13, 17, 23, 0.9); backdrop-filter: blur(10px); position: sticky; top: 0; z-index: 100; }
.nav-container { max-width: 1100px; margin: 0 auto; padding: 1rem 1.5rem; display: flex; justify-content: space-between; align-items: center; }
.brand-logo { font-size: 1.3rem; font-weight: 700; color: #fff; }
.brand-accent { color: var(--accent-cyan); }
.nav-links { display: flex; align-items: center; gap: 1.5rem; }
.nav-links a { color: var(--text-muted); font-size: 0.95rem; }
.nav-links a:hover { color: #fff; }

.btn { display: inline-block; padding: 0.75rem 1.5rem; border-radius: 8px; font-weight: 600; font-size: 0.95rem; cursor: pointer; transition: 0.2s; }
.btn-primary { background: var(--accent-cyan); color: #0d1117; }
.btn-secondary { background: var(--card-bg); border: 1px solid var(--card-border); color: var(--text-main); }
.btn:hover { transform: translateY(-2px); opacity: 0.95; }
.btn-nav { padding: 0.4rem 0.8rem; border-radius: 6px; background: var(--card-bg); border: 1px solid var(--card-border); color: var(--accent-cyan) !important; }

.badge { display: inline-block; padding: 0.3rem 0.8rem; border-radius: 20px; font-size: 0.8rem; font-weight: 600; background: rgba(57, 197, 207, 0.15); color: var(--accent-cyan); margin-bottom: 1rem; border: 1px solid rgba(57, 197, 207, 0.3); }
.hero-section, .article-hero { padding: 5rem 0 3rem; text-align: center; }
.hero-title { font-size: 2.5rem; font-weight: 800; line-height: 1.3; margin-bottom: 1.5rem; letter-spacing: -0.5px; }
.text-gradient { background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.hero-desc { font-size: 1.15rem; color: var(--text-muted); max-width: 800px; margin: 0 auto 2rem; }
.hero-cta { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

.section-title { font-size: 1.8rem; font-weight: 700; text-align: center; margin-bottom: 2.5rem; }
.section-subtitle { text-align: center; color: var(--text-muted); margin-top: -1.8rem; margin-bottom: 2.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1.5rem; }
.card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; padding: 2rem; display: flex; flex-direction: column; gap: 1rem; }
.card-icon { font-size: 2rem; }
.card-link { margin-top: auto; font-weight: 600; color: var(--accent-cyan); }

.timeline-table-wrapper { overflow-x: auto; border: 1px solid var(--card-border); border-radius: 12px; background: var(--card-bg); }
.timeline-table { width: 100%; border-collapse: collapse; text-align: left; font-size: 0.95rem; }
.timeline-table th, .timeline-table td { padding: 1.2rem; border-bottom: 1px solid var(--card-border); }
.timeline-table th { background: rgba(255, 255, 255, 0.03); color: var(--text-muted); font-weight: 600; }
.grade-cell { white-space: nowrap; }
.age-label { font-size: 0.8rem; color: var(--text-muted); font-weight: normal; }
.highlight-row { background: rgba(57, 197, 207, 0.04); }

.article-container { max-width: 850px; }
.article-card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; padding: 2.5rem; margin-bottom: 2rem; }
.article-card h2 { font-size: 1.4rem; margin-bottom: 1.2rem; color: var(--accent-blue); }
.step-box { display: flex; gap: 1.5rem; padding: 1.2rem 0; border-bottom: 1px solid var(--card-border); }
.step-box:last-child { border-bottom: none; }
.step-num { font-weight: 700; color: var(--accent-cyan); white-space: nowrap; }
.highlight-card { border-color: rgba(57, 197, 207, 0.4); background: rgba(57, 197, 207, 0.03); }
.styled-list { padding-left: 1.5rem; margin-top: 1rem; display: flex; flex-direction: column; gap: 0.8rem; }

.roadmap-cards-wrapper { display: flex; flex-direction: column; gap: 1.5rem; }
.roadmap-card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; padding: 1.8rem; }
.roadmap-card-highlight { border-color: var(--accent-cyan); box-shadow: 0 0 20px rgba(57, 197, 207, 0.1); }
.roadmap-card-header { display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid var(--card-border); padding-bottom: 0.8rem; margin-bottom: 1.2rem; }
.roadmap-grade { font-size: 1.3rem; font-weight: 700; color: var(--accent-cyan); }
.roadmap-card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1.5rem; }
.roadmap-track h4 { font-size: 0.95rem; margin-bottom: 0.5rem; color: var(--text-muted); }

.text-center { text-align: center; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

.site-footer { border-top: 1px solid var(--card-border); margin-top: 5rem; padding: 3rem 0; color: var(--text-muted); font-size: 0.875rem; text-align: center; }
.footer-container { display: flex; flex-direction: column; gap: 1.2rem; align-items: center; }
.footer-links { display: flex; gap: 1.5rem; }