:root {
  --bg: #0b0f14;
  --bg-elevated: #121820;
  --bg-card: #161d27;
  --border: #243044;
  --text: #e8edf5;
  --text-muted: #8b9bb4;
  --accent: #f59e0b;
  --accent-dim: #d97706;
  --cyan: #22d3ee;
  --green: #34d399;
  --font-sans: "DM Sans", "Noto Sans TC", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", monospace;
  --radius: 12px;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.45);
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(245, 158, 11, 0.12), transparent),
    radial-gradient(ellipse 60% 40% at 100% 50%, rgba(34, 211, 238, 0.06), transparent),
    linear-gradient(180deg, var(--bg) 0%, #0d1218 100%);
  pointer-events: none;
  z-index: -1;
}

a {
  color: var(--cyan);
  text-decoration: none;
  transition: opacity 0.2s;
}

a:hover {
  opacity: 0.85;
}

.container {
  width: min(1120px, 92vw);
  margin: 0 auto;
}

/* Nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  background: rgba(11, 15, 20, 0.82);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--accent), var(--accent-dim));
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-size: 1rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
}

.nav-links a:hover {
  color: var(--text);
  opacity: 1;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.85rem;
  font-family: inherit;
  transition: border-color 0.2s, color 0.2s;
}

.lang-btn:hover,
.lang-btn.active {
  border-color: var(--accent);
  color: var(--accent);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.9rem;
  border: none;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-dim));
  color: #0b0f14;
  box-shadow: 0 8px 24px rgba(245, 158, 11, 0.25);
}

.btn-ghost {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}

.btn-ghost:hover {
  border-color: var(--text-muted);
}

/* Hero */
.hero {
  padding: 96px 0 80px;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 999px;
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.25);
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 28px;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 24px;
}

.hero h1 span {
  background: linear-gradient(135deg, var(--accent) 0%, #fbbf24 50%, var(--cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 36px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
  margin-bottom: 64px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: 720px;
  margin: 0 auto;
}

.stat {
  padding: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.stat-num {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 6px;
}

.stat-label {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Sections */
section {
  padding: 80px 0;
}

.section-label {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-desc {
  color: var(--text-muted);
  max-width: 600px;
  margin-bottom: 48px;
}

/* Features */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.feature-card {
  padding: 28px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.2s, transform 0.2s;
}

.feature-card:hover {
  border-color: rgba(245, 158, 11, 0.35);
  transform: translateY(-2px);
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: rgba(245, 158, 11, 0.12);
  display: grid;
  place-items: center;
  font-size: 1.3rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Pipeline */
.pipeline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.pipeline-step {
  padding: 14px 20px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 0.88rem;
  font-weight: 600;
  text-align: center;
  min-width: 140px;
}

.pipeline-arrow {
  color: var(--accent);
  font-size: 1.2rem;
  flex-shrink: 0;
}

/* Models */
.models-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 12px;
}

.model-chip {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 0.88rem;
}

.model-chip span:first-child {
  font-weight: 600;
}

.model-chip code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--cyan);
  background: rgba(34, 211, 238, 0.08);
  padding: 2px 8px;
  border-radius: 6px;
}

/* Code blocks */
.code-block {
  background: #080b10;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 24px;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--text-muted);
}

.code-block pre {
  padding: 20px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.7;
  color: #c9d4e8;
}

.code-block .comment { color: #6b7a94; }
.code-block .cmd { color: var(--green); }
.code-block .flag { color: var(--cyan); }

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
}

/* Metrics */
.metrics-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.metric-tag {
  padding: 10px 18px;
  background: rgba(52, 211, 153, 0.1);
  border: 1px solid rgba(52, 211, 153, 0.25);
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--green);
}

/* Structure tree */
.tree-block {
  background: #080b10;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.8;
  color: var(--text-muted);
  overflow-x: auto;
  white-space: pre;
  margin: 0;
}

.tree-block .dir { color: var(--accent); }
.tree-block .file { color: var(--text); }
.tree-block .comment { color: #6b7a94; }

/* Footer */
.footer {
  padding: 48px 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 16px;
}

.footer-links a {
  color: var(--text-muted);
}

.footer-links a:hover {
  color: var(--text);
  opacity: 1;
}

/* Responsive */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .two-col { grid-template-columns: 1fr; }
  .pipeline { flex-direction: column; }
  .pipeline-arrow { transform: rotate(90deg); }
}

[data-lang="zh"] .lang-en { display: none !important; }
[data-lang="en"] .lang-zh { display: none !important; }