/* =========================================================================
   Deep Agent Landing Page — 干净的专业工具风
   Colors: 主站统一的蓝色系
   ========================================================================= */

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

:root {
  --bg: #0C0F1A;
  --bg-card: #131726;
  --bg-card-hover: #1A1F32;
  --border: #1E2338;
  --border-hover: #2A3050;
  --text: #E4E8F0;
  --text-dim: #8892A8;
  --text-muted: #546074;
  --accent: #3B82F6;
  --accent-dim: #2563EB;
  --accent-light: #60A5FA;
  --green: #22C55E;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
  --radius: 10px;
  --radius-sm: 6px;
  --container: 1080px;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

a { color: var(--accent-light); text-decoration: none; }
a:hover { color: #fff; }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

.accent { color: var(--accent-light); }

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(12, 15, 26, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-back {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: var(--text-dim);
  font-weight: 500;
}

.nav-back:hover { color: var(--accent-light); }

.nav-links { display: flex; gap: 24px; }
.nav-links a { font-size: 14px; color: var(--text-dim); font-weight: 500; }
.nav-links a:hover { color: #fff; }

/* --- Hero --- */
.hero {
  padding: 120px 0 64px;
  text-align: center;
  border-bottom: 1px solid var(--border);
}

.hero-badge {
  display: inline-block;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 100px;
  font-size: 12px;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: #fff;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-dim);
  max-width: 560px;
  margin: 0 auto 32px;
}

/* --- Install Widget --- */
.hero-install {
  margin-bottom: 28px;
}

.install-widget {
  display: inline-flex;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.install-body {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  font-family: var(--font-mono);
  font-size: 13px;
}

.install-prompt {
  color: var(--text-muted);
  font-weight: 600;
  flex-shrink: 0;
}

.install-body code {
  color: var(--text);
  white-space: nowrap;
}

.install-body .copy-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-dim);
  cursor: pointer;
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 12px;
  transition: color 0.15s, border-color 0.15s;
}

.install-body .copy-btn:hover {
  color: var(--accent-light);
  border-color: var(--accent);
}

.install-note {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: 10px;
}

/* --- Hero Links --- */
.hero-links {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-dim); color: #fff; }

.btn-secondary {
  background: transparent;
  color: var(--text-dim);
  border-color: var(--border);
}
.btn-secondary:hover { border-color: var(--border-hover); color: #fff; }

/* --- Section --- */
.section {
  padding: 80px 0;
  border-top: 1px solid var(--border);
}

.section-title {
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.02em;
  text-align: center;
  margin-bottom: 12px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-dim);
  text-align: center;
  max-width: 520px;
  margin: 0 auto 48px;
  line-height: 1.7;
}

/* --- Use Cases --- */
.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.use-case-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
}

.use-case-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.use-case-icon {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent-light);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(59, 130, 246, 0.2);
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.use-case-header h3 {
  font-size: 17px;
  font-weight: 700;
  color: #fff;
}

.use-case-card > p {
  font-size: 14px;
  color: var(--text-muted);
  font-style: italic;
  margin-bottom: 16px;
  padding: 10px 14px;
  background: rgba(0,0,0,0.2);
  border-radius: var(--radius-sm);
  border-left: 2px solid var(--border);
}

.use-case-results {
  list-style: none;
}

.use-case-results li {
  font-size: 13px;
  color: var(--text-dim);
  padding: 4px 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.check { color: var(--green); font-weight: 700; flex-shrink: 0; }

/* --- Features Section --- */
.section-features {
  background: linear-gradient(180deg, rgba(59, 130, 246, 0.02) 0%, transparent 100%);
}

.features-compare {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.compare-card { flex: 1; min-width: 200px; max-width: 280px; }

.compare-side {
  padding: 20px 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.compare-bad { background: rgba(255,255,255,0.02); border-color: rgba(255,255,255,0.06); }
.compare-good { background: rgba(59,130,246,0.06); border-color: rgba(59,130,246,0.2); }

.compare-title {
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.compare-good .compare-title { color: var(--accent-light); }

.compare-side ul { list-style: none; }
.compare-side li {
  font-size: 13px;
  color: var(--text-dim);
  padding: 5px 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.compare-bad li::before { content: "✗"; color: #EF4444; font-size: 12px; font-weight: 700; flex-shrink: 0; }
.compare-good li::before { content: "✓"; color: var(--green); font-size: 12px; font-weight: 700; flex-shrink: 0; }

.compare-vs {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  flex-shrink: 0;
  font-size: 13px;
  font-weight: 700;
  color: var(--text-muted);
}

/* --- Features Grid --- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  transition: border-color 0.2s;
}

.feature-card:hover { border-color: var(--border-hover); }

.feature-card h3 {
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.65;
}

/* --- Install Section --- */
.install-steps {
  max-width: 600px;
  margin: 0 auto;
  display: grid;
  gap: 20px;
}

.install-step {
  display: flex;
  gap: 16px;
}

.step-num {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 50%;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent-light);
  margin-top: 2px;
}

.step-content { flex: 1; }
.step-content h4 {
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 10px;
}

.step-code {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 13px;
}

.step-code code {
  flex: 1;
  color: var(--text);
  overflow-x: auto;
  white-space: nowrap;
}

.step-code .copy-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-dim);
  cursor: pointer;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 11px;
  transition: color 0.15s, border-color 0.15s;
}

.step-code .copy-btn:hover {
  color: var(--accent-light);
  border-color: var(--accent);
}

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--border);
  padding: 48px 0 32px;
}

.footer-grid {
  display: flex;
  gap: 60px;
  justify-content: center;
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.footer-col h4 {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-col a { font-size: 14px; color: var(--text-dim); }
.footer-col a:hover { color: #fff; }

.footer-copy {
  text-align: center;
  font-size: 13px;
  color: var(--text-muted);
}

/* --- Selection --- */
::selection {
  background: rgba(59, 130, 246, 0.25);
  color: #fff;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .container { padding: 0 16px; }
  .section { padding: 50px 0; }
  .section-title { font-size: 22px; }
  .section-desc { font-size: 14px; margin-bottom: 32px; }

  .hero { padding: 90px 0 48px; }
  .hero-title { font-size: 26px; }
  .hero-subtitle { font-size: 14px; }

  .install-body { font-size: 11px; padding: 10px 12px; flex-wrap: wrap; }
  .install-body code { font-size: 11px; overflow: hidden; text-overflow: ellipsis; }
  .hero-links { flex-direction: column; align-items: stretch; }
  .hero-links .btn { justify-content: center; }

  .use-cases-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }
  .features-compare { flex-direction: column; }
  .compare-card { max-width: 100%; width: 100%; }

  .step-code { font-size: 11px; flex-wrap: wrap; }
  .step-code code { font-size: 11px; }

  .footer-grid { gap: 32px; flex-direction: column; align-items: center; text-align: center; }
}