/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-bg: #ffffff;
  --color-surface: #f8fafc;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-primary: #6366f1;
  --color-primary-light: #eef2ff;
  --color-primary-dark: #4f46e5;
  --color-code-bg: #1e1e2e;
  --color-code-text: #cdd6f4;
  --color-code-header: #313244;
  --sidebar-width: 260px;
  --topbar-height: 60px;
  --content-max: 820px;
  --radius: 10px;
  --radius-sm: 6px;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--topbar-height) + 24px);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

code {
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.88em;
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
  padding: 2px 6px;
  border-radius: 4px;
}

/* ===== Top bar ===== */
.top-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-height);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
}

.top-bar-inner {
  max-width: 1280px;
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--color-text);
}

.logo-icon {
  width: 28px;
  height: 28px;
}

.logo-text {
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -0.02em;
}

.top-nav {
  display: flex;
  gap: 8px;
}

.top-nav-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 6px 14px;
  border-radius: 6px;
  transition: color 0.15s, background 0.15s;
  text-decoration: none;
}
.top-nav-link:hover {
  color: var(--color-text);
  background: var(--color-surface);
  text-decoration: none;
}
.top-nav-link.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
}

/* ===== Page layout ===== */
.page-layout {
  display: flex;
  max-width: 1280px;
  margin: 0 auto;
  padding-top: var(--topbar-height);
  min-height: 100vh;
}

/* ===== Sidebar ===== */
.sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  border-right: 1px solid var(--color-border);
  position: sticky;
  top: var(--topbar-height);
  height: calc(100vh - var(--topbar-height));
  overflow-y: auto;
}

.sidebar-inner {
  padding: 32px 24px;
}

.sidebar-heading {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

.toc,
.toc-sub {
  list-style: none;
}

.toc > li {
  margin-bottom: 4px;
}

.toc-link {
  display: block;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  transition: color 0.15s, background 0.15s;
  text-decoration: none;
}
.toc-link:hover,
.toc-link.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
  text-decoration: none;
}

.toc-sub {
  margin-left: 12px;
  border-left: 2px solid var(--color-border);
  padding-left: 0;
  margin-top: 2px;
}

.toc-sub .toc-link {
  font-size: 13px;
  font-weight: 400;
}

/* ===== Content ===== */
.content {
  flex: 1;
  min-width: 0;
  padding: 48px 56px 80px;
  max-width: calc(var(--content-max) + 112px);
}

.content h2 {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-top: 56px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--color-border);
}

.content h3 {
  font-size: 18px;
  font-weight: 600;
  margin-top: 36px;
  margin-bottom: 12px;
}

.content p {
  margin-bottom: 16px;
  color: var(--color-text);
}

.content ul {
  margin-bottom: 16px;
  padding-left: 24px;
}
.content li {
  margin-bottom: 6px;
}

/* ===== Hero ===== */
.hero {
  margin-bottom: 8px;
}

.badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-primary);
  background: var(--color-primary-light);
  padding: 4px 12px;
  border-radius: 100px;
  margin-bottom: 16px;
}

.hero h1 {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 20px;
}

.hero-sub {
  font-size: 16.5px;
  color: var(--color-text-muted);
  line-height: 1.7;
  max-width: 680px;
}

/* ===== Feature grid ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 20px;
  margin-bottom: 8px;
}

.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  transition: box-shadow 0.2s, border-color 0.2s;
}
.feature-card:hover {
  border-color: var(--color-primary);
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.08);
}

.feature-icon {
  width: 40px;
  height: 40px;
  background: var(--color-primary-light);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
  color: var(--color-primary);
}
.feature-icon svg {
  width: 20px;
  height: 20px;
}

.feature-card h3 {
  font-size: 15px;
  font-weight: 600;
  margin: 0 0 8px 0;
}

.feature-card p {
  font-size: 13.5px;
  color: var(--color-text-muted);
  margin: 0;
  line-height: 1.6;
}

/* ===== Tabs ===== */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: 0;
  margin-top: 20px;
}

.tab {
  background: none;
  border: none;
  font-family: inherit;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 10px 16px;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: color 0.15s, border-color 0.15s;
  white-space: nowrap;
}
.tab:hover {
  color: var(--color-text);
}
.tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.tab-panel {
  display: none;
  padding: 20px 0 0;
}
.tab-panel.active {
  display: block;
}

/* ===== Code blocks ===== */
.code-block {
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 20px;
  border: 1px solid #2a2a3c;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--color-code-header);
  padding: 8px 16px;
  font-size: 12px;
  font-weight: 500;
  color: #a6adc8;
}

.copy-btn {
  background: none;
  border: 1px solid #45475a;
  color: #a6adc8;
  font-family: inherit;
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
.copy-btn:hover {
  background: #45475a;
  color: #cdd6f4;
}

.code-block pre {
  background: var(--color-code-bg);
  margin: 0;
  padding: 18px 20px;
  overflow-x: auto;
}

.code-block code {
  background: none;
  color: var(--color-code-text);
  font-size: 13px;
  padding: 0;
  border-radius: 0;
  line-height: 1.65;
}

/* ===== Tool table ===== */
.tool-table-wrap {
  overflow-x: auto;
  margin: 20px 0;
}

.tool-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.tool-table th,
.tool-table td {
  text-align: left;
  padding: 12px 16px;
  border-bottom: 1px solid var(--color-border);
}

.tool-table thead th {
  background: var(--color-surface);
  font-weight: 600;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-muted);
}

.tool-table tbody td:first-child code {
  font-weight: 600;
}

/* ===== Callout ===== */
.callout {
  display: flex;
  gap: 12px;
  background: var(--color-primary-light);
  border: 1px solid #c7d2fe;
  border-radius: var(--radius);
  padding: 16px 20px;
  margin: 16px 0 8px;
  font-size: 13.5px;
  line-height: 1.6;
}

.callout-icon {
  flex-shrink: 0;
  color: var(--color-primary);
  width: 20px;
  height: 20px;
  margin-top: 1px;
}
.callout-icon svg {
  width: 20px;
  height: 20px;
}

.callout code {
  font-size: 12px;
}

/* ===== Prompt grid ===== */
.prompt-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-top: 20px;
}

.prompt-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px 22px;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.prompt-card:hover {
  border-color: var(--color-primary);
  box-shadow: 0 2px 12px rgba(99, 102, 241, 0.06);
}

.prompt-icon {
  font-size: 22px;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 1px;
}

.prompt-card p {
  margin: 0;
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.55;
}

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
}

.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 48px 32px 32px;
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h4 {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin-bottom: 14px;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  font-size: 14px;
  color: var(--color-text-muted);
  transition: color 0.15s;
  text-decoration: none;
}
.footer-col a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 20px;
  text-align: center;
}

.footer-bottom p {
  font-size: 13px;
  color: var(--color-text-muted);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .feature-grid,
  .prompt-grid {
    grid-template-columns: 1fr;
  }

  .footer-cols {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .sidebar {
    display: none;
  }

  .content {
    padding: 32px 20px 60px;
  }

  .top-bar-inner {
    padding: 0 16px;
  }

  .hero h1 {
    font-size: 26px;
  }

  .tabs {
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
  }

  .footer-cols {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }
}

@media (max-width: 480px) {
  .footer-cols {
    grid-template-columns: 1fr;
  }
}