:root,
.theme-auto,
.theme-light {
  --bg: #ffffff;
  --bg-secondary: #f5f6fa;
  --text: #1a1a2e;
  --text-secondary: #6b7280;
  --accent: #3C5DFF;
  --accent-hover: #2b4aee;
  --border: #e5e7eb;
  --code-bg: #f3f4f6;
  --nav-bg: #ffffff;
  --max-width: 960px;
}

@media (prefers-color-scheme: dark) {
  :root,
  .theme-auto {
    --bg: #0f172a;
    --bg-secondary: #1e293b;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --accent: #6b8aff;
    --accent-hover: #8da4ff;
    --border: #334155;
    --code-bg: #1e293b;
    --nav-bg: #0f172a;
  }
}

.theme-dark {
  --bg: #0f172a;
  --bg-secondary: #1e293b;
  --text: #e2e8f0;
  --text-secondary: #94a3b8;
  --accent: #6b8aff;
  --accent-hover: #8da4ff;
  --border: #334155;
  --code-bg: #1e293b;
  --nav-bg: #0f172a;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}

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

/* Nav */
nav {
  background: var(--nav-bg);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  height: 56px;
  gap: 24px;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 18px;
  color: var(--text) !important;
  text-decoration: none !important;
}
.dolphin-logo {
  flex-shrink: 0;
  display: block;
}
.nav-links { display: flex; gap: 16px; margin-left: auto; align-items: center; }
.nav-links a {
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
}
.nav-links a:hover { color: var(--text); text-decoration: none; }
.nav-links .active { color: var(--accent); font-weight: 600; }
.lang-switch {
  display: flex;
  gap: 4px;
  font-size: 13px;
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
}
.lang-switch a { color: var(--text-secondary); }
.lang-switch a.active { color: var(--accent); font-weight: 600; }
.lang-switch span { color: var(--border); }

/* Theme toggle */
.theme-toggle {
  display: flex;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
}
.theme-btn {
  cursor: pointer;
  background: none;
  border: none;
  padding: 3px 6px;
  border-radius: 4px;
  color: var(--text-secondary);
  font-size: 13px;
  font-family: inherit;
  line-height: 1;
}
.theme-btn:hover { color: var(--text); }
.theme-btn.active {
  background: var(--accent);
  color: #fff;
}

/* Main */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px;
}

/* Headings */
h1 { font-size: 2em; margin-bottom: 16px; font-weight: 700; }
h2 { font-size: 1.5em; margin-top: 32px; margin-bottom: 12px; font-weight: 600; padding-bottom: 6px; border-bottom: 1px solid var(--border); }
h3 { font-size: 1.2em; margin-top: 24px; margin-bottom: 8px; font-weight: 600; }
h4 { font-size: 1.05em; margin-top: 20px; margin-bottom: 6px; font-weight: 600; }
p, ul, ol { margin-bottom: 16px; }
ul, ol { padding-left: 24px; }
li { margin-bottom: 4px; }

/* Code */
code {
  font-family: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", monospace;
  font-size: 0.9em;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
}
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  margin-bottom: 20px;
  overflow-x: auto;
  font-size: 0.85em;
  line-height: 1.5;
}
pre code { background: none; padding: 0; border-radius: 0; }

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
  font-size: 0.9em;
}
th, td {
  border: 1px solid var(--border);
  padding: 10px 12px;
  text-align: left;
}
th {
  background: var(--bg-secondary);
  font-weight: 600;
}

/* Blockquote */
blockquote {
  border-left: 4px solid var(--accent);
  padding: 12px 16px;
  margin-bottom: 20px;
  background: var(--bg-secondary);
  border-radius: 0 8px 8px 0;
}
blockquote p:last-child { margin-bottom: 0; }

/* Hero on homepage */
.hero { text-align: center; padding: 60px 0 40px; }
.hero-logo { margin-bottom: 16px; display: block; margin-left: auto; margin-right: auto; }
.hero h1 { font-size: 2.8em; margin-bottom: 16px; }
.hero p { font-size: 1.2em; color: var(--text-secondary); max-width: 640px; margin: 0 auto 32px; }
.hero-links { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.hero-links a {
  display: inline-block;
  padding: 10px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 15px;
}
.btn-primary {
  background: var(--accent);
  color: #fff !important;
  box-shadow: 0 2px 8px rgba(60, 93, 255, 0.25);
}
.btn-primary:hover { background: var(--accent-hover); text-decoration: none !important; box-shadow: 0 4px 12px rgba(60, 93, 255, 0.35); transform: translateY(-1px); }
.btn-secondary {
  border: 1px solid var(--border);
  color: var(--text) !important;
}
.btn-secondary:hover { background: var(--bg-secondary); text-decoration: none !important; }

/* Feature grid */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin: 40px 0;
}
.feature-card {
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  transition: all 0.2s;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.feature-card:hover { border-color: var(--accent); box-shadow: 0 4px 12px rgba(60, 93, 255, 0.1); }
.feature-card h3 { margin-top: 0; border: none; }
.feature-card p { color: var(--text-secondary); font-size: 0.95em; margin-bottom: 0; }

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 24px;
  text-align: center;
  font-size: 13px;
  color: var(--text-secondary);
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
.footer-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

/* Section on doc pages */
.doc-section { margin-bottom: 48px; }

/* Table of contents inline (optional) */
.toc {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 24px;
  margin-bottom: 24px;
}
.toc p { font-weight: 600; margin-bottom: 8px; }
.toc ul { margin-bottom: 0; }
.toc li { font-size: 0.9em; }

/* Responsive */
@media (max-width: 640px) {
  main { padding: 24px 16px; }
  .hero h1 { font-size: 2em; }
  .hero p { font-size: 1em; }
  nav { padding: 0 16px; }
  .nav-inner { gap: 12px; }
  .nav-links { gap: 10px; }
}

/* Doc post-nav */
.post-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}
.post-nav a { font-size: 14px; }

/* Tip/callout */
.callout {
  padding: 12px 16px;
  border-radius: 8px;
  margin-bottom: 20px;
  font-size: 0.9em;
  border: 1px solid var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, var(--bg));
}

/* Doc layout */
.doc-layout {
  display: flex;
  gap: 32px;
  align-items: flex-start;
}
.doc-content {
  flex: 1;
  min-width: 0;
  max-width: 720px;
}
.doc-description {
  font-size: 1.1em;
  color: var(--text-secondary);
  margin-bottom: 32px;
}
/* On-page TOC */
.doc-toc {
  flex: 0 0 200px;
  position: sticky;
  top: 80px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  font-size: 13px;
}
.doc-toc-inner {
  border-right: 2px solid var(--border);
  padding-right: 12px;
}
.toc-label {
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.doc-toc nav ul { list-style: none; padding: 0; margin: 0; }
.doc-toc nav li { margin-bottom: 4px; }
.doc-toc nav a {
  color: var(--text-secondary);
  text-decoration: none;
  display: block;
  padding: 3px 0;
  transition: color 0.15s;
}
.doc-toc nav a:hover { color: var(--text); text-decoration: none; }
.doc-toc nav ul ul { padding-left: 12px; }
.doc-toc nav ul ul a { font-size: 12px; }
/* Responsive */
@media (max-width: 1200px) {
  main { max-width: 100vw; padding: 24px 16px; }
  .doc-toc { display: none; }
  .doc-content { max-width: 100%; }
}

/* Subsection grid on index pages */
.section-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin: 24px 0;
}
.section-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
}
.section-card h3 { margin-top: 0; border: none; font-size: 1em; }
.section-card p { font-size: 0.9em; color: var(--text-secondary); margin-bottom: 0; }