@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --bg: #fafafa;
  --bg-card: #fff;
  --text: #171717;
  --text-muted: #525252;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --border: #e5e5e5;
  --code-bg: #f4f4f5;
  --sidebar-bg: #fff;
  --header-bg: #fff;
  --header-border: #e5e5e5;
  --hero-bg: linear-gradient(135deg, #eff6ff 0%, #f0fdf4 50%, #fefce8 100%);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0a0a;
    --bg-card: #171717;
    --text: #fafafa;
    --text-muted: #a3a3a3;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --border: #262626;
    --code-bg: #262626;
    --sidebar-bg: #0f0f0f;
    --header-bg: #0a0a0a;
    --header-border: #262626;
    --hero-bg: linear-gradient(135deg, #1e3a5f 0%, #14532d 50%, #422006 100%);
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

/* ========== HEADER ========== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--header-bg);
  border-bottom: 1px solid var(--header-border);
  padding: 0 1.5rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.header-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.header-logo:hover {
  color: var(--accent);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.header-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  transition: color 0.15s, background 0.15s;
}

.header-nav a:hover {
  color: var(--accent);
  background: var(--code-bg);
}

.header-nav a.header-link-active {
  color: var(--accent);
  background: var(--code-bg);
}

.header-github {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background: var(--text);
  color: var(--bg) !important;
  border-radius: 8px;
  font-weight: 500;
  font-size: 0.9rem;
}

.header-github:hover {
  background: var(--text-muted) !important;
  color: var(--bg) !important;
}

.header-author {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
  padding-left: 1rem;
  border-left: 1px solid var(--border);
}

.header-author a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  color: var(--text-muted);
  border-radius: 8px;
  transition: color 0.15s, background 0.15s;
}

.header-author a:hover {
  color: var(--accent);
  background: var(--code-bg);
}

.header-author svg {
  width: 20px;
  height: 20px;
}

/* ========== LAYOUT ========== */
.layout {
  display: flex;
  min-height: calc(100vh - 60px);
}

/* ========== SIDEBAR ========== */
.sidebar {
  width: 260px;
  min-width: 260px;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  padding: 1.5rem 0;
  position: sticky;
  top: 60px;
  height: calc(100vh - 60px);
  overflow-y: auto;
}

.sidebar .logo {
  padding: 0 1.25rem 1rem;
  margin-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.sidebar .logo a {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.sidebar .logo a:hover {
  color: var(--accent);
}

.sidebar .nav-section {
  margin: 1rem 0;
}

.sidebar .nav-section-title {
  padding: 0.25rem 1.25rem;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.sidebar a {
  color: var(--text-muted);
  text-decoration: none;
  display: block;
  padding: 0.5rem 1.25rem;
  font-size: 0.9rem;
  border-radius: 0 8px 8px 0;
  border-left: 3px solid transparent;
  margin-left: 0.5rem;
  transition: color 0.15s, background 0.15s;
}

.sidebar a:hover {
  color: var(--text);
  background: var(--code-bg);
}

.sidebar a.active {
  color: var(--accent);
  font-weight: 500;
  border-left-color: var(--accent);
  background: var(--code-bg);
}

.sidebar .toc {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.sidebar .toc-title {
  padding: 0 1.25rem 0.5rem;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.sidebar .toc a {
  padding: 0.35rem 1.25rem 0.35rem 2rem;
  font-size: 0.85rem;
  margin-left: 0.5rem;
  border-left: none;
}

/* ========== MAIN CONTENT ========== */
.main {
  flex: 1;
  padding: 2.5rem 3rem 4rem;
  max-width: 720px;
}

.main h1 {
  font-size: 2.25rem;
  font-weight: 700;
  margin: 0 0 0.5rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.main .lead {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin: 0 0 2rem;
  line-height: 1.6;
}

.main h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin: 2.5rem 0 1rem;
  color: var(--text);
  scroll-margin-top: 5rem;
}

.main h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 1.5rem 0 0.75rem;
}

.main p {
  margin: 1rem 0;
  color: var(--text-muted);
}

.main a {
  color: var(--accent);
  text-decoration: none;
}

.main a:hover {
  text-decoration: underline;
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
}

.card strong {
  display: block;
  margin-bottom: 0.35rem;
  color: var(--text);
}

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

/* Callout */
.callout {
  background: var(--code-bg);
  border-left: 4px solid var(--accent);
  border-radius: 0 8px 8px 0;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
}

.callout p {
  margin: 0;
}

/* Code */
code {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 0.875em;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem;
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.6;
}

pre code {
  background: none;
  padding: 0;
}

p code, li code {
  background: var(--code-bg);
  padding: 0.2em 0.5em;
  border-radius: 6px;
  font-size: 0.9em;
}

/* Table */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--border);
}

th, td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: var(--code-bg);
  font-weight: 600;
  font-size: 0.9rem;
}

tr:last-child td {
  border-bottom: none;
}

/* Lists */
ul {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

li {
  margin: 0.5rem 0;
}

/* CTA Button */
.cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  background: var(--accent);
  color: white !important;
  border-radius: 8px;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.15s;
}

.cta:hover {
  background: var(--accent-hover);
  text-decoration: none;
}

/* Mobile */
.mobile-toggle {
  display: none;
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 110;
  background: var(--header-bg);
  border: 1px solid var(--border);
  padding: 0.5rem 1rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text);
}

@media (max-width: 900px) {
  .header-nav {
    display: none;
  }

  .sidebar {
    position: fixed;
    left: -280px;
    top: 60px;
    height: calc(100vh - 60px);
    width: 280px;
    z-index: 90;
    transition: left 0.25s;
    box-shadow: 4px 0 24px rgba(0,0,0,0.15);
  }

  .sidebar.open {
    left: 0;
  }

  .mobile-toggle {
    display: block;
  }

  .main {
    padding: 2rem 1.5rem 3rem;
  }
}

/* ========== FOOTER ========== */
.doc-footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.doc-footer a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}

.doc-footer a:hover {
  text-decoration: underline;
}