/* =========================================================
   Overload Documentation — Global Stylesheet
   ========================================================= */

/* --- CSS Custom Properties (Design Tokens) --- */
:root {
  /* Brand colors */
  --ov-primary: #4f46e5;
  --ov-primary-hover: #6366f1;
  --ov-primary-dark: #4338ca;
  --ov-accent: #0ea5e9;
  --ov-accent-hover: #38bdf8;
  --ov-success: #10b981;
  --ov-warning: #f59e0b;
  --ov-danger: #ef4444;

  /* Surfaces */
  --ov-bg: #f8fafc;
  --ov-bg-alt: #ffffff;
  --ov-surface: #f1f5f9;
  --ov-surface-hover: #e2e8f0;
  --ov-card: rgba(255, 255, 255, 0.9);
  --ov-card-border: rgba(99, 102, 241, 0.15);

  /* Text */
  --ov-text: #334155;
  --ov-text-muted: #64748b;
  --ov-text-dim: #94a3b8;
  --ov-heading: #0f172a;

  /* Misc */
  --ov-border: rgba(15, 23, 42, 0.08);
  --ov-code-bg: #f1f5f9;
  --ov-code-text: #0f172a;
  --ov-radius: 12px;
  --ov-radius-sm: 8px;
  --ov-shadow: 0 4px 24px rgba(0, 0, 0, 0.04);
  --ov-shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.08);
  --ov-transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --ov-sidebar-w: 280px;
  --ov-content-max: 900px;
  --ov-nav-h: 64px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
}

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

/* --- Scrollbar --- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--ov-text-dim);
  border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover { background: var(--ov-text-muted); }

/* --- Top Navigation --- */
.top-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--ov-nav-h);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--ov-border);
  display: flex;
  align-items: center;
  padding: 0 24px;
  z-index: 1000;
}

.top-nav__logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--ov-heading);
  letter-spacing: -0.02em;
}

.top-nav__logo svg {
  width: 32px;
  height: 32px;
}

.top-nav__badge {
  font-size: 0.65rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--ov-primary);
  color: #ffffff;
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-left: 4px;
}

.top-nav__links {
  margin-left: auto;
  display: flex;
  gap: 8px;
  align-items: center;
}

.top-nav__link {
  color: var(--ov-text-muted);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 6px 14px;
  border-radius: var(--ov-radius-sm);
  transition: all var(--ov-transition);
}

.top-nav__link:hover,
.top-nav__link.active {
  color: var(--ov-heading);
  background: var(--ov-surface-hover);
}

.top-nav__github {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--ov-text-muted);
  text-decoration: none;
  font-size: 0.875rem;
  padding: 6px 14px;
  border-radius: var(--ov-radius-sm);
  transition: all var(--ov-transition);
  border: 1px solid var(--ov-border);
  margin-left: 8px;
}

.top-nav__github:hover {
  color: var(--ov-heading);
  border-color: var(--ov-text-muted);
}

.top-nav__github svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* --- Hamburger --- */
.hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--ov-text);
  cursor: pointer;
  padding: 4px;
  margin-right: 12px;
}

.hamburger svg {
  width: 24px;
  height: 24px;
}

/* --- Layout --- */
.layout {
  display: flex;
  margin-top: var(--ov-nav-h);
  min-height: calc(100vh - var(--ov-nav-h));
}

/* --- Sidebar --- */
.sidebar {
  position: fixed;
  top: var(--ov-nav-h);
  left: 0;
  width: var(--ov-sidebar-w);
  height: calc(100vh - var(--ov-nav-h));
  background: var(--ov-bg-alt);
  border-right: 1px solid var(--ov-border);
  overflow-y: auto;
  padding: 24px 0;
  z-index: 500;
}

.sidebar__section {
  margin-bottom: 8px;
}

.sidebar__heading {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ov-text-dim);
  padding: 8px 24px 4px;
}

.sidebar__link {
  display: block;
  padding: 7px 24px 7px 32px;
  color: var(--ov-text-muted);
  text-decoration: none;
  font-size: 0.875rem;
  transition: all var(--ov-transition);
  border-left: 3px solid transparent;
}

.sidebar__link:hover {
  color: var(--ov-heading);
  background: rgba(99, 102, 241, 0.06);
}

.sidebar__link.active {
  color: var(--ov-primary-hover);
  border-left-color: var(--ov-primary);
  background: rgba(99, 102, 241, 0.08);
  font-weight: 500;
}

.sidebar__sub {
  padding-left: 16px;
}

.sidebar__sub .sidebar__link {
  font-size: 0.8125rem;
  padding-top: 5px;
  padding-bottom: 5px;
}

/* --- Main Content --- */
.content {
  margin-left: var(--ov-sidebar-w);
  flex: 1;
  padding: 48px 56px 120px;
  max-width: calc(var(--ov-content-max) + 112px);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  color: var(--ov-heading);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.3;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--ov-primary-hover), var(--ov-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: 1.75rem;
  margin-top: 64px;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--ov-border);
}

h3 {
  font-size: 1.25rem;
  margin-top: 40px;
  margin-bottom: 12px;
}

h4 {
  font-size: 1.05rem;
  margin-top: 28px;
  margin-bottom: 8px;
}

p {
  margin-bottom: 16px;
}

.subtitle {
  font-size: 1.15rem;
  color: var(--ov-text-muted);
  margin-bottom: 40px;
  line-height: 1.6;
}

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

a:hover {
  color: var(--ov-accent);
  text-decoration: underline;
}

strong {
  color: var(--ov-heading);
  font-weight: 600;
}

hr {
  border: none;
  border-top: 1px solid var(--ov-border);
  margin: 48px 0;
}

ul, ol {
  padding-left: 24px;
  margin-bottom: 16px;
}

li {
  margin-bottom: 6px;
}

li > code {
  font-size: 0.85em;
}

/* --- Code Blocks --- */
pre {
  background: var(--ov-code-bg);
  border: 1px solid var(--ov-border);
  border-radius: var(--ov-radius-sm);
  padding: 20px 24px;
  overflow-x: auto;
  margin-bottom: 24px;
  position: relative;
}

pre code {
  font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
  font-size: 0.85rem;
  color: var(--ov-code-text);
  line-height: 1.6;
}

code {
  font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
  font-size: 0.85em;
  background: rgba(99, 102, 241, 0.1);
  color: var(--ov-primary-hover);
  padding: 2px 7px;
  border-radius: 4px;
}

pre code {
  background: none;
  padding: 0;
  color: var(--ov-code-text);
}

/* Code language label */
pre[data-lang]::before {
  content: attr(data-lang);
  position: absolute;
  top: 8px;
  right: 12px;
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--ov-text-dim);
  background: var(--ov-surface);
  padding: 2px 8px;
  border-radius: 4px;
}

/* --- Tables --- */
.table-wrap {
  overflow-x: auto;
  margin-bottom: 24px;
  border-radius: var(--ov-radius-sm);
  border: 1px solid var(--ov-border);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

thead {
  background: var(--ov-surface);
}

th {
  text-align: left;
  padding: 12px 16px;
  font-weight: 600;
  color: var(--ov-heading);
  white-space: nowrap;
  border-bottom: 1px solid var(--ov-border);
}

td {
  padding: 10px 16px;
  border-bottom: 1px solid var(--ov-border);
  color: var(--ov-text);
}

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

tbody tr:hover {
  background: rgba(99, 102, 241, 0.04);
}

/* --- Cards --- */
.card {
  background: var(--ov-card);
  border: 1px solid var(--ov-card-border);
  border-radius: var(--ov-radius);
  padding: 28px;
  margin-bottom: 20px;
  backdrop-filter: blur(8px);
  transition: all var(--ov-transition);
}

.card:hover {
  border-color: rgba(99, 102, 241, 0.3);
  box-shadow: var(--ov-shadow);
}

.card__title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--ov-heading);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.card__title .icon {
  font-size: 1.3rem;
}

.card__desc {
  color: var(--ov-text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

/* --- Alerts / Callouts --- */
.callout {
  border-radius: var(--ov-radius-sm);
  padding: 16px 20px;
  margin-bottom: 24px;
  font-size: 0.9rem;
  line-height: 1.6;
  border-left: 4px solid;
}

.callout--info {
  background: rgba(6, 182, 212, 0.08);
  border-left-color: var(--ov-accent);
  color: #67e8f9;
}

.callout--warning {
  background: rgba(245, 158, 11, 0.08);
  border-left-color: var(--ov-warning);
  color: #fbbf24;
}

.callout--success {
  background: rgba(16, 185, 129, 0.08);
  border-left-color: var(--ov-success);
  color: #34d399;
}

.callout--danger {
  background: rgba(239, 68, 68, 0.08);
  border-left-color: var(--ov-danger);
  color: #f87171;
}

.callout strong {
  display: block;
  margin-bottom: 4px;
}

.callout code {
  background: rgba(255,255,255,0.06);
}

/* --- Badges --- */
.badge {
  display: inline-flex;
  align-items: center;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 999px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.badge--primary { background: rgba(99, 102, 241, 0.15); color: var(--ov-primary-hover); }
.badge--accent { background: rgba(6, 182, 212, 0.15); color: var(--ov-accent-hover); }
.badge--success { background: rgba(16, 185, 129, 0.15); color: var(--ov-success); }
.badge--warning { background: rgba(245, 158, 11, 0.15); color: var(--ov-warning); }

/* --- Feature list --- */
.feature-list {
  list-style: none;
  padding: 0;
}

.feature-list li {
  padding: 10px 0;
  padding-left: 28px;
  position: relative;
  border-bottom: 1px solid var(--ov-border);
}

.feature-list li:last-child {
  border-bottom: none;
}

.feature-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--ov-success);
  font-weight: 700;
}

/* --- Hero Section (index) --- */
.hero {
  text-align: center;
  padding: 80px 0 40px;
}

.hero h1 {
  font-size: 3.5rem;
  margin-bottom: 20px;
}

.hero .subtitle {
  max-width: 640px;
  margin: 0 auto 32px;
}

.hero__actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 48px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--ov-radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: all var(--ov-transition);
  cursor: pointer;
  border: none;
}

.btn--primary {
  background: var(--ov-primary);
  color: #ffffff;
}

.btn--primary:hover {
  background: var(--ov-primary-hover);
  text-decoration: none;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3);
}

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

.btn--outline:hover {
  border-color: var(--ov-primary);
  color: var(--ov-heading);
  text-decoration: none;
}

/* --- Steps --- */
.steps {
  counter-reset: step-counter;
  list-style: none;
  padding: 0;
}

.steps li {
  counter-increment: step-counter;
  position: relative;
  padding-left: 48px;
  padding-bottom: 24px;
  margin-bottom: 0;
  border-left: 2px solid var(--ov-border);
  margin-left: 15px;
}

.steps li:last-child {
  border-left-color: transparent;
  padding-bottom: 0;
}

.steps li::before {
  content: counter(step-counter);
  position: absolute;
  left: -16px;
  top: 0;
  width: 30px;
  height: 30px;
  background: var(--ov-primary);
  color: #ffffff;
  font-weight: 700;
  font-size: 0.8rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* --- Copy Button --- */
.copy-btn {
  position: absolute;
  top: 8px;
  right: 48px;
  background: var(--ov-surface);
  border: 1px solid var(--ov-border);
  color: var(--ov-text-muted);
  font-size: 0.7rem;
  padding: 3px 8px;
  border-radius: 4px;
  cursor: pointer;
  transition: all var(--ov-transition);
  opacity: 0;
}

pre:hover .copy-btn {
  opacity: 1;
}

.copy-btn:hover {
  color: var(--ov-heading);
  border-color: var(--ov-primary);
}

/* --- Footer --- */
.footer {
  text-align: center;
  padding: 40px 0;
  margin-top: 80px;
  border-top: 1px solid var(--ov-border);
  color: var(--ov-text-dim);
  font-size: 0.85rem;
}

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

/* --- Tabs --- */
.tabs {
  display: flex;
  gap: 4px;
  border-bottom: 1px solid var(--ov-border);
  margin-bottom: 24px;
}

.tab-btn {
  padding: 10px 20px;
  background: none;
  border: none;
  color: var(--ov-text-muted);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all var(--ov-transition);
  font-family: inherit;
}

.tab-btn:hover {
  color: var(--ov-heading);
}

.tab-btn.active {
  color: var(--ov-primary-hover);
  border-bottom-color: var(--ov-primary);
}

.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

/* --- Animations --- */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(-12px); }
  to { opacity: 1; transform: translateX(0); }
}

.fade-in {
  animation: fadeIn 0.5s ease forwards;
}

/* --- Syntax Highlighting (minimal) --- */
.kw { color: #a626a4; }
.str { color: #50a14f; }
.num { color: #986801; }
.cmt { color: #a0a1a7; font-style: italic; }
.fn { color: #4078f2; }
.op { color: #0184bc; }
.var { color: #c18401; }

/* --- TOC --- */
.toc {
  background: var(--ov-card);
  border: 1px solid var(--ov-card-border);
  border-radius: var(--ov-radius);
  padding: 24px 28px;
  margin-bottom: 40px;
}

.toc__title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ov-text-dim);
  margin-bottom: 12px;
}

.toc ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

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

.toc a {
  color: var(--ov-text-muted);
  font-size: 0.875rem;
  padding: 3px 0;
  display: block;
  transition: color var(--ov-transition);
}

.toc a:hover {
  color: var(--ov-primary-hover);
  text-decoration: none;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  .content {
    padding: 36px 32px 80px;
  }
}

@media (max-width: 768px) {
  .hamburger {
    display: block;
  }

  .sidebar {
    transform: translateX(-100%);
    transition: transform var(--ov-transition);
  }

  .sidebar.open {
    transform: translateX(0);
    box-shadow: var(--ov-shadow-lg);
  }

  .content {
    margin-left: 0;
    padding: 24px 20px 80px;
  }

  h1 { font-size: 2rem; }
  h2 { font-size: 1.4rem; }

  .hero h1 { font-size: 2.2rem; }
  .hero__actions { flex-direction: column; align-items: center; }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .top-nav__links {
    display: none;
  }
}

/* --- Scroll-linked active sidebar highlight --- */
.sidebar__link[data-section].active {
  color: var(--ov-primary-hover);
  border-left-color: var(--ov-primary);
  background: rgba(99, 102, 241, 0.08);
}

/* --- Anchor offset --- */
[id] {
  scroll-margin-top: calc(var(--ov-nav-h) + 24px);
}

/* --- Print --- */
@media print {
  .top-nav, .sidebar, .hamburger { display: none !important; }
  .content { margin-left: 0; padding: 0; max-width: 100%; }
  body { background: #fff; color: #111; }
  h1, h2, h3, h4, strong { color: #111; }
  code { background: #f0f0f0; color: #333; }
  pre { border-color: #ddd; }
}