:root {
  --bg: #ffffff;
  --surface: #f8f9fb;
  --surface-hover: #f0f1f4;
  --border: #e5e7eb;
  --text: #1a1a2e;
  --muted: #64748b;
  --accent: #4338CA;
  --accent-light: #818CF8;
  --accent-soft: rgba(67,56,202,0.08);
  --green: #16a34a;
  --yellow: #ca8a04;
  --red: #dc2626;
  --code-bg: #1e1e2e;
  --code-text: #e4e7ef;
  --radius: 10px;
  --radius-sm: 6px;
  --sidebar-w: 280px;
  --header-h: 60px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }

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

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

/* Layout */
.app-shell { display: flex; min-height: 100vh; }

/* Sidebar */
.sidebar {
  width: var(--sidebar-w);
  background: var(--surface);
  border-right: 1px solid var(--border);
  position: fixed;
  top: 0; bottom: 0; left: 0;
  overflow-y: auto;
  z-index: 40;
  padding: 20px 0;
  transition: transform 0.25s ease;
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

.sidebar-logo {
  padding: 0 20px 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.sidebar-logo svg { width: 32px; height: 32px; }
.sidebar-logo .wordmark { font-weight: 800; font-size: 18px; color: var(--text); }
.sidebar-logo .wordmark span { color: var(--accent); }
.sidebar-logo .version {
  font-size: 11px; font-weight: 500;
  background: var(--accent-soft); color: var(--accent);
  padding: 3px 8px; border-radius: 12px;
}

.sidebar-nav { padding: 0 12px; }
.sidebar-section { margin-bottom: 8px; }
.sidebar-section-title {
  font-size: 11px; font-weight: 700; text-transform: uppercase;
  color: var(--muted); letter-spacing: 0.06em;
  padding: 10px 12px 6px; cursor: pointer;
  display: flex; align-items: center; justify-content: space-between;
  user-select: none;
}
.sidebar-section-title:hover { color: var(--text); }
.sidebar-section-title .arrow { transition: transform 0.2s; font-size: 10px; }
.sidebar-section.collapsed .sidebar-links { display: none; }
.sidebar-section.collapsed .arrow { transform: rotate(-90deg); }
.sidebar-links { list-style: none; }
.sidebar-link {
  display: block; padding: 6px 12px 6px 20px;
  color: var(--muted); border-radius: var(--radius-sm);
  font-size: 13px; margin-bottom: 2px; transition: all 0.15s;
  cursor: pointer;
}
.sidebar-link:hover { background: var(--surface-hover); color: var(--text); text-decoration: none; }
.sidebar-link.active { background: var(--accent-soft); color: var(--accent); font-weight: 500; }

/* Header */
.header {
  height: var(--header-h);
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: fixed;
  top: 0; left: var(--sidebar-w); right: 0;
  z-index: 30;
  display: flex; align-items: center;
  justify-content: space-between;
  padding: 0 24px;
}
.header-left { display: flex; align-items: center; gap: 12px; }
.header-actions { display: flex; gap: 16px; align-items: center; }
.header-actions a { color: var(--muted); font-size: 13px; font-weight: 500; }
.header-actions a:hover { color: var(--text); text-decoration: none; }

/* Search */
.search { width: 280px; position: relative; }
.search input {
  width: 100%; background: var(--surface); border: 1px solid var(--border);
  border-radius: 20px; padding: 8px 16px 8px 36px;
  color: var(--text); font-size: 13px; outline: none;
  transition: border-color 0.2s;
}
.search input:focus { border-color: var(--accent); }
.search .s-icon {
  position: absolute; left: 12px; top: 50%;
  transform: translateY(-50%); opacity: 0.4;
}
.search-results {
  position: absolute; top: 100%; left: 0; right: 0;
  background: #fff; border: 1px solid var(--border);
  border-radius: var(--radius); margin-top: 4px;
  max-height: 300px; overflow-y: auto; display: none; z-index: 50;
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}
.search-results.visible { display: block; }
.search-result {
  display: block; padding: 8px 16px; color: var(--muted);
  font-size: 13px; border-bottom: 1px solid var(--border); cursor: pointer;
}
.search-result:last-child { border-bottom: none; }
.search-result:hover { background: var(--surface-hover); color: var(--text); }

/* Content */
.content {
  flex: 1;
  margin-left: var(--sidebar-w);
  margin-top: var(--header-h);
  padding: 40px 48px 80px;
  max-width: 900px;
}

/* Typography */
h1 { font-size: 36px; font-weight: 800; margin-bottom: 12px; letter-spacing: -0.02em; }
h2 { font-size: 22px; font-weight: 700; margin: 48px 0 16px; padding-bottom: 10px; border-bottom: 1px solid var(--border); }
h2:first-child { margin-top: 0; }
h3 { font-size: 17px; font-weight: 600; margin: 32px 0 10px; }
h4 { font-size: 15px; font-weight: 600; margin: 20px 0 8px; }
p { margin-bottom: 12px; color: var(--muted); }
strong { color: var(--text); font-weight: 600; }
ul, ol { padding-left: 20px; margin-bottom: 16px; }
li { margin-bottom: 6px; color: var(--muted); }
li code { color: var(--text); }

/* Code */
code {
  font-family: 'SF Mono', 'Fira Code', Menlo, monospace;
  font-size: 13px; background: var(--surface);
  padding: 2px 6px; border-radius: 4px; color: var(--accent);
}
pre {
  background: var(--code-bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px;
  overflow-x: auto; font-size: 13px; line-height: 1.65; margin: 16px 0;
  position: relative;
}
pre code { background: none; padding: 0; color: var(--code-text); }

/* Code block with copy button */
.code-block-wrapper {
  position: relative;
  margin: 16px 0;
}
.code-block-wrapper pre {
  margin: 0;
  padding-right: 60px;
}
.code-copy-btn {
  position: absolute;
  top: 8px; right: 8px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.1);
  color: rgba(255,255,255,0.6);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 11px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: all 0.15s;
  z-index: 2;
}
.code-copy-btn:hover {
  background: rgba(255,255,255,0.15);
  color: rgba(255,255,255,0.9);
  border-color: rgba(255,255,255,0.2);
}

/* Tables */
table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 16px 0; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--border); }
th { background: var(--surface); font-weight: 600; color: var(--text); }
td { color: var(--muted); }
td code { color: var(--text); }

/* Badges */
.badge { display: inline-block; padding: 3px 10px; border-radius: 12px; font-size: 11px; font-weight: 600; }
.badge-green { background: rgba(22,163,74,0.1); color: var(--green); }
.badge-yellow { background: rgba(202,138,4,0.1); color: var(--yellow); }
.badge-red { background: rgba(220,38,38,0.1); color: var(--red); }
.badge-accent { background: var(--accent-soft); color: var(--accent); }

/* Callout */
.callout {
  background: var(--surface); border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 14px 18px; margin: 20px 0;
}
.callout p { margin: 0; font-size: 14px; }
.callout-warn { border-left-color: var(--yellow); }
.callout-danger { border-left-color: var(--red); }

/* Hero Stats */
.hero-stats { display: flex; gap: 16px; margin: 24px 0 32px; flex-wrap: wrap; }
.hero-stat {
  background: var(--surface); border-radius: var(--radius);
  padding: 16px 20px; flex: 1; min-width: 120px; text-align: center;
  border: 1px solid var(--border);
}
.hero-stat .val { font-size: 22px; font-weight: 700; color: var(--text); display: block; }
.hero-stat .lbl { font-size: 12px; color: var(--muted); }

/* Playground — TypeScript Playground inspired */
.playground {
  border: 1px solid var(--border); border-radius: var(--radius);
  margin: 20px 0; overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.playground-toolbar {
  background: var(--surface); padding: 6px 12px;
  display: flex; justify-content: space-between; align-items: center;
  border-bottom: 1px solid var(--border);
}
.playground-toolbar-left { display: flex; align-items: center; gap: 8px; }
.playground-toolbar-right { display: flex; align-items: center; gap: 6px; }
.playground-title { font-size: 12px; font-weight: 600; color: var(--muted); }
.pg-btn {
  background: var(--surface); color: var(--muted); border: 1px solid var(--border);
  padding: 4px 10px; border-radius: 4px; font-size: 11px; font-weight: 500;
  cursor: pointer; display: flex; align-items: center; gap: 4px;
  transition: all 0.15s;
}
.pg-btn:hover { background: var(--surface-hover); color: var(--text); }
.pg-btn-run { background: var(--accent); color: #fff; border-color: var(--accent); }
.pg-btn-run:hover { opacity: 0.9; color: #fff; }

.playground-body { display: flex; min-height: 240px; }

/* Left panel: gutter + editor */
.playground-left {
  flex: 1; display: flex; min-width: 120px; position: relative;
}
.pg-gutter {
  width: 40px; padding: 16px 0; background: #16161e;
  overflow: hidden; flex-shrink: 0;
  border-right: 1px solid rgba(255,255,255,0.06);
}
.pg-line-num {
  height: 20.8px; /* matches editor line-height: 1.6 * 13px */
  font-family: 'SF Mono', Menlo, monospace; font-size: 11px;
  color: rgba(255,255,255,0.25); text-align: right;
  padding-right: 10px; line-height: 20.8px;
  user-select: none;
}
.playground-editor {
  font-family: 'SF Mono', 'Fira Code', Menlo, monospace;
  font-size: 13px; line-height: 1.6;
  background: var(--code-bg); color: var(--code-text);
  padding: 16px; padding-left: 12px;
  border: none; width: 100%;
  min-height: 240px; resize: none; outline: none;
  flex: 1; tab-size: 2;
  white-space: pre; overflow: auto;
}
.playground-editor::placeholder { color: rgba(255,255,255,0.3); }

/* Divider */
.playground-divider {
  width: 5px; background: var(--border); cursor: col-resize;
  flex-shrink: 0; transition: background 0.15s; position: relative;
}
.playground-divider:hover, .playground-divider:active { background: var(--accent); }
.playground-divider::after {
  content: ''; position: absolute; top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 2px; height: 20px; background: rgba(0,0,0,0.15); border-radius: 1px;
}

/* Right panel: tabs + output */
.playground-right { flex: 1; display: flex; flex-direction: column; min-width: 120px; min-height: 0; }

.pg-tabs {
  display: flex; background: var(--surface); border-bottom: 1px solid var(--border);
  padding: 0 8px; gap: 0;
}
.pg-tab {
  background: none; border: none; border-bottom: 2px solid transparent;
  padding: 8px 12px; font-size: 12px; font-weight: 500;
  color: var(--muted); cursor: pointer; display: flex; align-items: center; gap: 4px;
  transition: all 0.15s;
}
.pg-tab:hover { color: var(--text); }
.pg-tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.pg-tab-badge {
  background: var(--accent); color: #fff; font-size: 10px;
  padding: 1px 5px; border-radius: 8px; font-weight: 600;
}

.pg-output-result { flex: 1; overflow: auto; min-height: 0; }
.pg-output-result iframe { width: 100%; height: 100%; min-height: 200px; border: none; display: block; }

.pg-output-console {
  flex: 1; overflow: auto; padding: 12px; min-height: 0;
  font-family: 'SF Mono', Menlo, monospace; font-size: 12px;
  background: #fafafa;
}
.pg-console-empty { color: var(--muted); font-style: italic; }
.pg-console-entries { display: flex; flex-direction: column; gap: 4px; }
.pg-console-line {
  padding: 4px 8px; background: #fff; border: 1px solid var(--border);
  border-radius: 4px; white-space: pre-wrap; word-break: break-all;
  color: var(--text); line-height: 1.5;
}
.pg-console-chevron { color: var(--accent); font-weight: 700; margin-right: 4px; }

@media (max-width: 768px) {
  .playground-body { flex-direction: column; }
  .playground-left { min-width: 100%; min-height: 180px; }
  .playground-divider { width: 100%; height: 5px; cursor: row-resize; }
  .playground-divider::after { width: 20px; height: 2px; }
  .playground-right { min-height: 150px; }
  .playground-editor { min-height: 180px; }
}

/* Fullscreen mode */
.playground-fullscreen {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  z-index: 9999;
  border-radius: 0;
  margin: 0;
  border: none;
  box-shadow: none;
  display: flex;
  flex-direction: column;
  background: #ffffff;
}
.playground-fullscreen .playground-toolbar {
  flex-shrink: 0;
}
.playground-fullscreen .playground-body {
  flex: 1;
  min-height: 0;
  height: calc(100vh - 42px);
}
.playground-fullscreen .playground-left {
  min-height: 100%;
  height: 100%;
}
.playground-fullscreen .playground-editor {
  min-height: 100%;
  height: 100%;
}
.playground-fullscreen .playground-right {
  min-height: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
}
.playground-fullscreen .pg-tabs {
  flex-shrink: 0;
}
.playground-fullscreen .pg-output-result {
  flex: 1;
  min-height: 0;
  height: 0;
  background: #ffffff;
}
.playground-fullscreen .pg-output-result iframe {
  width: 100%;
  height: 100%;
  min-height: 0;
}
.playground-fullscreen .pg-output-console {
  flex: 1;
  min-height: 0;
  height: 0;
  overflow-y: auto;
}

/* Mobile toggle */
.sidebar-toggle {
  display: none; background: none; border: none;
  color: var(--text); cursor: pointer; padding: 6px;
}
.overlay {
  display: none; position: fixed; inset: 0;
  background: rgba(0,0,0,0.3); z-index: 35;
}
.overlay.open { display: block; }

@media (max-width: 1024px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .header { left: 0; }
  .content { margin-left: 0; padding: 32px 20px 80px; }
  .sidebar-toggle { display: block; }
  .search { width: 180px; }
}
@media (max-width: 640px) {
  .search { display: none; }
  h1 { font-size: 28px; }
  h2 { font-size: 20px; }
  pre { padding: 14px; font-size: 12px; }
}

/* ─── Breadcrumbs ─── */
.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px;
  font-size: 13px;
  margin-bottom: 20px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border, #e2e8f0);
}
.breadcrumb-link {
  color: var(--accent, #3b82f6);
  text-decoration: none;
  cursor: pointer;
}
.breadcrumb-link:hover {
  text-decoration: underline;
}
.breadcrumb-sep {
  color: var(--muted, #94a3b8);
  margin: 0 2px;
  user-select: none;
}
.breadcrumb-current {
  color: var(--fg, #1e293b);
  font-weight: 500;
}