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

:root {
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Fira Code", "Cascadia Code", Menlo, monospace;
  --font-size: 16px;
  --line-height: 1.7;
  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 14px;
  --sidebar-w: 300px;
  --content-max: 880px;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);

  --bg: #ffffff;
  --bg2: #f5f5f7;
  --bg3: #e8e8ed;
  --text: #1d1d1f;
  --text2: #6e6e73;
  --text3: #aeaeb2;
  --border: rgba(0,0,0,0.06);
  --border2: rgba(0,0,0,0.12);
  --blue: #0071e3;
  --blue-hover: #0077ed;
  --blue-light: rgba(0,113,227,0.08);
  --blue-glow: rgba(0,113,227,0.12);
  --code-bg: #f5f5f7;
  --code-border: rgba(0,0,0,0.06);
  --quote-bg: #f5f5f7;
  --quote-border: #0071e3;
  --table-border: rgba(0,0,0,0.06);
  --table-stripe: rgba(0,0,0,0.02);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.08);
  --shadow-xl: 0 20px 60px rgba(0,0,0,0.1);
  --overlay: rgba(0,0,0,0.25);
  --progress: #0071e3;
  --sidebar-bg: rgba(245,245,247,0.85);
}

[data-theme="dark"] {
  --bg: #1c1c1e;
  --bg2: #2c2c2e;
  --bg3: #3a3a3c;
  --text: #f5f5f7;
  --text2: #a1a1a6;
  --text3: #636366;
  --border: rgba(255,255,255,0.06);
  --border2: rgba(255,255,255,0.12);
  --blue: #2997ff;
  --blue-hover: #40a9ff;
  --blue-light: rgba(41,151,255,0.1);
  --blue-glow: rgba(41,151,255,0.18);
  --code-bg: #2c2c2e;
  --code-border: rgba(255,255,255,0.06);
  --quote-bg: #2c2c2e;
  --quote-border: #2997ff;
  --table-border: rgba(255,255,255,0.06);
  --table-stripe: rgba(255,255,255,0.02);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.4);
  --shadow-xl: 0 20px 60px rgba(0,0,0,0.5);
  --overlay: rgba(0,0,0,0.5);
  --progress: #2997ff;
  --sidebar-bg: rgba(44,44,46,0.88);
}

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

body {
  font-family: var(--font);
  font-size: var(--font-size);
  line-height: var(--line-height);
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background .35s var(--ease), color .35s var(--ease);
}

a { color: var(--blue); text-decoration: none; transition: color .2s }
a:hover { color: var(--blue-hover); text-decoration: underline }
::selection { background: var(--blue); color: #fff }

/* ===== Sidebar ===== */
#sidebar-overlay {
  display: none; position: fixed; inset: 0;
  background: var(--overlay); z-index: 98;
  -webkit-tap-highlight-color: transparent;
  backdrop-filter: blur(4px);
}

#sidebar {
  position: fixed; top: 0; left: 0; bottom: 0;
  width: var(--sidebar-w);
  background: var(--sidebar-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
  z-index: 100;
  transition: transform .35s var(--ease);
}

.sidebar-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 20px 12px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.sidebar-header .logo {
  font-size: 14px; font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
  text-transform: uppercase;
  opacity: .5;
}

.theme-toggle {
  width: 30px; height: 26px;
  border: 1px solid var(--border2);
  border-radius: var(--r-sm);
  background: transparent;
  color: var(--text2);
  font-size: 13px;
  cursor: pointer;
  line-height: 24px; text-align: center;
  transition: all .2s var(--ease);
}
.theme-toggle:hover {
  border-color: var(--blue);
  color: var(--blue);
  background: var(--blue-light);
}

/* Search */
.search-wrap {
  position: relative;
  padding: 10px 14px 8px;
  flex-shrink: 0;
}
.search-wrap input {
  width: 100%; padding: 8px 12px;
  font-size: 13px; font-family: var(--font);
  border: 1px solid var(--border2);
  border-radius: var(--r-md);
  background: var(--bg);
  color: var(--text);
  outline: none;
  transition: all .2s var(--ease);
}
.search-wrap input:focus {
  border-color: var(--blue);
  box-shadow: 0 0 0 3px var(--blue-glow);
}
.search-wrap input::placeholder { color: var(--text3) }

.search-clear {
  display: none; position: absolute;
  right: 20px; top: 50%; transform: translateY(-50%);
  width: 16px; height: 16px;
  border: none; border-radius: 50%;
  background: var(--text3); color: var(--bg);
  font-size: 9px; line-height: 16px; text-align: center;
  cursor: pointer;
}
.search-clear:hover { background: var(--text2) }

#search-results {
  display: none; position: absolute;
  top: 100%; left: 10px; right: 10px;
  max-height: 40vh; overflow-y: auto;
  background: var(--bg);
  border: 1px solid var(--border2);
  border-radius: var(--r-md);
  z-index: 200;
  box-shadow: var(--shadow-lg);
}
#search-results.show { display: block }
#search-results a {
  display: block; padding: 8px 14px;
  font-size: 13px; text-decoration: none;
  color: var(--text); border-bottom: 1px solid var(--border)
}
#search-results a:last-child { border: none }
#search-results a:hover { background: var(--blue-light) }
.sr-title { font-weight: 600; font-size: 13px }
.sr-context { font-size: 11.5px; color: var(--text2); margin-top: 1px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden }

/* TOC */
#toc-container {
  flex: 1; overflow-y: auto;
  padding: 6px 0 24px;
  -webkit-overflow-scrolling: touch;
}
#toc-container::-webkit-scrollbar { width: 3px }
#toc-container::-webkit-scrollbar-thumb { background: var(--text3); border-radius: 2px }

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

.toc-link {
  display: flex; align-items: center;
  padding: 4px 16px 4px 20px;
  font-size: 12.5px;
  color: var(--text2);
  text-decoration: none;
  line-height: 1.4;
  border-left: 2px solid transparent;
  transition: all .15s var(--ease);
}
.toc-link:hover {
  color: var(--text);
  background: var(--blue-light);
  text-decoration: none;
}
.toc-link.active {
  color: var(--blue);
  border-left-color: var(--blue);
  background: var(--blue-light);
  font-weight: 600;
}

.toc-toggle {
  background: none; border: none; cursor: pointer;
  font-size: 9px; color: var(--text3);
  padding: 0;
  width: 18px; height: 18px; line-height: 18px;
  text-align: center; flex-shrink: 0;
  transition: transform .2s var(--ease);
  border-radius: 4px; margin: 1px 0;
}
.toc-toggle:hover { color: var(--blue); background: var(--blue-light) }
.toc-toggle.open { transform: rotate(90deg) }

.toc-children {
  overflow: hidden;
  max-height: 0;
  transition: max-height .25s var(--ease);
}
.toc-children.open { max-height: 3000px }
.toc-children .toc-link { padding-left: 40px; font-size: 12px }
.toc-children .toc-children .toc-link { padding-left: 60px; font-size: 11.5px }

/* ===== Menu Button ===== */
#menu-toggle {
  display: none; position: fixed;
  top: 12px; left: 12px; z-index: 99;
  width: 36px; height: 36px;
  border: none; border-radius: var(--r-md);
  background: var(--blue);
  color: #fff; font-size: 16px;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  -webkit-tap-highlight-color: transparent;
  align-items: center; justify-content: center;
  transition: transform .15s, opacity .3s;
}
#menu-toggle:active { transform: scale(.92) }

/* ===== Content ===== */
#content {
  margin-left: var(--sidebar-w);
  max-width: var(--content-max);
  padding: 48px 64px 96px;
  min-height: 100vh;
}

/* Progress bar */
#progress-bar {
  position: fixed; top: 0; left: 0; right: 0;
  height: 2px; z-index: 90;
  background: transparent;
}
#progress-bar::after {
  content: ''; display: block; height: 100%;
  background: var(--progress);
  width: var(--pct, 0%);
  transition: width .08s linear;
}

/* Headings */
#content h1 {
  font-size: 2rem; font-weight: 700;
  letter-spacing: -.025em;
  margin: 0 0 12px;
  color: var(--text);
}
#content h2 {
  font-size: 1.45rem; font-weight: 650;
  letter-spacing: -.015em;
  margin: 44px 0 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
#content h3 {
  font-size: 1.15rem; font-weight: 600;
  margin: 34px 0 10px;
  letter-spacing: -.01em;
  color: var(--text);
}
#content h4 {
  font-size: 1rem; font-weight: 600;
  margin: 26px 0 8px;
  color: var(--text2);
}
#content h5 {
  font-size: .92rem; font-weight: 600;
  margin: 20px 0 6px;
  color: var(--text2);
}
#content p { margin-bottom: 18px }
#content ul, #content ol { margin: 8px 0 18px 24px }
#content li { margin-bottom: 4px }

/* Blockquote */
#content blockquote {
  border-left: 3px solid var(--quote-border);
  padding: 14px 22px;
  margin: 18px 0;
  background: var(--quote-bg);
  color: var(--text2);
  border-radius: 0 var(--r-sm) var(--r-sm) 0;
}
#content blockquote p:last-child { margin-bottom: 0 }

/* Code */
#content code {
  font-family: var(--font-mono);
  font-size: .85em;
  padding: 2px 7px;
  border-radius: 4px;
  background: var(--code-bg);
  color: var(--blue);
  border: 1px solid var(--code-border);
  word-break: break-word;
}
#content pre {
  background: var(--code-bg);
  padding: 18px 22px;
  border-radius: var(--r-md);
  overflow-x: auto;
  font-size: 13px;
  margin: 18px 0;
  font-family: var(--font-mono);
  line-height: 1.55;
  border: 1px solid var(--code-border);
  -webkit-overflow-scrolling: touch;
}
#content pre code {
  font-size: inherit; padding: 0;
  background: none; color: var(--text);
  border: none; word-break: normal;
}

/* Tables */
#content table {
  width: 100%; border-collapse: collapse;
  margin: 18px 0; font-size: 14px;
  border: 1px solid var(--table-border);
  display: block; overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
#content thead { background: var(--bg2) }
#content th, #content td {
  padding: 7px 12px; text-align: left;
  border: 1px solid var(--table-border);
  white-space: nowrap;
}
#content th {
  font-weight: 600; font-size: 12px;
  color: var(--text2);
  text-transform: uppercase;
  letter-spacing: .04em;
}
#content tbody tr:nth-child(even) { background: var(--table-stripe) }
#content tbody tr:hover { background: var(--blue-light) }

/* Images & diagrams */
#content img {
  max-width: 100%; height: auto;
  margin: 24px 0;
  border-radius: var(--r-md);
  border: 1px solid var(--border2);
  box-shadow: var(--shadow-sm);
}
#content .mermaid-wrapper {
  margin: 24px 0;
  padding: 20px;
  background: var(--bg2);
  border-radius: var(--r-md);
  border: 1px solid var(--border);
  overflow-x: auto;
}
#content .mermaid-wrapper svg { max-width: 100%; height: auto }

#content hr {
  border: none; border-top: 1px solid var(--border);
  margin: 36px 0;
}

/* ===== Feature Map — Link Card ===== */
.markmap-link-card {
  display: flex;
  align-items: center;
  gap: 20px;
  margin: 28px 0;
  padding: 24px 28px;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  transition: border-color .2s var(--ease);
}
.markmap-link-card:hover { border-color: var(--blue) }

.markmap-link-icon {
  font-size: 36px;
  flex-shrink: 0;
  line-height: 1;
}
.markmap-link-text {
  flex: 1;
  font-size: 14px;
  line-height: 1.6;
  color: var(--text2);
}
.markmap-link-text strong {
  display: block;
  font-size: 16px;
  color: var(--text);
  margin-bottom: 2px;
}

.markmap-link-btn {
  flex-shrink: 0;
  font: 500 14px/1 var(--font);
  background: var(--blue);
  color: #fff;
  padding: 10px 20px;
  border-radius: var(--r-md);
  text-decoration: none;
  white-space: nowrap;
  transition: opacity .2s var(--ease);
}
.markmap-link-btn:hover { opacity: .85 }

/* ===== Mermaid ===== */
pre.mermaid {
  display: none;
}
.mermaid-placeholder {
  display: flex; align-items: center; justify-content: center;
  padding: 40px 20px; background: var(--code-bg);
  border-radius: var(--r-md); border: 1px solid var(--code-border);
  color: var(--text3); font-size: 13px;
}

/* ===== Responsive ===== */
@media (max-width: 1023px) {
  #sidebar { transform: translateX(-100%) }
  #sidebar.open { transform: translateX(0) }
  #sidebar-overlay.show { display: block }
  #content { margin-left: 0; padding: 56px 24px 80px }
  #menu-toggle { display: flex }
  .toc-link { padding: 6px 20px 6px 24px }
  .toc-children .toc-link { padding-left: 44px }
  .toc-children .toc-children .toc-link { padding-left: 64px }
}
@media (max-width: 480px) {
  #content { padding: 52px 16px 64px }
  #content h1 { font-size: 1.5rem }
  #content h2 { font-size: 1.2rem; margin: 32px 0 10px }
  #content h3 { font-size: 1.05rem; margin: 24px 0 8px }
  #content table { font-size: 12.5px }
  #content th, #content td { padding: 5px 7px }
  #content pre { padding: 12px 14px; font-size: 12px }
  #content blockquote { padding: 10px 14px }
  #content ul, #content ol { margin-left: 18px }
  #sidebar { width: 100% }
  #menu-toggle { top: 10px; left: 10px; width: 34px; height: 34px; font-size: 15px }
  #search-results { position: fixed; top: auto; left: 0; right: 0; max-height: 60vh; margin: 0 8px }
}