:root {
  --bg: #0f1117;
  --panel: #171a23;
  --panel-2: #1e222d;
  --border: #2a2f3a;
  --text: #e6e8ee;
  --muted: #9aa3b2;
  --accent: #6ea8fe;
  --accent-2: #7ee787;
  --accent-3: #f6c177;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}
header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 22px; border-bottom: 1px solid var(--border);
  background: var(--panel); position: sticky; top: 0; z-index: 10;
}
.brand { display: flex; align-items: baseline; gap: 12px; }
.brand h1 { font-size: 20px; margin: 0; }
.subtitle { color: var(--muted); font-size: 13px; }
.version-switch { display: flex; gap: 6px; background: var(--panel-2); padding: 4px; border-radius: 10px; }
.version-switch button {
  border: 0; background: transparent; color: var(--muted);
  padding: 7px 16px; border-radius: 7px; cursor: pointer; font-size: 14px; transition: .15s;
}
.version-switch button:hover { color: var(--text); }
.version-switch button.active { background: var(--accent); color: #08111f; font-weight: 600; }

.header-right { display: flex; align-items: center; gap: 16px; }
.top-links { display: flex; gap: 8px; }
.top-links a {
  display: inline-flex; align-items: center; gap: 6px;
  color: var(--muted); text-decoration: none; font-size: 13px;
  padding: 6px 11px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--panel-2);
  transition: .15s;
}
.top-links a svg { display: block; flex-shrink: 0; }
.top-links a:hover { color: var(--text); border-color: var(--accent); }

.layout { display: flex; height: calc(100vh - 61px); }
.sidebar {
  width: 320px; min-width: 320px; border-right: 1px solid var(--border);
  background: var(--panel); overflow-y: auto; padding: 16px;
}
#search {
  width: 100%; padding: 9px 12px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--panel-2);
  color: var(--text); font-size: 14px; margin-bottom: 14px;
}
#search:focus { outline: none; border-color: var(--accent); }
.chap-title {
  font-size: 13px; color: var(--accent-3); font-weight: 700;
  margin: 14px 0 6px; letter-spacing: .3px;
  display: flex; align-items: center; gap: 6px;
  cursor: pointer; user-select: none; border-radius: 6px; padding: 4px 6px;
}
.chap-title:hover { background: var(--panel-2); }
.chap-arrow { display: inline-block; width: 12px; font-size: 10px; color: var(--muted); transition: transform .15s; }
.chap-title.collapsed .chap-arrow { transform: rotate(-90deg); }
.chap-name { flex: 1; }
.chap-group.collapsed { display: none; }
.kp-item {
  padding: 8px 10px; border-radius: 7px; cursor: pointer;
  font-size: 14px; color: var(--text); display: flex; flex-direction: column; gap: 2px;
}
.kp-item:hover { background: var(--panel-2); }
.kp-item.active { background: var(--accent); color: #08111f; }
.kp-item.active .kp-tags { color: #0b2238; }
.kp-tags { font-size: 11px; color: var(--muted); }
.kp-item.hidden { display: none; }
.chap-title.hidden { display: none; }

main {
  flex: 1; overflow-y: auto; padding: 36px 48px; max-width: 900px;
}
.placeholder { color: var(--muted); font-size: 16px; margin-top: 60px; text-align: center; }
.kp-header { border-bottom: 1px solid var(--border); padding-bottom: 12px; margin-bottom: 20px; }
.kp-header .crumb { color: var(--muted); font-size: 13px; }
.kp-header .ver-badge {
  display: inline-block; font-size: 12px; padding: 2px 10px; border-radius: 20px;
  margin-left: 8px; background: var(--panel-2); color: var(--accent-2);
}
.kp-body h2 { font-size: 22px; margin-top: 4px; }
.kp-body h3 { font-size: 17px; color: var(--accent); }
.kp-body p { margin: 12px 0; }
.kp-body code {
  background: var(--panel-2); padding: 2px 6px; border-radius: 5px;
  font-family: "SF Mono", Menlo, Consolas, monospace; font-size: 13px; color: var(--accent-2);
}
.kp-body pre {
  background: var(--panel-2); padding: 14px 16px; border-radius: 8px;
  overflow-x: auto; border: 1px solid var(--border);
}
.kp-body pre code { background: none; padding: 0; color: var(--text); }
.kp-body figure.diagram {
  margin: 18px 0; padding: 14px 16px; text-align: center;
  background: var(--panel-2); border: 1px solid var(--border); border-radius: 10px;
}
.kp-body figure.diagram svg { max-width: 100%; height: auto; }
.kp-body strong { color: #fff; }
.kp-body ul, .kp-body ol { padding-left: 22px; }
.kp-body .katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }
.kp-body blockquote.note {
  margin: 14px 0; padding: 12px 16px;
  background: rgba(110, 168, 254, 0.08);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0; color: #d4def0;
}
.kp-body blockquote.note strong { color: var(--accent); }
.kp-body blockquote.example {
  margin: 16px 0; padding: 14px 18px;
  background: rgba(126, 231, 135, 0.07);
  border-left: 3px solid var(--accent-2);
  border-radius: 0 8px 8px 0; color: #d6ead8;
}
.kp-body blockquote.example strong { color: var(--accent-2); }
.kp-body blockquote.example > div { margin: 5px 0; }
.kp-body blockquote.example > div:empty { height: 6px; margin: 0; }
.missing { color: var(--accent-3); background: var(--panel-2); padding: 14px 16px; border-radius: 8px; border: 1px dashed var(--border); }
@media (max-width: 760px) {
  .layout { flex-direction: column; height: auto; }
  .sidebar { width: 100%; min-width: 0; }
  main { padding: 24px; }
}