/* ============================================================
   站点样式 —— 网络安全学习站（零依赖，原生 CSS）
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 20px; }

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

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}

.skip-link {
  position: absolute; left: 12px; top: -48px; z-index: 99;
  background: var(--primary); color: var(--primary-contrast);
  padding: 8px 14px; border-radius: var(--radius-sm);
  transition: top var(--motion);
}
.skip-link:focus { top: 12px; text-decoration: none; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; align-items: center; gap: 18px;
  min-height: 58px; flex-wrap: wrap; padding-top: 6px; padding-bottom: 6px;
}
.brand {
  display: inline-flex; align-items: center; gap: 8px;
  font-weight: 700; color: var(--text); letter-spacing: .2px;
}
.brand svg { color: var(--primary); }
.brand:hover { text-decoration: none; }
.site-nav { display: flex; gap: 4px; flex-wrap: wrap; }
.site-nav a {
  padding: 6px 10px; border-radius: var(--radius-sm);
  color: var(--text-muted); font-size: 14.5px;
}
.site-nav a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }

.search { position: relative; margin-left: auto; }
.search input {
  width: 210px; max-width: 52vw;
  padding: 7px 12px;
  border: 1px solid var(--border); border-radius: 999px;
  background: var(--surface); color: var(--text);
  font: inherit; font-size: 14px;
}
.search input:focus { border-color: var(--primary); outline: 2px solid var(--focus); outline-offset: 1px; }
.search-results {
  position: absolute; right: 0; top: calc(100% + 8px);
  width: 340px; max-width: 82vw; max-height: 60vh; overflow: auto;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 6px; z-index: 40;
}
.search-results a {
  display: block; padding: 8px 10px; border-radius: var(--radius-sm);
  color: var(--text);
}
.search-results a:hover, .search-results a:focus-visible { background: var(--surface-2); text-decoration: none; }
.search-results .sr-title { display: block; font-size: 14px; font-weight: 600; }
.search-results .sr-meta { display: block; font-size: 12px; color: var(--text-muted); }
.search-empty { padding: 10px; color: var(--text-muted); font-size: 14px; }

.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 50%;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  cursor: pointer; transition: background var(--motion);
}
.icon-btn:hover { background: var(--surface-2); }
:root[data-theme="light"] .icon-moon { display: none; }
:root[data-theme="dark"] .icon-sun { display: none; }

/* ---------- hero / stats ---------- */
.hero {
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  padding: 44px 0 8px;
}
.hero-eyebrow {
  margin: 0 0 6px; color: var(--accent);
  font-size: 13px; font-weight: 700; letter-spacing: 2px;
}
.hero h1 { margin: 0 0 10px; font-size: 40px; line-height: 1.2; letter-spacing: 1px; }
.hero-sub { margin: 0; max-width: 620px; color: var(--text-muted); font-size: 16.5px; }
.hero-actions { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
.hero-shield { color: var(--primary); opacity: .9; flex-shrink: 0; }

.stat-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px;
  margin: 26px 0 18px;
}
.stat { text-align: center; padding: 14px 8px; }
.stat strong { display: block; font-size: 26px; color: var(--primary); }
.stat span { font-size: 13px; color: var(--text-muted); }

/* ---------- cards / modules ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px 20px;
}
.module-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px;
  margin: 18px 0 30px;
}
.module-card h3 { margin: 0 0 2px; font-size: 18px; display: flex; align-items: baseline; gap: 8px; }
.module-no {
  color: var(--accent); font-family: var(--font-mono); font-size: 14px; font-weight: 700;
}
.module-meta { margin: 0 0 10px; color: var(--text-muted); font-size: 13px; }
.kp-list { list-style: none; margin: 0; padding: 0; }
.kp-list li {
  display: flex; align-items: baseline; justify-content: space-between; gap: 10px;
  padding: 6px 0; border-top: 1px dashed var(--border); font-size: 14.5px;
}
.kp-list li:first-child { border-top: 0; }
.kp-id { font-family: var(--font-mono); font-size: 12.5px; color: var(--accent); }
.li-meta { color: var(--text-muted); font-size: 12.5px; white-space: nowrap; flex-shrink: 0; }

/* ---------- progress ---------- */
.progress-block { margin: 18px 0; }
.progress-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.progress-nums { color: var(--text-muted); font-size: 14px; }
.progressbar {
  height: 10px; border-radius: 999px; overflow: hidden;
  background: var(--surface-2); margin: 10px 0 12px;
  border: 1px solid var(--border);
}
.progressbar i {
  display: block; height: 100%; width: 0;
  background: linear-gradient(90deg, var(--primary), var(--ok));
  border-radius: 999px;
  transition: width var(--motion);
}
.progress-actions { display: flex; gap: 8px; }

/* ---------- buttons / chips ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 16px; border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface); color: var(--text);
  font: inherit; font-size: 14.5px; cursor: pointer;
  transition: background var(--motion), transform var(--motion);
}
.btn:hover { background: var(--surface-2); text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--primary); color: var(--primary-contrast); border-color: var(--primary); }
.btn-primary:hover { background: var(--primary); filter: brightness(1.08); }
.btn-ghost { background: transparent; }
.btn-sm { padding: 5px 12px; font-size: 13px; }
.btn-mark[aria-pressed="true"] { background: var(--ok-soft); border-color: var(--ok); color: var(--ok); font-weight: 600; }

.chip {
  display: inline-flex; align-items: center;
  padding: 2px 10px; border-radius: 999px;
  background: var(--surface-2); border: 1px solid var(--border);
  font-size: 12.5px; color: var(--text-muted); white-space: nowrap;
}
.chip-tag { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 35%, var(--border)); }
.chip-link { color: var(--primary); }
.chip-link:hover { background: var(--primary-soft); text-decoration: none; }
.chip-row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.chip-level.lv-entry { background: var(--lv-entry-soft); color: var(--lv-entry); border-color: transparent; }
.chip-level.lv-core { background: var(--lv-core-soft); color: var(--lv-core); border-color: transparent; }
.chip-level.lv-advanced { background: var(--lv-advanced-soft); color: var(--lv-advanced); border-color: transparent; }
.chip-level.lv-frontier { background: var(--lv-frontier-soft); color: var(--lv-frontier); border-color: transparent; }

/* ---------- page scaffolding ---------- */
h1 { font-size: 30px; line-height: 1.3; margin: 30px 0 8px; }
.page-desc { color: var(--text-muted); margin: 0 0 18px; }
.breadcrumb {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
  margin: 22px 0 0; font-size: 13.5px; color: var(--text-muted);
}
.breadcrumb span[aria-hidden] { opacity: .5; }

.kp-header { margin: 10px 0 18px; }
.kp-kicker {
  margin: 0; font-family: var(--font-mono); font-size: 13px;
  color: var(--accent); letter-spacing: .5px;
}
.kp-header h1 { margin: 4px 0 12px; }
.kp-actions { display: flex; gap: 8px; margin-top: 14px; }

.callout {
  margin: 18px 0; padding: 14px 16px;
  background: var(--primary-soft);
  border: 1px solid var(--border); border-left: 4px solid var(--primary);
  border-radius: var(--radius-sm);
}
.callout strong { display: block; margin-bottom: 8px; font-size: 14px; }

.pn-nav {
  display: grid; grid-template-columns: 1fr 1fr; gap: 14px;
  margin: 26px 0 40px;
}
.pn { display: flex; flex-direction: column; gap: 4px; color: var(--text); }
.pn-next { text-align: right; align-items: flex-end; }
.pn:hover { text-decoration: none; border-color: var(--primary); }
.pn-label { font-size: 12px; color: var(--text-muted); }

/* ---------- prose（正文阅读节奏） ---------- */
.prose { font-size: 16px; }
.prose h2 {
  font-size: 20px; margin: 30px 0 10px; padding-top: 14px;
  border-top: 1px solid var(--border);
}
.prose h2:first-child { border-top: 0; margin-top: 4px; padding-top: 0; }
.prose h3 { font-size: 16.5px; margin: 20px 0 8px; }
.prose p { margin: 10px 0; }
.prose ul, .prose ol { margin: 10px 0; padding-left: 24px; }
.prose li { margin: 4px 0; }
.prose blockquote {
  margin: 14px 0; padding: 10px 16px;
  border-left: 4px solid var(--accent);
  background: var(--surface-2); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-muted);
}
.prose code {
  font-family: var(--font-mono); font-size: .88em;
  background: var(--surface-2);
  padding: 1.5px 6px; border-radius: 6px;
  border: 1px solid var(--border);
}
.prose strong { color: var(--text); }

.code-block {
  margin: 16px 0; border-radius: var(--radius-sm); overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.code-block figcaption {
  font-family: var(--font-mono); font-size: 11.5px; letter-spacing: 1px;
  padding: 6px 14px;
  background: var(--code-bg); color: #7d95ad;
  border-bottom: 1px solid rgba(128,160,190,.18);
}
.code-block pre { margin: 0; padding: 14px 16px; overflow-x: auto; }
.code-block code {
  display: block;
  font-family: var(--font-mono); font-size: 13.5px; line-height: 1.7;
  background: var(--code-bg); color: var(--code-text);
  border: 0; padding: 0;
}

/* 代码高亮 token 色（两主题共用，取中明度配色） */
.tok-str { color: #8fd18f; }
.tok-com { color: #6f8497; font-style: italic; }
.tok-kw { color: #7cb3ee; font-weight: 600; }
.tok-num { color: #e5a13f; }

.table-wrap { overflow-x: auto; margin: 14px 0; }
.prose table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
.prose th, .prose td {
  border: 1px solid var(--border);
  padding: 8px 12px; text-align: left; vertical-align: top;
}
.prose th { background: var(--surface-2); font-size: 13.5px; }
.prose tbody tr:nth-child(even) { background: color-mix(in srgb, var(--surface-2) 45%, transparent); }

/* ---------- path 页 ---------- */
.path-ol { list-style: none; margin: 18px 0 30px; padding: 0; counter-reset: step; }
.path-step { display: flex; gap: 14px; margin-bottom: 12px; }
.path-no {
  flex-shrink: 0; width: 34px; height: 34px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: var(--primary); color: var(--primary-contrast);
  font-weight: 700; font-size: 15px; margin-top: 6px;
}
.path-card { flex: 1; padding: 12px 16px; }
.path-title { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; font-weight: 600; }
.path-summary { margin: 6px 0 0; color: var(--text-muted); font-size: 14px; }

/* ---------- map 页 ---------- */
.map-figure { padding: 10px; }
.map-scroll { overflow-x: auto; padding: 6px 2px; }
.map-figure svg { min-width: 720px; display: block; margin: 0 auto; }
.map-figure figcaption { color: var(--text-muted); font-size: 13px; padding: 8px 8px 2px; }
.map-edge {
  fill: none; stroke: var(--edge); stroke-width: 1.6;
  opacity: .8;
}
.map-arrow { fill: var(--edge); }
.map-node rect {
  fill: var(--surface);
  stroke: var(--border);
  stroke-width: 1.4;
  transition: stroke var(--motion);
}
.map-node:hover rect { stroke: var(--primary); }
.map-node a { cursor: pointer; }
.map-node-id { font-family: var(--font-mono); font-size: 11px; fill: var(--accent); text-anchor: middle; }
.map-node-title { font-size: 11px; fill: var(--text); text-anchor: middle; }
.map-node.lv-core rect { stroke: var(--lv-core); }
.map-node.lv-advanced rect { stroke: var(--lv-advanced); }
.map-node.lv-frontier rect { stroke: var(--lv-frontier); }
.map-band { font-size: 12.5px; fill: var(--text-muted); font-weight: 600; }

.map-legend-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-bottom: 34px; }
.map-legend-module h3 { margin: 0 0 8px; font-size: 16px; }

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 30px; padding: 22px 0 34px;
  color: var(--text-muted); font-size: 13.5px;
}
.site-footer p { margin: 4px 0; }
.foot-note { opacity: .8; }

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .module-grid, .map-legend-grid { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: repeat(2, 1fr); }
  .hero { flex-direction: column; align-items: flex-start; padding-top: 28px; }
  .hero h1 { font-size: 31px; }
  .pn-nav { grid-template-columns: 1fr; }
  .pn-next { text-align: left; align-items: flex-start; }
}
@media (max-width: 620px) {
  .search { order: 10; width: 100%; margin-left: 0; }
  .search input { width: 100%; max-width: none; }
  .header-inner { gap: 10px; }
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
}