:root {
  --ink: #102b3f;
  --ink-soft: #486173;
  --paper: #f6f9f8;
  --surface: rgba(255, 255, 255, .92);
  --line: #dce7e7;
  --cyan: #00a8a8;
  --cyan-dark: #007f83;
  --cyan-wash: #dff7f4;
  --amber: #f0a83a;
  --shadow: 0 18px 50px rgba(16, 43, 63, .08);
  --sidebar: 292px;
  --topbar: 72px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(rgba(0, 127, 131, .035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 127, 131, .035) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
  font-family: "Avenir Next", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--cyan-dark); text-decoration: none; }
a:hover { color: var(--cyan); }
button, input { font: inherit; }

.topbar {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--topbar);
  z-index: 50;
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr) auto;
  align-items: center;
  padding: 0 28px;
  background: rgba(246, 249, 248, .88);
  border-bottom: 1px solid rgba(16, 43, 63, .1);
  backdrop-filter: blur(18px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  font-weight: 800;
  letter-spacing: -.03em;
}
.brand img { width: 38px; height: 38px; object-fit: contain; }
.brand-mark { display: flex; flex-direction: column; line-height: 1.05; }
.brand-mark small {
  margin-top: 4px;
  color: var(--ink-soft);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.topbar-center { min-width: 0; padding: 0 24px; }
.search-trigger {
  width: min(620px, 100%);
  height: 42px;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 14px;
  color: var(--ink-soft);
  background: rgba(255, 255, 255, .82);
  border: 1px solid var(--line);
  border-radius: 12px;
  cursor: pointer;
  transition: .2s ease;
}
.search-trigger:hover { border-color: #9fcfcd; box-shadow: 0 8px 24px rgba(16, 43, 63, .07); }
.search-trigger svg { width: 18px; }
.search-trigger span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.search-trigger kbd {
  margin-left: auto;
  padding: 2px 8px;
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  border-radius: 7px;
  color: #728793;
  background: #fff;
  font-size: 12px;
}

.top-actions { display: flex; align-items: center; gap: 10px; }
.lang-link, .home-link {
  height: 38px;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 0 12px;
  color: var(--ink);
  border-radius: 10px;
  font-size: 14px;
  font-weight: 700;
}
.lang-link:hover, .home-link:hover { background: #fff; color: var(--cyan-dark); }
.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: #fff;
  color: var(--ink);
  cursor: pointer;
}

.sidebar {
  position: fixed;
  z-index: 40;
  top: var(--topbar);
  bottom: 0;
  left: 0;
  width: var(--sidebar);
  padding: 24px 18px 36px 24px;
  overflow-y: auto;
  background: rgba(246, 249, 248, .82);
  border-right: 1px solid rgba(16, 43, 63, .1);
  backdrop-filter: blur(12px);
}
.sidebar-intro {
  margin: 0 6px 24px;
  padding: 14px 16px;
  color: #286061;
  background: var(--cyan-wash);
  border: 1px solid #c3ebe7;
  border-radius: 14px;
  font-size: 13px;
}
.sidebar-intro strong { display: block; color: var(--cyan-dark); font-size: 14px; }
.nav-group { margin: 0 0 22px; }
.nav-group-title {
  margin: 0 8px 7px;
  color: #728793;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.nav-group a {
  position: relative;
  display: block;
  margin: 2px 0;
  padding: 8px 12px 8px 16px;
  color: #395467;
  border-radius: 9px;
  font-size: 14px;
  font-weight: 600;
  transition: .16s ease;
}
.nav-group a:hover { color: var(--cyan-dark); background: rgba(255,255,255,.8); transform: translateX(2px); }
.nav-group a.active { color: #fff; background: var(--ink); box-shadow: 0 8px 20px rgba(16,43,63,.16); }
.nav-group a.active::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 50%;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: #66e5dc;
  transform: translateY(-50%);
}

.page-shell {
  margin-left: var(--sidebar);
  padding-top: var(--topbar);
  min-height: 100vh;
}
.page-grid {
  display: grid;
  grid-template-columns: minmax(0, 860px) 220px;
  gap: 64px;
  width: min(1180px, calc(100% - 72px));
  margin: 0 auto;
  padding: 56px 0 100px;
  align-items: start;
}
.article {
  min-width: 0;
  padding: 54px clamp(28px, 5vw, 68px) 72px;
  background: var(--surface);
  border: 1px solid rgba(16, 43, 63, .1);
  border-radius: 24px;
  box-shadow: var(--shadow);
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 22px;
  color: var(--cyan-dark);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .13em;
  text-transform: uppercase;
}
.eyebrow::before { content: ""; width: 22px; height: 2px; background: var(--cyan); }
.article > h1:first-of-type, .article-header h1 {
  margin: 0 0 18px;
  color: var(--ink);
  font-family: "DIN Alternate", "Avenir Next", "PingFang SC", sans-serif;
  font-size: clamp(34px, 5vw, 54px);
  line-height: 1.08;
  letter-spacing: -.045em;
}
.article-header {
  margin-bottom: 38px;
  padding-bottom: 30px;
  border-bottom: 1px solid var(--line);
}
.article-header p { margin: 0; color: var(--ink-soft); font-size: 17px; }
.article-content h1 { display: none; }
.article-content h2 {
  margin: 54px 0 18px;
  padding-top: 10px;
  color: var(--ink);
  font-size: 27px;
  line-height: 1.25;
  letter-spacing: -.025em;
}
.article-content h2::before {
  content: attr(data-step);
  display: block;
  margin-bottom: 8px;
  color: var(--cyan);
  font-family: "DIN Alternate", monospace;
  font-size: 12px;
  letter-spacing: .14em;
}
.article-content h3 { margin: 36px 0 12px; font-size: 20px; line-height: 1.35; }
.article-content p { margin: 14px 0; color: #344f61; }
.article-content strong { color: var(--ink); }
.article-content ul, .article-content ol { padding-left: 1.4em; color: #344f61; }
.article-content li { margin: 8px 0; padding-left: 3px; }
.article-content li::marker { color: var(--cyan); font-weight: 800; }
.article-content blockquote {
  margin: 24px 0;
  padding: 18px 22px;
  color: #275c60;
  background: linear-gradient(135deg, #e8f8f5, #f6fbfa);
  border: 0;
  border-left: 4px solid var(--cyan);
  border-radius: 4px 14px 14px 4px;
}
.article-content blockquote p { margin: 0; color: inherit; }
.article-content img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 26px auto;
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: 0 18px 45px rgba(16,43,63,.12);
}
.article-content table {
  width: 100%;
  margin: 24px 0;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 14px;
  font-size: 14px;
}
.article-content th, .article-content td { padding: 12px 14px; text-align: left; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.article-content th { color: var(--ink); background: #eef6f5; }
.article-content tr:last-child td { border-bottom: 0; }
.article-content th:last-child, .article-content td:last-child { border-right: 0; }
.article-content code { padding: 2px 6px; color: #b64b29; background: #fff3ea; border-radius: 6px; font-family: "SFMono-Regular", Consolas, monospace; font-size: .9em; }
.article-content pre { padding: 20px; overflow: auto; color: #d9f5f2; background: #102b3f; border-radius: 14px; }
.article-content pre code { padding: 0; color: inherit; background: transparent; }

.page-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  margin-top: 52px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: #758994;
  font-size: 13px;
}
.page-footer a { font-weight: 700; }

.toc {
  position: sticky;
  top: calc(var(--topbar) + 34px);
  padding-top: 10px;
}
.toc-title { margin-bottom: 13px; color: #728793; font-size: 11px; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.toc a { display: block; padding: 5px 0 5px 14px; color: #6a7f8b; border-left: 1px solid var(--line); font-size: 13px; line-height: 1.45; }
.toc a:hover, .toc a.current { color: var(--cyan-dark); border-left-color: var(--cyan); }

.search-panel {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: none;
  padding: 9vh 20px 20px;
  background: rgba(7, 28, 42, .58);
  backdrop-filter: blur(9px);
}
.search-panel.open { display: block; }
.search-box {
  width: min(720px, 100%);
  max-height: 78vh;
  margin: 0 auto;
  overflow: hidden;
  background: #fff;
  border-radius: 20px;
  box-shadow: 0 28px 90px rgba(0,0,0,.24);
}
.search-input-wrap { display: flex; align-items: center; gap: 12px; padding: 18px 20px; border-bottom: 1px solid var(--line); }
.search-input-wrap svg { width: 22px; color: var(--cyan-dark); }
.search-input { width: 100%; border: 0; outline: 0; color: var(--ink); font-size: 18px; }
.search-close { border: 0; background: transparent; color: #82939c; cursor: pointer; }
.search-results { max-height: calc(78vh - 70px); padding: 10px; overflow-y: auto; }
.search-result { display: block; padding: 14px 16px; color: var(--ink); border-radius: 12px; }
.search-result:hover { color: var(--ink); background: #edf8f6; }
.search-result strong { display: block; margin-bottom: 3px; }
.search-result span { display: block; overflow: hidden; color: var(--ink-soft); font-size: 13px; text-overflow: ellipsis; white-space: nowrap; }
.search-empty { padding: 46px 20px; color: #728793; text-align: center; }
.sidebar-overlay { display: none; }

@media (max-width: 1100px) {
  .page-grid { grid-template-columns: minmax(0, 1fr); width: min(850px, calc(100% - 52px)); }
  .toc { display: none; }
}

@media (max-width: 820px) {
  :root { --topbar: 64px; }
  .topbar { grid-template-columns: 1fr auto; padding: 0 16px; }
  .topbar-center { grid-column: 1 / -1; position: absolute; top: 74px; left: 16px; right: 16px; display: none; }
  .home-link { display: none; }
  .menu-toggle { display: inline-grid; place-items: center; }
  .sidebar { top: 0; z-index: 80; width: min(330px, 88vw); padding-top: 82px; transform: translateX(-105%); transition: transform .25s ease; box-shadow: 20px 0 60px rgba(16,43,63,.18); }
  body.menu-open .sidebar { transform: translateX(0); }
  .sidebar-overlay { position: fixed; inset: 0; z-index: 70; display: block; visibility: hidden; opacity: 0; background: rgba(7,28,42,.38); transition: .25s ease; }
  body.menu-open .sidebar-overlay { visibility: visible; opacity: 1; }
  .page-shell { margin-left: 0; }
  .page-grid { width: calc(100% - 24px); padding: 30px 0 70px; }
  .article { padding: 36px 22px 54px; border-radius: 18px; }
  .article-header h1 { font-size: 36px; }
  .article-content h2 { margin-top: 42px; font-size: 24px; }
  .page-footer { align-items: flex-start; flex-direction: column; }
}