:root {
  color-scheme: light;
  --bg: #ffffff;
  --sidebar: #f7f7f7;
  --ink: #24292f;
  --muted: #6e7781;
  --line: #d8dee4;
  --link: #0969da;
  --hover: #eef3f8;
  --mark: #fff1a7;
  --reader-font-size: 19px;
  --content-width: 920px;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #1f2328;
  --sidebar: #171b20;
  --ink: #e6edf3;
  --muted: #9da7b1;
  --line: #30363d;
  --link: #79c0ff;
  --hover: #26313d;
  --mark: #6b5f20;
}

* {
  box-sizing: border-box;
}

html {
  scroll-padding-top: 70px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  display: grid;
  min-height: 100vh;
  grid-template-columns: 300px minmax(0, 1fr);
  grid-template-rows: 50px minmax(0, 1fr);
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-column: 1 / -1;
  grid-template-columns: auto auto minmax(220px, 480px) auto;
  align-items: center;
  gap: 10px;
  height: 50px;
  padding: 0 12px;
  border-bottom: 1px solid var(--line);
  background: var(--bg);
}

.brand {
  color: var(--ink);
  font-size: 16px;
  font-weight: 700;
}

.search-box {
  display: flex;
  align-items: center;
  height: 34px;
  min-width: 0;
  gap: 6px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg);
  color: var(--muted);
}

.search-box input,
.search-box input {
  width: 100%;
  min-width: 0;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--ink);
}

.toolbar {
  display: flex;
  gap: 6px;
}

.icon-button {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg);
  color: var(--ink);
}

.icon-button:hover {
  background: var(--hover);
}

.menu-button,
.close-sidebar {
  display: none;
}

.sidebar {
  position: sticky;
  top: 50px;
  height: calc(100vh - 50px);
  overflow: auto;
  border-right: 1px solid var(--line);
  background: var(--sidebar);
}

.sidebar-head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 10px;
  padding: 16px 16px 8px;
}

.sidebar-head strong,
.sidebar-head span {
  display: block;
}

.sidebar-head span {
  margin-top: 4px;
  color: var(--muted);
  font-size: 12px;
}

.home-link {
  display: block;
  padding: 8px 16px;
  color: var(--ink);
  font-weight: 600;
}

.outline {
  padding: 0 8px 18px;
}

.category {
  margin: 10px 0 14px;
}

.category h2 {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin: 0 0 4px;
  padding: 6px 8px;
  color: var(--ink);
  font-size: 14px;
  font-weight: 600;
}

.category small {
  color: var(--muted);
  font-size: 12px;
  font-weight: 400;
}

.category ul,
.chapter-toc {
  margin: 0;
  padding-left: 0;
}

.category ul {
  list-style: none;
}

.category li {
  margin: 0;
  font-size: 14px;
}

.category a {
  display: block;
  overflow: hidden;
  padding: 4px 8px 4px 16px;
  border-radius: 4px;
  color: var(--ink);
  text-overflow: ellipsis;
  white-space: nowrap;
}

.category a:hover,
.category a.active {
  background: var(--hover);
  color: var(--link);
  text-decoration: none;
}

.main {
  min-width: 0;
  padding: 28px 34px 64px;
}

.main:focus {
  outline: none;
}

.content {
  max-width: var(--content-width);
  margin: 0 auto;
  font-size: var(--reader-font-size);
  line-height: 1.85;
}

.content h1 {
  margin: 0 0 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  font-size: 34px;
  line-height: 1.25;
  font-weight: 700;
}

.content h2 {
  margin: 34px 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--line);
  font-size: 24px;
  line-height: 1.35;
}

.content h3 {
  margin: 22px 0 8px;
  font-size: 18px;
}

.content p {
  margin: 0 0 1em;
  overflow-wrap: anywhere;
}

.content .meta,
.breadcrumb,
.continue,
.empty {
  color: var(--muted);
  font-size: 15px;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.continue {
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--sidebar);
}

.chapter-toc li {
  margin: 3px 0;
  padding-left: 2px;
}

.chapter-toc {
  columns: 2 260px;
  margin-bottom: 28px;
  padding-left: 24px;
}

.chapter {
  padding-top: 12px;
}

.chapter h2 {
  scroll-margin-top: 68px;
}

mark {
  border-radius: 2px;
  background: var(--mark);
  color: inherit;
}

.search-results {
  position: sticky;
  top: 62px;
  z-index: 12;
  max-width: var(--content-width);
  max-height: 58vh;
  overflow: auto;
  margin: 0 auto 22px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.12);
}

.search-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}

.search-head button {
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg);
  color: var(--ink);
}

.result-group {
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

.result-group:first-of-type {
  border-top: 0;
}

.result-group h3 {
  margin: 0 0 6px;
  color: var(--muted);
  font-size: 13px;
}

.result {
  display: block;
  padding: 7px 8px;
  border-radius: 4px;
}

.result:hover {
  background: var(--hover);
  text-decoration: none;
}

.result strong,
.result small {
  display: block;
}

.result small,
.result-group p {
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 860px) {
  .app-shell {
    grid-template-columns: 1fr;
    grid-template-rows: auto minmax(0, 1fr);
  }

  .topbar {
    grid-template-columns: auto minmax(0, 1fr) auto;
    height: auto;
    min-height: 50px;
    row-gap: 8px;
    padding: 8px 12px;
  }

  .menu-button {
    display: grid;
  }

  .search-box {
    grid-column: 1 / -1;
    order: 2;
  }

  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 30;
    width: min(86vw, 320px);
    height: 100vh;
    transform: translateX(-105%);
    transition: transform 160ms ease;
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.18);
  }

  body.sidebar-open {
    overflow: hidden;
  }

  body.sidebar-open .sidebar {
    transform: translateX(0);
  }

  .close-sidebar {
    display: grid;
  }

  .main {
    padding: 22px 18px 54px;
  }

  .content h1 {
    font-size: 30px;
  }

  .content h2 {
    font-size: 22px;
  }

  .chapter-toc {
    columns: 1;
  }
}

@media (max-width: 520px) {
  .brand {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .toolbar .icon-button {
    width: 32px;
  }

  .content {
    font-size: calc(var(--reader-font-size) - 1px);
  }
}