:root {
  --bg: #efe8dc;
  --bg-accent: #e4d8c6;
  --paper: #fffcf7;
  --ink: #25211d;
  --muted: #625a52;
  --faint: #756b61;
  --line: #d9d3c9;
  --chip: #ece8df;
  --accent: #b25738;
  --accent-deep: #8d3f28;
  --ok: #2f6b4f;
  --ok-bg: #e7f2ea;
  --warn-bg: #f7efe4;
  --header: rgba(255, 252, 247, 0.92);
  --shadow: 0 18px 50px rgba(47, 36, 24, 0.08);
  --serif: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "STSong", "Times New Roman", serif;
  --sans: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  --mono: "Cascadia Mono", "Sarasa Mono SC", "Consolas", monospace;
}

html[data-theme="dark"] {
  --bg: #1d1b18;
  --bg-accent: #2a2622;
  --paper: #242321;
  --ink: #f1ede6;
  --muted: #c4bcb3;
  --faint: #aea69d;
  --line: #47413a;
  --chip: #38342f;
  --accent: #c9795e;
  --accent-deep: #e3b09c;
  --ok: #8fbfa4;
  --ok-bg: #2a3b32;
  --warn-bg: #3a3128;
  --header: rgba(36, 35, 33, 0.92);
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.28);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, var(--bg-accent), transparent 28rem),
    var(--bg);
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.75;
}

a {
  color: var(--accent-deep);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--accent);
}

.skip {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 20;
  padding: 0.6rem 0.9rem;
  background: var(--paper);
  color: var(--ink);
}

.skip:focus {
  top: 1rem;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 4vw;
  background: var(--header);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(16px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: inherit;
  text-decoration: none;
}

.brand img {
  width: 36px;
  height: 36px;
}

.brand strong {
  display: block;
  font-family: var(--serif);
  font-size: 1.02rem;
  letter-spacing: 0.02em;
}

.brand span {
  display: block;
  color: var(--faint);
  font-size: 0.78rem;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--chip);
  color: var(--ink);
  border-radius: 999px;
  padding: 0.38rem 0.8rem;
  font: inherit;
  font-size: 0.86rem;
  cursor: pointer;
  text-decoration: none;
}

.btn:hover,
.btn.is-current {
  border-color: var(--accent);
  color: var(--accent-deep);
}

.wrap {
  width: min(1180px, calc(100% - 8vw));
  margin: 2.2rem auto 4rem;
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  gap: 2rem;
  min-width: 0;
  max-width: 100%;
}

.toc {
  position: sticky;
  top: 5.4rem;
  align-self: start;
  max-height: calc(100vh - 6.4rem);
  overflow: auto;
  padding-right: 0.4rem;
  min-width: 0;
  max-width: 100%;
}

.toc h2 {
  margin: 0 0 0.7rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--faint);
}

.toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc a {
  display: block;
  padding: 0.28rem 0.4rem;
  border-left: 2px solid transparent;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.86rem;
  line-height: 1.45;
}

.toc a.is-active,
.toc a:hover {
  border-left-color: var(--accent);
  color: var(--ink);
}

.paper {
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  padding: clamp(1.5rem, 4vw, 3.2rem);
  min-width: 0;
}

.kicker {
  margin: 0 0 0.6rem;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.14em;
}

h1 {
  margin: 0 0 0.8rem;
  font-family: var(--serif);
  font-size: clamp(2rem, 5vw, 2.8rem);
  line-height: 1.25;
  font-weight: 700;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 1.2rem;
  margin: 0 0 1.4rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin: 0 0 1.6rem;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  background: var(--ok-bg);
  color: var(--ok);
  font-size: 0.86rem;
  font-weight: 600;
}

.lede {
  font-size: 1.06rem;
  color: var(--muted);
}

h2 {
  margin: 2.2rem 0 0.8rem;
  padding-top: 0.4rem;
  font-family: var(--serif);
  font-size: 1.45rem;
  scroll-margin-top: 5.2rem;
}

h3 {
  margin: 1.4rem 0 0.55rem;
  font-size: 1.05rem;
}

p,
li {
  color: var(--ink);
}

ul, ol {
  padding-left: 1.2rem;
}

.note {
  margin: 1rem 0;
  padding: 0.9rem 1rem;
  background: var(--warn-bg);
  border-left: 3px solid var(--accent);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0 1.4rem;
  font-size: 0.92rem;
}

th, td {
  border: 1px solid var(--line);
  padding: 0.65rem 0.7rem;
  vertical-align: top;
  text-align: left;
}

th {
  background: var(--chip);
  font-weight: 650;
}

.muted {
  color: var(--muted);
}

code, .mono {
  font-family: var(--mono);
  font-size: 0.88em;
}

.footer {
  width: min(1180px, calc(100% - 8vw));
  margin: 0 auto 3rem;
  color: var(--faint);
  font-size: 0.88rem;
}

.footer strong {
  color: var(--muted);
}

@media (max-width: 920px) {
  .wrap {
    grid-template-columns: minmax(0, 1fr);
  }

  .toc {
    position: static;
    max-height: none;
    padding: 1rem;
    background: var(--paper);
    border: 1px solid var(--line);
  }

  .toc ol {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.15rem 0.8rem;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .toc ol {
    grid-template-columns: 1fr;
  }

  table {
    display: block;
    overflow-x: auto;
  }
}

@media print {
  .topbar, .toc, .actions, .skip {
    display: none !important;
  }

  body {
    background: #fff;
  }

  .wrap, .footer {
    width: auto;
    margin: 0;
    display: block;
  }

  .paper {
    border: 0;
    box-shadow: none;
    padding: 0;
  }

  a {
    color: inherit;
    text-decoration: none;
  }
}