@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:ital,wght@0,400;0,500;1,400&display=swap');

:root {
  --paper: #fdfbf7;
  --paper-2: #f5f5f5;
  --ink: #1a1a1a;
  --rule: #e0e0e0;
  --dim: #5a5a5a;
  --mono: 'JetBrains Mono', ui-monospace, 'SFMono-Regular', 'Menlo', 'Courier New', monospace;
}

*,
*::before,
*::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 16.5px;
  line-height: 1.8;
  letter-spacing: .01em;
  transition: none;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 40;
  pointer-events: none;
  opacity: .28;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='0.38'/%3E%3C/svg%3E");
}

img { max-width: 100%; height: auto; }

a { color: inherit; }

/* ---------- 页头 ---------- */

.masthead {
  position: sticky;
  top: 0;
  z-index: 30;
  background: var(--paper);
  border-bottom: 1px solid var(--ink);
}

.brandrow {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 13px;
  border-bottom: 1px solid var(--rule);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 40px;
  padding: 6px 2px;
  font-size: 17px;
  font-weight: 500;
  letter-spacing: -.01em;
  text-decoration: none;
}

.mark {
  display: inline-grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border: 1px solid var(--ink);
  border-radius: 6px;
  font-size: 13px;
  line-height: 1;
}

.brand:hover .bname { background: var(--ink); color: var(--paper); }

.finder {
  display: flex;
  margin-left: auto;
  min-width: 0;
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 10px;
  overflow: hidden;
}

.finder input {
  width: 118px;
  min-width: 0;
  padding: 9px 10px;
  border: 0;
  background: transparent;
  color: var(--ink);
  font: inherit;
  font-size: 15px;
}

.finder input:focus {
  outline: 2px solid var(--ink);
  outline-offset: -2px;
}

.finder button {
  min-height: 40px;
  padding: 0 11px;
  border: 0;
  border-left: 1px solid var(--rule);
  background: var(--paper-2);
  color: var(--ink);
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}

.finder button:hover { background: var(--ink); color: var(--paper); }

.bar { background: var(--paper-2); }

.bar nav {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 6px;
}

.bar ul {
  display: flex;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
}

.bar li { flex: 0 0 auto; }

.bar a {
  display: block;
  min-height: 44px;
  padding: 13px 11px;
  border-bottom: 2px solid transparent;
  font-size: 15px;
  white-space: nowrap;
  text-decoration: none;
}

.bar a:hover { background: var(--ink); color: var(--paper); }

.bar a.is-on {
  border-bottom-color: var(--ink);
  font-weight: 500;
}

/* ---------- 头图 ---------- */

.hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  display: grid;
  place-items: center;
  min-height: min(45vh, 360px);
  padding: 40px 18px;
  background: var(--paper-2);
  border-bottom: 1px solid var(--rule);
}

.huge {
  position: absolute;
  right: 2%;
  bottom: -.18em;
  z-index: 0;
  color: var(--ink);
  font-size: clamp(120px, 32vw, 300px);
  font-weight: 500;
  line-height: .75;
  letter-spacing: -.07em;
  opacity: .07;
  pointer-events: none;
  user-select: none;
}

.plate {
  position: absolute;
  z-index: 1;
  margin: 0;
  padding: 5px;
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 4px;
  box-shadow: 5px 5px 0 rgba(26, 26, 26, .07);
}

.plate img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  filter: grayscale(1) contrast(1.06);
}

.plate.is-blank {
  aspect-ratio: 3 / 4;
  background: repeating-linear-gradient(0deg, #fff 0 8px, #f4f4f4 8px 9px);
}

.plate-a {
  left: 2%;
  top: 11%;
  width: 24%;
  max-width: 168px;
  transform: rotate(-3.5deg);
}

.plate-b {
  right: 3%;
  top: 41%;
  width: 21%;
  max-width: 148px;
  transform: rotate(3deg);
}

.hero h1 {
  position: relative;
  z-index: 2;
  max-width: min(15em, 74%);
  margin: 0;
  padding: 0 4px;
  font-size: clamp(23px, 4.4vw, 42px);
  font-weight: 500;
  line-height: 1.32;
  letter-spacing: -.02em;
  text-align: center;
}

/* ---------- 正文与侧栏 ---------- */

.sheet {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 272px;
  align-items: start;
  max-width: 1180px;
  margin: 0 auto;
}

.copy {
  min-width: 0;
  padding: 0 22px 48px;
  border-right: 1px solid var(--rule);
  overflow-wrap: anywhere;
}

.copy > article {
  margin: 26px 0 0;
  padding: 22px 20px;
  background: #fff;
  border: 1px solid var(--rule);
  border-bottom: 3px solid var(--ink);
  border-radius: 18px;
  scroll-margin-top: 112px;
}

.copy h2 {
  margin: 0 0 12px;
  font-size: clamp(20px, 2.4vw, 25px);
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: -.01em;
}

.copy h3 {
  margin: 1.5em 0 .5em;
  font-size: 18px;
  font-weight: 500;
}

.copy p { margin: 0 0 1.05em; }
.copy h2 + p,
.copy h3 + p { margin-top: .1em; }

.copy ul,
.copy ol {
  margin: 0 0 1.1em;
  padding-left: 1.35em;
}

.copy li { margin: .25em 0; }

.copy a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.copy a:hover {
  background: var(--ink);
  color: var(--paper);
  text-decoration: none;
}

.copy img {
  display: block;
  margin: 1em 0;
  border: 1px solid var(--rule);
  border-radius: 10px;
}

.copy blockquote {
  margin: 1.2em 0;
  padding: .5em 1em;
  background: var(--paper-2);
  border-left: 3px solid var(--ink);
}

.copy blockquote p:last-child { margin: 0; }

.copy table {
  display: block;
  margin: 1em 0;
  overflow-x: auto;
  border-collapse: collapse;
  font-size: 15px;
}

.copy th,
.copy td {
  padding: 8px 10px;
  border: 1px solid var(--rule);
  text-align: left;
}

.copy code {
  padding: .1em .35em;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-radius: 4px;
  font-size: .92em;
}

.copy pre {
  overflow-x: auto;
  padding: 12px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-radius: 8px;
}

.copy pre code { padding: 0; border: 0; background: none; }

.copy time { font-size: 14px; color: var(--dim); }

/* ---------- 右侧栏 ---------- */

.rail {
  position: sticky;
  top: 104px;
  padding: 26px 18px 40px;
  font-size: 15px;
}

.rail h2 {
  margin: 0 0 4px;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .26em;
}

.rail .subtitle {
  margin: 0 0 14px;
  color: var(--dim);
  font-size: 13px;
  letter-spacing: .1em;
}

.jump {
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  counter-reset: j;
  border-top: 1px solid var(--rule);
}

.jump li {
  counter-increment: j;
  border-bottom: 1px solid var(--rule);
}

.jump a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  min-height: 42px;
  padding: 10px 2px;
  font-size: 14.5px;
  text-decoration: none;
}

.jump a::before {
  content: counter(j, decimal-leading-zero);
  color: var(--dim);
  font-size: 12px;
  letter-spacing: .05em;
}

.jump a:hover { background: var(--ink); color: var(--paper); }
.jump a:hover::before { color: var(--paper); }

.sub {
  padding: 14px 13px 15px;
  background: #fff;
  border: 1px solid var(--rule);
  border-bottom: 3px solid var(--ink);
  border-radius: 14px;
}

.sub-t {
  margin: 0 0 9px;
  font-size: 14px;
}

.sub input {
  width: 100%;
  min-height: 42px;
  padding: 9px 10px;
  background: var(--paper);
  color: var(--ink);
  border: 1px solid var(--rule);
  border-radius: 8px;
  font: inherit;
  font-size: 15px;
}

.sub input:focus {
  outline: 2px solid var(--ink);
  outline-offset: -2px;
}

.sub button {
  width: 100%;
  min-height: 42px;
  margin-top: 9px;
  background: var(--ink);
  color: var(--paper);
  border: 1px solid var(--ink);
  border-radius: 8px;
  font: inherit;
  font-size: 15px;
  cursor: pointer;
}

.sub button:hover { background: var(--paper); color: var(--ink); }

/* ---------- 页脚 ---------- */

.foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 14px 18px;
  background: var(--paper-2);
  border-top: 1px solid var(--ink);
}

.foot p {
  margin: 0;
  color: var(--dim);
  font-size: 13.5px;
}

.foot small { font-size: 13.5px; }

.foot a {
  display: inline-block;
  min-height: 40px;
  padding: 6px 2px;
  border-bottom: 1px solid var(--rule);
  line-height: 1.9;
  text-decoration: none;
}

.foot a:hover { background: var(--ink); color: var(--paper); }

/* ---------- 断点 ---------- */

@media (max-width: 900px) {
  .sheet { grid-template-columns: minmax(0, 1fr); }

  .copy {
    padding: 0 14px 34px;
    border-right: 0;
    border-bottom: 1px solid var(--rule);
  }

  .rail {
    position: static;
    padding: 22px 14px 34px;
  }
}

@media (max-width: 560px) {
  body { font-size: 16px; }

  .finder input { width: 92px; }

  .hero {
    min-height: min(45vh, 320px);
    padding: 32px 12px;
  }

  .hero h1 { max-width: 80%; }

  .copy > article {
    padding: 18px 15px;
    border-radius: 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

button[aria-expanded]{min-width:44px;min-height:44px}