/* zh 子域 · 实验室记录本 Lab notebook */
:root {
  --paper: #f4f1e6;
  --paper-deep: #ebe6d4;
  --grid: rgba(122, 158, 128, 0.28);
  --grid-soft: rgba(122, 158, 128, 0.16);
  --ink: #1d3a2f;
  --ink-soft: #3a5648;
  --rule: #8aa392;
  --stamp: #b42318;
  --hole: #cfc8b4;
  --card: rgba(255, 252, 244, 0.72);
}

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

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    repeating-linear-gradient(
      0deg,
      transparent 0 23px,
      var(--grid-soft) 23px 24px
    ),
    repeating-linear-gradient(
      90deg,
      transparent 0 23px,
      var(--grid) 23px 24px
    );
  font-family: Georgia, "Palatino Linotype", "Songti SC", SimSun, "STSong", serif;
  font-size: 17px;
  line-height: 1.85;
}

img,
svg {
  max-width: 100%;
  vertical-align: middle;
}

a {
  color: #245544;
}

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

p {
  margin: 0 0 1em;
}

h1,
h2,
h3 {
  font-weight: 700;
  line-height: 1.35;
  margin: 0 0 0.55em;
}

h1 {
  font-size: 1.72rem;
}

h2 {
  font-size: 1.28rem;
  padding-bottom: 0.35em;
  border-bottom: 1px solid var(--rule);
  box-shadow: 0 1px 0 rgba(138, 163, 146, 0.35);
}

h3 {
  font-size: 1.05rem;
}

.skip {
  position: absolute;
  left: -999px;
}

.skip:focus {
  left: 12px;
  top: 12px;
  z-index: 40;
  background: #fff;
  padding: 6px 10px;
}

/* —— 实验封面 —— */
.cover {
  background: linear-gradient(180deg, #efe9d6 0%, #e6e0cc 100%);
  border-bottom: 3px double var(--ink);
  position: relative;
  z-index: 8;
}

.cover-inner {
  width: min(1080px, calc(100% - 28px));
  margin: 0 auto;
  padding: 18px 0 14px;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px 24px;
  align-items: center;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-size: 1.28rem;
  letter-spacing: 0.04em;
}

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

.brand-mark {
  flex: 0 0 36px;
}

.cover-meta {
  text-align: right;
}

.rec-no {
  margin: 0;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}

.stamp {
  display: inline-block;
  margin-top: 6px;
  padding: 2px 8px;
  border: 2px solid var(--stamp);
  color: var(--stamp);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  transform: rotate(-4deg);
}

.toc-nav {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  padding-top: 6px;
  border-top: 1px dashed var(--rule);
}

.toc-nav a {
  color: var(--ink);
  text-decoration: none;
  font-size: 0.95rem;
}

.toc-nav a span {
  color: var(--rule);
  margin-right: 8px;
  font-family: Georgia, "Palatino Linotype", serif;
}

.toc-nav a:hover {
  color: var(--stamp);
}

.toc-nav a.is-on {
  border-bottom: 2px solid var(--ink);
}

.nav-toggle {
  display: none;
  border: 1px solid var(--ink);
  background: transparent;
  color: var(--ink);
  width: 40px;
  height: 36px;
  padding: 0;
  cursor: pointer;
}

.nav-toggle:hover {
  background: rgba(29, 58, 47, 0.06);
}

/* —— 本册装订 —— */
.notebook {
  position: relative;
  width: min(1080px, calc(100% - 20px));
  margin: 22px auto 40px;
  background: var(--card);
  border: 1px solid #d5d0bf;
  box-shadow: 0 10px 0 rgba(29, 58, 47, 0.04), 0 0 0 1px rgba(138, 163, 146, 0.25);
  padding: 28px 36px 36px 88px;
  min-height: 70vh;
}

.notebook::before {
  content: "";
  position: absolute;
  left: 58px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, transparent, var(--rule) 8%, var(--rule) 92%, transparent);
}

.holes {
  position: absolute;
  left: 16px;
  top: 36px;
  bottom: 36px;
  width: 26px;
  background-image: radial-gradient(circle at 13px 12px, #f7f3e6 0 6px, var(--hole) 6.5px 8px, #8a8370 8.2px 9px, transparent 9.5px);
  background-size: 26px 54px;
  background-repeat: repeat-y;
  filter: drop-shadow(3px 2px 1px rgba(29, 58, 47, 0.18));
}

.step {
  position: relative;
  margin: 0 0 2.2rem;
}

.step-no {
  position: absolute;
  left: -62px;
  top: 4px;
  width: 42px;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--rule);
  text-align: right;
}

.kicker {
  margin: 0 0 0.4em;
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  color: var(--ink-soft);
  text-transform: uppercase;
}

.lead {
  font-size: 1.05rem;
}

.meta-line {
  font-size: 0.88rem;
  color: var(--ink-soft);
}

.rack {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.vial {
  border: 1px dashed var(--rule);
  background: rgba(244, 241, 230, 0.65);
  padding: 14px 16px 6px;
}

.obs {
  border-left: 3px solid var(--ink);
  padding: 4px 0 4px 14px;
  margin: 0 0 1.1em;
}

.bench {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.bench article {
  border: 1px solid #d2ccb8;
  padding: 14px 16px 8px;
  background: #faf7ec;
}

.bench h3 {
  margin-bottom: 0.35em;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border: 1px solid var(--ink);
  background: #1d3a2f;
  color: #f4f1e6;
  text-decoration: none;
  font-size: 0.95rem;
}

.btn:hover {
  background: #245544;
  color: #fff;
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
}

.btn-ghost:hover {
  background: rgba(29, 58, 47, 0.08);
  color: var(--ink);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0.6em 0 1em;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  margin: 0.4em 0 1em;
}

th,
td {
  border: 1px solid #c9c3ae;
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

th {
  background: #e8e3d0;
}

.pollute {
  color: var(--stamp);
}

.review {
  margin: 0 0 1.3em;
  padding: 12px 14px 4px;
  background: #f8f4e8;
  border: 1px solid #d8d2bf;
}

.review header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.9rem;
  margin-bottom: 0.4em;
}

.review strong {
  display: block;
}

.faq dt {
  font-weight: 700;
  margin: 0.9em 0 0.25em;
}

.faq dd {
  margin: 0 0 0.4em;
}

.cta-box {
  border: 2px solid var(--stamp);
  padding: 16px 18px 8px;
  margin: 1.2em 0;
  background: rgba(180, 35, 24, 0.04);
}

.foot {
  border-top: 3px double var(--ink);
  background: #e8e2cf;
  padding: 22px 16px 28px;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.foot-inner {
  width: min(1080px, calc(100% - 20px));
  margin: 0 auto;
}

.foot p {
  margin: 0 0 0.55em;
}

@media (max-width: 820px) {
  .cover-inner {
    grid-template-columns: 1fr auto;
  }

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    grid-column: 2;
    grid-row: 1;
  }

  .cover-meta {
    grid-column: 1 / -1;
    text-align: left;
  }

  .toc-nav {
    display: none;
    flex-direction: column;
    gap: 10px;
  }

  .toc-nav.is-open {
    display: flex;
  }

  .notebook {
    padding: 22px 16px 28px 22px;
  }

  .notebook::before,
  .holes,
  .step-no {
    display: none;
  }

  .rack,
  .bench {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 1.4rem;
  }
}