:root {
  color-scheme: light dark;

  --bg: #F7F8F8;
  --ink: #1F2528;       /* 14.6:1 on bg */
  --ink-read: #37434A;  /* body text on project pages: 9.6:1 */
  --ink-2: #4E5A5F;     /* secondary: 6.7:1 */
  --meta: #66727A;      /* labels, states: 4.6:1 */
  --rule: #D9DFE1;
  --underline: #7F939B; /* 3.0:1 */
  --accent: #2F6173;    /* link hover, focus ring, the one figure: 6.4:1 */
  --select: #D3E0E5;

  --serif: "Hedvig Letters Serif", Georgia, "Times New Roman", serif;
  --sans: "Hedvig Letters Sans", "Helvetica Neue", Arial, sans-serif;
  --zh: "Noto Serif SC", "Songti SC", "STSong", "SimSun", serif;

  /* five sizes */
  --fs-meta: 0.8125rem;
  --fs-body: 1rem;
  --fs-read: 1.125rem;
  --fs-title: clamp(1.375rem, 1.2rem + 0.5vw, 1.5rem);
  --fs-display: clamp(2rem, 1.5rem + 1.9vw, 2.75rem);

  --gutter: clamp(16px, 4vw, 40px);
  --measure: 36rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14191B;
    --ink: #E3E8EA;       /* 14.4:1 */
    --ink-read: #C3CDD1;  /* 11:1 */
    --ink-2: #A7B3B8;     /* 8.3:1 */
    --meta: #86939A;      /* 5.6:1 */
    --rule: #263035;
    --underline: #5A7480; /* 3.6:1 */
    --accent: #8DB7C8;    /* 8.2:1 */
    --select: #28404A;
  }
  body {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }
}

/* ---------- base ---------- */

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 var(--fs-body)/1.625 var(--sans);
  font-kerning: normal;
}

h1, h2, h3, p, ol, ul, dl, dd, figure { margin: 0; padding: 0; }
ol, ul { list-style: none; }

::selection { background: var(--select); color: var(--ink); }

:lang(zh) { font-family: var(--zh); }

a {
  color: inherit;
  text-decoration-line: underline;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--underline);
  text-underline-offset: 0.22em;
  transition: color 160ms ease-out, text-decoration-color 160ms ease-out;
}
a:hover { text-decoration-color: var(--accent); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

.ext { margin-left: 0.15em; font-size: 0.85em; }
.nowrap { white-space: nowrap; }

.skip {
  position: absolute;
  left: var(--gutter);
  top: 0.75rem;
  z-index: 1;
  padding: 0.35rem 0.6rem;
  background: var(--bg);
  transform: translateY(-200%);
}
.skip:focus { transform: none; }

/* ---------- page: one measure; on wide screens the name moves to a side column ---------- */

.page {
  max-width: calc(var(--measure) + 2 * var(--gutter));
  margin-inline: auto;
  padding: 2.5rem var(--gutter) 3.5rem;
}

.site-name {
  font: 400 var(--fs-title)/1.2 var(--serif);
  letter-spacing: -0.005em;
}
.site-name a { text-decoration-color: transparent; }
.site-name a:hover { text-decoration-color: var(--accent); }

.zh-name {
  margin-top: 0.2rem;
  font: 400 var(--fs-body)/1.6 var(--zh);
  letter-spacing: 0.14em;
  color: var(--meta);
}

.affil { margin-top: 1rem; color: var(--ink-2); }

.contact {
  margin-top: 0.35rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0 1.25rem;
  color: var(--ink-2);
}

.back {
  display: inline-block;
  margin-top: 0.6rem;
  color: var(--ink-2);
}

.site-foot {
  margin-top: 4rem;
  font-size: var(--fs-meta);
  color: var(--meta);
}

/* ---------- index ---------- */

.intro {
  margin-top: 2.5rem;
  font-size: var(--fs-read);
  line-height: 1.55;
  text-wrap: pretty;
}

.label {
  font: 400 var(--fs-body)/1.5 var(--serif);
  color: var(--meta);
}

.group { margin-top: 3.5rem; scroll-margin-top: 2rem; }
.group .label { margin-bottom: 0.6rem; }

.index { border-bottom: 1px solid var(--rule); }

.row {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  column-gap: 1.5rem;
  align-items: baseline;
  padding: 1.05rem 0 1.2rem;
  border-top: 1px solid var(--rule);
}

.row h3 {
  font: 400 var(--fs-title)/1.22 var(--serif);
  letter-spacing: -0.006em;
  text-wrap: balance;
}

.row .state {
  font-size: var(--fs-meta);
  color: var(--meta);
  white-space: nowrap;
}

.row .desc {
  grid-column: 1 / -1;
  margin-top: 0.3rem;
  color: var(--ink-2);
  text-wrap: pretty;
}

/* the whole row is the link's hit area; the title stays the only link text */
.row h3 a::after { content: ""; position: absolute; inset: 0; }
.row:hover h3 a { text-decoration-color: var(--accent); }
.row h3 a:focus-visible { outline: none; }
.row h3 a:focus-visible::after {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 2px;
}

.now { margin-top: 3.5rem; }
.now p { color: var(--ink-2); text-wrap: pretty; }
.now .label + p { margin-top: 0.3rem; }
.now p + p { margin-top: 0.2rem; }

/* ---------- project pages ---------- */

.article { margin-top: 3rem; }

.kicker { font-size: var(--fs-meta); color: var(--meta); }

.article h1 {
  margin-top: 0.5rem;
  font: 400 var(--fs-display)/1.1 var(--serif);
  letter-spacing: -0.012em;
  text-wrap: balance;
}

.summary {
  margin-top: 1.1rem;
  font-size: var(--fs-read);
  line-height: 1.55;
  text-wrap: pretty;
}

.facts {
  margin-top: 1.75rem;
  padding-block: 0.9rem;
  border-block: 1px solid var(--rule);
  display: grid;
  grid-template-columns: 5.5rem minmax(0, 1fr);
  gap: 0.45rem 1.25rem;
  line-height: 1.55;
}
.facts dt { color: var(--meta); }
.facts dd { color: var(--ink-2); overflow-wrap: anywhere; }

.prose { margin-top: 2rem; }
.prose p,
.prose li {
  font-size: var(--fs-read);
  line-height: 1.6;
  color: var(--ink-read);
  text-wrap: pretty;
}
.prose > * + * { margin-top: 1.1rem; }
.prose li { position: relative; padding-left: 1.1rem; }
.prose li::before { content: "\2013"; position: absolute; left: 0; color: var(--meta); }
.prose li + li { margin-top: 0.35rem; }

.pager {
  margin-top: 4rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  color: var(--ink-2);
}

/* Xiake: the route list */
.routes {
  margin-top: 2.25rem;
  width: 100%;
  border-collapse: collapse;
  line-height: 1.5;
}
.routes caption {
  padding-bottom: 0.6rem;
  text-align: left;
  font: 400 var(--fs-body)/1.5 var(--serif);
  color: var(--meta);
}
.routes th,
.routes td {
  padding: 0.6rem 0;
  border-top: 1px solid var(--rule);
  text-align: left;
  vertical-align: baseline;
  font-weight: 400;
}
.routes thead th { padding-top: 0; border-top: 0; font-size: var(--fs-meta); color: var(--meta); }
.routes .n { padding-left: 1.5rem; white-space: nowrap; color: var(--ink-2); }
.routes tbody th [lang] { color: var(--meta); white-space: nowrap; }
.routes .via { display: block; font-size: var(--fs-meta); color: var(--meta); }
.routes tfoot th,
.routes tfoot td { border-bottom: 1px solid var(--rule); color: var(--ink-2); }

/* Football: the one figure, a number line of closing-line value */
.figure {
  margin-top: 2.25rem;
  padding: 1.1rem 0 1rem;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--rule);
}
.fig-label { font-size: var(--fs-meta); line-height: 1.5; color: var(--ink-2); }
.fig-label + .track { margin-top: 0.2rem; }
.track + .fig-label { margin-top: 1rem; }
.track { position: relative; height: 2.6rem; }
.track::before {
  content: "";
  position: absolute;
  left: 40%;
  top: 0.35rem;
  bottom: 0;
  width: 1px;
  background: var(--ink);
}
.pt {
  position: absolute;
  left: var(--at);
  bottom: 0.3rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
  transform: translateX(-50%);
}
.band {
  position: absolute;
  left: var(--from);
  width: calc(var(--to) - var(--from));
  bottom: 0.55rem;
  height: 3px;
  background: var(--accent);
}
.band::before,
.band::after {
  content: "";
  position: absolute;
  top: -5px;
  width: 1px;
  height: 13px;
  background: var(--accent);
}
.band::before { left: 0; }
.band::after { right: 0; }
.val {
  position: absolute;
  left: var(--at);
  top: 0;
  transform: translateX(-50%);
  font: 400 var(--fs-body)/1.2 var(--serif);
  white-space: nowrap;
}
.axis {
  position: relative;
  height: 1.6rem;
  margin-top: 0.35rem;
  border-top: 1px solid var(--meta);
}
.axis span {
  position: absolute;
  left: var(--at);
  top: 0.3rem;
  transform: translateX(-50%);
  font-size: var(--fs-meta);
  line-height: 1;
  color: var(--meta);
}
.axis span::before {
  content: "";
  position: absolute;
  left: 50%;
  top: calc(-0.3rem - 1px);
  width: 1px;
  height: 4px;
  background: var(--meta);
}
.axis span:first-child { transform: none; }
.axis span:first-child::before { left: 0; }
.axis span:last-child { transform: translateX(-100%); }
.axis span:last-child::before { left: auto; right: 0; }
.figure figcaption {
  margin-top: 0.9rem;
  line-height: 1.55;
  color: var(--ink-2);
  text-wrap: pretty;
}

/* ---------- narrow screens ---------- */

@media (max-width: 39.99rem) {
  .row { grid-template-columns: minmax(0, 1fr); }
  .row .state { order: -1; margin-bottom: 0.2rem; }
}

@media (max-width: 59.99rem) {
  .page { padding-top: 1.5rem; }
  .intro { margin-top: 1.75rem; }
  /* project pages: the name becomes a one-line header */
  p.site-name { font-size: var(--fs-body); }
  .site:has(.back) {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: baseline;
    gap: 0 1.5rem;
  }
  .back { margin-top: 0; }
}

/* ---------- wide screens: name block in a side column ---------- */

@media (min-width: 60rem) {
  .page {
    display: grid;
    grid-template-columns: 14rem minmax(0, var(--measure));
    column-gap: clamp(3.5rem, 7vw, 7rem);
    justify-content: center;
    max-width: 67rem;
    padding: 6rem 2.5rem 5rem;
  }
  .site {
    grid-row: 1 / span 2;
    align-self: start;
  }
  .page > main,
  .site-foot { grid-column: 2; }
  /* cross-column baselines: name with intro or kicker, back link with the title */
  .back { margin-top: 1.8rem; }
  .intro { margin-top: 0.15rem; }
  .article { margin-top: 0.47rem; }
}

@media (prefers-color-scheme: dark) {
  .figure { border-top-color: var(--ink-2); }
}

@media (forced-colors: active) {
  .pt, .band, .band::before, .band::after, .track::before, .axis span::before {
    forced-color-adjust: none;
    background: CanvasText;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; }
}