/* ===== reset ===== */
*, *::before, *::after { box-sizing: border-box; }
html, body, h1, h2, h3, h4, p, ul, ol, li, figure, blockquote, dl, dd, table, th, td, details, summary, fieldset { margin: 0; padding: 0; }
ul, ol { list-style: none; }
img, svg { max-width: 100%; display: block; }
table { border-collapse: collapse; width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; }
input, select, textarea { font: inherit; }
:root { color-scheme: dark; }

/* ===== tokens ===== */
:root {
  --c-night-deep: #0B1626;
  --c-night-mid: #12233D;
  --c-night-soft: #1C3557;
  --c-sand: #C8A03C;
  --c-poplar: #E0762F;
  --c-silver: #C9D1DA;
  --c-silver-dim: #8B97A8;
  --c-paper: #F0EBE1;
  --c-moss: #7C8B6A;
  --c-clay: #A9543A;
  --c-rock-line: #2B3A55;

  --font-head: "PingFang SC", "Noto Sans SC", "Source Han Sans SC", "Microsoft YaHei", "Heiti SC", sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", "SFMono-Regular", ui-monospace, Menlo, Consolas, "Courier New", monospace;

  --fs-12: 12px;
  --fs-14: 14px;
  --fs-16: 16px;
  --fs-20: 20px;
  --fs-28: 28px;
  --fs-44: 44px;
  --fs-72: 72px;

  --gutter: 24px;
  --page-x: clamp(20px, 6vw, 160px);
  --maxw: 1320px;
  --maxw-narrow: 880px;

  --dur-rule: 240ms;
  --dur-hover: 120ms;
  --dur-seg: 160ms;
  --ease: cubic-bezier(.22, .61, .36, 1);

  --haar: 1px solid var(--c-rock-line);
}

/* ===== base ===== */
html { -webkit-text-size-adjust: 100%; }
body {
  background-color: var(--c-night-deep);
  color: var(--c-silver);
  font-family: var(--font-head);
  font-size: var(--fs-16);
  line-height: 1.9;
  letter-spacing: .01em;
  min-height: 100vh;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(43,58,85,.34) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(43,58,85,.22) 0 1px, transparent 1px 96px);
  opacity: .5;
}
h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 900;
  letter-spacing: -.01em;
  line-height: 1.18;
  color: var(--c-paper);
}
h1 { font-size: clamp(30px, 5vw, var(--fs-44)); }
h2 { font-size: clamp(22px, 3vw, var(--fs-28)); }
h3 { font-size: var(--fs-20); }
p { margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }
a { color: var(--c-silver); text-decoration: none; }
a:hover { color: var(--c-poplar); }
strong { font-weight: 900; color: var(--c-paper); }
small { font-size: var(--fs-12); }
code, kbd, samp, .mono, time, .num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
abbr, .unit { font-family: var(--font-mono); color: var(--c-silver-dim); font-size: .86em; }
hr { border: 0; border-top: var(--haar); margin: 28px 0; }
::selection { background: var(--c-sand); color: var(--c-night-deep); }

:focus-visible {
  outline: 2px solid var(--c-poplar);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 99;
  padding: 12px 18px;
  background: var(--c-paper);
  color: var(--c-night-deep);
  font-size: var(--fs-14);
  border: var(--haar);
}
.skip-link:focus {
  left: 12px;
  top: 12px;
}

/* ===== containers ===== */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding-inline: var(--page-x);
}
.container--wide { max-width: 1560px; }
.container--narrow { max-width: var(--maxw-narrow); }

/* ===== header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--c-night-deep);
  border-bottom: var(--haar);
}
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  height: 2px;
  width: 0;
  background: var(--c-sand);
  transition: width 90ms linear;
}
.site-header__brandbar {
  background: var(--c-night-mid);
  border-bottom: var(--haar);
}
.site-header__brandbar-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  min-height: 44px;
  flex-wrap: wrap;
}
.brandmark {
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-head);
}
.brandmark__name {
  font-size: var(--fs-16);
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--c-paper);
}
.brandmark__version {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-sand);
  letter-spacing: .02em;
}
.brandbar__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  margin-left: auto;
  font-size: var(--fs-12);
  line-height: 1.6;
}
.meta-chip {
  font-family: var(--font-mono);
  color: var(--c-silver-dim);
  border: var(--haar);
  padding: 3px 8px;
  background: var(--c-night-deep);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: var(--haar);
  background: var(--c-night-deep);
  color: var(--c-silver);
  cursor: pointer;
  min-height: 34px;
}
.nav-toggle__bars {
  width: 16px;
  height: 2px;
  background: var(--c-sand);
  position: relative;
  display: block;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: var(--c-sand);
}
.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }
.nav-toggle__text { font-family: var(--font-mono); font-size: var(--fs-12); }

.site-header__navbar { background: var(--c-night-deep); }
.site-header__navbar-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 52px;
}
.primary-nav { flex: 1 1 auto; min-width: 0; }
.primary-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
}
.primary-nav__item { position: relative; }
.primary-nav__link {
  display: block;
  padding: 15px 14px;
  font-size: var(--fs-14);
  color: var(--c-silver);
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: color var(--dur-hover) var(--ease), border-color var(--dur-hover) var(--ease);
}
.primary-nav__link:hover {
  color: var(--c-paper);
  border-bottom-color: var(--c-poplar);
}
.primary-nav__link[aria-current="page"] {
  color: var(--c-sand);
  border-bottom-color: var(--c-sand);
  font-weight: 900;
}
.navbar__index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
  white-space: nowrap;
}

/* ===== footer ===== */
.site-footer {
  margin-top: 72px;
  background: var(--c-night-mid);
  border-top: var(--haar);
  position: relative;
  z-index: 1;
}
.site-footer__inner { padding-block: 48px 28px; }
.site-footer__columns {
  display: grid;
  grid-template-columns: 1fr 1.2fr 1fr 1.6fr;
  gap: var(--gutter);
  align-items: start;
}
.footer-col { border-top: var(--haar); padding-top: 14px; }
.footer-col--index { padding-top: 14px; }
.footer-col--version { margin-top: 0; }
.footer-col--contact { margin-top: 0; }
.footer-col--legal { margin-top: 0; }
.footer-col__title {
  font-size: var(--fs-14);
  font-weight: 900;
  color: var(--c-paper);
  margin-bottom: 10px;
  letter-spacing: .01em;
}
.footer-col__text {
  font-size: var(--fs-12);
  line-height: 1.8;
  color: var(--c-silver-dim);
  margin-bottom: 8px;
}
.footer-col__legal {
  font-family: var(--font-mono);
  color: var(--c-silver);
}
.footer-col__list { display: grid; gap: 6px; }
.footer-col__list a {
  font-size: var(--fs-12);
  font-family: var(--font-mono);
  color: var(--c-silver);
  border-bottom: 1px solid transparent;
}
.footer-col__list a:hover {
  color: var(--c-poplar);
  border-bottom-color: var(--c-poplar);
}
.site-footer__baseline {
  margin-top: 32px;
  padding-top: 16px;
  border-top: var(--haar);
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
}
.site-footer__copy, .site-footer__contact { margin: 0; }

/* ===== frame (框景) ===== */
.frame {
  position: relative;
  border: var(--haar);
  background: var(--c-night-deep);
  padding: clamp(20px, 3vw, 40px);
}
.frame__corner {
  position: absolute;
  width: 12px;
  height: 12px;
  border: 0;
  border-color: var(--c-sand);
  border-style: solid;
  border-width: 0;
}
.frame__corner--tl { top: -1px; left: -1px; border-top-width: 2px; border-left-width: 2px; }
.frame__corner--tr { top: -1px; right: -1px; border-top-width: 2px; border-right-width: 2px; }
.frame__corner--bl { bottom: -1px; left: -1px; border-bottom-width: 2px; border-left-width: 2px; }
.frame__corner--br { bottom: -1px; right: -1px; border-bottom-width: 2px; border-right-width: 2px; }

/* ===== sections ===== */
.section {
  position: relative;
  z-index: 1;
  padding-block: clamp(40px, 6vw, 88px);
}
.section--paper {
  background: var(--c-paper);
  color: var(--c-night-deep);
  border-top: var(--haar);
  border-bottom: var(--haar);
}
.section--paper h1, .section--paper h2, .section--paper h3 { color: var(--c-night-deep); }
.section--paper a { color: var(--c-night-deep); }
.section--paper a:hover { color: var(--c-clay); }
.section--paper .section-head__num { color: var(--c-clay); }
.section--paper .rule { background: var(--c-night-soft); }
.section-head {
  display: flex;
  align-items: baseline;
  gap: 20px;
  margin-bottom: 28px;
  border-bottom: var(--haar);
  padding-bottom: 10px;
}
.section--paper .section-head { border-bottom-color: var(--c-night-soft); }
.section-head__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: calc(var(--fs-28) * 1.1);
  font-weight: 700;
  line-height: 1;
  color: var(--c-sand);
  min-width: 2.6ch;
}
.section-head__title { font-size: var(--fs-20); }
.section-head__meta {
  margin: 0 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
}
.section--paper .section-head__meta { color: var(--c-night-soft); }

.rule {
  height: 2px;
  background: var(--c-sand);
  border: 0;
  margin: 0 0 20px;
  transform-origin: left center;
}
.rule--gold { background: var(--c-sand); }
.rule--wide { width: 100%; }
[data-rule] { transform: scaleX(0); transition: transform var(--dur-rule) var(--ease); }
[data-rule].is-drawn { transform: scaleX(1); }

/* ===== split ===== */
.split {
  display: grid;
  gap: var(--gutter);
  align-items: start;
}
.split--3-9 { grid-template-columns: 3fr 9fr; }
.split--5-7 { grid-template-columns: 5fr 7fr; }
.split--4-8 { grid-template-columns: 4fr 8fr; }
.offset-left { margin-left: -24px; }

/* ===== buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: var(--fs-14);
  font-family: var(--font-head);
  font-weight: 900;
  letter-spacing: .01em;
  border: 1px solid var(--c-sand);
  color: var(--c-night-deep);
  background: var(--c-sand);
  cursor: pointer;
  transition: background var(--dur-hover) var(--ease), color var(--dur-hover) var(--ease), border-color var(--dur-hover) var(--ease);
}
.btn:hover { background: var(--c-poplar); border-color: var(--c-poplar); color: var(--c-night-deep); }
.btn--ghost {
  background: transparent;
  color: var(--c-silver);
  border-color: var(--c-rock-line);
}
.btn--ghost:hover {
  background: var(--c-night-soft);
  border-color: var(--c-poplar);
  color: var(--c-paper);
}
.btn--gold {
  background: transparent;
  color: var(--c-sand);
  border-color: var(--c-sand);
}
.btn--gold:hover { background: var(--c-sand); color: var(--c-night-deep); }

/* ===== crumbs ===== */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
  padding-block: 16px;
  border-bottom: var(--haar);
}
.crumbs__item { display: inline-flex; align-items: center; gap: 6px; }
.crumbs__item + .crumbs__item::before { content: "/"; color: var(--c-rock-line); }
.crumbs__item[aria-current="page"] { color: var(--c-sand); }

/* ===== prose ===== */
.prose { max-width: 8fr; }
.prose p { font-size: var(--fs-16); line-height: 1.9; margin-bottom: 1em; }
.prose p:last-child { margin-bottom: 0; }
.prose h2 { margin: 32px 0 12px; }
.prose h3 { margin: 24px 0 10px; }
.prose ul { display: grid; gap: 8px; margin: 0 0 1em; }
.prose li {
  padding-left: 18px;
  position: relative;
  font-size: var(--fs-16);
}
.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .82em;
  width: 8px;
  height: 1px;
  background: var(--c-sand);
}

/* ===== terms ===== */
.term {
  border-top: var(--haar);
  padding: 16px 0;
}
.term__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-sand);
  margin-bottom: 6px;
}
.term__body { font-size: var(--fs-16); }
.term__body p { margin-bottom: .6em; }

/* ===== disclosure ===== */
.disclosure {
  border: var(--haar);
  background: var(--c-night-mid);
  margin-bottom: 10px;
}
.disclosure__summary {
  cursor: pointer;
  padding: 12px 16px;
  font-size: var(--fs-14);
  font-weight: 900;
  color: var(--c-paper);
  display: flex;
  gap: 12px;
  align-items: baseline;
}
.disclosure__summary::marker { color: var(--c-sand); }
.disclosure__summary:hover { color: var(--c-sand); }
.disclosure__body {
  padding: 0 16px 16px;
  font-size: var(--fs-14);
  color: var(--c-silver-dim);
  border-top: var(--haar);
  padding-top: 12px;
}

/* ===== status tags ===== */
.status-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  padding: 2px 8px;
  border: 1px solid currentColor;
  white-space: nowrap;
}
.status-tag--synced { color: var(--c-moss); }
.status-tag--review { color: var(--c-clay); }
.status-tag--diff { color: var(--c-poplar); }

/* ===== segmented ===== */
.segmented {
  display: grid;
  gap: 0;
  border: var(--haar);
  background: var(--c-night-mid);
}
.segmented__input {
  position: absolute;
  width: 1px; height: 1px;
  opacity: 0;
  pointer-events: none;
}
.segmented__label {
  display: inline-block;
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  color: var(--c-silver-dim);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: color var(--dur-seg) var(--ease), border-color var(--dur-seg) var(--ease);
}
.segmented__label:hover { color: var(--c-paper); }
.segmented__input:checked + .segmented__label {
  color: var(--c-sand);
  border-bottom-color: var(--c-sand);
  font-weight: 700;
}
.segmented__input:focus-visible + .segmented__label {
  outline: 2px solid var(--c-poplar);
  outline-offset: -2px;
}
.segmented__panel { padding: 20px 16px; border-top: var(--haar); }
.segmented__panel[hidden] { display: none; }

/* ===== matrix ===== */
.matrix-wrap { overflow-x: auto; border: var(--haar); }
.matrix {
  width: 100%;
  min-width: 720px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  font-variant-numeric: tabular-nums;
}
.matrix__head th, .matrix__head td {
  background: var(--c-night-soft);
  color: var(--c-paper);
  font-size: var(--fs-12);
  text-align: left;
  padding: 10px 12px;
  border-bottom: var(--haar);
  border-right: var(--haar);
  white-space: nowrap;
  font-weight: 700;
}
.matrix--sticky .matrix__head th { position: sticky; top: 0; z-index: 2; }
.matrix__row td {
  padding: 10px 12px;
  border-bottom: var(--haar);
  border-right: var(--haar);
  color: var(--c-silver);
}
.matrix__row:nth-child(odd) td { background: var(--c-night-mid); }
.matrix__row:hover td { background: var(--c-night-soft); color: var(--c-paper); }
.matrix__index {
  color: var(--c-silver-dim);
  font-size: var(--fs-12);
  text-align: right;
  width: 3.6em;
}
.matrix__cell--num { color: var(--c-sand); }
.matrix__cell--city { color: var(--c-paper); }
.matrix-grid-highlight .matrix__row td:not(.is-hot),
.matrix-grid-highlight .matrix__head th:not(.is-hot) { opacity: .6; }
.matrix__row td.is-hot, .matrix__head th.is-hot {
  background: var(--c-night-soft);
  opacity: 1;
  transition: opacity var(--dur-hover) var(--ease), background var(--dur-hover) var(--ease);
}

/* ===== filter bar ===== */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}
.filter-bar__btn {
  padding: 6px 12px;
  border: var(--haar);
  background: var(--c-night-deep);
  color: var(--c-silver-dim);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  cursor: pointer;
  transition: color var(--dur-hover) var(--ease), border-color var(--dur-hover) var(--ease);
}
.filter-bar__btn:hover { color: var(--c-paper); border-color: var(--c-poplar); }
.filter-bar__btn[aria-pressed="true"] {
  color: var(--c-night-deep);
  background: var(--c-sand);
  border-color: var(--c-sand);
  font-weight: 700;
}

/* ===== figures ===== */
.figure { margin: 24px 0; }
.figure__frame {
  position: relative;
  border: var(--haar);
  background: var(--c-night-mid);
  overflow: hidden;
  aspect-ratio: 16 / 9;
}
.figure__frame > img, .figure__frame > picture > img, .figure__frame > svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.72) contrast(1.04);
}
.figure__frame--map { aspect-ratio: 4 / 3; }
.figure__frame--tall { aspect-ratio: 3 / 4; }
.figure__caption {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
  border-left: 2px solid var(--c-sand);
  padding-left: 10px;
}
.section--paper .figure__caption { color: var(--c-night-soft); }

/* ===== tick axis ===== */
.tick-axis {
  display: flex;
  align-items: flex-start;
  gap: 0;
  margin: 18px 0;
  border-top: var(--haar);
  padding-top: 0;
}
.tick-axis__mark {
  flex: 1 1 0;
  position: relative;
  padding-top: 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
  border-left: var(--haar);
  padding-left: 8px;
  min-width: 0;
}
.tick-axis__mark::before {
  content: "";
  position: absolute;
  top: -1px; left: 0;
  width: 1px; height: 10px;
  background: var(--c-sand);
}
.tick-axis__mark.is-current { color: var(--c-sand); }

/* ===== section axis (页面阶段使用) ===== */
.sectionAxis {
  display: grid;
  gap: 10px;
  border-left: var(--haar);
  padding-left: 14px;
}
.sectionAxis__item {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--c-silver-dim);
  border-left: 2px solid transparent;
  padding-left: 8px;
  margin-left: -16px;
  transition: color var(--dur-seg) var(--ease), border-color var(--dur-seg) var(--ease);
}
.sectionAxis__item.is-active {
  color: var(--c-sand);
  border-left-color: var(--c-sand);
}

/* ===== to top ===== */
.to-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 45;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  background: var(--c-night-mid);
  color: var(--c-silver);
  border: 1px solid var(--c-sand);
  cursor: pointer;
}
.to-top:hover { background: var(--c-sand); color: var(--c-night-deep); }
.to-top[hidden] { display: none; }

/* ===== grid helpers ===== */
.grid { display: grid; gap: var(--gutter); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--off-axis > *:nth-child(2n) { transform: translateX(24px); }
.stack > * + * { margin-top: 16px; }

/* ===== responsive ===== */
@media (max-width: 1080px) {
  .site-footer__columns { grid-template-columns: 1fr 1fr; }
  .navbar__index { display: none; }
}

@media (max-width: 900px) {
  .split--3-9, .split--5-7, .split--4-8 { grid-template-columns: 1fr; }
  .offset-left { margin-left: 0; }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  body { font-size: var(--fs-14); }
  .nav-toggle { display: inline-flex; }
  .brandbar__meta { margin-left: 0; width: 100%; order: 3; }
  .site-header__brandbar-inner { gap: 12px; padding-block: 10px; align-items: flex-start; }
  .site-header__brandbar-inner .nav-toggle { margin-left: auto; }

  .site-header__navbar-inner { display: block; min-height: 0; }
  .primary-nav {
    display: none;
    border-top: var(--haar);
  }
  .primary-nav[data-open] { display: block; }
  .primary-nav__list { display: grid; grid-template-columns: 1fr; }
  .primary-nav__link {
    padding: 12px 4px;
    font-size: var(--fs-14);
    border-bottom: var(--haar);
    border-left: 3px solid transparent;
  }
  .primary-nav__link[aria-current="page"] {
    border-bottom-color: var(--c-rock-line);
    border-left-color: var(--c-sand);
    padding-left: 10px;
  }

  .section-head { flex-wrap: wrap; gap: 10px; }
  .section-head__meta { margin-left: 0; width: 100%; }
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
  .grid--off-axis > *:nth-child(2n) { transform: none; }
  .site-footer__columns { grid-template-columns: 1fr; }
  .site-footer__baseline { flex-direction: column; }
  .to-top { right: 12px; bottom: 12px; }
}

@media (max-width: 480px) {
  :root { --page-x: 16px; }
  .meta-chip:nth-child(3) { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  [data-rule] { transform: scaleX(1); }
}