/* ============================================================
   KAIYUN 轮次中枢 · 共享样式表 /assets/site.css
   1 重置  2 变量  3 基础排版  4 布局工具  5 通用组件
   6 头部  7 页脚  8 动效与辅助  9 响应式  10 降低动效
   ============================================================ */

/* ---------- 1. 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 72px; }
body, h1, h2, h3, h4, h5, p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; padding: 0; }
ul, ol { list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }
[hidden] { display: none !important; }

/* ---------- 2. 变量与主题 ---------- */
:root {
  --ink-900: #0A1310;
  --ink-800: #0F2019;
  --ink-700: #16332B;
  --charcoal: #191B1A;
  --lime: #C8FF3D;
  --lava: #FF5C24;
  --cyan: #2FE0C8;
  --violet: #8A6BFF;
  --silver: #C7D2CD;
  --silver-dim: #8A968F;
  --paper: #E8EBE4;

  --accent: #C8FF3D;
  --accent-rgb: 200 255 61;
  --accent-soft: rgb(200 255 61 / .14);

  --rail-w: 216px;
  --topbar-h: 56px;
  --gutter: 24px;
  --maxw: 1360px;
  --edge: clamp(16px, 4vw, 56px);

  --line: rgb(199 210 205 / .16);
  --line-strong: rgb(199 210 205 / .32);

  --font-display: "Inter Tight", "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", sans-serif;
  --font-body: "Inter", "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", sans-serif;
  --font-data: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;

  --ease: cubic-bezier(.2, .8, .2, 1);
  --z-rail: 60;
}

html[data-accent="cyan"] { --accent: #2FE0C8; --accent-rgb: 47 224 200; --accent-soft: rgb(47 224 200 / .14); }
html[data-accent="violet"] { --accent: #8A6BFF; --accent-rgb: 138 107 255; --accent-soft: rgb(138 107 255 / .16); }

/* ---------- 3. 基础排版 ---------- */
body {
  background-color: var(--ink-900);
  background-image: linear-gradient(to right, rgb(199 210 205 / .035) 1px, transparent 1px);
  background-size: calc(100% / 12) 100%;
  background-attachment: fixed;
  color: var(--silver);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

p { max-width: 68ch; }

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

::selection { background: var(--accent); color: var(--ink-900); }

.display-1 {
  font-family: var(--font-display);
  font-weight: 900;
  font-stretch: 80%;
  font-size: clamp(2.6rem, 6.4vw, 5rem);
  line-height: .98;
  letter-spacing: -.02em;
  color: var(--paper);
}

.heading {
  font-family: var(--font-display);
  font-weight: 900;
  font-stretch: 82%;
  font-size: clamp(1.6rem, 3.2vw, 2.5rem);
  line-height: 1.08;
  letter-spacing: -.01em;
  color: var(--paper);
}

.heading--sm { font-size: clamp(1.15rem, 2vw, 1.5rem); line-height: 1.2; }

.lede { font-size: 17.5px; line-height: 1.75; color: var(--silver); max-width: 68ch; }

.muted { color: var(--silver-dim); font-size: 14px; line-height: 1.7; }

.mono { font-family: var(--font-data); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--accent);
}

.eyebrow::before { content: ""; width: 22px; height: 1px; background: var(--accent); }

.vnote {
  writing-mode: vertical-rl;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .28em;
  text-transform: uppercase;
  color: var(--silver-dim);
  line-height: 1;
}

.vnote--edge { position: absolute; top: 28px; right: 0; transform: rotate(180deg); }

/* ---------- 4. 布局工具 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--edge);
}

.section { padding-block: 72px; position: relative; }
.section--tight { padding-block: 48px; }

.grid { display: grid; gap: var(--gutter); }
.grid--2, .grid--3, .grid--4, .grid--3-7, .grid--4-6, .grid--7-3 { grid-template-columns: 1fr; }

@media (min-width: 840px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3-7 { grid-template-columns: 3fr 7fr; }
  .grid--4-6 { grid-template-columns: 4fr 6fr; }
  .grid--7-3 { grid-template-columns: 7fr 3fr; }
}

@media (min-width: 1024px) {
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

.bleed-right { margin-right: calc(-1 * var(--edge)); }
.bleed-left { margin-left: calc(-1 * var(--edge)); }

.slant-top { clip-path: polygon(0 2.2%, 100% 0, 100% 100%, 0 100%); }
.slant-both { clip-path: polygon(0 2.4%, 100% 0, 100% 97.6%, 0 100%); }

/* ---------- 5. 通用组件 ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 22px;
  font-family: var(--font-data);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--silver-dim);
}

.crumbs__sep { color: var(--line-strong); }
.crumbs a { border-bottom: 1px solid transparent; }
.crumbs a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.crumbs [aria-current="page"] { color: var(--silver); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 11px 20px;
  border: 1px solid var(--line-strong);
  color: var(--silver);
  font-family: var(--font-data);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .1em;
  transition: background-color .18s var(--ease), color .18s var(--ease), border-color .18s var(--ease);
}

.btn::after { content: "\2192"; transition: transform .18s var(--ease); }
.btn:hover { border-color: var(--accent); color: var(--accent); }
.btn:hover::after { transform: translateX(4px); }

.btn--solid { background: var(--accent); border-color: var(--accent); color: var(--ink-900); }
.btn--solid:hover { background: var(--paper); border-color: var(--paper); color: var(--ink-900); }

.btn--ghost { background: transparent; }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid var(--line-strong);
  color: var(--silver-dim);
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .12em;
  line-height: 1.5;
}

.tag--accent { border-color: var(--accent); color: var(--accent); }
.tag--lava { border-color: var(--lava); color: var(--lava); }
.tag--paper { background: var(--paper); border-color: var(--paper); color: var(--ink-900); }

.paper {
  position: relative;
  background: var(--ink-800);
  border: 1px solid var(--line);
  padding: 24px;
}

.paper::before {
  content: "";
  position: absolute;
  inset: -1px -1px auto -1px;
  height: 3px;
  background: var(--accent);
}

.paper--stack { box-shadow: 12px 12px 0 -1px var(--ink-700), 12px 12px 0 0 var(--line); }

.paper__top {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 18px;
}

.paper__tab {
  display: inline-block;
  padding: 4px 10px;
  background: var(--paper);
  color: var(--ink-900);
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .16em;
  transform: rotate(-1.2deg);
}

.paper__stamp {
  font-family: var(--font-data);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--silver-dim);
  white-space: nowrap;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  background: var(--ink-900);
  -webkit-overflow-scrolling: touch;
}

.data-table { min-width: 640px; font-size: 14px; line-height: 1.6; }

.data-table caption {
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--silver-dim);
}

.data-table thead th {
  position: sticky;
  top: 0;
  z-index: 2;
  padding: 11px 14px;
  background: var(--ink-700);
  border-bottom: 1px solid var(--line-strong);
  color: var(--silver-dim);
  font-family: var(--font-data);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: .1em;
  text-align: left;
  white-space: nowrap;
}

.data-table tbody tr:nth-child(odd) { background: var(--ink-800); }
.data-table tbody tr:nth-child(even) { background: var(--ink-700); }

.data-table td {
  padding: 11px 14px;
  border-bottom: 1px solid var(--line);
  color: var(--silver);
}

.data-table td.num {
  font-family: var(--font-data);
  text-align: right;
  color: var(--paper);
}

.data-table td.peak {
  border-left: 3px solid var(--lava);
  color: var(--paper);
  font-weight: 600;
}

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line-strong);
}

.tab {
  margin-bottom: -1px;
  padding: 11px 18px;
  border-bottom: 2px solid transparent;
  color: var(--silver-dim);
  font-family: var(--font-data);
  font-size: 12.5px;
  letter-spacing: .1em;
  transition: color .18s var(--ease), background-color .18s var(--ease), border-color .18s var(--ease);
}

.tab:hover { color: var(--silver); background: rgb(199 210 205 / .05); }
.tab[aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); background: var(--accent-soft); }
.tabpanel { padding-block: 8px; }

.filterbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  background: var(--ink-800);
  border: 1px solid var(--line);
}

.filterbar__count {
  margin-left: auto;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--silver-dim);
}

.filterbar__count b { color: var(--accent); }

.round-band {
  position: relative;
  overflow: hidden;
  background: var(--ink-800);
  border-block: 1px solid var(--line);
}

.round-band__track {
  display: flex;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  cursor: grab;
  scrollbar-width: thin;
  touch-action: pan-x;
}

.round-band__track.is-dragging { cursor: grabbing; user-select: none; }
.round-band__track::-webkit-scrollbar { height: 3px; }
.round-band__track::-webkit-scrollbar-thumb { background: var(--line-strong); }

.round-band__item {
  flex: 0 0 auto;
  min-width: 76px;
  padding: 14px 16px;
  border-right: 1px solid var(--line);
  scroll-snap-align: start;
  text-align: center;
  color: var(--silver-dim);
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: .04em;
  transition: color .18s var(--ease), background-color .18s var(--ease);
}

.round-band__item:hover { color: var(--paper); background: rgb(199 210 205 / .06); }
.round-band__item.is-done { color: var(--silver); }
.round-band__item.is-current { background: var(--accent); color: var(--ink-900); font-weight: 700; }

.figure {
  position: relative;
  overflow: hidden;
  background: var(--ink-700);
  border: 1px solid var(--line);
}

.figure__media {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background:
    repeating-linear-gradient(45deg, rgb(199 210 205 / .05) 0 2px, transparent 2px 8px),
    radial-gradient(120% 90% at 20% 15%, var(--ink-700), var(--ink-900));
}

.figure__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.55) contrast(1.12) brightness(.86);
}

.figure--tall .figure__media { aspect-ratio: 3 / 4; }
.figure--square .figure__media { aspect-ratio: 1 / 1; }
.figure--wide .figure__media { aspect-ratio: 21 / 9; }

.figure__grid {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .5;
  mix-blend-mode: screen;
  background-image:
    linear-gradient(to right, rgb(var(--accent-rgb) / .16) 1px, transparent 1px),
    linear-gradient(to bottom, rgb(var(--accent-rgb) / .16) 1px, transparent 1px);
  background-size: 25% 25%;
}

.figure__cap {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 9px 12px;
  background: var(--ink-800);
  border-top: 1px solid var(--line);
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--silver-dim);
}

/* ---------- 6. 头部 ---------- */
.skip-link {
  position: absolute;
  top: -120px;
  left: 12px;
  z-index: calc(var(--z-rail) + 20);
  padding: 10px 16px;
  background: var(--accent);
  color: var(--ink-900);
  font-family: var(--font-data);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .08em;
  transition: top .18s var(--ease);
}

.skip-link:focus { top: 12px; }

.site-header { position: relative; z-index: var(--z-rail); }

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: var(--accent);
  pointer-events: none;
  z-index: calc(var(--z-rail) + 10);
}

.topbar { display: none; }
.nav-scrim { display: none; }

.rail {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: var(--z-rail);
  width: var(--rail-w);
  background: var(--ink-900);
  border-right: 1px solid var(--line);
  overflow-y: auto;
  overscroll-behavior: contain;
}

.rail::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 3px;
  height: 42%;
  background: linear-gradient(180deg, var(--accent), transparent);
  opacity: .55;
  pointer-events: none;
}

.rail__inner {
  display: flex;
  flex-direction: column;
  gap: 22px;
  min-height: 100%;
  padding: 26px 20px 22px;
}

.rail__brand {
  position: relative;
  display: block;
  padding-bottom: 16px;
  border-bottom: 2px solid var(--line-strong);
}

.rail__brand::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 48px;
  height: 2px;
  background: var(--accent);
}

.rail__brand-mark {
  display: block;
  font-family: var(--font-display);
  font-weight: 900;
  font-stretch: 82%;
  font-size: 22px;
  line-height: 1;
  letter-spacing: .06em;
  color: var(--paper);
}

.rail__brand-sub {
  display: block;
  margin-top: 7px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--silver-dim);
}

.rail__list { display: flex; flex-direction: column; gap: 2px; }

.rail__link {
  position: relative;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  padding: 10px 12px 10px 14px;
  border-left: 2px solid transparent;
  transition: background-color .18s var(--ease), border-color .18s var(--ease);
}

.rail__link-cn { font-size: 15.5px; font-weight: 600; letter-spacing: .02em; color: var(--silver); }

.rail__link-en {
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: .18em;
  color: var(--silver-dim);
}

.rail__link:hover { background: rgb(199 210 205 / .06); border-left-color: var(--line-strong); }
.rail__link:hover .rail__link-cn { color: var(--paper); }

.rail__link[aria-current="page"] { background: var(--accent-soft); border-left-color: var(--accent); }
.rail__link[aria-current="page"] .rail__link-cn { color: var(--accent); font-weight: 800; }
.rail__link[aria-current="page"] .rail__link-en { color: var(--accent); opacity: .78; }

.rail__tools {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: auto;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.rail__switch { display: flex; flex-direction: column; gap: 4px; }

.rail__switch-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  border: 1px solid transparent;
  color: var(--silver-dim);
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .08em;
  text-align: left;
  transition: color .18s var(--ease), border-color .18s var(--ease), background-color .18s var(--ease);
}

.rail__dot { width: 9px; height: 9px; flex: 0 0 auto; border-radius: 50%; background: currentColor; }
.rail__switch-btn[data-accent-btn="lime"] .rail__dot { background: var(--lime); }
.rail__switch-btn[data-accent-btn="cyan"] .rail__dot { background: var(--cyan); }
.rail__switch-btn[data-accent-btn="violet"] .rail__dot { background: var(--violet); }

.rail__switch-btn:hover { color: var(--silver); border-color: var(--line); }
.rail__switch-btn.is-active {
  color: var(--paper);
  border-color: var(--line-strong);
  background: rgb(199 210 205 / .06);
}

.rail__jump { display: flex; flex-direction: column; gap: 6px; }

.rail__jump-label {
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: .2em;
  color: var(--silver-dim);
}

.rail__jump-row { display: flex; gap: 6px; }

.rail__jump-input {
  flex: 1 1 auto;
  min-width: 0;
  padding: 7px 9px;
  background: var(--ink-800);
  border: 1px solid var(--line);
  color: var(--paper);
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: .08em;
}

.rail__jump-input::placeholder { color: var(--silver-dim); letter-spacing: .06em; }
.rail__jump-input:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.rail__jump-out {
  min-height: 2.6em;
  font-family: var(--font-data);
  font-size: 11px;
  line-height: 1.5;
  letter-spacing: .04em;
  color: var(--silver-dim);
}

.rail__jump-out[data-state="ok"] { color: var(--accent); }
.rail__jump-out[data-state="err"] { color: var(--lava); }

.rail__ticker {
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-family: var(--font-data);
  font-size: 10.5px;
  line-height: 1.6;
  letter-spacing: .06em;
  color: var(--silver-dim);
}

@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
  body { background-size: calc((100vw - var(--rail-w)) / 12) 100%; }
}

/* ---------- 7. 页脚 ---------- */
.site-footer {
  position: relative;
  z-index: 2;
  margin-top: 96px;
  background: var(--charcoal);
  border-top: 1px solid var(--line);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 160px;
  height: 3px;
  background: var(--accent);
}

.footer__inner {
  max-width: var(--maxw);
  margin-inline: auto;
  padding: 56px var(--edge) 32px;
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px 24px;
}

.footer__brand {
  font-family: var(--font-display);
  font-weight: 900;
  font-stretch: 82%;
  font-size: 22px;
  line-height: 1.1;
  letter-spacing: .03em;
  color: var(--paper);
}

.footer__desc {
  margin-top: 12px;
  max-width: 38ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--silver-dim);
}

.footer__badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin-top: 16px;
  padding: 4px 10px;
  background: var(--accent);
  color: var(--ink-900);
  font-family: var(--font-data);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .14em;
}

.footer__badge::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink-900);
  animation: ky-pulse 2s var(--ease) infinite;
}

@keyframes ky-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .25; }
}

.footer__label {
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-data);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--silver-dim);
}

.footer__links { display: flex; flex-direction: column; gap: 9px; }

.footer__links a {
  width: fit-content;
  border-bottom: 1px solid transparent;
  font-size: 14.5px;
  color: var(--silver);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.footer__links a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.footer__contact { display: flex; flex-direction: column; gap: 12px; }
.footer__contact li { display: flex; flex-direction: column; gap: 3px; }

.footer__key {
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: .2em;
  color: var(--silver-dim);
}

.footer__val {
  font-size: 14px;
  line-height: 1.6;
  color: var(--silver);
  word-break: break-word;
}

.footer__bar {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 28px;
  margin-top: 44px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.footer__icp {
  font-family: var(--font-data);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--silver-dim);
}

.footer__region {
  max-width: 62ch;
  font-size: 13px;
  line-height: 1.65;
  color: var(--silver-dim);
}

.footer__legal { display: flex; flex-wrap: wrap; gap: 18px; }

.footer__legal a {
  padding-bottom: 2px;
  border-bottom: 1px solid var(--line-strong);
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--silver-dim);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.footer__legal a:hover { color: var(--accent); border-bottom-color: var(--accent); }

@media (min-width: 640px) {
  .footer__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 1024px) {
  .footer__grid { grid-template-columns: 1.6fr 1fr 1fr 1.3fr; gap: 40px 32px; }
  .footer__inner { padding: 64px var(--edge) 34px; }
}

/* ---------- 8. 动效与辅助 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity .5s var(--ease), transform .5s var(--ease);
}

[data-reveal].is-visible { opacity: 1; transform: none; }

/* ---------- 9. 响应式：移动抽屉 ---------- */
@media (max-width: 1023px) {
  .topbar {
    display: flex;
    align-items: center;
    gap: 12px;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: calc(var(--z-rail) + 2);
    height: var(--topbar-h);
    padding: 0 16px;
    background: rgb(10 19 16 / .94);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--line);
  }

  .topbar__mark {
    font-family: var(--font-display);
    font-weight: 900;
    font-stretch: 84%;
    font-size: 16px;
    letter-spacing: .04em;
    color: var(--paper);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    padding: 8px 10px;
    border: 1px solid var(--line-strong);
    color: var(--silver);
  }

  .nav-toggle__bars { display: flex; flex-direction: column; gap: 4px; width: 18px; }

  .nav-toggle__bars i {
    display: block;
    height: 2px;
    background: var(--accent);
    transition: transform .2s var(--ease), opacity .2s var(--ease);
  }

  .nav-toggle__text {
    font-family: var(--font-data);
    font-size: 11px;
    letter-spacing: .16em;
  }

  .site-header[data-open] .nav-toggle__bars i:nth-child(1) { transform: translateY(6px) rotate(45deg); }
  .site-header[data-open] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
  .site-header[data-open] .nav-toggle__bars i:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

  body { padding-top: var(--topbar-h); }

  .rail {
    width: min(320px, 86vw);
    padding-top: var(--topbar-h);
    transform: translateX(-100%);
    transition: transform .28s var(--ease);
    box-shadow: 24px 0 60px rgb(0 0 0 / .55);
    will-change: transform;
  }

  .site-header[data-open] .rail { transform: translateX(0); }

  .nav-scrim {
    display: block;
    position: fixed;
    inset: 0;
    z-index: calc(var(--z-rail) - 1);
    background: rgb(4 8 6 / .72);
    opacity: 0;
    pointer-events: none;
    transition: opacity .24s var(--ease);
  }

  .site-header[data-open] .nav-scrim { opacity: 1; pointer-events: auto; }

  .scroll-progress { top: auto; bottom: 0; }
}

@media (max-width: 599px) {
  .section { padding-block: 48px; }
  .paper { padding: 18px; }
  .paper--stack { box-shadow: 8px 8px 0 -1px var(--ink-700), 8px 8px 0 0 var(--line); }
  .footer__bar { flex-direction: column; gap: 12px; }
}

/* ---------- 10. 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  [data-reveal] { opacity: 1; transform: none; }
  .round-band__track { scroll-behavior: auto; }
  .round-band__track.is-dragging { cursor: pointer; }
}