/* =========================================================
   OP7服务 · 共享站点样式 /assets/site.css
   版本轨道 × 数据控制台
   ========================================================= */

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

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

body, h1, h2, h3, h4, h5, h6, p, ul, ol, li, figure, blockquote, dl, dt, dd {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }
img, svg, video { display: block; max-width: 100%; }
table { border-collapse: collapse; }

button {
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
  color: inherit;
  font: inherit;
  text-align: inherit;
}

input, select, textarea { font: inherit; color: inherit; }
a { color: inherit; text-decoration: none; }
[hidden] { display: none !important; }

/* ---------- tokens ---------- */
:root {
  color-scheme: dark;

  --ink: #070B14;
  --hull: #0E1729;
  --glass: #16233A;
  --cyan: #35E6D2;
  --orange: #FF7A2F;
  --pulse: linear-gradient(120deg, #35E6D2 0%, #4C8BFF 100%);
  --text: #E9F1FF;
  --muted: #9AA9C4;
  --line: #22304A;
  --ok: #3DDC97;
  --warn: #FFC24B;

  --sans: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", -apple-system,
          BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
  --mono: ui-monospace, "JetBrains Mono", "Cascadia Mono", Menlo, Consolas,
          "Noto Sans Mono CJK SC", monospace;

  --hdr: 70px;
  --w: 1240px;
  --gut: clamp(18px, 4vw, 40px);
  --gap: clamp(16px, 2.2vw, 32px);
  --rad: 3px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- base ---------- */
body {
  min-height: 100vh;
  background:
    radial-gradient(120% 62% at 94% -10%, rgba(53, 230, 210, .10), transparent 62%),
    radial-gradient(86% 52% at 2% 14%, rgba(76, 139, 255, .075), transparent 64%),
    var(--ink);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.75;
  letter-spacing: .012em;
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
}

/* 贯穿全站的版本轨道 */
body::before {
  content: "";
  position: fixed;
  top: 0;
  bottom: 0;
  left: max(14px, 3.2vw);
  width: 1px;
  background: linear-gradient(180deg,
    transparent 0%,
    rgba(34, 48, 74, .95) 10%,
    rgba(34, 48, 74, .95) 90%,
    transparent 100%);
  pointer-events: none;
  z-index: 0;
}

h1, h2, h3, h4 {
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.18;
  color: var(--text);
}

h1 { font-size: clamp(2rem, 5vw, 4rem); }
h2 { font-size: clamp(1.45rem, 2.8vw, 2.15rem); }
h3 { font-size: clamp(1.1rem, 1.7vw, 1.35rem); }
h4 { font-size: 1rem; }

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

#main-content { display: block; position: relative; z-index: 1; }
#main-content:focus { outline: none; }

/* ---------- text utilities ---------- */
.mono {
  font-family: var(--mono);
  font-size: .86em;
  letter-spacing: .04em;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
  text-transform: uppercase;
}

.lead {
  font-size: clamp(1.02rem, 1.6vw, 1.26rem);
  line-height: 1.7;
  color: #C6D3EA;
  max-width: 48ch;
}

.prose {
  max-width: 68ch;
  color: var(--muted);
}

.prose > * + * { margin-top: 1.2em; }
.prose h2, .prose h3 { color: var(--text); margin-top: 1.75em; }
.prose strong { color: var(--text); font-weight: 700; }
.prose a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.prose code {
  font-family: var(--mono);
  font-size: .88em;
  color: var(--cyan);
  background: rgba(53, 230, 210, .09);
  padding: 1px 6px;
  border-radius: 2px;
}

/* ---------- layout ---------- */
.wrap {
  width: 100%;
  max-width: var(--w);
  margin-inline: auto;
  padding-inline: var(--gut);
}

.section {
  position: relative;
  padding-block: clamp(48px, 7vw, 98px);
}

.section--tight { padding-block: clamp(26px, 4vw, 52px); }

.grid {
  display: grid;
  gap: var(--gap);
  align-items: start;
}

.grid--7-5 { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }
.grid--8-4 { grid-template-columns: minmax(0, 8fr) minmax(0, 4fr); }
.grid--5-7 { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }

.sec-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 16px;
  margin-bottom: clamp(20px, 3vw, 38px);
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.sec-head__no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--cyan);
}

.sec-head__title { margin: 0; }

.sec-head__note {
  margin-left: auto;
  font-size: 13.5px;
  color: var(--muted);
  font-family: var(--mono);
  letter-spacing: .03em;
}

.rail { position: relative; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: 2px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  transition: transform .18s var(--ease), background .18s var(--ease),
              color .18s var(--ease), border-color .18s var(--ease),
              box-shadow .18s var(--ease);
}

.btn--primary {
  background: var(--pulse);
  color: #04121A;
}

.btn--primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 30px -14px rgba(53, 230, 210, .85);
}

.btn--ghost {
  border-color: var(--line);
  background: rgba(22, 35, 58, .5);
  color: var(--text);
}

.btn--ghost:hover {
  border-color: rgba(53, 230, 210, .6);
  color: var(--cyan);
}

.btn--quiet {
  padding-inline: 2px;
  color: var(--muted);
  background: none;
}

.btn--quiet::after {
  content: "→";
  font-family: var(--mono);
  transition: transform .18s var(--ease);
}

.btn--quiet:hover { color: var(--cyan); }
.btn--quiet:hover::after { transform: translateX(4px); }

.btn--sm { padding: 8px 15px; font-size: 13.5px; }

/* ---------- skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 300;
  background: var(--cyan);
  color: #04121A;
  font-size: 14px;
  font-weight: 700;
  padding: 9px 16px;
  border-radius: 2px;
  transform: translateY(-180%);
  transition: transform .2s var(--ease);
}

.skip-link:focus { transform: translateY(0); }

/* ---------- command bar ---------- */
.cmd-bar {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(7, 11, 20, .84);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  backdrop-filter: blur(16px) saturate(140%);
  border-bottom: 1px solid var(--line);
}

.cmd-bar__inner {
  position: relative;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(12px, 2vw, 30px);
  width: 100%;
  max-width: var(--w);
  margin-inline: auto;
  padding-inline: var(--gut);
  height: var(--hdr);
  transition: height .26s var(--ease);
}

[data-header][data-scrolled] .cmd-bar__inner { height: 56px; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.brand__mark {
  flex: none;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
  color: #04121A;
  background: var(--pulse);
  padding: 3px 7px;
  border-radius: 2px;
  line-height: 1.4;
}

.brand__name {
  font-size: clamp(15px, 1.4vw, 17px);
  font-weight: 800;
  letter-spacing: -.01em;
  white-space: nowrap;
}

.brand__chapter {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--muted);
  padding-left: 12px;
  border-left: 1px solid var(--line);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 20ch;
}

[data-header][data-scrolled] .brand__chapter { color: var(--cyan); }

/* ---------- primary nav ---------- */
.nav { min-width: 0; }

.nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.nav__list::-webkit-scrollbar { display: none; }

.nav__item { flex: none; }

.nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  font-size: 14.5px;
  color: var(--muted);
  border-radius: 2px;
  white-space: nowrap;
  transition: color .18s var(--ease), background .18s var(--ease);
}

.nav__link:hover {
  color: var(--text);
  background: rgba(53, 230, 210, .07);
}

.nav__link[aria-current="page"] { color: var(--text); }

.nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 2px;
  height: 2px;
  border-radius: 2px;
  background: var(--pulse);
}

/* ---------- command bar tools ---------- */
.cmd-bar__tools {
  display: flex;
  align-items: center;
  gap: 8px;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 11px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(22, 35, 58, .55);
  color: var(--muted);
  font-size: 13px;
  transition: color .18s var(--ease), border-color .18s var(--ease),
              background .18s var(--ease);
}

.icon-btn:hover {
  color: var(--text);
  border-color: rgba(53, 230, 210, .55);
  background: rgba(53, 230, 210, .08);
}

.icon-btn__glyph {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--cyan);
}

.icon-btn__label { white-space: nowrap; }

.icon-btn--menu { display: none; }

.bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 3px;
  width: 14px;
  height: 12px;
}

.bars i {
  display: block;
  height: 1.5px;
  border-radius: 1px;
  background: currentColor;
  transition: transform .18s var(--ease), opacity .18s var(--ease);
}

.icon-btn[aria-expanded="true"] .bars i:nth-child(1) {
  transform: translateY(4.5px) rotate(45deg);
}

.icon-btn[aria-expanded="true"] .bars i:nth-child(2) { opacity: 0; }

.icon-btn[aria-expanded="true"] .bars i:nth-child(3) {
  transform: translateY(-4.5px) rotate(-45deg);
}

/* ---------- search panel ---------- */
.cmd-search {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  z-index: 5;
  background: rgba(7, 11, 20, .96);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 34px 60px -44px #000;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  pointer-events: none;
  transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s;
}

.cmd-search[data-open] {
  opacity: 1;
  visibility: visible;
  transform: none;
  pointer-events: auto;
}

.cmd-search__inner {
  width: 100%;
  max-width: var(--w);
  margin-inline: auto;
  padding: 18px var(--gut) 24px;
}

.cmd-search__field {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(14, 23, 41, .82);
  transition: border-color .18s var(--ease), box-shadow .18s var(--ease);
}

.cmd-search__field:focus-within {
  border-color: rgba(53, 230, 210, .75);
  box-shadow: 0 0 0 1px rgba(53, 230, 210, .22);
}

.cmd-search__key {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--cyan);
}

.cmd-search__input {
  flex: 1;
  min-width: 0;
  border: 0;
  outline: none;
  background: none;
  font-size: 15px;
  letter-spacing: .02em;
}

.cmd-search__input::placeholder { color: #5B6B87; }

.cmd-search__list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 8px;
  margin-top: 14px;
}

.cmd-search__link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  padding: 11px 14px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(14, 23, 41, .62);
  transition: border-color .18s var(--ease), background .18s var(--ease),
              transform .18s var(--ease);
}

.cmd-search__link:hover,
.cmd-search__link:focus-visible {
  border-color: rgba(53, 230, 210, .6);
  background: rgba(53, 230, 210, .08);
  transform: translateX(3px);
}

.cmd-search__no {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--cyan);
}

.cmd-search__name { font-size: 14.5px; font-weight: 600; }

.cmd-search__path {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--muted);
}

.cmd-search__empty {
  margin-top: 16px;
  font-size: 14px;
  color: var(--muted);
  font-family: var(--mono);
  letter-spacing: .03em;
}

/* ---------- scroll meter ---------- */
.scroll-meter {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 6;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}

.scroll-meter__fill {
  display: block;
  height: 100%;
  width: 0;
  background: var(--pulse);
}

/* ---------- site footer ---------- */
.site-foot {
  position: relative;
  z-index: 1;
  margin-top: clamp(60px, 9vw, 140px);
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg,
    rgba(14, 23, 41, .55) 0%,
    rgba(7, 11, 20, .96) 46%);
}

.site-foot::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--pulse);
  opacity: .55;
}

.site-foot__inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.4fr;
  gap: var(--gap);
  padding-top: clamp(40px, 5vw, 68px);
}

.site-foot__bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  justify-content: space-between;
  align-items: center;
  margin-top: clamp(30px, 4vw, 54px);
  padding-block: 18px 26px;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: #6C7C99;
}

.foot-brand { display: grid; gap: 16px; justify-items: start; }

.foot-col__title {
  margin-bottom: 15px;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .14em;
  color: var(--cyan);
}

.foot-list li + li { margin-top: 9px; }

.foot-list__link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 14.5px;
  color: var(--muted);
  transition: color .18s var(--ease);
}

.foot-list__link::before {
  content: "";
  width: 6px;
  height: 1px;
  background: currentColor;
  opacity: .55;
  transition: width .18s var(--ease);
}

.foot-list__link:hover { color: var(--cyan); }
.foot-list__link:hover::before { width: 14px; }

.foot-meta {
  display: grid;
  gap: 2px;
  font-size: 14px;
}

.foot-meta__row {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px dashed rgba(34, 48, 74, .8);
}

.foot-meta__row dt {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--muted);
  padding-top: 2px;
}

.foot-meta__row dd {
  color: #C6D3EA;
  line-height: 1.6;
  word-break: break-word;
}

.foot-note {
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
  max-width: 34ch;
}

.foot-note--sm {
  margin-top: 14px;
  font-size: 12.5px;
  max-width: 30ch;
}

.foot-copy, .foot-icp { margin: 0; }

/* ---------- breadcrumbs ---------- */
.crumbs { padding-block: 16px 0; }

.crumbs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--muted);
}

.crumbs__item { display: inline-flex; align-items: center; gap: 10px; }

.crumbs__item + .crumbs__item::before {
  content: "/";
  color: #3A4A66;
}

.crumbs__link { color: var(--muted); transition: color .18s var(--ease); }
.crumbs__link:hover { color: var(--cyan); }
.crumbs__item[aria-current="page"] { color: var(--text); }

/* ---------- cards ---------- */
.card {
  position: relative;
  padding: clamp(18px, 2.2vw, 28px);
  border: 1px solid var(--line);
  border-radius: var(--rad);
  background: var(--hull);
}

.card--index {
  background: linear-gradient(180deg, rgba(22, 35, 58, .68), rgba(14, 23, 41, .92));
  border-color: rgba(53, 230, 210, .22);
}

.card--data { padding: clamp(16px, 2vw, 22px) clamp(18px, 2.4vw, 30px); }

.card--doc {
  background: rgba(22, 35, 58, .58);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-color: rgba(34, 48, 74, .9);
  box-shadow: 0 26px 62px -38px #000;
}

.card--lap { position: relative; z-index: 2; }

.card__no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--cyan);
}

.card__title {
  margin-top: 10px;
  font-size: clamp(1.02rem, 1.6vw, 1.24rem);
  font-weight: 700;
  line-height: 1.4;
}

.card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  margin-top: 12px;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .05em;
  color: var(--muted);
}

.card__body {
  margin-top: 12px;
  font-size: 15px;
  color: var(--muted);
}

/* ---------- tags ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid currentColor;
  border-radius: 2px;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  line-height: 1.55;
  color: var(--muted);
}

.tag--cyan { color: var(--cyan); }
.tag--orange { color: var(--orange); }
.tag--ok { color: var(--ok); }
.tag--warn { color: var(--warn); }

/* ---------- media ---------- */
.media {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--rad);
  overflow: hidden;
  background: var(--hull);
}

.media__frame {
  position: relative;
  display: block;
  aspect-ratio: 16 / 10;
  background-color: var(--hull);
  background-image:
    linear-gradient(135deg, rgba(53, 230, 210, .13), rgba(76, 139, 255, .05) 52%, rgba(255, 122, 47, .10)),
    linear-gradient(rgba(34, 48, 74, .62) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 48, 74, .62) 1px, transparent 1px);
  background-size: auto, 44px 44px, 44px 44px;
}

.media__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media__cap {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .05em;
  color: var(--muted);
}

.media--wide .media__frame { aspect-ratio: 21 / 9; }
.media--tall .media__frame { aspect-ratio: 4 / 5; }

/* ---------- expandable group ---------- */
.group {
  border: 1px solid var(--line);
  border-radius: var(--rad);
  background: var(--hull);
  transition: border-color .18s var(--ease);
}

.group + .group { margin-top: 12px; }
.group[data-open] { border-color: rgba(53, 230, 210, .32); }

.group__head {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 16px clamp(16px, 2vw, 22px);
}

.group__toggle {
  flex: none;
  position: relative;
  width: 22px;
  height: 22px;
  margin-left: auto;
  border: 1px solid var(--line);
  border-radius: 50%;
  transition: border-color .18s var(--ease);
}

.group__toggle::before,
.group__toggle::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  background: var(--cyan);
  transform: translate(-50%, -50%);
  transition: transform .18s var(--ease), opacity .18s var(--ease);
}

.group__toggle::before { width: 9px; height: 1px; }
.group__toggle::after { width: 1px; height: 9px; }

.group[data-open] .group__toggle { border-color: rgba(53, 230, 210, .6); }

.group[data-open] .group__toggle::after {
  transform: translate(-50%, -50%) scaleY(0);
  opacity: 0;
}

.group__body {
  padding: 0 clamp(16px, 2vw, 22px) 18px;
  font-size: 15px;
  color: var(--muted);
}

.group__body:not([hidden]) { animation: gfade .18s var(--ease) both; }

@keyframes gfade {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: none; }
}

/* ---------- pulse band ---------- */
.pulse-band {
  position: relative;
  height: 2px;
  border-radius: 2px;
  background: var(--line);
  overflow: hidden;
}

.pulse-band::after {
  content: "";
  position: absolute;
  top: 0;
  left: -40%;
  width: 40%;
  height: 100%;
  background: var(--pulse);
  animation: pulse-run 6s cubic-bezier(.45, 0, .55, 1) infinite;
}

@keyframes pulse-run {
  0% { left: -40%; }
  100% { left: 100%; }
}

/* ---------- copy state ---------- */
[data-copy] { cursor: pointer; }

[data-copy][data-copied]::after {
  content: " 已复制";
  font-family: var(--mono);
  font-size: .82em;
  letter-spacing: .06em;
  color: var(--ok);
}

/* ---------- reveal ---------- */
html.js-on [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .44s var(--ease), transform .44s var(--ease);
}

html.js-on [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- responsive ---------- */
@media (max-width: 1023px) {
  .grid--7-5,
  .grid--8-4,
  .grid--5-7 { grid-template-columns: minmax(0, 1fr); }

  .site-foot__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    row-gap: clamp(28px, 4vw, 44px);
  }
}

@media (max-width: 900px) {
  .cmd-bar__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    height: 60px;
    gap: 12px;
  }

  [data-header][data-scrolled] .cmd-bar__inner { height: 54px; }

  .brand__chapter { display: none; }

  .nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    max-height: calc(100vh - 60px);
    overflow-y: auto;
    background: rgba(7, 11, 20, .975);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid var(--line);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    pointer-events: none;
    transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s;
  }

  .nav[data-open] {
    opacity: 1;
    visibility: visible;
    transform: none;
    pointer-events: auto;
  }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px var(--gut) 20px;
    overflow: visible;
  }

  .nav__link {
    padding: 15px 2px;
    font-size: 16.5px;
    border-bottom: 1px solid rgba(34, 48, 74, .55);
    border-radius: 0;
  }

  .nav__link[aria-current="page"] { color: var(--cyan); }

  .nav__link[aria-current="page"]::after {
    left: 0;
    right: auto;
    bottom: 12px;
    width: 20px;
  }

  .icon-btn--menu { display: inline-flex; }

  .cmd-search__list { grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); }
}

@media (max-width: 599px) {
  body { font-size: 16px; }

  .section { padding-block: clamp(38px, 9vw, 62px); }

  .sec-head__note { margin-left: 0; width: 100%; }

  .site-foot__inner { grid-template-columns: minmax(0, 1fr); }

  .site-foot__bottom { font-size: 11.5px; }

  .foot-meta__row { grid-template-columns: minmax(0, 1fr); gap: 2px; }

  .cmd-search__list { grid-template-columns: minmax(0, 1fr); }

  .icon-btn__label { display: none; }

  .icon-btn { padding: 8px; }
}

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

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  .pulse-band::after { left: 0; width: 100%; }

  html.js-on [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .cmd-bar__inner { transition: none; }
}