/* =========================================================
   贝斯特品牌 · 共享站点样式
   文件路径：/assets/site.css
   区块：1 Reset / 2 Tokens / 3 基础排版 / 4 跳转与页头
        5 页脚 / 6 区块骨架 / 7 网格 / 8 组件 / 9 媒体
        10 动效与进度 / 11 响应式与可访问性
   ========================================================= */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body,
h1, h2, h3, h4,
p, figure, blockquote,
dl, dd, ul, ol { margin: 0; }

ul, ol { padding: 0; list-style: none; }

img, svg, video { display: block; max-width: 100%; }

button, input, select, textarea { font: inherit; color: inherit; }

button {
  background: none;
  border: 0;
  padding: 0;
}

a { color: inherit; }

[id] { scroll-margin-top: 7rem; }

/* ---------- 2. Tokens ---------- */
:root {
  --bs-deep: #0B2A4A;
  --bs-ink: #071A2F;
  --bs-gold: #F4B740;
  --bs-mint: #38C9B8;
  --bs-coral: #FF7A59;
  --bs-sky: #6FA8FF;
  --bs-paper: #F7F9FC;
  --bs-mist: #DCE4EE;
  --bs-graphite: #4A5A70;
  --bs-green: #2E9E7E;

  --bs-font-display: "HarmonyOS Sans SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --bs-font-body: "Noto Sans SC", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --bs-font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;

  --bs-r-lg: 32px;
  --bs-r-md: 24px;
  --bs-r-sm: 14px;
  --bs-r-pill: 999px;

  --bs-shell: 1280px;
  --bs-gutter: clamp(1rem, 4vw, 3rem);
  --bs-ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  background: var(--bs-paper);
  color: var(--bs-ink);
  font-family: var(--bs-font-body);
  font-size: clamp(1rem, 0.97rem + 0.15vw, 1.0625rem);
  font-weight: 400;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--bs-font-display);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--bs-ink);
  text-wrap: balance;
}

h1 { font-size: clamp(2.4rem, 5.6vw, 4.6rem); line-height: 1.02; }
h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); }
h3 { font-size: clamp(1.18rem, 1.8vw, 1.45rem); }
h4 { font-size: 1.05rem; letter-spacing: -0.01em; }

p { margin-bottom: 1.1em; }
p:last-child { margin-bottom: 0; }

a {
  color: var(--bs-deep);
  text-underline-offset: 0.22em;
  text-decoration-thickness: 1px;
}

a:hover { color: #0d3c68; }

strong { font-weight: 700; }

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

:focus-visible {
  outline: 3px solid var(--bs-sky);
  outline-offset: 3px;
  border-radius: 4px;
}

.bs-shell {
  width: 100%;
  max-width: var(--bs-shell);
  margin-inline: auto;
  padding-inline: var(--bs-gutter);
}

.bs-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ---------- 4. 跳转链接与页头 ---------- */
.bs-skip {
  position: absolute;
  top: 0;
  left: 0.75rem;
  z-index: 200;
  transform: translateY(-150%);
  display: inline-block;
  padding: 0.7rem 1.2rem;
  border-radius: 0 0 var(--bs-r-sm) var(--bs-r-sm);
  background: var(--bs-gold);
  color: var(--bs-ink);
  font-family: var(--bs-font-display);
  font-size: 0.9rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform 0.22s var(--bs-ease);
}

.bs-skip:focus,
.bs-skip:focus-visible { transform: translateY(0); }

.bs-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--bs-ink);
  color: var(--bs-paper);
  box-shadow: 0 14px 34px -26px rgba(7, 26, 47, 0.95);
}

.bs-header__bar {
  background: linear-gradient(100deg, var(--bs-ink) 0%, var(--bs-deep) 56%, #113A63 100%);
  border-bottom: 1px solid rgba(247, 249, 252, 0.08);
}

.bs-header__bar-inner {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto auto;
  align-items: center;
  gap: clamp(0.75rem, 2vw, 1.75rem);
  padding-block: 0.8rem;
}

.bs-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  min-width: 0;
  color: var(--bs-paper);
  text-decoration: none;
}

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

.bs-brand__mark {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 12px;
  background: linear-gradient(145deg, var(--bs-gold), #DD9A10);
  color: var(--bs-ink);
  font-family: var(--bs-font-mono);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.06em;
}

.bs-brand__text { display: block; min-width: 0; }

.bs-brand__name {
  display: block;
  font-family: var(--bs-font-display);
  font-size: 1.02rem;
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.bs-brand__line {
  display: block;
  overflow: hidden;
  font-family: var(--bs-font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  color: rgba(247, 249, 252, 0.58);
  white-space: nowrap;
  text-overflow: ellipsis;
}

.bs-header__tagline {
  justify-self: center;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0;
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  color: rgba(247, 249, 252, 0.7);
}

.bs-header__tagline::before {
  content: "";
  flex: 0 0 auto;
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: var(--bs-mint);
  box-shadow: 0 0 0 4px rgba(56, 201, 184, 0.16);
}

.bs-header__cta { flex: 0 0 auto; }

.bs-navtoggle {
  display: none;
  align-items: center;
  gap: 0.55rem;
  padding: 0.55rem 0.95rem;
  border: 1px solid rgba(247, 249, 252, 0.28);
  border-radius: var(--bs-r-pill);
  background: rgba(247, 249, 252, 0.06);
  color: var(--bs-paper);
  font-family: var(--bs-font-display);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: background 0.18s var(--bs-ease), border-color 0.18s var(--bs-ease);
}

.bs-navtoggle:hover { background: rgba(247, 249, 252, 0.15); }

.bs-navtoggle__bars {
  display: grid;
  gap: 4px;
  width: 1.05rem;
}

.bs-navtoggle__bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.2s var(--bs-ease);
}

.bs-navtoggle[aria-expanded="true"] .bs-navtoggle__bars span:first-child {
  transform: translateY(3px) rotate(45deg);
}

.bs-navtoggle[aria-expanded="true"] .bs-navtoggle__bars span:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

.bs-navtoggle__label { line-height: 1; }

.bs-header__nav {
  background: var(--bs-deep);
  border-top: 1px solid rgba(247, 249, 252, 0.07);
}

.bs-header__nav-inner {
  display: flex;
  align-items: center;
  gap: clamp(1rem, 3vw, 2.5rem);
  padding-block: 0.3rem;
}

.bs-navnote {
  flex: 0 0 auto;
  margin: 0;
  font-family: var(--bs-font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(247, 249, 252, 0.42);
  white-space: nowrap;
}

.bs-nav { margin-left: auto; }

.bs-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: clamp(0.25rem, 1.2vw, 1.25rem);
}

.bs-nav__link {
  position: relative;
  display: inline-block;
  padding: 0.6rem 0.15rem;
  font-family: var(--bs-font-display);
  font-size: 0.94rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: rgba(247, 249, 252, 0.76);
  text-decoration: none;
  transition: color 0.18s var(--bs-ease);
}

.bs-nav__link::after {
  content: "";
  position: absolute;
  left: 0.15rem;
  right: 0.15rem;
  bottom: 0.24rem;
  height: 2px;
  border-radius: 2px;
  background: var(--bs-gold);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.22s var(--bs-ease);
}

.bs-nav__link:hover { color: #ffffff; }
.bs-nav__link:hover::after { transform: scaleX(1); }

.bs-nav__link[aria-current="page"] { color: var(--bs-gold); }
.bs-nav__link[aria-current="page"]::after { transform: scaleX(1); }

/* ---------- 5. 页脚 ---------- */
.bs-footer {
  margin-top: clamp(3rem, 8vw, 6rem);
  background: var(--bs-ink);
  color: rgba(247, 249, 252, 0.78);
  font-size: 0.94rem;
}

.bs-footer::before {
  content: "";
  display: block;
  height: 4px;
  background: linear-gradient(90deg,
    var(--bs-mint) 0%,
    var(--bs-sky) 28%,
    var(--bs-gold) 62%,
    var(--bs-coral) 100%);
}

.bs-footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr) minmax(0, 1.15fr);
  gap: clamp(1.75rem, 4vw, 3.5rem);
  padding-block: clamp(2.5rem, 6vw, 4.25rem);
}

.bs-footer__brand { min-width: 0; }

.bs-footer__title {
  margin-bottom: 0.45rem;
  font-family: var(--bs-font-display);
  font-size: clamp(1.2rem, 2.2vw, 1.55rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.35;
  color: #ffffff;
}

.bs-footer__sub {
  margin-bottom: 1rem;
  font-family: var(--bs-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--bs-gold);
}

.bs-footer__note {
  max-width: 36ch;
  margin: 0;
  font-size: 0.82rem;
  line-height: 1.75;
  color: rgba(247, 249, 252, 0.55);
}

.bs-footer__cols {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1.25rem, 3vw, 2rem);
}

.bs-footer__col { min-width: 0; }

.bs-footer__heading {
  margin-bottom: 0.95rem;
  font-family: var(--bs-font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(247, 249, 252, 0.45);
}

.bs-footer__list {
  display: grid;
  gap: 0.55rem;
}

.bs-footer__link {
  display: inline-block;
  color: rgba(247, 249, 252, 0.82);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--bs-ease), border-color 0.18s var(--bs-ease);
}

.bs-footer__link:hover,
.bs-footer__link:focus-visible {
  color: var(--bs-gold);
  border-bottom-color: currentColor;
}

.bs-footer__contact {
  display: grid;
  gap: 0.6rem;
  align-content: start;
  min-width: 0;
}

.bs-footer__contact-row {
  display: grid;
  grid-template-columns: 3.1rem minmax(0, 1fr);
  gap: 0.6rem;
  align-items: baseline;
  margin: 0;
  font-size: 0.9rem;
}

.bs-footer__label {
  font-family: var(--bs-font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(247, 249, 252, 0.45);
}

.bs-footer__value {
  overflow-wrap: anywhere;
  color: rgba(247, 249, 252, 0.9);
}

.bs-footer__base {
  border-top: 1px solid rgba(247, 249, 252, 0.12);
  background: rgba(0, 0, 0, 0.18);
}

.bs-footer__base-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 1.5rem;
  padding-block: 1.1rem;
  font-family: var(--bs-font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: rgba(247, 249, 252, 0.5);
}

.bs-footer__legal { margin: 0; }

/* ---------- 6. 区块骨架 ---------- */
.bs-section { padding-block: clamp(2.75rem, 6vw, 5.5rem); }
.bs-section--tight { padding-block: clamp(1.75rem, 3.5vw, 2.75rem); }

.bs-section--ink {
  background: var(--bs-deep);
  color: rgba(247, 249, 252, 0.9);
}

.bs-section--ink h1,
.bs-section--ink h2,
.bs-section--ink h3,
.bs-section--ink h4 { color: #ffffff; }

.bs-section--ink .bs-eyebrow { color: rgba(247, 249, 252, 0.6); }
.bs-section--ink .bs-lead { color: rgba(247, 249, 252, 0.72); }
.bs-section--ink .bs-section__sub { color: rgba(247, 249, 252, 0.68); }
.bs-section--ink .bs-btn--line,
.bs-footer .bs-btn--line {
  color: var(--bs-paper);
  border-color: rgba(247, 249, 252, 0.3);
}
.bs-section--ink .bs-btn--line:hover,
.bs-footer .bs-btn--line:hover {
  background: rgba(247, 249, 252, 0.1);
  border-color: var(--bs-gold);
}

.bs-section__head {
  display: grid;
  gap: 0.85rem;
  max-width: 64ch;
  margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
}

.bs-section__title { font-size: clamp(1.6rem, 3vw, 2.4rem); }

.bs-section__sub {
  margin: 0;
  color: var(--bs-graphite);
}

.bs-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--bs-font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--bs-graphite);
}

.bs-eyebrow::before {
  content: "";
  flex: 0 0 auto;
  width: 1.6rem;
  height: 2px;
  border-radius: 2px;
  background: var(--bs-gold);
}

.bs-lead {
  max-width: 48ch;
  font-size: clamp(1.02rem, 1.5vw, 1.22rem);
  line-height: 1.8;
  color: var(--bs-graphite);
}

/* ---------- 7. 网格 ---------- */
.bs-grid {
  display: grid;
  gap: clamp(1rem, 2.4vw, 2.25rem);
  align-items: start;
}

.bs-grid--7-5 { grid-template-columns: 7fr 5fr; }
.bs-grid--5-7 { grid-template-columns: 5fr 7fr; }
.bs-grid--8-4 { grid-template-columns: 8fr 4fr; }
.bs-grid--4-8 { grid-template-columns: 4fr 8fr; }
.bs-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.bs-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

/* ---------- 8. 组件 ---------- */
.bs-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.78em 1.45em;
  border: 1.5px solid transparent;
  border-radius: var(--bs-r-pill);
  background: var(--bs-gold);
  color: var(--bs-ink);
  font-family: var(--bs-font-display);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.18s var(--bs-ease), color 0.18s var(--bs-ease),
              transform 0.18s var(--bs-ease), box-shadow 0.18s var(--bs-ease);
}

.bs-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 26px -16px rgba(7, 26, 47, 0.65);
}

.bs-btn:active { transform: translateY(0); }

.bs-btn--gold { background: var(--bs-gold); color: var(--bs-ink); }
.bs-btn--mint { background: var(--bs-mint); color: #052B27; }
.bs-btn--coral { background: var(--bs-coral); color: #3D1104; }

.bs-btn--line {
  background: transparent;
  color: var(--bs-deep);
  border-color: var(--bs-mist);
}

.bs-btn--line:hover {
  background: rgba(11, 42, 74, 0.06);
  border-color: var(--bs-deep);
}

.bs-btn--sm {
  padding: 0.6em 1.1em;
  font-size: 0.85rem;
}

.bs-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 0.28em 0.85em;
  border: 1px solid var(--bs-mist);
  border-radius: var(--bs-r-pill);
  background: #ffffff;
  color: var(--bs-graphite);
  font-family: var(--bs-font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  line-height: 1.6;
}

.bs-tag--mint { background: #E6F7F4; border-color: #9FE3DA; color: #0F6E64; }
.bs-tag--coral { background: #FFEDE8; border-color: #FFC2B2; color: #A63A1E; }
.bs-tag--gold { background: #FFF3D9; border-color: #F4B740; color: #7A5410; }
.bs-tag--ink { background: #E7EDF5; border-color: #C6D3E3; color: var(--bs-deep); }

.bs-exhibit {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.4rem 0.9rem;
  font-family: var(--bs-font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--bs-graphite);
}

.bs-exhibit__no {
  font-weight: 700;
  color: var(--bs-deep);
}

.bs-exhibit__label { letter-spacing: 0.14em; }

.bs-section--ink .bs-exhibit { color: rgba(247, 249, 252, 0.6); }
.bs-section--ink .bs-exhibit__no { color: var(--bs-gold); }

.bs-panel {
  position: relative;
  padding: clamp(1.15rem, 2.2vw, 1.9rem);
  border: 1px solid var(--bs-mist);
  border-radius: var(--bs-r-md);
  background: #ffffff;
}

.bs-panel--ink {
  background: linear-gradient(160deg, var(--bs-deep), var(--bs-ink));
  border-color: rgba(247, 249, 252, 0.14);
  color: rgba(247, 249, 252, 0.86);
}

.bs-panel--ink h2,
.bs-panel--ink h3,
.bs-panel--ink h4 { color: #ffffff; }

.bs-panel--mint { background: #F1FBF9; border-color: #B8E9E1; }
.bs-panel--coral { background: #FFF4F0; border-color: #FFCABB; }

.bs-track { display: grid; gap: 1.15rem; }

.bs-step {
  position: relative;
  min-height: 2rem;
  padding-left: 2.75rem;
}

.bs-step::before {
  content: "";
  position: absolute;
  left: 0.89rem;
  top: 2.1rem;
  bottom: -1.15rem;
  width: 2px;
  background: linear-gradient(to bottom, rgba(74, 90, 112, 0.4), rgba(74, 90, 112, 0.04));
}

.bs-step:last-child::before { display: none; }

.bs-step__no {
  position: absolute;
  left: 0;
  top: 0.1em;
  display: grid;
  place-items: center;
  width: 1.8rem;
  height: 1.8rem;
  border-radius: var(--bs-r-pill);
  background: var(--bs-gold);
  color: var(--bs-ink);
  font-family: var(--bs-font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.bs-step__body { margin: 0; }

.bs-track--mint .bs-step__no { background: var(--bs-mint); color: #052B27; }
.bs-track--coral .bs-step__no { background: var(--bs-coral); color: #3D1104; }

.bs-stat { display: grid; gap: 0.2rem; }

.bs-stat__value {
  font-family: var(--bs-font-mono);
  font-size: clamp(1.7rem, 3.4vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--bs-deep);
  font-variant-numeric: tabular-nums;
}

.bs-stat__label {
  font-family: var(--bs-font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bs-graphite);
}

.bs-section--ink .bs-stat__value { color: var(--bs-gold); }
.bs-section--ink .bs-stat__label { color: rgba(247, 249, 252, 0.6); }

.bs-band {
  padding: clamp(1.35rem, 3vw, 2.5rem);
  border-radius: var(--bs-r-lg);
  background: linear-gradient(100deg, var(--bs-deep), var(--bs-ink));
  color: rgba(247, 249, 252, 0.86);
}

.bs-band__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: clamp(1rem, 3vw, 2.5rem);
}

.bs-fold {
  overflow: hidden;
  border: 1px solid var(--bs-mist);
  border-radius: var(--bs-r-sm);
  background: #ffffff;
}

.bs-fold + .bs-fold { margin-top: 0.75rem; }

.bs-fold summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.95rem 1.15rem;
  font-family: var(--bs-font-display);
  font-size: 0.98rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  transition: background 0.18s var(--bs-ease);
}

.bs-fold summary::-webkit-details-marker { display: none; }

.bs-fold summary::after {
  content: "+";
  flex: 0 0 auto;
  font-family: var(--bs-font-mono);
  font-size: 1.05rem;
  color: var(--bs-graphite);
}

.bs-fold[open] summary::after { content: "–"; }
.bs-fold summary:hover { background: rgba(11, 42, 74, 0.045); }

.bs-fold__body {
  padding: 0 1.15rem 1.1rem;
  font-size: 0.95rem;
  color: var(--bs-graphite);
}

.bs-divider {
  height: 1px;
  border: 0;
  margin-block: clamp(1.5rem, 3vw, 2.5rem);
  background: var(--bs-mist);
}

.bs-crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  font-family: var(--bs-font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--bs-graphite);
}

.bs-crumb a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--bs-ease), border-color 0.18s var(--bs-ease);
}

.bs-crumb a:hover {
  color: var(--bs-deep);
  border-bottom-color: currentColor;
}

.bs-crumb__sep {
  color: var(--bs-graphite);
  opacity: 0.5;
}

.bs-prose { max-width: 68ch; }

.bs-prose h2 {
  margin: 1.8em 0 0.6em;
  font-size: clamp(1.4rem, 2.4vw, 1.9rem);
}

.bs-prose h3 { margin: 1.6em 0 0.5em; }
.bs-prose p { margin-bottom: 1.2em; }

.bs-prose ul,
.bs-prose ol {
  margin-bottom: 1.2em;
  padding-left: 1.35em;
}

.bs-prose ul { list-style: disc; }
.bs-prose ol { list-style: decimal; }
.bs-prose li { margin-bottom: 0.4em; }

.bs-prose blockquote {
  margin: 1.5em 0;
  padding: 0.25em 0 0.25em 1.25em;
  border-left: 3px solid var(--bs-gold);
  color: var(--bs-graphite);
}

.bs-index {
  position: sticky;
  top: 1.5rem;
  display: grid;
  gap: 0.9rem;
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--bs-mist);
  border-radius: var(--bs-r-md);
  background: #ffffff;
}

.bs-index__title {
  margin: 0;
  font-family: var(--bs-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--bs-graphite);
}

.bs-index__list { display: grid; gap: 0.3rem; }

.bs-index__link {
  display: block;
  padding: 0.35rem 0.7rem;
  border-left: 2px solid var(--bs-mist);
  font-size: 0.9rem;
  color: var(--bs-graphite);
  text-decoration: none;
  transition: color 0.18s var(--bs-ease),
              border-color 0.18s var(--bs-ease),
              background 0.18s var(--bs-ease);
}

.bs-index__link:hover {
  color: var(--bs-deep);
  border-left-color: var(--bs-sky);
}

.bs-index__link[aria-current] {
  color: var(--bs-deep);
  font-weight: 600;
  border-left-color: var(--bs-gold);
  background: rgba(244, 183, 64, 0.12);
}

/* ---------- 9. 媒体容器 ---------- */
.bs-media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border-radius: var(--bs-r-md);
  background:
    linear-gradient(135deg,
      rgba(56, 201, 184, 0.34) 0%,
      rgba(11, 42, 74, 0.16) 46%,
      rgba(255, 122, 89, 0.32) 100%),
    var(--bs-deep);
  isolation: isolate;
}

.bs-media--device { aspect-ratio: 4 / 3; }
.bs-media--tall { aspect-ratio: 4 / 5; }

.bs-media > img,
.bs-media > picture > img,
.bs-media > video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.bs-media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0;
  padding: 0.75rem 1rem;
  background: linear-gradient(to top, rgba(7, 26, 47, 0.85), rgba(7, 26, 47, 0));
  color: rgba(247, 249, 252, 0.92);
  font-family: var(--bs-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

/* ---------- 10. 动效与进度 ---------- */
.bs-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 120;
  width: 100%;
  height: 3px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--bs-mint), var(--bs-gold) 60%, var(--bs-coral));
  pointer-events: none;
}

.bs-reveal-ready [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 320ms var(--bs-ease), transform 320ms var(--bs-ease);
  transition-delay: var(--bs-reveal-delay, 0ms);
}

.bs-reveal-ready [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 11. 响应式与可访问性 ---------- */
@media (max-width: 980px) {
  .bs-grid--7-5,
  .bs-grid--5-7,
  .bs-grid--8-4,
  .bs-grid--4-8,
  .bs-grid--3 { grid-template-columns: minmax(0, 1fr); }

  .bs-index { position: static; }

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

  .bs-footer__brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .bs-header__bar-inner {
    grid-template-columns: minmax(0, 1fr) auto;
    row-gap: 0.5rem;
  }

  .bs-brand { grid-column: 1; grid-row: 1; }

  .bs-navtoggle {
    display: inline-flex;
    grid-column: 2;
    grid-row: 1;
    justify-self: end;
  }

  .bs-header__tagline {
    grid-column: 1 / -1;
    grid-row: 2;
    justify-self: start;
    font-size: 0.72rem;
    letter-spacing: 0.03em;
  }

  .bs-header__cta { display: none; }

  .bs-header__nav { display: none; }

  .bs-header[data-open] .bs-header__nav { display: block; }

  .bs-header__nav-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 0.4rem;
    padding-block: 0.85rem 1.2rem;
  }

  .bs-navnote { display: none; }

  .bs-nav { margin-left: 0; }

  .bs-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.15rem;
  }

  .bs-nav__link {
    display: block;
    padding: 0.72rem 0.9rem;
    border-radius: var(--bs-r-sm);
    background: rgba(247, 249, 252, 0.05);
    font-size: 1rem;
  }

  .bs-nav__link::after { display: none; }

  .bs-nav__link[aria-current="page"] {
    background: rgba(244, 183, 64, 0.14);
    color: var(--bs-gold);
  }
}

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

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

  .bs-footer__cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .bs-footer__base-inner { justify-content: flex-start; }

  .bs-brand__line { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .bs-reveal-ready [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .bs-btn:hover { transform: none; }
}