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

html {
  margin: 0;
  padding: 0;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 150px;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.32;
  letter-spacing: .01em;
}

p, figure, blockquote { margin: 0; }

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

a { color: inherit; }

button { font: inherit; color: inherit; border: 0; background: none; }

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

table { border-collapse: collapse; width: 100%; }

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

/* ============ 2. 变量 ============ */
:root {
  --night: #07110F;
  --deep: #0E2420;
  --grass: #1F6F4A;
  --grass-lift: #3FA46A;
  --amber: #F2A63B;
  --amber-soft: #FFD9A0;
  --cyan: #4FF0D0;
  --wine: #6B1F3A;
  --indigo: #23204F;
  --paper: #F4F7F3;
  --text: #101A18;
  --muted: #8FA39B;
  --muted-ink: #56655F;

  --line-dark: rgba(143, 163, 155, .26);
  --line-light: rgba(16, 26, 24, .14);

  --font-display: "Barlow Condensed", "Oswald", "Arial Narrow", "Helvetica Neue", Arial, sans-serif;
  --font-heading: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: var(--font-heading);
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --cut: 16px;
  --cut-shape: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 16px 100%, 0 calc(100% - 16px));
  --cut-shape-sm: polygon(0 0, calc(100% - 9px) 0, 100% 9px, 100% 100%, 9px 100%, 0 calc(100% - 9px));
}

/* ============ 3. 容器与骨架 ============ */
.wrap {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 22px;
}

.wrap--narrow { max-width: 720px; }

.wrap--wide { max-width: 1360px; }

.section { padding: 64px 0; }

.section--night { background: var(--night); color: var(--paper); }
.section--deep { background: var(--deep); color: var(--paper); }
.section--grass { background: var(--grass); color: #F1FFF8; }
.section--wine { background: var(--wine); color: #FFEDF3; }
.section--indigo { background: var(--indigo); color: #EDEBFF; }
.section--paper { background: var(--paper); color: var(--text); }
.section--ink { background: var(--text); color: var(--paper); }

.section__head {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 28px;
}

.section__index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--amber);
}

.section__title { font-size: clamp(24px, 3.2vw, 36px); }

.section__lead {
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

.section--grass .section__lead { color: rgba(241, 255, 248, .84); }
.section--wine .section__lead { color: rgba(255, 237, 243, .84); }
.section--indigo .section__lead { color: rgba(237, 235, 255, .82); }
.section--paper .section__index { color: var(--grass); }
.section--paper .section__lead { color: var(--muted-ink); }

.stack { display: flex; flex-direction: column; gap: 16px; }
.cluster { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; }

/* ============ 4. 网格 ============ */
.grid { display: grid; gap: 22px; }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--5-7 { grid-template-columns: 5fr 7fr; }
.grid--7-5 { grid-template-columns: 7fr 5fr; }
.grid--3-9 { grid-template-columns: 3fr 9fr; }

/* ============ 5. 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5em;
  padding: 12px 20px;
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.2;
  text-decoration: none;
  color: var(--paper);
  background: rgba(244, 247, 243, .08);
  cursor: pointer;
  clip-path: var(--cut-shape-sm);
  transition: background .2s ease, color .2s ease, transform .2s ease;
}

.btn:hover { transform: translateY(-1px); }

.btn--primary { background: var(--grass); color: #F1FFF8; }
.btn--primary:hover { background: var(--grass-lift); color: #06140F; }

.btn--amber { background: var(--amber); color: var(--night); }
.btn--amber:hover { background: var(--amber-soft); }

.btn--ghost {
  color: var(--paper);
  background: transparent;
  box-shadow: inset 0 0 0 1px rgba(143, 163, 155, .5);
}
.btn--ghost:hover { color: var(--cyan); box-shadow: inset 0 0 0 1px var(--cyan); }

.btn--outline {
  color: var(--text);
  background: transparent;
  box-shadow: inset 0 0 0 1px rgba(16, 26, 24, .32);
}
.btn--outline:hover { color: var(--grass); box-shadow: inset 0 0 0 1px var(--grass); }

.btn--sm { padding: 8px 14px; font-size: 13px; }

/* ============ 6. 标签、索引、装饰 ============ */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  color: var(--amber);
}

.tag {
  display: inline-block;
  padding: 4px 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  background: rgba(79, 240, 208, .14);
  color: var(--cyan);
  clip-path: var(--cut-shape-sm);
}

.tag--amber { background: rgba(242, 166, 59, .18); color: var(--amber); }
.tag--wine { background: var(--wine); color: #FFE7EF; }
.tag--indigo { background: var(--indigo); color: #DCD8FF; }

.index-num {
  font-family: var(--font-display);
  font-size: 44px;
  line-height: 1;
  letter-spacing: .04em;
  color: rgba(143, 163, 155, .5);
}

.cut { clip-path: var(--cut-shape); }

.dashline {
  height: 1px;
  border: 0;
  margin: 0;
  color: var(--grass-lift);
  opacity: .45;
  background-image: repeating-linear-gradient(90deg, currentColor 0 8px, transparent 8px 17px);
}

.dashline--tilt { transform: rotate(-1.4deg); }

/* ============ 7. 卡片 ============ */
.card {
  padding: 22px;
  background: var(--deep);
  color: var(--paper);
  clip-path: var(--cut-shape);
}

.card--light {
  background: #FFFFFF;
  color: var(--text);
  box-shadow: inset 0 0 0 1px var(--line-light);
}

.card--wine { background: var(--wine); }
.card--indigo { background: var(--indigo); }

.card__index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--amber);
}

.card__title { margin-top: 8px; font-size: 20px; }

.card__meta {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted);
}

.card__body {
  margin-top: 10px;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(244, 247, 243, .78);
}

.card--light .card__body { color: #43524C; }
.card--light .card__meta { color: var(--muted-ink); }

/* ============ 8. 正文与面包屑 ============ */
.prose {
  max-width: 74ch;
  font-size: 17px;
  line-height: 1.85;
  color: var(--text);
}

.prose > * + * { margin-top: 1.1em; }

.prose h2 {
  margin-top: 1.9em;
  padding-top: .55em;
  font-size: clamp(22px, 2.6vw, 28px);
  border-top: 2px solid var(--grass);
}

.prose h3 { margin-top: 1.6em; font-size: 20px; }

.prose ul, .prose ol { list-style: revert; padding-left: 1.4em; }
.prose li + li { margin-top: .4em; }

.prose a {
  color: var(--grass);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose blockquote {
  margin: 1.6em 0;
  padding: 14px 20px;
  border-left: 4px solid var(--amber);
  background: rgba(242, 166, 59, .12);
}

.prose code {
  padding: 2px 6px;
  font-family: var(--font-mono);
  font-size: .9em;
  background: rgba(16, 26, 24, .07);
}

.breadcrumb {
  padding: 14px 0;
  background: var(--paper);
  border-bottom: 1px solid var(--line-light);
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted-ink);
}

.breadcrumb__item { display: inline-flex; align-items: center; gap: 8px; }

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: var(--muted-ink);
  opacity: .6;
}

.breadcrumb__link { text-decoration: none; border-bottom: 1px solid transparent; }
.breadcrumb__link:hover { border-color: var(--grass); }
.breadcrumb__current { color: var(--text); }

/* ============ 9. 章节目录 ============ */
.toc {
  padding: 18px;
  background: var(--deep);
  color: var(--paper);
  clip-path: var(--cut-shape);
}

.toc__title {
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--amber);
}

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

.toc__link {
  display: block;
  padding: 7px 10px;
  font-size: 14px;
  color: rgba(244, 247, 243, .74);
  text-decoration: none;
  border-left: 2px solid transparent;
}

.toc__link:hover { color: var(--paper); background: rgba(31, 111, 74, .3); }

.toc__link[aria-current="true"] {
  color: var(--cyan);
  border-left-color: var(--cyan);
  background: rgba(79, 240, 208, .1);
}

/* ============ 10. 媒体容器 ============ */
.media {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(150deg, var(--deep) 0%, var(--night) 55%, rgba(31, 111, 74, .92) 135%);
  clip-path: var(--cut-shape);
}

.media::after {
  content: "";
  position: absolute;
  left: -20%;
  right: -20%;
  bottom: 14%;
  height: 2px;
  z-index: 2;
  pointer-events: none;
  background-image: repeating-linear-gradient(90deg, rgba(79, 240, 208, .7) 0 10px, transparent 10px 22px);
  transform: rotate(-4deg);
}

.media__img, .media img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media__label {
  position: absolute;
  left: 14px;
  bottom: 14px;
  z-index: 3;
  padding: 4px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--amber-soft);
  background: rgba(7, 17, 15, .74);
}

.media--wide { aspect-ratio: 16 / 9; }
.media--band { aspect-ratio: 24 / 9; }
.media--square { aspect-ratio: 1 / 1; }
.media--tall { aspect-ratio: 3 / 4; }

.media__caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  color: var(--muted-ink);
}

/* ============ 11. 页头 ============ */
.skip-link {
  position: absolute;
  left: 12px;
  top: -70px;
  z-index: 200;
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--night);
  background: var(--cyan);
  text-decoration: none;
  transition: top .18s ease;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--night);
  color: var(--paper);
  border-bottom: 1px solid rgba(79, 240, 208, .2);
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(112deg, rgba(63, 164, 106, .13) 0 2px, transparent 2px 28px);
}

.masthead { position: relative; background: var(--night); }

.masthead__row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 16px;
  padding-top: 16px;
  padding-bottom: 12px;
  transition: padding .22s ease;
}

.masthead__utility {
  display: flex;
  align-items: center;
  gap: 18px;
  min-width: 0;
}

.util-link {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px dashed transparent;
  white-space: nowrap;
}

.util-link:hover { color: var(--cyan); border-bottom-color: var(--cyan); }

.masthead__brand { display: flex; justify-content: center; }

.brand {
  display: grid;
  grid-template-columns: auto auto;
  align-items: center;
  justify-content: center;
  gap: 0 10px;
  text-decoration: none;
  color: inherit;
}

.brand__mark {
  padding: 2px 7px;
  font-family: var(--font-display);
  font-size: 18px;
  letter-spacing: .06em;
  background: var(--amber);
  color: var(--night);
  clip-path: polygon(0 0, calc(100% - 7px) 0, 100% 7px, 100% 100%, 7px 100%, 0 calc(100% - 7px));
}

.brand__name {
  font-family: var(--font-heading);
  font-size: 27px;
  font-weight: 600;
  letter-spacing: .05em;
  transition: font-size .22s ease;
}

.brand__tagline {
  grid-column: 1 / -1;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--muted);
  text-align: center;
}

.masthead__actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
}

.util-lang {
  padding-left: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted);
  border-left: 1px solid var(--line-dark);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--paper);
  cursor: pointer;
  box-shadow: inset 0 0 0 1px rgba(143, 163, 155, .45);
  clip-path: var(--cut-shape-sm);
}

.nav-toggle:hover { color: var(--cyan); box-shadow: inset 0 0 0 1px var(--cyan); }

.nav-toggle__bars {
  position: relative;
  display: inline-block;
  width: 16px;
  height: 10px;
  border-top: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
}

.nav-toggle__bars::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  background: currentColor;
  transform: translateY(-1px);
}

.nav-toggle[aria-expanded="true"] { color: var(--cyan); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars { border-color: var(--cyan); }

.nav-row {
  border-top: 1px solid var(--line-dark);
  background: linear-gradient(180deg, rgba(14, 36, 32, .55), rgba(7, 17, 15, 0));
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2px;
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 13px 14px;
  font-size: 15px;
  color: rgba(244, 247, 243, .8);
  text-decoration: none;
  transition: background .18s ease, color .18s ease, padding .22s ease;
}

.nav-link::before {
  content: attr(data-index);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--muted);
}

.nav-link:hover { color: #FFFFFF; background: rgba(31, 111, 74, .38); }

.nav-link[aria-current="page"] { color: var(--amber); }
.nav-link[aria-current="page"]::before { color: var(--cyan); }

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 7px;
  height: 2px;
  background: var(--cyan);
}

.nav-cta { display: none; }

.progress-bar {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  transform: scaleX(var(--progress, 0));
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--grass-lift), var(--cyan) 55%, var(--amber));
}

/* 收缩态 */
.site-header[data-condensed="true"] .masthead__row {
  padding-top: 7px;
  padding-bottom: 6px;
}

.site-header[data-condensed="true"] .brand__name { font-size: 20px; }
.site-header[data-condensed="true"] .brand__tagline { display: none; }
.site-header[data-condensed="true"] .nav-link { padding: 8px 12px; font-size: 14px; }
.site-header[data-condensed="true"] .btn--sm { padding: 6px 12px; }

/* ============ 12. 页脚 ============ */
.footer-band {
  background: var(--deep);
  color: var(--paper);
  border-top: 3px solid var(--grass);
  border-bottom: 1px solid var(--line-dark);
}

.band {
  display: flex;
  align-items: center;
  gap: 20px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 22px;
}

.band__lead {
  display: flex;
  flex-direction: column;
  gap: 3px;
  flex: 0 0 auto;
}

.band__tag {
  align-self: flex-start;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  background: var(--amber);
  color: var(--night);
}

.band__note {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--muted);
  white-space: nowrap;
}

.band__track {
  display: flex;
  flex: 1 1 auto;
  min-width: 0;
  overflow-x: auto;
  scrollbar-width: thin;
  cursor: grab;
  scroll-behavior: smooth;
}

.band__track[data-dragging="true"] { cursor: grabbing; }

.band__item {
  flex: 0 0 auto;
  min-width: 186px;
  padding: 0 18px;
  border-left: 1px solid var(--line-dark);
}

.band__teams {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  line-height: 1.4;
  white-space: nowrap;
}

.band__team { color: rgba(244, 247, 243, .88); }

.band__score {
  font-family: var(--font-mono);
  font-size: 20px;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.band__meta {
  margin-top: 3px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--muted);
  white-space: nowrap;
}

.band__link {
  flex: 0 0 auto;
  max-width: 230px;
  padding-left: 20px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--amber-soft);
  text-decoration: none;
  border-left: 1px solid var(--line-dark);
}

.band__link:hover { color: var(--cyan); }

.site-footer {
  position: relative;
  padding: 56px 0 26px;
  background: var(--night);
  color: var(--paper);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(220px, 1.7fr) repeat(3, minmax(120px, .8fr));
  gap: 32px;
}

.footer-brand__name {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 600;
  letter-spacing: .05em;
}

.footer-brand__line {
  margin-top: 10px;
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(244, 247, 243, .74);
}

.footer-brand__note {
  margin-top: 10px;
  max-width: 34ch;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.75;
  color: var(--muted);
}

.footer-col__title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--amber);
}

.footer-col__list { display: grid; gap: 10px; }

.footer-col__link {
  font-size: 14px;
  color: rgba(244, 247, 243, .8);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.footer-col__link:hover { color: var(--cyan); border-bottom-color: var(--cyan); }

.footer-contact {
  display: grid;
  gap: 8px;
  margin-top: 38px;
  padding-top: 22px;
  border-top: 1px solid var(--line-dark);
}

.footer-contact__line {
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--muted);
  word-break: break-word;
}

.footer-contact__label {
  display: inline-block;
  min-width: 5.5em;
  color: var(--grass-lift);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  margin-top: 22px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: rgba(143, 163, 155, .92);
}

.to-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 70;
  display: inline-flex;
  align-items: center;
  padding: 10px 15px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--paper);
  background: var(--deep);
  cursor: pointer;
  clip-path: var(--cut-shape-sm);
  box-shadow: inset 0 0 0 1px rgba(79, 240, 208, .42);
  transition: opacity .24s ease, transform .24s ease, visibility .24s ease, background .2s ease;
}

.to-top:hover { background: var(--grass); }

.to-top[data-visible="false"] {
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
}

/* ============ 13. 显现 ============ */
[data-reveal] {
  transition: opacity .5s ease, transform .5s cubic-bezier(.22, .8, .3, 1);
}

html[data-js="on"] [data-reveal]:not([data-reveal="in"]) {
  opacity: 0;
  transform: translate3d(-24px, 24px, 0);
}

[data-reveal="in"] { opacity: 1; transform: none; }

/* ============ 14. 响应式 ============ */
@media (max-width: 1024px) {
  .masthead__utility { display: none; }
  .grid--3, .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: minmax(200px, 1.4fr) repeat(3, minmax(110px, .9fr)); gap: 24px; }
}

@media (max-width: 880px) {
  html { scroll-padding-top: 96px; }

  .masthead__row { grid-template-columns: 1fr auto 1fr; padding-top: 10px; padding-bottom: 10px; }
  .brand__name { font-size: 20px; }
  .brand__tagline { display: none; }
  .util-lang { display: none; }
  .masthead__cta { display: none; }
  .nav-toggle { display: inline-flex; }

  .nav-row { border-top: 0; background: none; }

  .site-nav {
    position: fixed;
    inset: 0;
    z-index: 120;
    display: block;
    padding: 88px 24px 32px;
    overflow-y: auto;
    background: linear-gradient(165deg, var(--deep) 0%, var(--night) 58%, var(--indigo) 150%);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-12px);
    transition: opacity .22s ease, transform .22s ease, visibility .22s ease;
  }

  .site-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .site-nav__list { flex-direction: column; gap: 0; justify-content: flex-start; }

  .nav-link {
    justify-content: flex-start;
    padding: 16px 4px;
    font-size: 19px;
    border-bottom: 1px solid var(--line-dark);
  }

  .nav-link[aria-current="page"]::after { left: 4px; right: auto; width: 3px; height: auto; top: 16px; bottom: 16px; }

  .nav-cta { display: inline-flex; margin-top: 20px; }

  .grid--2, .grid--3, .grid--4, .grid--5-7, .grid--7-5, .grid--3-9 {
    grid-template-columns: minmax(0, 1fr);
  }

  .section { padding: 46px 0; }

  .band { flex-wrap: wrap; gap: 12px; }
  .band__track { order: 3; width: 100%; }
  .band__item { min-width: 168px; padding: 0 14px; }
  .band__item:first-child { border-left: 1px solid var(--line-dark); }
  .band__link { order: 4; width: 100%; max-width: none; padding: 12px 0 0; border-left: 0; border-top: 1px solid var(--line-dark); }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 26px; }
  .footer-brand { grid-column: 1 / -1; }

  .to-top { right: 12px; bottom: 12px; }
}

@media (max-width: 520px) {
  .wrap { padding: 0 16px; }
  body { font-size: 16px; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .card { padding: 18px; }
  .index-num { font-size: 34px; }
}

/* ============ 15. 偏好与打印 ============ */
@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; }
  html[data-js="on"] [data-reveal]:not([data-reveal="in"]) { opacity: 1; transform: none; }
  .btn:hover { transform: none; }
}