.page-about {
  --about-text: #C7DAE8;
  --about-rail: 52px;
  --about-gap: clamp(20px, 3.4vw, 44px);
  background: var(--ink-900);
  color: var(--ice);
  font-family: var(--font-body);
}

.page-about a:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  padding-top: clamp(18px, 3vw, 30px);
}

.page-about .crumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--fog-dim);
}

.page-about .crumbs__item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.page-about .crumbs__item + .crumbs__item::before {
  content: "/";
  color: var(--line);
}

.page-about .crumbs__link {
  color: var(--fog);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.page-about .crumbs__link:hover {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------- 首屏 ---------- */
.about-hero {
  position: relative;
  padding: clamp(28px, 5vw, 48px) 0 clamp(34px, 6vw, 64px);
}

.about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px);
  background-size: 96px 96px;
  opacity: 0.25;
  pointer-events: none;
  -webkit-mask-image: linear-gradient(to bottom, #000, transparent 88%);
  mask-image: linear-gradient(to bottom, #000, transparent 88%);
}

.about-hero__inner {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 44px);
  align-items: start;
}

.about-hero__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(34px, 6.4vw, 72px);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--ice);
  margin: 14px 0 0;
  max-width: 20ch;
}

.about-hero__lead {
  margin: 20px 0 0;
  max-width: 56ch;
  font-size: 17px;
  line-height: 1.78;
  color: var(--about-text);
}

.about-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 18px 40px;
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.about-fact {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.about-fact__num {
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.about-fact__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--fog);
}

/* ---------- 章节索引 ---------- */
.about-index {
  border-top: 2px solid var(--cyan);
  padding-top: 14px;
}

.about-index__head {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--fog-dim);
}

.about-index__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

.about-index__link {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 9px 10px;
  border-left: 2px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--ice);
  text-decoration: none;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}

.about-index__link:hover {
  background: rgba(41, 240, 220, 0.08);
  border-left-color: var(--cyan);
}

.about-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan);
  letter-spacing: 0.06em;
}

.about-index__label {
  font-size: 15px;
  line-height: 1.5;
}

/* ---------- 章节骨架 ---------- */
.about-sec {
  padding: clamp(40px, 6.5vw, 86px) 0;
  border-top: 1px solid var(--line);
}

.about-sec__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}

.about-sec__rail {
  display: flex;
  align-items: center;
  gap: 10px;
}

.about-sec__num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.about-sec__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--fog-dim);
}

.about-sec__body,
.about-sec__main {
  min-width: 0;
}

.about-sec__body > h2,
.about-sec__main > h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(25px, 3.2vw, 42px);
  line-height: 1.12;
  letter-spacing: -0.015em;
  color: var(--ice);
  margin: 0 0 16px;
  max-width: 26ch;
}

.about-sec__body > p,
.about-sec__main > p {
  margin: 0 0 16px;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--about-text);
  max-width: 62ch;
}

.about-sec__body > p:last-child,
.about-sec__main > p:last-child {
  margin-bottom: 0;
}

/* ---------- 图片 ---------- */
.about-figure {
  margin: 0;
  min-width: 0;
}

.about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--panel);
  object-fit: cover;
}

.about-figure figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.03em;
  color: var(--fog-dim);
}

.about-band {
  margin-top: clamp(26px, 4vw, 44px);
}

/* ---------- 团队分工 ---------- */
.about-teams {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin: 26px 0 0;
}

.about-team {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--cyan);
  border-radius: var(--radius-md);
  background: var(--panel);
}

.about-team:nth-child(2) {
  border-top-color: var(--orange);
}

.about-team:nth-child(3) {
  border-top-color: var(--green);
}

.about-teams .about-team__name {
  margin: 0;
  font-family: var(--font-display);
  font-size: 20px;
  letter-spacing: -0.01em;
  color: var(--ice);
}

.about-teams .about-team__count {
  margin: 4px 0 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fog);
}

.about-teams .about-team__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-text);
}

/* ---------- 覆盖范围 ---------- */
.about-cov {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  margin: 26px 0 0;
}

.about-cov__stats {
  display: grid;
  gap: 12px;
}

.about-stat {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--panel);
}

.about-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(30px, 4.6vw, 46px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.about-stat:nth-child(2) .about-stat__num {
  color: var(--ice);
}

.about-stat:nth-child(3) .about-stat__num {
  color: var(--orange);
}

.about-stat__label {
  font-size: 14px;
  line-height: 1.5;
  color: var(--fog);
}

.about-sources {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--line);
}

.about-sources li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-soft);
}

.about-sources__key {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.about-sources__txt {
  font-size: 15px;
  line-height: 1.6;
  color: var(--about-text);
}

.about-sec__main > .about-note {
  margin-top: 24px;
  padding: 16px 18px;
  border-left: 3px solid var(--orange);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: rgba(255, 138, 61, 0.07);
  font-size: 15px;
  line-height: 1.75;
  color: var(--about-text);
  max-width: 78ch;
}

/* ---------- 时间轴 ---------- */
.about-timeline {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  position: relative;
}

.about-timeline::before {
  content: "";
  position: absolute;
  left: 76px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan), rgba(41, 240, 220, 0.06));
}

.about-tl__item {
  position: relative;
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  column-gap: 20px;
  padding-bottom: clamp(20px, 3vw, 30px);
}

.about-tl__item:last-child {
  padding-bottom: 0;
}

.about-tl__year {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--orange);
  padding-top: 4px;
}

.about-tl__body {
  position: relative;
  min-width: 0;
  padding-top: 2px;
}

.about-tl__body::before {
  content: "";
  position: absolute;
  left: -12px;
  top: 9px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--cyan);
  transition: background-color 0.15s ease, box-shadow 0.15s ease;
}

.about-tl__item:hover .about-tl__body::before,
.about-tl__item:focus-within .about-tl__body::before {
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(41, 240, 220, 0.18);
}

.about-tl__body h3 {
  margin: 0 0 6px;
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--ice);
}

.about-tl__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--fog);
  max-width: 62ch;
}

/* ---------- 合作 ---------- */
.about-partners {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.about-partners li {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--panel);
  font-size: 15px;
  line-height: 1.65;
  color: var(--about-text);
}

.about-partners__num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1;
  color: var(--green);
}

.about-partners__txt {
  min-width: 0;
}

.about-sec__body > .about-partners + p {
  margin-top: 18px;
}

/* ---------- 开始使用 ---------- */
.about-sec--start {
  background: var(--panel);
}

.about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.about-cta__hint {
  margin: 20px 0 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--fog);
  max-width: 62ch;
}

.about-cta__hint a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(41, 240, 220, 0.35);
  transition: border-color 0.15s ease;
}

.about-cta__hint a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .about-teams {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }
}

@media (min-width: 760px) {
  .about-sources {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(20px, 3vw, 40px);
  }

  .about-sources li:nth-last-child(-n + 2) {
    border-bottom: 1px solid var(--line-soft);
  }
}

@media (min-width: 860px) {
  .about-cov {
    grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
    gap: clamp(24px, 4vw, 48px);
    align-items: center;
  }
}

@media (min-width: 980px) {
  .about-sec__grid {
    grid-template-columns: var(--about-rail) minmax(0, 7fr) minmax(0, 5fr);
    column-gap: var(--about-gap);
  }

  .about-sec--full .about-sec__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }

  .about-sec__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    align-self: start;
    position: sticky;
    top: 118px;
  }

  .about-sec__body {
    grid-column: 2;
  }

  .about-sec__main {
    grid-column: 2 / -1;
  }

  .about-figure {
    grid-column: 3;
    grid-row: 1;
  }
}

@media (min-width: 1024px) {
  .about-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(32px, 5vw, 72px);
  }
}

@media (max-width: 420px) {
  .page-about .about-tl__item {
    grid-template-columns: 48px minmax(0, 1fr);
    column-gap: 16px;
  }

  .page-about .about-timeline::before {
    left: 57px;
  }

  .page-about .about-tl__body::before {
    left: -11px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about a,
  .page-about .about-tl__body::before,
  .page-about .about-index__link,
  .page-about .about-cta__hint a {
    transition-duration: 0.001ms;
  }
}