.page-about {
  position: relative;
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(22px, 5vw, 56px) 0 clamp(40px, 7vw, 84px);
  background:
    radial-gradient(120% 90% at 10% 0%, rgba(122, 92, 255, 0.28), transparent 60%),
    radial-gradient(90% 80% at 94% 16%, rgba(33, 230, 214, 0.16), transparent 62%),
    var(--ink-900);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -110px;
  right: -140px;
  width: min(520px, 62vw);
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  background: linear-gradient(140deg, rgba(122, 92, 255, 0.32), rgba(33, 230, 214, 0.12) 58%, transparent);
  filter: blur(12px);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(33, 230, 214, 0.55), rgba(122, 92, 255, 0.35), transparent);
}

.page-about .about-hero .container {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .breadcrumbs {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .about-hero .eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan);
  margin: 0;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(34px, 7.4vw, 70px);
  line-height: 1.12;
  letter-spacing: 0.04em;
  color: var(--paper);
  max-width: 20ch;
}

.page-about .about-hero__lead {
  margin: clamp(16px, 2.6vw, 24px) 0 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.78);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: clamp(26px, 4.6vw, 46px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .about-hero__stats .stat {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: linear-gradient(160deg, rgba(19, 26, 58, 0.9), rgba(11, 16, 38, 0.7));
}

.page-about .about-hero__stats .stat__value {
  display: block;
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: clamp(21px, 3vw, 28px);
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-hero__stats .stat__unit {
  margin-left: 3px;
  font-size: 0.52em;
  color: var(--muted);
}

.page-about .about-hero__stats .stat__label {
  display: block;
  margin-top: 7px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 页面骨架 ---------- */
.page-about .about-shell {
  display: grid;
  gap: clamp(20px, 4vw, 44px);
  padding-block: clamp(30px, 5vw, 64px) clamp(40px, 6vw, 88px);
}

.page-about .about-rail {
  min-width: 0;
}

.page-about .about-rail__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.page-about .about-rail__toc {
  overflow-x: auto;
  padding-bottom: 4px;
  -webkit-overflow-scrolling: touch;
}

.page-about .toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 8px;
}

.page-about .toc__link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 15px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(19, 26, 58, 0.6);
  color: var(--muted);
  text-decoration: none;
  font-size: 13.5px;
  white-space: nowrap;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.page-about .toc__link::before {
  content: "";
  width: 6px;
  height: 6px;
  flex: none;
  border-radius: 50%;
  background: var(--line);
  transition: background 0.2s ease, box-shadow 0.2s ease;
}

.page-about .toc__link:hover,
.page-about .toc__link:focus-visible {
  color: var(--paper);
  border-color: rgba(33, 230, 214, 0.55);
}

.page-about .toc__link[aria-current="true"] {
  color: var(--cyan);
  border-color: rgba(33, 230, 214, 0.7);
  background: rgba(33, 230, 214, 0.08);
}

.page-about .toc__link[aria-current="true"]::before {
  background: var(--cyan);
  box-shadow: 0 0 10px rgba(33, 230, 214, 0.9);
}

.page-about .about-body {
  min-width: 0;
}

.page-about .about-body > .section + .section {
  margin-top: clamp(30px, 5vw, 62px);
  padding-top: clamp(30px, 5vw, 62px);
  border-top: 1px solid rgba(42, 47, 69, 0.75);
}

/* ---------- 章节标题 ---------- */
.page-about .section__index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.page-about .section__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(26px, 4.6vw, 46px);
  line-height: 1.18;
  letter-spacing: 0.04em;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .section__lead {
  margin: 12px 0 0;
  max-width: 62ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.72);
}

/* ---------- 时间轴 ---------- */
.page-about .stage-timeline {
  position: relative;
  margin-top: clamp(24px, 4vw, 44px);
  padding: clamp(20px, 3.4vw, 34px) clamp(16px, 3vw, 30px);
  border-radius: var(--radius-xl);
  background: var(--ink-900);
  overflow: hidden;
}

.page-about .stage-timeline__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.24;
  pointer-events: none;
  z-index: 0;
}

.page-about .stage-timeline::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: var(--radius-xl);
  background: linear-gradient(180deg, rgba(11, 16, 38, 0.62), rgba(11, 16, 38, 0.94));
  pointer-events: none;
  z-index: 0;
}

.page-about .stage-timeline::before {
  content: "";
  position: absolute;
  left: calc(clamp(16px, 3vw, 30px) + 6px);
  top: clamp(26px, 4vw, 40px);
  bottom: clamp(26px, 4vw, 40px);
  width: 1px;
  background: linear-gradient(180deg, rgba(33, 230, 214, 0.65), rgba(122, 92, 255, 0.5) 48%, rgba(255, 122, 69, 0.45));
  z-index: 1;
}

.page-about .stage-timeline__list {
  position: relative;
  z-index: 2;
  list-style: none;
  margin: 0;
  padding: 0 0 0 22px;
  display: grid;
  gap: clamp(22px, 4vw, 42px);
}

.page-about .stage-timeline__marker {
  margin: 0 0 10px;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.page-about .stage-timeline__num {
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(38px, 8vw, 84px);
  line-height: 0.95;
  letter-spacing: 0.02em;
  color: rgba(232, 236, 248, 0.15);
}

.page-about .stage-timeline__phase {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .stage-timeline__card {
  padding: clamp(18px, 3vw, 30px);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(42, 47, 69, 0.95);
  background: linear-gradient(165deg, rgba(19, 26, 58, 0.94), rgba(13, 19, 44, 0.88));
  transition: transform 0.26s ease, border-color 0.26s ease, box-shadow 0.26s ease;
}

.page-about .stage-timeline__card:hover,
.page-about .stage-timeline__card:focus-within {
  transform: translateY(-4px);
  border-color: rgba(33, 230, 214, 0.6);
  box-shadow: var(--shadow-card);
}

.page-about .about-chapter .card__meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .about-chapter .card__title {
  margin: 9px 0 0;
  font-size: clamp(18px, 2.5vw, 23px);
  font-weight: 600;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-chapter .card__text {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.74);
}

/* ---------- 分层 ---------- */
.page-about .layer-layout {
  margin-top: clamp(22px, 3.6vw, 40px);
  display: grid;
  gap: clamp(20px, 3.4vw, 36px);
}

.page-about .layer-stack {
  display: grid;
  gap: 14px;
}

.page-about .layer-stack__item {
  --layer-color: var(--cyan);
  position: relative;
  padding: 18px 20px 18px 24px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--layer-color);
  border-radius: var(--radius-lg);
  background: linear-gradient(90deg, rgba(19, 26, 58, 0.96), rgba(19, 26, 58, 0.55));
  transition: transform 0.24s ease, border-color 0.24s ease;
}

.page-about .layer-stack__item:hover {
  transform: translateX(4px);
  border-color: var(--layer-color);
}

.page-about .layer-stack__item--video {
  --layer-color: var(--cyan);
}

.page-about .layer-stack__item--electronic {
  --layer-color: var(--violet);
}

.page-about .layer-stack__item--sport {
  --layer-color: var(--orange);
}

.page-about .layer-stack__tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--layer-color);
}

.page-about .layer-stack__name {
  margin: 7px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(20px, 3vw, 26px);
  letter-spacing: 0.05em;
  color: var(--paper);
}

.page-about .layer-stack__text {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(232, 236, 248, 0.72);
}

.page-about .layer-figure {
  margin: 0;
}

/* ---------- 内容来源 ---------- */
.page-about .lineup {
  margin-top: clamp(22px, 3.6vw, 40px);
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  align-items: center;
}

.page-about .orbit {
  position: relative;
  width: min(100%, 400px);
  aspect-ratio: 1 / 1;
  margin-inline: auto;
  display: grid;
  place-items: center;
}

.page-about .orbit__ring {
  position: absolute;
  border-radius: 50%;
  border: 1px dashed rgba(42, 47, 69, 1);
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.page-about .orbit__ring--outer {
  inset: 0;
  border-color: rgba(255, 122, 69, 0.4);
}

.page-about .orbit__ring--mid {
  inset: 15%;
  border-color: rgba(122, 92, 255, 0.45);
}

.page-about .orbit__ring--inner {
  inset: 30%;
  border-color: rgba(33, 230, 214, 0.5);
}

.page-about .orbit__ring--outer:hover {
  border-color: var(--orange);
  box-shadow: 0 0 26px rgba(255, 122, 69, 0.28);
}

.page-about .orbit__ring--mid:hover {
  border-color: var(--violet);
  box-shadow: 0 0 26px rgba(122, 92, 255, 0.32);
}

.page-about .orbit__ring--inner:hover {
  border-color: var(--cyan);
  box-shadow: 0 0 26px rgba(33, 230, 214, 0.3);
}

.page-about .orbit__tag {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 5px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--ink-800);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--muted);
  white-space: nowrap;
}

.page-about .orbit__core {
  position: relative;
  z-index: 2;
  width: 40%;
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 8px;
  border: 1px solid rgba(33, 230, 214, 0.5);
  background: radial-gradient(circle at 38% 28%, rgba(33, 230, 214, 0.28), rgba(122, 92, 255, 0.22) 72%);
  font-family: var(--font-display);
  font-size: clamp(12.5px, 2.4vw, 15px);
  letter-spacing: 0.08em;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .lineup__notes {
  display: grid;
  gap: 18px;
}

.page-about .lineup__note {
  padding-left: 16px;
  border-left: 2px solid var(--violet);
}

.page-about .lineup__note--cyan {
  border-left-color: var(--cyan);
}

.page-about .lineup__note--violet {
  border-left-color: var(--orange);
}

.page-about .lineup__note-title {
  margin: 0;
  font-size: 16.5px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .lineup__note-text {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.72);
}

.page-about .link-arrow {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(33, 230, 214, 0.4);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .link-arrow:hover,
.page-about .link-arrow:focus-visible {
  color: var(--paper);
  border-color: var(--paper);
}

/* ---------- 服务保障 ---------- */
.page-about .assure {
  margin-top: clamp(22px, 3.6vw, 40px);
  padding: clamp(20px, 3.4vw, 34px);
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  background: linear-gradient(160deg, rgba(19, 26, 58, 0.95), rgba(11, 16, 38, 0.85));
  display: grid;
  gap: 18px;
}

.page-about .assure .data-bar__label {
  font-size: 14px;
  color: var(--paper);
}

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

.page-about .assure .data-bar--pink .data-bar__value {
  color: var(--pink);
}

.page-about .assure .data-bar--gold .data-bar__value {
  color: var(--gold);
}

.page-about .assure__note {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.72);
}

.page-about .assure__actions {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 值守 ---------- */
.page-about .rhythm-figure {
  margin: clamp(22px, 3.6vw, 36px) 0 0;
}

.page-about .rhythm-grid {
  margin-top: clamp(18px, 3vw, 28px);
  display: grid;
  gap: 14px;
}

.page-about .rhythm-card {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: rgba(19, 26, 58, 0.68);
  transition: border-color 0.24s ease, transform 0.24s ease;
}

.page-about .rhythm-card:hover {
  transform: translateY(-4px);
  border-color: rgba(33, 230, 214, 0.5);
}

.page-about .rhythm-card__index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .rhythm-card__title {
  margin: 8px 0 0;
  font-size: 17px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .rhythm-card__text {
  margin: 9px 0 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.72);
}

/* ---------- 下一步 ---------- */
.page-about .next-grid {
  margin-top: clamp(20px, 3.4vw, 36px);
  display: grid;
  gap: 16px;
}

.page-about .next-card {
  padding: clamp(22px, 3.4vw, 32px);
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  background:
    radial-gradient(120% 120% at 0% 0%, rgba(122, 92, 255, 0.22), transparent 62%),
    rgba(19, 26, 58, 0.85);
}

.page-about .next-card__tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--violet);
}

.page-about .next-card__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(20px, 3vw, 27px);
  letter-spacing: 0.04em;
  line-height: 1.32;
  color: var(--paper);
}

.page-about .next-card__text {
  margin: 12px 0 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(232, 236, 248, 0.72);
}

.page-about .about-links {
  margin-top: clamp(22px, 3.6vw, 36px);
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-links .chip {
  display: inline-flex;
  align-items: center;
  padding: 11px 19px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(19, 26, 58, 0.7);
  color: var(--paper);
  font-size: 14.5px;
  text-decoration: none;
  transition: transform 0.22s ease, border-color 0.22s ease, color 0.22s ease;
}

.page-about .about-links .chip:hover,
.page-about .about-links .chip:focus-visible {
  transform: translateY(-2px);
  border-color: rgba(33, 230, 214, 0.65);
  color: var(--cyan);
}

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

/* ---------- 平板与桌面 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .rhythm-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .next-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 920px) {
  .page-about .stage-timeline {
    padding: clamp(28px, 3.6vw, 44px) clamp(24px, 3.4vw, 44px);
  }

  .page-about .stage-timeline::before {
    left: 50%;
    top: clamp(38px, 4vw, 56px);
    bottom: clamp(38px, 4vw, 56px);
  }

  .page-about .stage-timeline__list {
    padding-left: 0;
    gap: clamp(28px, 3.6vw, 48px);
  }

  .page-about .stage-timeline__item {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    column-gap: clamp(34px, 6vw, 76px);
    align-items: center;
  }

  .page-about .stage-timeline__item:nth-child(odd) {
    grid-template-areas: "mark card";
  }

  .page-about .stage-timeline__item:nth-child(even) {
    grid-template-areas: "card mark";
  }

  .page-about .stage-timeline__marker {
    grid-area: mark;
    margin: 0;
  }

  .page-about .stage-timeline__item:nth-child(odd) .stage-timeline__marker {
    align-items: flex-end;
    text-align: right;
  }

  .page-about .stage-timeline__card {
    grid-area: card;
  }

  .page-about .layer-layout {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: center;
  }

  .page-about .layer-stack {
    gap: 16px;
  }

  .page-about .layer-stack__item:nth-child(2) {
    margin-left: 22px;
  }

  .page-about .layer-stack__item:nth-child(3) {
    margin-left: 44px;
  }

  .page-about .lineup {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  }
}

@media (min-width: 1000px) {
  .page-about .about-shell {
    grid-template-columns: 208px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
  }

  .page-about .about-rail__toc {
    overflow: visible;
  }

  .page-about .toc__list {
    display: grid;
    gap: 6px;
  }

  .page-about .toc__link {
    border-color: transparent;
    background: transparent;
    padding: 7px 10px;
  }
}