.page-about {
  --ab-line: rgba(58, 63, 69, 0.5);
  --ab-line-soft: rgba(58, 63, 69, 0.24);
  --ab-line-dark: rgba(242, 237, 228, 0.14);
  --ab-pad: clamp(56px, 8vw, 112px);
  display: block;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  overflow-x: hidden;
  overflow-x: clip;
}

.page-about .ab-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .about-chron,
.page-about .about-method,
.page-about .about-versions,
.page-about .about-boundary {
  scroll-margin-top: 92px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(116px, 15vw, 180px) 0 clamp(52px, 7vw, 92px);
  background: var(--ink);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(58, 63, 69, 0.42) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(58, 63, 69, 0.42) 1px, transparent 1px);
  background-size: clamp(72px, 9vw, 128px) clamp(72px, 9vw, 128px);
  -webkit-mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.25) 100%);
  mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.25) 100%);
  pointer-events: none;
}

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

.page-about .about-hero__grid {
  display: grid;
  gap: 34px;
  margin-top: clamp(26px, 3.6vw, 46px);
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: 164px minmax(0, 1fr) minmax(230px, 330px);
    gap: clamp(24px, 3.2vw, 52px);
    align-items: start;
  }
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--ab-line);
}

.page-about .about-rail__list li {
  border-bottom: 1px solid var(--ab-line-dark);
}

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--grey-ink);
  text-decoration: none;
  transition: color 180ms var(--ease), transform 180ms var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--cyan);
  transform: translateX(4px);
}

.page-about .about-rail__idx {
  color: var(--amber);
  font-weight: 700;
}

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

.page-about .about-hero__title {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(32px, 6.6vw, 80px);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: 24px 0 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.35vw, 17px);
  line-height: 1.85;
  color: var(--grey-ink);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 24px;
  margin: clamp(28px, 3.6vw, 46px) 0 0;
  padding-top: 26px;
  border-top: 1px solid var(--ab-line-dark);
}

.page-about .about-hero__stat {
  margin: 0;
}

.page-about .about-hero__stat dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--grey-ink);
}

.page-about .about-hero__stat dd {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 40px);
  font-weight: 700;
  line-height: 1;
  color: var(--paper);
}

.page-about .about-hero__stat dd small {
  margin-left: 0.16em;
  font-size: 12px;
  font-weight: 500;
  color: var(--cyan);
}

.page-about .about-hero__figure {
  position: relative;
  margin: 0;
}

.page-about .about-hero__figure::after {
  content: "";
  position: absolute;
  top: 18px;
  left: 18px;
  right: -18px;
  bottom: -18px;
  border: 1px solid var(--ab-line);
  border-radius: var(--r-organic-sm);
  z-index: 0;
  pointer-events: none;
}

@media (min-width: 900px) {
  .page-about .about-hero__figure {
    margin-top: 42px;
  }
}

.page-about .about-hero__frame {
  position: relative;
  z-index: 1;
  aspect-ratio: 4 / 3;
  overflow: hidden;
  border-radius: var(--r-organic-sm);
  background: var(--stone);
}

.page-about .about-hero__frame .media-frame__inner,
.page-about .about-versions__frame .media-frame__inner {
  display: block;
  width: 100%;
  height: 100%;
}

.page-about .about-hero__frame .media-frame__img,
.page-about .about-versions__frame .media-frame__img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(0.82) contrast(1.08);
}

/* ---------- 通用章节标题 ---------- */
.page-about .ab-head {
  display: grid;
  gap: 12px;
  max-width: 760px;
}

.page-about .ab-head__index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--terracotta);
}

.page-about .ab-head__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(25px, 3.4vw, 42px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .ab-head__text {
  margin: 0;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--stone);
}

.page-about .ab-head--on-dark .ab-head__index {
  color: var(--amber);
}

.page-about .ab-head--on-dark .ab-head__title {
  color: var(--paper);
}

.page-about .ab-head--on-dark .ab-head__text {
  color: var(--grey-ink);
}

/* ---------- 赛季编年 ---------- */
.page-about .about-chron {
  background: var(--paper);
  color: var(--ink);
  padding: var(--ab-pad) 0;
}

.page-about .about-chron__layout {
  margin-top: clamp(34px, 4.6vw, 60px);
  display: grid;
  gap: 26px;
}

.page-about .about-chron__scale {
  display: none;
}

@media (min-width: 880px) {
  .page-about .about-chron__layout {
    grid-template-columns: 72px minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .about-chron__scale {
    display: block;
    position: relative;
  }
}

.page-about .about-chron__axis {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  color: var(--ab-line);
}

.page-about .about-chron__list {
  counter-reset: ab-season;
  display: block;
}

.page-about .about-chron__item {
  counter-increment: ab-season;
  position: relative;
  border-top: 1px solid var(--ab-line-soft);
}

.page-about .about-chron__item:last-child {
  border-bottom: 1px solid var(--ab-line-soft);
}

.page-about .about-chron__heading {
  margin: 0;
  font: inherit;
}

.page-about .about-chron__trigger {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr) 26px;
  grid-template-areas:
    "num season icon"
    "num label icon";
  gap: 6px 14px;
  align-items: start;
  width: 100%;
  padding: 22px 0;
  background: none;
  border: 0;
  text-align: left;
  cursor: pointer;
  color: inherit;
  font: inherit;
}

@media (min-width: 700px) {
  .page-about .about-chron__trigger {
    grid-template-columns: 64px minmax(0, 1fr) 30px;
    padding: 26px 0;
  }
}

.page-about .about-chron__num {
  grid-area: num;
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--terracotta);
}

.page-about .about-chron__num::after {
  content: counter(ab-season, decimal-leading-zero);
}

.page-about .about-chron__season {
  grid-area: season;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--stone);
}

.page-about .about-chron__label {
  grid-area: label;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(18px, 2vw, 25px);
  line-height: 1.32;
  color: var(--ink);
  transition: color 180ms var(--ease);
}

.page-about .about-chron__trigger:hover .about-chron__label,
.page-about .about-chron__trigger:focus-visible .about-chron__label {
  color: var(--signal);
}

.page-about .about-chron__trigger .accordion__icon {
  grid-area: icon;
  position: relative;
  align-self: center;
  justify-self: end;
  width: 22px;
  height: 22px;
  border: 1px solid var(--ab-line);
  border-radius: 50%;
  transition: border-color 200ms var(--ease);
}

.page-about .about-chron__trigger .accordion__icon::before,
.page-about .about-chron__trigger .accordion__icon::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  background: var(--ink);
  transform: translate(-50%, -50%);
  transition: transform 220ms var(--ease), opacity 220ms var(--ease);
}

.page-about .about-chron__trigger .accordion__icon::before {
  width: 9px;
  height: 1.5px;
}

.page-about .about-chron__trigger .accordion__icon::after {
  width: 1.5px;
  height: 9px;
}

.page-about .about-chron__trigger[aria-expanded="true"] .accordion__icon {
  border-color: var(--signal);
}

.page-about .about-chron__trigger[aria-expanded="true"] .accordion__icon::after {
  transform: translate(-50%, -50%) scaleY(0);
  opacity: 0;
}

.page-about .about-chron__panel {
  padding: 0 0 26px;
}

.page-about .about-chron__panel[hidden] {
  display: none;
}

@media (min-width: 700px) {
  .page-about .about-chron__panel {
    padding: 0 40px 30px 64px;
  }
}

.page-about .about-chron__text {
  margin: 0;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--stone);
}

.page-about .about-chron__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-chron__facts li {
  display: inline-flex;
  align-items: baseline;
  gap: 4px;
  padding: 6px 13px;
  border: 1px solid var(--ab-line-soft);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.55);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.page-about .about-chron__facts .ab-num {
  font-size: 13px;
  color: var(--deep-cyan);
}

.page-about .about-ongoing {
  margin-top: 26px;
  padding: clamp(24px, 3.4vw, 40px);
  border-radius: var(--r-organic);
  background: var(--ink);
  color: var(--paper);
}

.page-about .about-ongoing__flag {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--amber);
}

.page-about .about-ongoing__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(232, 163, 61, 0.18);
}

.page-about .about-ongoing__title {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 2.2vw, 26px);
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-ongoing__text {
  margin: 14px 0 0;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--grey-ink);
}

.page-about .about-ongoing__stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  gap: 22px;
  margin: 26px 0 0;
  padding: 24px 0 0;
  list-style: none;
  border-top: 1px solid var(--ab-line-dark);
}

.page-about .about-ongoing__value {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.2vw, 36px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-ongoing__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--grey-ink);
}

/* ---------- 核定四步 ---------- */
.page-about .about-method {
  position: relative;
  padding: var(--ab-pad) 0;
  background: var(--ink);
  color: var(--paper);
  overflow: hidden;
}

.page-about .about-method__tabs {
  display: grid;
  gap: 24px;
  margin-top: clamp(32px, 4.4vw, 54px);
}

.page-about .about-method__tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-method__tab {
  padding: 11px 18px;
  border: 1px solid var(--ab-line-dark);
  border-radius: 999px;
  background: transparent;
  color: var(--grey-ink);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color 180ms var(--ease), border-color 180ms var(--ease), background-color 180ms var(--ease);
}

.page-about .about-method__tab:hover,
.page-about .about-method__tab:focus-visible {
  color: var(--paper);
  border-color: rgba(79, 227, 208, 0.55);
}

.page-about .about-method__tab[aria-selected="true"] {
  color: var(--ink);
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .about-method__panel {
  padding: clamp(22px, 3vw, 34px);
  border: 1px solid var(--ab-line-dark);
  border-radius: var(--r-organic-sm);
  background: rgba(74, 10, 20, 0.28);
}

.page-about .about-method__step {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .about-method__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 2.2vw, 26px);
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-method__text {
  margin: 14px 0 0;
  max-width: 70ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--grey-ink);
}

.page-about .about-method__criteria {
  display: grid;
  gap: 18px;
  margin: 24px 0 0;
  padding-top: 22px;
  border-top: 1px solid var(--ab-line-dark);
}

@media (min-width: 760px) {
  .page-about .about-method__criteria {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px 30px;
  }
}

.page-about .about-method__criteria dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-method__criteria dd {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--paper);
}

.page-about .about-method__banner {
  margin-top: clamp(36px, 4.6vw, 64px);
  height: clamp(190px, 30vw, 420px);
  overflow: hidden;
  border-radius: var(--r-organic-sm);
  background: var(--stone);
  line-height: 0;
}

.page-about .about-method__banner img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.7) contrast(1.1) brightness(0.88);
}

/* ---------- 团队与分工 ---------- */
.page-about .about-team {
  background: var(--paper);
  color: var(--ink);
  padding: var(--ab-pad) 0;
}

.page-about .about-team__grid {
  display: grid;
  gap: 18px;
  margin-top: clamp(32px, 4.4vw, 54px);
}

@media (min-width: 780px) {
  .page-about .about-team__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }
}

.page-about .about-team__card {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: clamp(22px, 2.8vw, 32px);
  border: 1px solid var(--ab-line-soft);
  border-top: 3px solid var(--signal);
  border-radius: 0 0 var(--r-organic-sm) var(--r-organic-sm);
  background: rgba(255, 255, 255, 0.55);
}

.page-about .about-team__role {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--stone);
}

.page-about .about-team__count {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(38px, 4.6vw, 56px);
  font-weight: 700;
  line-height: 1;
  color: var(--ink);
}

.page-about .about-team__count small {
  margin-left: 0.14em;
  font-size: 13px;
  font-weight: 500;
  color: var(--terracotta);
}

.page-about .about-team__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--stone);
}

.page-about .about-team__note {
  margin: clamp(24px, 3vw, 36px) 0 0;
  max-width: 72ch;
  padding-left: 18px;
  border-left: 2px solid var(--moss);
  font-size: 14px;
  line-height: 1.85;
  color: var(--stone);
}

/* ---------- 数据台版本 ---------- */
.page-about .about-versions {
  background: var(--sub-red);
  color: var(--paper);
  padding: var(--ab-pad) 0;
}

.page-about .about-versions__layout {
  display: grid;
  gap: 30px;
  margin-top: clamp(32px, 4.4vw, 56px);
}

@media (min-width: 900px) {
  .page-about .about-versions__layout {
    grid-template-columns: minmax(0, 300px) minmax(0, 1fr);
    gap: clamp(30px, 4vw, 64px);
    align-items: start;
  }
}

.page-about .about-versions__figure {
  margin: 0;
}

.page-about .about-versions__frame {
  aspect-ratio: 5 / 7;
  overflow: hidden;
  border-radius: var(--r-organic-sm);
  background: var(--stone);
}

.page-about .about-versions__caption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(242, 237, 228, 0.72);
}

.page-about .about-versions__tabs {
  display: grid;
  gap: 22px;
}

.page-about .about-versions__tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-versions__tab {
  padding: 10px 20px;
  border: 1px solid var(--ab-line-dark);
  border-radius: 999px;
  background: transparent;
  color: rgba(242, 237, 228, 0.75);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: background-color 180ms var(--ease), color 180ms var(--ease), border-color 180ms var(--ease);
}

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

.page-about .about-versions__tab[aria-selected="true"] {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
  font-weight: 700;
}

.page-about .about-versions__panel {
  padding: clamp(22px, 2.8vw, 32px);
  border: 1px solid var(--ab-line-dark);
  border-radius: var(--r-organic-sm);
  background: rgba(11, 13, 16, 0.32);
}

.page-about .about-versions__year {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .about-versions__name {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 2.2vw, 26px);
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-versions__text {
  margin: 14px 0 0;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--grey-ink);
}

/* ---------- 服务范围与边界 ---------- */
.page-about .about-boundary {
  background: var(--paper);
  color: var(--ink);
  padding: var(--ab-pad) 0;
}

.page-about .about-boundary__grid {
  display: grid;
  gap: 0;
  margin-top: clamp(30px, 4vw, 52px);
  border-top: 1px solid var(--ab-line-soft);
}

.page-about .about-boundary__col {
  padding: 26px 0;
  border-bottom: 1px solid var(--ab-line-soft);
}

@media (min-width: 760px) {
  .page-about .about-boundary__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-boundary__col {
    padding: 30px 34px;
  }

  .page-about .about-boundary__col:nth-child(odd) {
    padding-left: 0;
  }

  .page-about .about-boundary__col:nth-child(even) {
    border-left: 1px solid var(--ab-line-soft);
  }
}

.page-about .about-boundary__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 17px;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-boundary__col p {
  margin: 12px 0 0;
  max-width: 46ch;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--stone);
}

/* ---------- 页尾导航 ---------- */
.page-about .about-cta {
  background: var(--red);
  color: var(--paper);
  padding: clamp(44px, 6vw, 82px) 0;
}

.page-about .about-cta__inner {
  display: grid;
  gap: 28px;
}

@media (min-width: 880px) {
  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    gap: clamp(30px, 5vw, 80px);
    align-items: center;
  }
}

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

.page-about .about-cta__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(24px, 3vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-cta__links {
  display: grid;
  border-top: 1px solid rgba(242, 237, 228, 0.26);
}

.page-about .about-cta__link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 2px;
  border-bottom: 1px solid rgba(242, 237, 228, 0.26);
  color: var(--paper);
  text-decoration: none;
  font-size: 15px;
  line-height: 1.6;
  transition: color 180ms var(--ease), padding-left 180ms var(--ease);
}

.page-about .about-cta__link::after {
  content: "→";
  flex: none;
  font-family: var(--font-mono);
  color: var(--cyan);
  transition: transform 180ms var(--ease);
}

.page-about .about-cta__link:hover,
.page-about .about-cta__link:focus-visible {
  color: var(--cyan);
  padding-left: 10px;
}

.page-about .about-cta__link:hover::after,
.page-about .about-cta__link:focus-visible::after {
  transform: translateX(4px);
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-chron__label,
  .page-about .about-cta__link,
  .page-about .about-cta__link::after,
  .page-about .about-chron__trigger .accordion__icon::before,
  .page-about .about-chron__trigger .accordion__icon::after {
    transition-duration: 120ms;
    transform: none;
  }
}