.page-about {
  background-color: var(--paper-100);
  color: var(--ink-900);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: 20px 44px;
  background:
    radial-gradient(720px 320px at 92% -10%, rgba(53, 224, 212, 0.16), transparent 62%),
    var(--paper-100);
  border-bottom: 2px solid var(--ink-900);
}

.page-about .about-hero .breadcrumbs {
  margin-bottom: 22px;
}

.page-about .about-hero__inner {
  max-width: 64ch;
}

.page-about .about-hero__kicker {
  display: inline-block;
  margin: 0 0 14px;
  padding: 3px 10px;
  background: var(--ink-900);
  color: var(--path-400);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.18em;
}

.page-about .about-hero__title {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(27px, 5.4vw, 44px);
  line-height: 1.26;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 40em;
  font-size: var(--text-body);
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  border: 2px solid var(--ink-900);
  background: var(--paper-100);
}

.page-about .about-hero__fact {
  display: grid;
  gap: 3px;
  padding: 14px 16px;
  border-right: 1px solid var(--paper-300);
  border-bottom: 1px solid var(--paper-300);
}

.page-about .about-hero__fact:nth-child(2n) {
  border-right: 0;
}

.page-about .about-hero__fact:nth-last-child(-n + 2) {
  border-bottom: 0;
}

.page-about .about-hero__factnum {
  font-size: 21px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .about-hero__factlabel {
  font-size: 13px;
  color: var(--ink-500);
}

/* ---------- 主体与网格 ---------- */
.page-about .about-body {
  padding-block: 44px 64px;
}

.page-about .layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

.page-about .index-rail {
  position: static;
  padding: 16px;
  border: 2px solid var(--ink-900);
  background: var(--paper-100);
}

.page-about .index-rail__label {
  margin: 0 0 12px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--ink-500);
}

.page-about .index-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .index-list__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 8px;
  font-size: 14px;
  color: var(--ink-700);
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: background-color 160ms ease-out, border-color 160ms ease-out, color 160ms ease-out;
}

.page-about .index-list__link:hover {
  background: var(--path-200);
  color: var(--ink-900);
}

.page-about .index-list__link.is-current {
  border-left-color: var(--action-500);
  background: var(--path-200);
  color: var(--ink-900);
  font-weight: 700;
}

.page-about .index-list__link:focus-visible {
  outline: 2px solid var(--action-500);
  outline-offset: 2px;
}

.page-about .index-list__num {
  font-size: 12px;
  color: var(--ink-500);
}

.page-about .index-list__link.is-current .index-list__num {
  color: var(--action-500);
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding-block: 40px;
  border-top: 2px solid var(--paper-300);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec__head {
  display: grid;
  gap: 12px;
  margin-bottom: 22px;
}

.page-about .about-sec__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 26px;
  background: var(--path-400);
  color: var(--ink-900);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.page-about .about-sec__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(20px, 3.6vw, 28px);
  line-height: 1.36;
  color: var(--ink-900);
}

.page-about .about-sec__lede {
  margin: 0;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-500);
}

.page-about .about-sec__body p {
  margin: 0 0 16px;
  max-width: 40em;
  font-size: var(--text-body);
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .about-sec__body p:last-child {
  margin-bottom: 0;
}

/* ---------- 引文卡 ---------- */
.page-about .about-quote {
  margin: 28px 0 0;
  padding: 24px 22px;
  background: var(--ink-900);
  border: 2px solid var(--ink-900);
  border-left: 6px solid var(--path-400);
  box-shadow: var(--shadow-hard);
  transition: border-color 160ms ease-out;
}

.page-about .about-quote:hover {
  border-left-color: var(--action-500);
}

.page-about .about-quote:focus-visible {
  outline: 2px solid var(--action-500);
  outline-offset: 3px;
}

.page-about .about-quote blockquote {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(19px, 3vw, 24px);
  line-height: 1.7;
  color: var(--paper-100);
}

.page-about .about-quote__cap {
  display: block;
  margin-top: 14px;
  font-size: 13px;
  color: var(--path-200);
}

/* ---------- 图 ---------- */
.page-about .about-figure {
  margin: 28px 0;
  border: 2px solid var(--ink-900);
  background: var(--ink-700);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  min-height: 180px;
  object-fit: cover;
  background:
    repeating-linear-gradient(90deg, rgba(53, 224, 212, 0.14) 0 1px, transparent 1px 42px),
    linear-gradient(135deg, var(--ink-700), var(--ink-900));
}

.page-about .about-figure figcaption {
  padding: 12px 16px;
  background: var(--ink-900);
  color: var(--path-200);
  font-size: 13px;
  line-height: 1.7;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline__item {
  position: relative;
  display: grid;
  gap: 8px;
  padding: 0 0 26px 26px;
  border-left: 2px solid var(--paper-300);
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 7px;
  width: 12px;
  height: 12px;
  background: var(--path-400);
  border: 2px solid var(--ink-900);
}

.page-about .about-timeline__year {
  display: inline-block;
  justify-self: start;
  padding: 3px 10px;
  border: 2px solid var(--ink-900);
  background: var(--paper-100);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink-900);
  transition: background-color 160ms ease-out, color 160ms ease-out;
}

.page-about .about-timeline__item:hover .about-timeline__year,
.page-about .about-timeline__item:focus-within .about-timeline__year {
  background: var(--ink-900);
  color: var(--path-400);
}

.page-about .about-timeline__title {
  margin: 0 0 4px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.5;
  color: var(--ink-900);
}

.page-about .about-timeline__body p {
  margin: 0;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-700);
}

/* ---------- 团队分工表 ---------- */
.page-about .about-table {
  margin-top: 28px;
  border: 2px solid var(--ink-900);
  background: var(--paper-100);
}

.page-about .about-table__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 5px;
  padding: 15px 16px;
  border-bottom: 1px solid var(--paper-300);
}

.page-about .about-table__row:nth-child(odd) {
  background: rgba(226, 213, 191, 0.32);
}

.page-about .about-table__row:last-child {
  border-bottom: 0;
}

.page-about .about-table__key {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--ink-900);
}

.page-about .about-table__val {
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-700);
}

/* ---------- 节奏清单 ---------- */
.page-about .about-cadence {
  display: grid;
  gap: 2px;
  margin-top: 24px;
  border: 2px solid var(--ink-900);
  background: var(--paper-300);
}

.page-about .about-cadence__item {
  display: grid;
  gap: 4px;
  padding: 15px 16px;
  background: var(--paper-100);
}

.page-about .about-cadence__num {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--action-500);
}

.page-about .about-cadence__label {
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-700);
}

/* ---------- 文字链 ---------- */
.page-about .about-cta {
  margin: 24px 0 0;
}

.page-about .arrow-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 3px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-900);
  text-decoration: none;
  border-bottom: 2px solid var(--path-400);
}

.page-about .arrow-link:focus-visible {
  outline: 2px solid var(--action-500);
  outline-offset: 3px;
}

.page-about .arrow-link__arrow {
  color: var(--action-500);
  transition: transform 160ms ease-out;
}

.page-about .arrow-link:hover .arrow-link__arrow {
  transform: translateX(4px);
}

/* ---------- 收束区 ---------- */
.page-about .about-close {
  margin-top: 56px;
  padding: 30px 22px;
  background: var(--ink-900);
  border: 2px solid var(--ink-900);
  box-shadow: var(--shadow-hard);
}

.page-about .about-close h2 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(20px, 3.2vw, 26px);
  line-height: 1.4;
  color: var(--paper-100);
}

.page-about .about-close p {
  margin: 0;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--path-200);
}

.page-about .about-close__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .about-close .btn {
  background: var(--paper-100);
  color: var(--ink-900);
  border-color: var(--paper-100);
  box-shadow: none;
}

.page-about .about-close .btn--primary {
  background: var(--action-500);
  color: var(--ink-900);
  border-color: var(--action-500);
}

.page-about .about-close .btn:focus-visible {
  outline: 2px solid var(--path-400);
  outline-offset: 3px;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .about-cadence__item {
    grid-template-columns: minmax(0, 170px) minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }

  .page-about .about-timeline__item {
    grid-template-columns: minmax(0, 150px) minmax(0, 1fr);
    gap: 20px;
    align-items: start;
  }

  .page-about .about-timeline__year {
    margin-top: 2px;
  }
}

@media (min-width: 720px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-hero__fact {
    border-bottom: 0;
    border-right: 1px solid var(--paper-300);
  }

  .page-about .about-hero__fact:nth-child(2n) {
    border-right: 1px solid var(--paper-300);
  }

  .page-about .about-hero__fact:last-child {
    border-right: 0;
  }

  .page-about .about-table__row {
    grid-template-columns: minmax(0, 200px) minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
    min-height: 44px;
  }
}

@media (min-width: 1024px) {
  .page-about .layout {
    grid-template-columns: minmax(0, 210px) minmax(0, 1fr);
    gap: 56px;
  }

  .page-about .index-rail {
    position: sticky;
    top: 92px;
  }

  .page-about .index-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .about-sec {
    padding-block: 48px;
  }

  .page-about .about-close {
    padding: 40px 36px;
  }
}