.page-about {
  --ab-rail: 190px;
  --ab-body: 680px;
}

/* ===== 面包屑 ===== */
.page-about .ds-breadcrumb {
  padding-top: 96px;
}
.page-about .ds-breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.page-about .ds-breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--copper-soft);
}
.page-about .ds-breadcrumb a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.page-about .ds-breadcrumb a:hover,
.page-about .ds-breadcrumb a:focus-visible {
  color: var(--ink);
  border-color: var(--copper);
}

/* ===== 首屏 ===== */
.page-about .mission-hero {
  padding: 32px 0 52px;
}
.page-about .mission-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
  align-items: start;
}
.page-about .mission-hero__lead h1 {
  margin: 16px 0 0;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(2.05rem, 5vw, 3.7rem);
  line-height: 1.13;
  letter-spacing: -0.012em;
  color: var(--ink);
}
.page-about .mission-hero__lede {
  margin: 24px 0 0;
  padding-left: 20px;
  border-left: 3px solid var(--copper);
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--text);
}
.page-about .mission-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .mission-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--copper-soft);
  border: 1px solid var(--ink);
  border-radius: var(--radius-card);
  overflow: hidden;
}
.page-about .mission-fact {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 20px;
  background: var(--ink);
  color: var(--paper);
}
.page-about .mission-fact__value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--paper);
}
.page-about .mission-fact__label {
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  color: var(--copper-soft);
}

/* ===== 正文骨架：左目录 + 右长文 ===== */
.page-about .mission-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
  padding-bottom: 88px;
}

.page-about .mission-rail {
  min-width: 0;
}
.page-about .mission-rail__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}
.page-about .mission-rail__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}
.page-about .mission-rail__list li {
  flex: 0 0 auto;
}
.page-about .mission-rail__list a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 15px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--card);
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 0.2s var(--ease), background-color 0.2s var(--ease);
}
.page-about .mission-rail__list a:hover,
.page-about .mission-rail__list a:focus-visible {
  border-color: var(--copper);
  background: var(--note);
}
.page-about .mission-rail__year {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--copper);
  letter-spacing: 0.04em;
}
.page-about .mission-rail__label {
  font-size: 0.82rem;
  color: var(--muted);
}

/* ===== 章节 ===== */
.page-about .mission-flow {
  min-width: 0;
}
.page-about .mission-chapter {
  scroll-margin-top: 104px;
  padding-top: 8px;
  padding-bottom: 52px;
  border-top: 1px solid var(--line-soft);
}
.page-about .mission-chapter--last {
  padding-bottom: 0;
  border-bottom: 1px solid var(--line-soft);
}
.page-about .mission-chapter__no {
  margin: 26px 0 6px;
  font-family: var(--font-mono);
  font-size: 2.3rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--copper);
}
.page-about .mission-chapter h2 {
  margin: 10px 0 0;
  max-width: 15em;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(1.5rem, 3.1vw, 2.1rem);
  line-height: 1.3;
  color: var(--ink);
}
.page-about .mission-chapter__lede {
  margin: 20px 0 0;
  max-width: var(--ab-body);
  padding-left: 16px;
  border-left: 3px solid var(--note);
  font-size: 1.1rem;
  line-height: 1.78;
  font-weight: 500;
  color: var(--ink);
}
.page-about .mission-chapter > p:not(.mission-chapter__no):not(.mission-chapter__lede):not(.ds-eyebrow) {
  margin: 18px 0 0;
  max-width: var(--ab-body);
  line-height: 1.92;
  color: var(--text);
}
.page-about .mission-chapter h3 {
  font-family: var(--font-head);
  color: var(--ink);
}

/* ===== 图片 ===== */
.page-about .mission-media {
  margin: 30px 0 0;
  border-radius: var(--radius-card);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--card);
}
.page-about .mission-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .mission-media--band {
  margin-top: 24px;
  border-radius: var(--radius-card);
}
.page-about .mission-media .ds-media__caption {
  padding: 12px 16px;
  font-size: 0.8rem;
  line-height: 1.7;
  color: var(--muted);
  border-top: 1px solid var(--line-soft);
}

/* ===== 时间线 ===== */
.page-about .mission-timeline {
  position: relative;
  margin: 30px 0 0;
  padding: 0 0 0 30px;
  list-style: none;
}
.page-about .mission-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 12px;
  bottom: 26px;
  width: 2px;
  background: linear-gradient(to bottom, var(--copper) 0%, var(--copper-soft) 55%, var(--line) 100%);
}
.page-about .mission-timeline__item {
  position: relative;
  padding-bottom: 28px;
}
.page-about .mission-timeline__item:last-child {
  padding-bottom: 0;
}
.page-about .mission-timeline__item::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--copper-soft);
  transition: background-color 0.3s var(--ease), border-color 0.3s var(--ease);
}
.page-about .mission-timeline__item.is-lit::before {
  background: var(--copper);
  border-color: var(--copper);
}
.page-about .mission-chapter .mission-timeline__period {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--copper);
}
.page-about .mission-chapter .mission-timeline__title {
  margin: 6px 0 0;
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.5;
}
.page-about .mission-timeline__item p:last-child {
  margin: 8px 0 0;
  max-width: 34em;
  line-height: 1.88;
  color: var(--text);
}

/* ===== 团队 ===== */
.page-about .mission-team {
  display: grid;
  gap: 18px;
  margin-top: 28px;
}
.page-about .mission-team__card {
  padding: 24px 22px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  border-top: 3px solid var(--copper);
}
.page-about .mission-team__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1;
  color: var(--copper);
}
.page-about .mission-team__role {
  margin: 10px 0 0;
  font-size: 1.1rem;
  font-weight: 700;
}
.page-about .mission-team__card p {
  margin: 10px 0 0;
  line-height: 1.88;
  color: var(--text);
}

/* ===== 覆盖 ===== */
.page-about .mission-reach {
  margin: 26px 0 0;
  border-top: 1px solid var(--line);
}
.page-about .mission-reach__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-soft);
}
.page-about .mission-reach__row dt {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  color: var(--ink);
  font-weight: 700;
}
.page-about .mission-reach__row dd {
  margin: 0;
  line-height: 1.88;
  color: var(--text);
}

/* ===== 标准 ===== */
.page-about .mission-rules {
  display: grid;
  gap: 1px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  overflow: hidden;
}
.page-about .mission-rules__item {
  position: relative;
  padding: 20px 22px 22px;
  background: var(--card);
}
.page-about .mission-rules__no {
  display: inline-block;
  margin-bottom: 8px;
  padding: 2px 9px;
  border-radius: var(--radius-pill);
  background: var(--note);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--copper);
}
.page-about .mission-rules__item h3 {
  margin: 0;
  font-size: 1.06rem;
  font-weight: 700;
  line-height: 1.5;
}
.page-about .mission-rules__item p {
  margin: 8px 0 0;
  line-height: 1.86;
  color: var(--text);
}
.page-about .mission-highlight {
  margin: 24px 0 0;
  max-width: var(--ab-body);
  padding: 14px 18px;
  border-radius: var(--radius-card);
  background: var(--note);
  color: var(--ink);
  font-size: 1rem;
  line-height: 1.8;
  font-weight: 500;
}

/* ===== 接下来 ===== */
.page-about .mission-next {
  display: grid;
  gap: 16px;
  margin-top: 28px;
}
.page-about .mission-next__card {
  padding: 22px;
  border: 1px solid var(--line);
  border-left: 4px solid var(--copper);
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
  background: transparent;
}
.page-about .mission-next__no {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--copper);
}
.page-about .mission-next__card h3 {
  margin: 8px 0 0;
  font-size: 1.08rem;
  font-weight: 700;
  line-height: 1.5;
}
.page-about .mission-next__card p {
  margin: 8px 0 0;
  line-height: 1.86;
  color: var(--text);
}

.page-about .mission-cta {
  margin-top: 30px;
  padding: 26px 24px;
  border-radius: var(--radius-card);
  background: var(--ink);
  color: var(--paper);
}
.page-about .mission-cta__text {
  margin: 0;
  line-height: 1.9;
  color: var(--paper);
}
.page-about .mission-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

/* ===== 滚动显现 ===== */
.page-about .mission-chapter[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.32s var(--ease), transform 0.32s var(--ease);
}
.page-about .mission-chapter[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ===== 平板 ===== */
@media (min-width: 700px) {
  .page-about .mission-hero {
    padding: 40px 0 64px;
  }
  .page-about .mission-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 3fr);
    gap: 44px;
    align-items: end;
  }
  .page-about .mission-hero__facts {
    grid-template-columns: 1fr;
  }
  .page-about .mission-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .mission-rules {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .mission-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1px;
    background: var(--line-soft);
    border: 1px solid var(--line);
    border-radius: var(--radius-card);
    overflow: hidden;
  }
  .page-about .mission-next__card {
    border: 0;
    border-top: 3px solid var(--copper);
    border-radius: 0;
    background: var(--card);
  }
  .page-about .mission-reach__row {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 20px;
  }
  .page-about .mission-cta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    padding: 30px 32px;
  }
  .page-about .mission-cta__text {
    max-width: 40em;
  }
  .page-about .mission-cta__links {
    margin-top: 0;
    flex: 0 0 auto;
  }
}

/* ===== 桌面：左侧年份索引常驻 ===== */
@media (min-width: 1000px) {
  .page-about .mission-body {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 60px;
    align-items: start;
    padding-bottom: 110px;
  }
  .page-about .mission-rail {
    position: sticky;
    top: 104px;
    align-self: start;
  }
  .page-about .mission-rail__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }
  .page-about .mission-rail__list a {
    justify-content: flex-start;
    width: 100%;
    padding: 9px 12px;
    border: 0;
    border-left: 3px solid var(--line);
    border-radius: 0 var(--radius-pill) var(--radius-pill) 0;
    background: transparent;
  }
  .page-about .mission-rail__list a:hover,
  .page-about .mission-rail__list a:focus-visible {
    border-left-color: var(--copper);
    background: var(--note);
  }
  .page-about .mission-chapter {
    padding-bottom: 64px;
  }
  .page-about .mission-chapter__no {
    font-size: 2.8rem;
    margin-top: 30px;
  }
}

/* ===== 减弱动效 ===== */
@media (prefers-reduced-motion: reduce) {
  .page-about .mission-chapter[data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .page-about .mission-timeline__item::before {
    transition: none;
  }
}