.page-about {
  --about-grid: 860px;
  --about-grid-wide: 1080px;
  --about-measure: 34em;
  background: var(--c-paper);
  color: var(--c-ink);
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--c-ink);
  color: var(--c-paper);
  padding: 26px 0 46px;
  border-bottom: var(--bd) solid var(--c-ink);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -50px;
  bottom: -70px;
  width: 260px;
  height: 260px;
  background: repeating-linear-gradient(-60deg, var(--c-flame) 0 12px, transparent 12px 26px);
  opacity: .34;
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

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

.page-about .about-hero .breadcrumb__list {
  flex-wrap: wrap;
  gap: 6px;
  font-size: var(--fs-12);
}

.page-about .about-hero .breadcrumb__link {
  color: var(--c-caramel);
  text-decoration: none;
}

.page-about .about-hero .breadcrumb__link:hover {
  color: var(--c-flame);
}

.page-about .about-hero .breadcrumb__sep {
  color: rgba(246, 243, 239, .45);
}

.page-about .about-hero .breadcrumb__current {
  color: rgba(246, 243, 239, .72);
}

.page-about .about-hero__kicker {
  display: inline-block;
  margin: 22px 0 0;
  padding: 6px 12px;
  border: 2px solid var(--c-flame);
  color: var(--c-flame);
  font-family: var(--f-mono);
  font-size: var(--fs-12);
  font-variant-numeric: tabular-nums;
  letter-spacing: .06em;
}

.page-about .about-hero__title {
  margin: 18px 0 0;
  font-family: var(--f-display);
  font-weight: 900;
  font-size: clamp(34px, 9vw, 72px);
  line-height: 1.1;
  letter-spacing: -.01em;
  max-width: 15em;
}

.page-about .about-hero__accent {
  display: block;
  color: var(--c-flame);
}

.page-about .about-hero__lead {
  margin: 22px 0 0;
  max-width: 30em;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: rgba(246, 243, 239, .82);
}

.page-about .about-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 30px;
  margin: 30px 0 0;
  padding: 20px 0 0;
  list-style: none;
  border-top: 1px solid rgba(246, 243, 239, .2);
}

.page-about .about-hero__fact {
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.page-about .about-hero__fact strong {
  font-family: var(--f-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-26);
  font-weight: 700;
  color: var(--c-flame);
  line-height: 1;
}

.page-about .about-hero__fact span {
  font-size: var(--fs-14);
  color: rgba(246, 243, 239, .68);
}

/* ===== 本页目录 ===== */
.page-about .about-nav {
  background: var(--c-paper);
  border-bottom: var(--bd) solid var(--c-ink);
}

.page-about .about-nav__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin: 0;
  padding: 14px 0;
  list-style: none;
}

.page-about .about-nav__link {
  display: inline-block;
  padding: 5px 11px;
  border: 2px solid var(--c-ink);
  color: var(--c-ink);
  background: var(--c-white);
  font-size: var(--fs-12);
  font-weight: 700;
  text-decoration: none;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}

.page-about .about-nav__link:hover {
  background: var(--c-flame);
  color: var(--c-ink);
  transform: translateY(-2px);
}

/* ===== 章节骨架 ===== */
.page-about .about-sec {
  padding: 44px 0 52px;
  border-top: var(--bd) solid var(--c-ink);
}

.page-about .about-sec__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  max-width: var(--about-grid);
  margin-inline: auto;
}

.page-about .about-sec__grid--wide {
  max-width: var(--about-grid-wide);
}

.page-about .about-sec__index {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: 52px;
  line-height: .9;
  letter-spacing: -.02em;
  font-variant-numeric: tabular-nums;
  color: var(--c-flame);
}

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

.page-about .about-sec__title {
  margin: 0;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-20);
  line-height: 1.4;
  letter-spacing: .02em;
}

.page-about .about-sec__lead {
  margin: 10px 0 0;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--c-tungsten);
  max-width: 30em;
}

.page-about .about-prose > p {
  margin: 18px 0 0;
  max-width: var(--about-measure);
  font-size: var(--fs-17);
  line-height: 1.85;
}

/* ===== 四条内容线 ===== */
.page-about .about-lines {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-line {
  margin-top: 20px;
  padding: 2px 0 2px 18px;
  border-left: var(--bd) solid var(--c-flame);
}

.page-about .about-line__name {
  margin: 0;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-17);
  letter-spacing: .01em;
}

.page-about .about-line__desc {
  margin: 6px 0 0;
  max-width: 32em;
  font-size: var(--fs-17);
  line-height: 1.8;
}

/* ===== 02 规模档案（夜蓝区） ===== */
.page-about .about-sec--night {
  background: var(--c-night);
  color: var(--c-paper);
  border-top-color: var(--c-night);
}

.page-about .about-sec--night .about-sec__title {
  color: var(--c-white);
}

.page-about .about-sec--night .about-sec__lead {
  color: rgba(246, 243, 239, .7);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-stat {
  padding: 18px 16px 20px;
  border: 2px solid rgba(246, 243, 239, .26);
  background: rgba(255, 255, 255, .04);
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--f-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: var(--fs-34);
  line-height: 1;
  color: var(--c-flame);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 12px;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(246, 243, 239, .74);
}

/* ===== 03 生产流程 ===== */
.page-about .about-flowmap {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .flowmap__node {
  position: relative;
  padding: 14px 12px 16px;
  border: var(--bd) solid var(--c-ink);
  background: var(--c-white);
  box-shadow: var(--sh-sm);
  transition: transform var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease);
}

.page-about .flowmap__node:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--sh-md);
}

.page-about .flowmap__node:nth-child(even) {
  background: var(--c-caramel);
}

.page-about .flowmap__num {
  display: block;
  font-family: var(--f-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-12);
  font-weight: 700;
  color: var(--c-lava);
  letter-spacing: .08em;
}

.page-about .flowmap__label {
  display: block;
  margin-top: 6px;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-17);
  line-height: 1.3;
}

.page-about .flowmap__desc {
  margin: 8px 0 0;
  font-size: var(--fs-14);
  line-height: 1.65;
  color: var(--c-tungsten);
}

.page-about .about-sec .media-frame {
  margin-top: 28px;
}

/* ===== 04 团队分工 ===== */
.page-about .about-sec--white {
  background: var(--c-white);
}

.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: 26px;
}

.page-about .about-team__card {
  padding: 18px 16px 20px;
  border: var(--bd) solid var(--c-ink);
  background: var(--c-paper);
  box-shadow: var(--sh-sm);
  transition: transform var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease);
}

.page-about .about-team__card:hover {
  transform: translate(-4px, -4px);
  box-shadow: var(--sh-md);
}

.page-about .about-team__num {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--c-flame);
  border: 2px solid var(--c-flame);
  padding: 2px 8px;
}

.page-about .about-team__name {
  margin: 12px 0 0;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-20);
  line-height: 1.35;
}

.page-about .about-team__desc {
  margin: 10px 0 0;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--c-iron);
}

/* ===== 05 迭代节奏（阶段轴） ===== */
.page-about .about-timeline {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  margin: 32px 0 0;
  padding: 0 0 0 32px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 6px;
  bottom: 10px;
  width: var(--bd);
  background: var(--c-ink);
}

.page-about .tl-node {
  position: relative;
}

.page-about .tl-node__dot {
  position: absolute;
  left: -32px;
  top: 4px;
  width: 18px;
  height: 18px;
  box-sizing: border-box;
  background: var(--c-flame);
  border: var(--bd) solid var(--c-ink);
}

.page-about .tl-node__title {
  margin: 0;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-20);
  line-height: 1.35;
}

.page-about .tl-node__desc {
  margin: 8px 0 0;
  max-width: 30em;
  font-size: var(--fs-17);
  line-height: 1.8;
}

/* ===== 06 协作与覆盖 ===== */
.page-about .about-coverage__figure {
  max-width: var(--about-grid);
  margin: 28px auto 0;
  padding: 0 var(--pad-x);
}

/* ===== 07 看懂数据 ===== */
.page-about .about-panel {
  margin-top: 24px;
  padding: 20px 18px 22px;
  border: var(--bd) solid var(--c-ink);
  background: var(--c-night);
  color: var(--c-paper);
  box-shadow: var(--sh-md);
}

.page-about .about-panel__title {
  margin: 0;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-14);
  letter-spacing: .08em;
  color: var(--c-cyan);
}

.page-about .about-panel__calc {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 12px;
  margin-top: 16px;
}

.page-about .about-panel__item {
  font-size: var(--fs-14);
  line-height: 1.6;
  color: rgba(246, 243, 239, .78);
}

.page-about .about-panel__item b {
  display: inline-block;
  margin-right: 6px;
  font-family: var(--f-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-26);
  font-weight: 700;
  color: var(--c-paper);
  line-height: 1;
}

.page-about .about-panel__item--result b {
  color: var(--c-flame);
}

.page-about .about-panel__op {
  font-family: var(--f-mono);
  font-size: var(--fs-20);
  color: var(--c-cyan);
}

/* ===== 08 从哪开始（炽焰区） ===== */
.page-about .about-sec--flame {
  background: var(--c-flame);
  color: var(--c-ink);
  border-top-color: var(--c-ink);
}

.page-about .about-sec--flame .about-sec__index {
  color: var(--c-ink);
}

.page-about .about-sec--flame .about-sec__lead {
  color: var(--c-ink);
}

.page-about .about-start {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-start__item {
  display: flex;
  flex-direction: column;
  padding: 18px 16px 18px;
  border: var(--bd) solid var(--c-ink);
  background: var(--c-white);
  box-shadow: var(--sh-sm);
  transition: transform var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease);
}

.page-about .about-start__item:hover {
  transform: translate(-4px, -4px);
  box-shadow: var(--sh-md);
}

.page-about .about-start__name {
  margin: 0;
  font-family: var(--f-sans);
  font-weight: 900;
  font-size: var(--fs-17);
  line-height: 1.45;
}

.page-about .about-start__desc {
  margin: 8px 0 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--c-tungsten);
}

.page-about .about-start__link {
  margin-top: 16px;
  align-self: flex-start;
  display: inline-block;
  padding: 9px 14px;
  border: 2px solid var(--c-ink);
  background: var(--c-ink);
  color: var(--c-paper);
  font-size: var(--fs-14);
  font-weight: 700;
  text-decoration: none;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .about-start__link:hover {
  background: var(--c-cyan);
  color: var(--c-ink);
}

/* ===== 图片基础规则在本页内的微调 ===== */
.page-about .media-frame__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .media-frame__caption {
  display: block;
  margin-top: 10px;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--c-tungsten);
}

.page-about .about-sec--night .media-frame__caption,
.page-about .about-panel + .about-prose {
  color: rgba(246, 243, 239, .68);
}

/* ===== 断点 ===== */
@media (min-width: 700px) {
  .page-about .about-hero {
    padding: 40px 0 76px;
  }

  .page-about .about-hero::after {
    width: 340px;
    height: 340px;
    right: -60px;
    bottom: -110px;
  }

  .page-about .about-sec {
    padding: 64px 0 76px;
  }

  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-flowmap {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

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

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

@media (min-width: 820px) {
  .page-about .about-sec__grid {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 4px 40px;
    align-items: start;
  }

  .page-about .about-sec__index {
    font-size: 96px;
    line-height: .84;
  }
}

@media (min-width: 900px) {
  .page-about .about-timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 24px;
    padding: 0;
    margin-top: 44px;
    border-top: var(--bd) solid var(--c-ink);
  }

  .page-about .about-timeline::before {
    display: none;
  }

  .page-about .tl-node {
    padding-top: 28px;
  }

  .page-about .tl-node__dot {
    left: 0;
    top: -11px;
  }

  .page-about .tl-node:nth-child(2) .tl-node__body {
    margin-top: 34px;
  }

  .page-about .tl-node:nth-child(4) .tl-node__body {
    margin-top: 34px;
  }

  .page-about .tl-node__desc {
    font-size: var(--fs-14);
    line-height: 1.75;
  }
}

@media (min-width: 1100px) {
  .page-about .about-team {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-stat__num {
    font-size: var(--fs-48);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-nav__link,
  .page-about .flowmap__node,
  .page-about .about-team__card,
  .page-about .about-start__item,
  .page-about .about-start__link {
    transition: none;
  }

  .page-about .about-nav__link:hover,
  .page-about .flowmap__node:hover,
  .page-about .about-team__card:hover,
  .page-about .about-start__item:hover {
    transform: none;
  }
}