.page-about {
  display: block;
  padding-bottom: 88px;
}

/* ============ 页头 ============ */

.page-about .about-head {
  padding-top: 26px;
}

.page-about .about-kicker {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin: 22px 0 14px;
  padding: 6px 14px 6px 11px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--cyan);
  background: rgba(47, 227, 200, .07);
  border: 1px solid rgba(47, 227, 200, .28);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 8px, 100% 100%, 8px 100%, 0 calc(100% - 8px));
}

.page-about .about-kicker-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  background: var(--cyan);
  transform: rotate(45deg);
  box-shadow: 0 0 10px rgba(47, 227, 200, .75);
}

.page-about h1 {
  margin: 0 0 18px;
  font-size: clamp(28px, 6.2vw, 54px);
  line-height: 1.15;
  font-weight: 900;
  letter-spacing: -.012em;
  color: var(--white);
}

.page-about .about-lede {
  max-width: var(--read-max);
  margin: 0 0 34px;
  font-size: 17px;
  line-height: 1.82;
  color: var(--mist);
}

.page-about .about-lede strong {
  color: var(--white);
  font-weight: 700;
  box-shadow: inset 0 -6px 0 rgba(47, 227, 200, .22);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--rail-line);
  border: 1px solid var(--rail-line);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, var(--cut) 100%, 0 calc(100% - var(--cut)));
  overflow: hidden;
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 16px;
  background: var(--steel);
}

.page-about .about-facts .num {
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  color: var(--white);
}

.page-about .about-fact-label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--mist);
}

/* ============ 主体骨架 ============ */

.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  margin-top: 52px;
}

.page-about .about-rail {
  position: relative;
  margin-bottom: 34px;
}

.page-about .about-rail-track {
  display: none;
}

.page-about .about-rail-list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail-list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail-list a {
  display: inline-block;
  padding: 8px 13px;
  white-space: nowrap;
  font-size: 13px;
  line-height: 1.2;
  color: var(--mist);
  text-decoration: none;
  background: var(--steel);
  border: 1px solid var(--rail-line);
  clip-path: polygon(6px 0, 100% 0, 100% calc(100% - 6px), calc(100% - 6px) 100%, 0 100%, 0 6px);
  transition: color var(--fast) var(--ease), border-color var(--fast) var(--ease), background var(--fast) var(--ease);
}

.page-about .about-rail-list a:hover,
.page-about .about-rail-list a:focus-visible {
  color: var(--white);
  border-color: rgba(47, 227, 200, .5);
  background: #142033;
}

.page-about .about-rail-subs {
  display: none;
}

/* ============ 章节 ============ */

.page-about .about-sec {
  margin-top: 44px;
  padding-top: 40px;
  border-top: 1px solid var(--rail-line);
}

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

.page-about .about-sec h2 {
  margin: 0 0 18px;
  font-size: clamp(21px, 3.6vw, 31px);
  line-height: 1.26;
  font-weight: 800;
  letter-spacing: -.008em;
  color: var(--white);
}

.page-about .about-sec h3 {
  margin: 0 0 8px;
  font-size: 17px;
  line-height: 1.4;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-sec p {
  max-width: var(--read-max);
  margin: 0 0 15px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--mist);
}

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

.page-about .about-sec a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 227, 200, .4);
  transition: border-color var(--fast) var(--ease), color var(--fast) var(--ease);
}

.page-about .about-sec a:hover,
.page-about .about-sec a:focus-visible {
  color: var(--white);
  border-bottom-color: var(--orange);
}

/* ============ 起步章节 ============ */

.page-about .about-start {
  display: grid;
  gap: 26px;
}

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

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--rail-line);
  background: var(--steel);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, var(--cut) 100%, 0 calc(100% - var(--cut)));
  object-fit: cover;
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.65;
  color: var(--mist);
}

.page-about .about-figure--wide {
  margin-top: 26px;
}

/* ============ 团队卡片 ============ */

.page-about .about-team {
  display: grid;
  gap: 14px;
  margin-top: 26px;
}

.page-about .about-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 24px 20px 22px 56px;
  background: var(--steel);
  border: 1px solid var(--rail-line);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, var(--cut) 100%, 0 calc(100% - var(--cut)));
  transition: border-color var(--base) var(--ease), background var(--base) var(--ease);
}

.page-about .about-card:hover,
.page-about .about-card:focus-within {
  border-color: rgba(47, 227, 200, .45);
  background: #131E31;
}

.page-about .about-card-title {
  position: absolute;
  left: 15px;
  top: 24px;
  margin: 0;
  writing-mode: vertical-rl;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .16em;
  color: var(--mist);
  transition: color var(--base) var(--ease);
}

.page-about .about-card:hover .about-card-title,
.page-about .about-card:focus-within .about-card-title {
  color: var(--cyan);
}

.page-about .about-card-num {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 0 0 12px;
  font-size: 13px;
  color: var(--mist);
}

.page-about .about-card-num .num {
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  color: var(--white);
}

.page-about .about-card-body {
  margin: 0;
  max-width: none;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-card-more {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin: 0;
  max-width: none;
  font-size: 13px;
  line-height: 1.72;
  color: var(--cyan);
  transition: max-height 280ms var(--ease), opacity 200ms var(--ease), margin-top 280ms var(--ease);
}

.page-about .about-card:hover .about-card-more,
.page-about .about-card:focus-within .about-card-more {
  max-height: 160px;
  opacity: 1;
  margin-top: 12px;
}

/* ============ 三道实测 ============ */

.page-about .about-steps-wrap {
  margin-top: 26px;
  background: var(--rail-line);
  border: 1px solid var(--rail-line);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, var(--cut) 100%, 0 calc(100% - var(--cut)));
  overflow: hidden;
}

.page-about .about-steps {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-step {
  padding: 22px 20px 20px;
  background: var(--steel);
}

.page-about .about-step[data-tone="body"] {
  --step-tone: var(--cyan);
}

.page-about .about-step[data-tone="config"] {
  --step-tone: var(--orange);
}

.page-about .about-step[data-tone="update"] {
  --step-tone: var(--magenta);
}

.page-about .about-step::before {
  content: "";
  display: block;
  width: 30px;
  height: 3px;
  margin-bottom: 16px;
  background: var(--step-tone, var(--rail-line));
}

.page-about .about-step-idx {
  display: block;
  margin-bottom: 10px;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--step-tone, var(--mist));
}

.page-about .about-step-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--white);
}

.page-about .about-step-sum {
  margin: 0;
  max-width: none;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-step-more {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--rail-line);
}

.page-about .about-step-more summary {
  display: flex;
  align-items: center;
  gap: 7px;
  cursor: pointer;
  list-style: none;
  font-size: 13px;
  line-height: 1.4;
  color: var(--mist);
  transition: color var(--fast) var(--ease);
}

.page-about .about-step-more summary::-webkit-details-marker {
  display: none;
}

.page-about .about-step-more summary::before {
  content: "+";
  font-family: var(--mono);
  font-size: 14px;
  color: var(--step-tone, var(--mist));
}

.page-about .about-step-more[open] summary::before {
  content: "–";
}

.page-about .about-step-more summary:hover {
  color: var(--white);
}

.page-about .about-step-more p {
  margin: 10px 0 0;
  max-width: none;
  font-size: 13px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-figure--flow {
  margin-top: 24px;
}

/* ============ 年份节点 ============ */

.page-about .about-years {
  position: relative;
  margin: 26px 0 0;
  padding: 0 0 0 26px;
  list-style: none;
}

.page-about .about-years::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--rail-line);
}

.page-about .about-year {
  position: relative;
  padding-bottom: 28px;
}

.page-about .about-year:last-child {
  padding-bottom: 0;
}

.page-about .about-year::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 8px;
  width: 10px;
  height: 10px;
  background: var(--steel);
  border: 2px solid var(--rail-line);
  transform: rotate(45deg);
  transition: background var(--base) var(--ease), border-color var(--base) var(--ease), box-shadow var(--base) var(--ease);
}

.page-about .about-year-num {
  display: block;
  margin-bottom: 6px;
  font-size: 21px;
  font-weight: 700;
  letter-spacing: .07em;
  color: var(--white);
}

.page-about .about-year-body h3 {
  margin: 0 0 7px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--white);
}

.page-about .about-year-body p {
  margin: 0;
  max-width: var(--read-max);
  font-size: 15px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-year:target::before {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 14px rgba(47, 227, 200, .7);
}

.page-about .about-year:target .about-year-num {
  color: var(--cyan);
}

/* ============ 合作与认可 ============ */

.page-about .about-metrics {
  display: grid;
  gap: 1px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  background: var(--rail-line);
  border: 1px solid var(--rail-line);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, var(--cut) 100%, 0 calc(100% - var(--cut)));
  overflow: hidden;
}

.page-about .about-metrics li {
  display: grid;
  grid-template-columns: 86px minmax(0, 1fr);
  align-items: baseline;
  gap: 16px;
  padding: 16px 18px;
  background: var(--steel);
}

.page-about .about-metrics .num {
  font-size: 22px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--white);
  text-align: right;
}

.page-about .about-metric-label {
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-honors {
  margin-top: 26px;
  padding: 20px 20px 20px 22px;
  background: linear-gradient(180deg, rgba(108, 124, 240, .1), rgba(108, 124, 240, 0) 92%);
  border-left: 3px solid var(--indigo);
}

.page-about .about-honors-title {
  margin: 0 0 8px;
  max-width: none;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--indigo);
}

.page-about .about-honors p {
  margin: 0;
  max-width: var(--read-max);
  font-size: 15px;
  line-height: 1.8;
  color: var(--mist);
}

/* ============ 接下来 ============ */

.page-about .about-next {
  display: grid;
  gap: 0;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-next-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 16px;
  padding: 20px 0;
  border-top: 1px solid var(--rail-line);
}

.page-about .about-next-item:last-child {
  border-bottom: 1px solid var(--rail-line);
}

.page-about .about-next-idx {
  font-size: 16px;
  font-weight: 700;
  line-height: 1.6;
  color: var(--magenta);
}

.page-about .about-next-item h3 {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--white);
}

.page-about .about-next-item p {
  margin: 0;
  max-width: var(--read-max);
  font-size: 15px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-next-cta {
  margin-top: 26px;
  max-width: var(--read-max);
  font-size: 15px;
  line-height: 1.9;
  color: var(--mist);
}

/* ============ 平板 ============ */

@media (min-width: 620px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-facts li {
    padding: 20px;
  }

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

@media (min-width: 720px) {
  .page-about .about-start {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 30px;
    align-items: start;
  }

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

  .page-about .about-team {
    grid-template-columns: 1fr 1.14fr 0.9fr;
    align-items: stretch;
  }

  .page-about .about-years {
    padding-left: 0;
  }

  .page-about .about-years::before {
    left: 108px;
    top: 10px;
    bottom: 10px;
  }

  .page-about .about-year {
    display: grid;
    grid-template-columns: 88px minmax(0, 1fr);
    column-gap: 40px;
    padding-bottom: 32px;
  }

  .page-about .about-year::before {
    left: 103px;
    top: 6px;
    margin: 0;
  }

  .page-about .about-year-num {
    margin-bottom: 0;
    text-align: right;
  }

  .page-about .about-year-body h3 {
    margin-top: -2px;
  }
}

/* ============ 桌面端左侧轨道 ============ */

@media (min-width: 1080px) {
  .page-about .about-body {
    grid-template-columns: 212px minmax(0, 1fr);
    column-gap: 56px;
    margin-top: 68px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 88px;
    align-self: start;
    margin-bottom: 0;
    padding-left: 24px;
  }

  .page-about .about-rail-track {
    display: block;
    position: absolute;
    left: 5px;
    top: 6px;
    bottom: 6px;
    width: 2px;
    background: var(--rail-line);
  }

  .page-about .about-rail-list {
    display: block;
    padding: 0;
    overflow: visible;
  }

  .page-about .about-rail-list > li + li {
    margin-top: 2px;
  }

  .page-about .about-rail-list a {
    display: block;
    position: relative;
    padding: 8px 0;
    background: none;
    border: 0;
    clip-path: none;
    font-size: 13.5px;
  }

  .page-about .about-rail-list a::before {
    content: "";
    position: absolute;
    left: -24px;
    top: 50%;
    width: 9px;
    height: 9px;
    margin-top: -4.5px;
    background: var(--rail-line);
    transform: rotate(45deg);
    transition: background var(--base) var(--ease), box-shadow var(--base) var(--ease);
  }

  .page-about .about-rail-list a:hover,
  .page-about .about-rail-list a:focus-visible {
    background: none;
    border: 0;
    color: var(--white);
  }

  .page-about .about-rail-list a:hover::before,
  .page-about .about-rail-list a:focus-visible::before {
    background: var(--cyan);
    box-shadow: 0 0 12px rgba(47, 227, 200, .7);
  }

  .page-about .about-rail-subs {
    display: block;
    margin: 2px 0 8px;
    padding: 0 0 0 2px;
    list-style: none;
  }

  .page-about .about-rail-subs li + li {
    margin-top: 0;
  }

  .page-about .about-rail-subs a {
    padding: 3px 0;
    font-family: var(--mono);
    font-size: 11.5px;
    letter-spacing: .08em;
    color: rgba(147, 163, 184, .72);
  }

  .page-about .about-rail-subs a::before {
    width: 5px;
    height: 5px;
    margin-top: -2.5px;
    left: -23px;
    border-radius: 0;
  }

  .page-about .about-rail-subs a:hover::before {
    background: var(--magenta);
    box-shadow: 0 0 10px rgba(194, 75, 240, .65);
  }

  .page-about .about-sec {
    margin-top: 52px;
    padding-top: 46px;
  }

  .page-about .about-metrics li {
    grid-template-columns: 104px minmax(0, 1fr);
  }

  .page-about .about-metrics .num {
    font-size: 24px;
  }
}

@media (min-width: 1240px) {
  .page-about .about-body {
    grid-template-columns: 232px minmax(0, 1fr);
    column-gap: 64px;
  }
}

/* ============ 减弱动效 ============ */

@media (prefers-reduced-motion: reduce) {
  .page-about .about-card,
  .page-about .about-card-more,
  .page-about .about-card-title,
  .page-about .about-year::before,
  .page-about .about-rail-list a,
  .page-about .about-rail-list a::before {
    transition-duration: 1ms;
  }
}