.page-about {
  --about-gap: clamp(18px, 2.6vw, 30px);
  --about-section-pad: clamp(46px, 7vw, 92px);
  --about-frame-cut: clamp(22px, 3.4vw, 40px);
  display: block;
  background: var(--lake);
  color: var(--snow);
}

.page-about .about-section {
  padding: var(--about-section-pad) 0;
}

/* ---------- 首屏框景 ---------- */

.page-about .about-hero {
  padding: clamp(18px, 3vw, 34px) 0 clamp(30px, 5vw, 56px);
  background:
    radial-gradient(120% 88% at 82% 4%, rgba(27, 108, 168, .5), transparent 62%),
    linear-gradient(180deg, var(--ink) 0%, var(--lake) 100%);
}

.page-about .about-hero__frame {
  position: relative;
  overflow: hidden;
  padding: clamp(24px, 4.4vw, 54px);
  background: linear-gradient(155deg, rgba(14, 75, 114, .88), rgba(7, 26, 38, .95) 70%);
  border: 1px solid var(--line-light-2);
  clip-path: polygon(
    0 0,
    calc(100% - var(--about-frame-cut)) 0,
    100% var(--about-frame-cut),
    100% 100%,
    var(--about-frame-cut) 100%,
    0 calc(100% - var(--about-frame-cut))
  );
}

.page-about .about-hero__frame::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: linear-gradient(90deg, var(--orange) 0 22%, var(--lime) 40%, transparent 78%);
}

.page-about .about-hero__frame::after {
  content: "";
  position: absolute;
  right: -70px;
  bottom: -80px;
  width: 260px;
  height: 260px;
  background: repeating-linear-gradient(45deg, rgba(183, 243, 74, .16) 0 2px, transparent 2px 13px);
  transform: rotate(-8deg);
  pointer-events: none;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(16px, 2.4vw, 26px);
}

.page-about .about-hero h1 {
  margin: 10px 0 18px;
  max-width: 22ch;
  font-size: clamp(30px, 5.4vw, 58px);
  line-height: 1.12;
  letter-spacing: -0.035em;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-hero__lead {
  max-width: 62ch;
  margin: 0;
  padding-left: 16px;
  border-left: 3px solid var(--orange);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.9;
  color: rgba(247, 251, 255, .84);
}

.page-about .about-hero__stats {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  margin: clamp(26px, 4vw, 42px) 0 0;
  padding: clamp(20px, 3vw, 28px) 0 0;
  list-style: none;
  border-top: 1px solid var(--line-light);
}

.page-about .about-stat {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-left: 14px;
}

.page-about .about-stat::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 3px;
  background: var(--blue);
}

.page-about .about-stat--orange::before { background: var(--orange); }
.page-about .about-stat--lime::before { background: var(--lime); }

.page-about .about-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(32px, 5.2vw, 52px);
  line-height: 1;
  letter-spacing: -0.04em;
  font-variant-numeric: tabular-nums;
  color: var(--snow);
}

.page-about .about-stat__unit {
  font-size: .62em;
  color: var(--orange);
  margin-left: 2px;
}

.page-about .about-stat__label {
  font-size: 13px;
  line-height: 1.6;
  letter-spacing: .01em;
  color: rgba(247, 251, 255, .66);
}

/* ---------- 青海起点 ---------- */

.page-about .about-origin {
  background: var(--lake);
}

.page-about .about-origin__grid {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  align-items: center;
}

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

.page-about .about-origin__text {
  margin: 0 0 14px;
  max-width: 60ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.9;
  color: rgba(247, 251, 255, .8);
}

.page-about .about-origin__points {
  display: grid;
  gap: 12px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-origin__points li {
  position: relative;
  padding-left: 26px;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(247, 251, 255, .88);
}

.page-about .about-origin__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 14px;
  height: 3px;
  background: var(--orange);
}

/* ---------- 时间轴 ---------- */

.page-about .about-timeline-section {
  background: linear-gradient(180deg, var(--lake) 0%, var(--ink) 100%);
}

.page-about .about-timeline__intro {
  max-width: 56ch;
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(247, 251, 255, .72);
}

.page-about .about-timeline {
  position: relative;
  display: grid;
  gap: var(--about-gap);
  margin: clamp(30px, 4.6vw, 52px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline__item {
  position: relative;
  padding: clamp(20px, 2.6vw, 28px) clamp(20px, 2.6vw, 28px) clamp(20px, 2.6vw, 28px) clamp(40px, 4vw, 56px);
  background: rgba(7, 26, 38, .58);
  border: 1px solid var(--line-light);
  border-left: 3px solid var(--blue);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
  transition: transform .2s ease, background .2s ease, border-color .2s ease;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 18px;
  top: clamp(26px, 3vw, 34px);
  width: 11px;
  height: 11px;
  background: var(--orange);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
}

.page-about .about-timeline__item::after {
  content: "";
  position: absolute;
  left: 23px;
  top: calc(clamp(26px, 3vw, 34px) + 18px);
  bottom: calc(-1 * var(--about-gap));
  width: 1px;
  background: linear-gradient(180deg, rgba(27, 108, 168, .8), rgba(27, 108, 168, 0));
}

.page-about .about-timeline__item:nth-child(even) { border-left-color: var(--orange); }
.page-about .about-timeline__item:nth-child(even)::before { background: var(--lime); }
.page-about .about-timeline__item:last-child::after { display: none; }

.page-about .about-timeline__item:hover,
.page-about .about-timeline__item:focus-within {
  transform: translateX(5px);
  background: rgba(14, 75, 114, .5);
  border-color: var(--lime);
}

.page-about .about-timeline__index {
  position: absolute;
  top: 8px;
  right: 14px;
  font-family: var(--font-mono);
  font-size: clamp(38px, 6vw, 66px);
  line-height: 1;
  letter-spacing: -0.05em;
  color: rgba(247, 251, 255, .1);
  pointer-events: none;
}

.page-about .about-timeline__phase {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--lime);
}

.page-about .about-timeline__title {
  margin: 0 0 10px;
  font-size: clamp(19px, 2.2vw, 24px);
  line-height: 1.35;
  letter-spacing: -0.02em;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-timeline__text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(247, 251, 255, .76);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  background: var(--lake);
}

.page-about .about-team__grid {
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
  align-items: center;
}

.page-about .about-team__text {
  margin: 0;
  max-width: 54ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.9;
  color: rgba(247, 251, 255, .8);
}

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

.page-about .about-team__roles {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 14px;
  margin-top: clamp(26px, 4vw, 44px);
}

.page-about .about-role {
  position: relative;
  padding: 22px 18px;
  background: rgba(7, 26, 38, .62);
  border: 1px solid var(--line-light);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
  transition: border-color .2s ease, background .2s ease, transform .2s ease;
}

.page-about .about-role:hover,
.page-about .about-role:focus-within {
  transform: translateY(-4px);
  border-color: var(--lime);
  background: rgba(14, 75, 114, .55);
}

.page-about .about-role__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(28px, 3.4vw, 36px);
  line-height: 1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--orange);
}

.page-about .about-role__unit {
  font-size: .46em;
  margin-left: 3px;
  color: var(--rock);
}

.page-about .about-role__name {
  margin: 12px 0 8px;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--snow);
}

.page-about .about-role__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(247, 251, 255, .7);
}

/* ---------- 合作生态 ---------- */

.page-about .about-eco {
  background: var(--ink);
}

.page-about .about-eco__intro {
  max-width: 58ch;
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(247, 251, 255, .72);
}

.page-about .about-eco__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: clamp(24px, 3.6vw, 42px);
}

.page-about .about-eco__card {
  padding: 24px 20px;
  background: var(--ink-2);
  border-top: 3px solid var(--orange);
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 0 100%);
  transition: background .2s ease, transform .2s ease;
}

.page-about .about-eco__card:nth-child(2) { border-top-color: var(--lime); }
.page-about .about-eco__card:nth-child(3) { border-top-color: var(--blue); }

.page-about .about-eco__card:hover,
.page-about .about-eco__card:focus-within {
  transform: translateY(-4px);
  background: var(--ink-3);
}

.page-about .about-eco__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(38px, 5vw, 54px);
  line-height: 1;
  letter-spacing: -0.04em;
  font-variant-numeric: tabular-nums;
  color: var(--snow);
}

.page-about .about-eco__name {
  margin: 10px 0 10px;
  font-size: 16px;
  font-weight: 700;
  color: var(--lime);
}

.page-about .about-eco__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: rgba(247, 251, 255, .74);
}

.page-about .about-eco__media {
  margin: clamp(24px, 3.6vw, 42px) 0 0;
}

.page-about .about-eco__note {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 18px 20px;
  border-left: 3px solid var(--lime);
  background: rgba(183, 243, 74, .07);
  font-size: 14px;
  line-height: 1.8;
  color: rgba(247, 251, 255, .82);
}

/* ---------- 视觉系统 ---------- */

.page-about .about-visual {
  background: linear-gradient(180deg, var(--ink) 0%, var(--lake-2) 100%);
}

.page-about .about-visual__lead {
  max-width: 60ch;
  margin: 16px 0 0;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.9;
  color: rgba(247, 251, 255, .8);
}

.page-about .about-visual__palette {
  display: grid;
  gap: 12px;
  margin: clamp(24px, 3.4vw, 38px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-sw {
  display: grid;
  grid-template-columns: 34px 1fr;
  grid-template-areas:
    "chip name"
    "chip use";
  gap: 2px 14px;
  align-items: center;
  padding: 14px 16px;
  background: rgba(7, 26, 38, .55);
  border: 1px solid var(--line-light);
}

.page-about .about-sw__chip {
  grid-area: chip;
  width: 34px;
  height: 34px;
  display: block;
  clip-path: polygon(0 0, calc(100% - 9px) 0, 100% 9px, 100% 100%, 0 100%);
}

.page-about .about-sw__chip--lake { background: var(--lake); }
.page-about .about-sw__chip--paper { background: var(--paper); }
.page-about .about-sw__chip--orange { background: var(--orange); }
.page-about .about-sw__chip--lime { background: var(--lime); }

.page-about .about-sw__name {
  grid-area: name;
  font-size: 15px;
  font-weight: 700;
  color: var(--snow);
}

.page-about .about-sw__use {
  grid-area: use;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(247, 251, 255, .66);
}

.page-about .about-visual__text {
  max-width: 60ch;
  margin: clamp(22px, 3vw, 32px) 0 0;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(247, 251, 255, .78);
}

/* ---------- 收尾行动 ---------- */

.page-about .about-next {
  background: var(--lake);
}

.page-about .about-next__panel {
  position: relative;
  padding: clamp(26px, 4.4vw, 52px);
  background: linear-gradient(140deg, rgba(244, 122, 31, .14), rgba(7, 26, 38, .92) 58%);
  border: 1px solid var(--line-light-2);
  clip-path: polygon(
    var(--about-frame-cut) 0,
    100% 0,
    100% calc(100% - var(--about-frame-cut)),
    calc(100% - var(--about-frame-cut)) 100%,
    0 100%,
    0 var(--about-frame-cut)
  );
}

.page-about .about-next__text {
  max-width: 60ch;
  margin: 16px 0 0;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.9;
  color: rgba(247, 251, 255, .82);
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 3.4vw, 36px);
}

.page-about .about-next__contact {
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding-top: 18px;
  border-top: 1px solid var(--line-light);
  font-size: 14px;
  line-height: 1.8;
  color: rgba(247, 251, 255, .74);
}

.page-about .about-next__contact a {
  color: var(--orange-hi);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-next__contact a:hover { color: var(--lime); }

/* ---------- 图片 ---------- */

.page-about .media {
  overflow: hidden;
}

.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px 24px;
  }

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

@media (min-width: 900px) {
  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-timeline {
    padding-left: clamp(0px, 2vw, 26px);
  }
}

@media (max-width: 480px) {
  .page-about .about-hero__frame::after {
    display: none;
  }

  .page-about .about-timeline__item {
    padding-left: 34px;
  }

  .page-about .about-timeline__item::before {
    left: 14px;
  }

  .page-about .about-timeline__item::after {
    left: 19px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__item,
  .page-about .about-role,
  .page-about .about-eco__card {
    transition: none;
  }

  .page-about .about-timeline__item:hover,
  .page-about .about-timeline__item:focus-within,
  .page-about .about-role:hover,
  .page-about .about-role:focus-within,
  .page-about .about-eco__card:hover,
  .page-about .about-eco__card:focus-within {
    transform: none;
  }
}