.page-about {
  --about-rail: 172px;
  --about-pad: clamp(16px, 2.4vw, 28px);
  --about-notch: 22px;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

/* ── 页头 ── */
.page-about .about-head {
  padding-block: clamp(22px, 3.6vw, 44px) clamp(10px, 2vw, 18px);
}

.page-about .about-head .page-head__title {
  max-width: 18ch;
  font-size: clamp(30px, 5.6vw, 62px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin-top: 10px;
}

.page-about .about-head .page-head__lede {
  max-width: 60ch;
  margin-top: clamp(12px, 1.6vw, 20px);
  font-size: clamp(15.5px, 1.35vw, 18px);
  line-height: 1.78;
  color: var(--muted);
}

/* ── 概览数字带 ── */
.page-about .about-kpis {
  padding-block: clamp(8px, 1.6vw, 16px) clamp(26px, 4vw, 46px);
}

.page-about .kpi {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.page-about .kpi__item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .kpi__num {
  font-size: clamp(30px, 4.4vw, 48px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.02em;
}

.page-about .kpi__num em {
  font-style: normal;
  font-size: 0.4em;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-left: 4px;
}

.page-about .kpi__label {
  font-size: 14px;
  line-height: 1.5;
  color: var(--muted);
}

/* ── 章节通用 ── */
.page-about .section {
  padding-block: clamp(26px, 4vw, 52px);
  border-top: 1px solid var(--line);
}

.page-about .section__head {
  margin-bottom: clamp(16px, 2.4vw, 28px);
}

/* ── 时间轴 ── */
.page-about .about-tlfig {
  margin: 0 0 clamp(20px, 3vw, 34px);
}

.page-about .tl {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .tl__rail {
  padding: 14px 16px;
  background: var(--panel);
  box-shadow: inset 0 0 0 1px var(--line);
  clip-path: polygon(0 0, 100% 0, calc(100% - 14px) 100%, 0 100%);
}

.page-about .tl__rail .verrail__title {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--muted);
}

.page-about .tl__rail .verrail__list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .tl__rail .verrail__link {
  display: inline-block;
  padding: 5px 10px;
  font-size: 12.5px;
  line-height: 1.4;
  color: var(--muted);
  text-decoration: none;
  background: var(--ink);
  border: 1px solid var(--line);
  transition: color .2s ease, border-color .2s ease, background-color .2s ease;
}

.page-about .tl__rail .verrail__link:hover,
.page-about .tl__rail .verrail__link:focus-visible,
.page-about .tl__rail .verrail__link[aria-current="true"] {
  color: var(--ink-on-accent);
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .tl__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: clamp(14px, 2.2vw, 24px);
}

.page-about .tl__item {
  position: relative;
  padding-left: clamp(18px, 3vw, 32px);
}

.page-about .tl__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: clamp(20px, 2.4vw, 28px);
  width: 9px;
  height: 9px;
  background: var(--ink);
  border: 2px solid var(--cyan);
  transform: rotate(45deg);
}

.page-about .tl__item::after {
  content: "";
  position: absolute;
  left: 6px;
  top: calc(clamp(20px, 2.4vw, 28px) + 15px);
  bottom: calc(-1 * clamp(14px, 2.2vw, 24px));
  width: 1px;
  background: var(--line);
}

.page-about .tl__item:last-child::after {
  display: none;
}

.page-about .tl__card {
  position: relative;
  padding: var(--about-pad);
  background: var(--panel);
  box-shadow: inset 0 0 0 1px var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-notch)), calc(100% - var(--about-notch)) 100%, 0 100%);
  transition: background-color .25s ease, box-shadow .25s ease;
}

.page-about .tl__card--a { --about-notch: 16px; }
.page-about .tl__card--b { --about-notch: 26px; }
.page-about .tl__card--c { --about-notch: 40px; }

.page-about .tl__card:hover,
.page-about .tl__card:focus-within {
  background: var(--panel-2);
  box-shadow: inset 0 0 0 1px var(--cyan);
}

.page-about .tl__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 12px;
  margin-bottom: 10px;
}

.page-about .tl__title {
  margin: 0;
  font-size: clamp(17px, 2vw, 23px);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .tl__text {
  margin: 0;
  max-width: 68ch;
  font-size: clamp(14.5px, 1.15vw, 16px);
  line-height: 1.78;
  color: var(--muted);
}

.page-about .tl__vers {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .tl__vers li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 10px 12px;
  background: var(--ink);
  box-shadow: inset 0 0 0 1px var(--line);
  font-size: 14.5px;
  line-height: 1.65;
  color: var(--muted);
}

.page-about .tl__vers li .vnum {
  flex: none;
}

.page-about a.vnum {
  text-decoration: none;
}

.page-about a.vnum:hover,
.page-about a.vnum:focus-visible {
  background: var(--orange);
  color: var(--ink-on-warm);
}

.page-about .tl__actions {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ── 版本号规则 ── */
.page-about .about-rule .grid--split {
  align-items: start;
  gap: clamp(20px, 3vw, 40px);
}

.page-about .rule__lead p {
  margin: 0 0 14px;
  max-width: 46ch;
  font-size: clamp(15px, 1.2vw, 16.5px);
  line-height: 1.8;
  color: var(--muted);
}

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

.page-about .rule__lead .vnum {
  font-family: var(--f-mono);
}

.page-about .vn {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  padding: var(--about-pad);
  background: var(--panel-2);
  box-shadow: inset 0 0 0 1px var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), calc(100% - 28px) 100%, 0 100%);
}

.page-about .vn__seg {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: clamp(12px, 1.6vw, 18px);
  background: var(--ink);
  box-shadow: inset 0 0 0 1px var(--line);
}

.page-about .vn__num {
  font-family: var(--f-mono);
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  line-height: 1;
  color: var(--ink-on-accent);
  background: var(--cyan);
  padding: 6px 14px;
  width: fit-content;
}

.page-about .vn__lab {
  font-size: 13.5px;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.page-about .vn__sub {
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .about-rulefig {
  margin: clamp(22px, 3vw, 36px) 0 0;
}

/* ── 团队 ── */
.page-about .about-team__lede {
  margin: 0 0 clamp(18px, 2.4vw, 28px);
  max-width: 68ch;
  font-size: clamp(15px, 1.2vw, 16.5px);
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-team__cell .panel__title {
  color: var(--cyan);
}

/* ── 服务覆盖 ── */
.page-about .about-cover__grid {
  grid-template-columns: 1fr;
  align-items: start;
  gap: clamp(20px, 3vw, 38px);
}

.page-about .about-cover__text p {
  margin: 0 0 14px;
  max-width: 46ch;
  font-size: clamp(15px, 1.2vw, 16.5px);
  line-height: 1.8;
  color: var(--muted);
}

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

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

/* ── 生态合作 ── */
.page-about .about-eco .panel__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
}

.page-about .about-eco .panel__title {
  margin: 0;
}

/* ── 版本说明节奏 ── */
.page-about .about-since .grid--split {
  align-items: start;
  gap: clamp(20px, 3vw, 40px);
}

.page-about .about-since__text p {
  margin: 0 0 14px;
  max-width: 48ch;
  font-size: clamp(15px, 1.2vw, 16.5px);
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-since__text a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 229, 255, .4);
  transition: border-color .2s ease, color .2s ease;
}

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

.page-about .about-since__side {
  display: grid;
  gap: 1px;
  background: var(--line);
  box-shadow: inset 0 0 0 1px var(--line);
}

.page-about .about-since__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  padding: clamp(14px, 2vw, 20px);
  background: var(--panel);
}

.page-about .about-since__num {
  font-family: var(--f-mono);
  font-size: clamp(24px, 3vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--orange);
}

.page-about .about-since__cap {
  font-size: 13.5px;
  color: var(--muted);
}

/* ── 收束 ── */
.page-about .about-cta__box {
  padding: clamp(22px, 3.4vw, 44px);
  background: var(--panel-2);
  box-shadow: inset 0 0 0 1px var(--line);
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-size: clamp(22px, 3.2vw, 34px);
  line-height: 1.2;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.page-about .about-cta__text {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  max-width: 62ch;
  font-size: clamp(15px, 1.2vw, 16.5px);
  line-height: 1.78;
  color: var(--muted);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ── 断点 ── */
@media (min-width: 560px) {
  .page-about .vn {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-since__row {
    align-items: center;
  }
}

@media (min-width: 820px) {
  .page-about .kpi {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: var(--gap);
    border-bottom: 1px solid var(--line);
  }

  .page-about .kpi__item {
    flex-direction: column;
    gap: 10px;
    border-bottom: 0;
    padding: clamp(16px, 2.2vw, 26px) 0;
  }

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

@media (min-width: 900px) {
  .page-about .grid--split {
    grid-template-columns: minmax(0, 2fr) minmax(0, 3fr);
  }
}

@media (min-width: 960px) {
  .page-about .tl {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
    gap: clamp(24px, 3.4vw, 46px);
  }

  .page-about .tl__rail {
    position: sticky;
    top: 112px;
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
  }

  .page-about .tl__rail .verrail__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 4px;
  }

  .page-about .tl__rail .verrail__link {
    display: block;
    width: 100%;
    box-sizing: border-box;
  }
}