.page-about {
  --about-rail: 200px;
  --about-line: rgba(30, 58, 95, 0.9);
  padding-bottom: clamp(48px, 9vw, 100px);
}

.page-about .breadcrumb {
  padding-top: clamp(14px, 3vw, 26px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(18px, 4vw, 34px) 0 clamp(26px, 5vw, 48px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -140px;
  left: -20%;
  right: -20%;
  height: 480px;
  background:
    radial-gradient(58% 76% at 28% 22%, rgba(0, 229, 255, 0.18), transparent 70%),
    radial-gradient(48% 66% at 82% 0%, rgba(123, 47, 247, 0.24), transparent 72%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(20px, 4vw, 40px);
}

.page-about .about-hero__intro h1 {
  margin: 10px 0 0;
  font-size: clamp(30px, 6.4vw, 58px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--ice);
}

.page-about .about-hero__lead {
  margin: 16px 0 0;
  max-width: 36em;
  color: var(--ice);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
}

.page-about .about-hero__sub {
  margin: 12px 0 0;
  max-width: 34em;
  color: var(--haze);
  font-size: 14.5px;
  line-height: 1.85;
}

.page-about .about-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.page-about .about-meta__item {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  padding: 6px 10px;
  border: 1px solid var(--steel);
  border-radius: 2px;
  background: rgba(17, 26, 46, 0.72);
  color: var(--haze);
}

.page-about .about-meta__item b {
  color: var(--amber);
  font-weight: 700;
}

.page-about .about-hero__figure {
  margin: 0;
  border-radius: 4px;
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: 22px;
}

.page-about .rail-label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--haze);
}

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

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

.page-about .rail-list li {
  flex: 0 0 auto;
}

.page-about .rail-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
  padding: 8px 12px;
  border: 1px solid var(--steel);
  border-radius: 3px;
  background: rgba(17, 26, 46, 0.55);
  color: var(--haze);
  font-size: 13px;
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .rail-link .mono {
  font-size: 11px;
  color: var(--amber);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--ice);
  border-color: var(--cyan);
}

.page-about .rail-link.is-active,
.page-about .rail-link[aria-current="location"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
  font-weight: 700;
}

.page-about .rail-link.is-active .mono,
.page-about .rail-link[aria-current="location"] .mono {
  color: var(--ink);
}

/* ---------- 档案面板 ---------- */
.page-about .about-stack {
  min-width: 0;
}

.page-about .dossier {
  position: relative;
  padding: clamp(20px, 3.4vw, 34px);
  border: 1px solid var(--steel);
  border-radius: 4px;
  background: var(--panel);
  box-shadow: 0 20px 44px -30px rgba(0, 0, 0, 0.95);
}

.page-about .dossier + .dossier {
  margin-top: clamp(18px, 3vw, 30px);
}

.page-about .dossier::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--violet) 52%, transparent 88%);
}

.page-about .dossier__head {
  margin-bottom: 14px;
}

.page-about .dossier__title {
  margin: 8px 0 0;
  font-size: clamp(20px, 3.4vw, 27px);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--ice);
}

.page-about .dossier__lead {
  margin: 0 0 18px;
  max-width: 36em;
  color: var(--haze);
  font-size: 14.5px;
  line-height: 1.85;
}

.page-about .dossier__tail {
  margin: 16px 0 0;
  color: var(--haze);
  font-size: 14.5px;
  line-height: 1.85;
}

.page-about .dossier__tail a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px dashed rgba(0, 229, 255, 0.55);
}

.page-about .dossier__tail a:hover {
  border-bottom-style: solid;
}

/* ---------- 版本时间轴 ---------- */
.page-about .trace {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .trace::before {
  content: "";
  position: absolute;
  top: 12px;
  bottom: 14px;
  left: 11px;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan), var(--violet) 62%, rgba(123, 47, 247, 0));
  opacity: 0.6;
}

.page-about .trace__item {
  position: relative;
  padding-left: 34px;
}

.page-about .trace__item + .trace__item {
  margin-top: 12px;
}

.page-about .trace__item::before {
  content: "";
  position: absolute;
  top: 18px;
  left: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--cyan);
  box-shadow: 0 0 12px rgba(0, 229, 255, 0.65);
}

.page-about .trace__card {
  border: 1px solid var(--steel);
  border-radius: 4px;
  background: linear-gradient(155deg, rgba(17, 26, 46, 0.94), rgba(13, 21, 38, 0.78));
  transition: border-color 0.2s var(--ease);
}

.page-about .trace__card[open] {
  border-color: rgba(0, 229, 255, 0.55);
}

.page-about .trace__sum {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding: 13px 15px;
  cursor: pointer;
  list-style: none;
}

.page-about .trace__sum::-webkit-details-marker {
  display: none;
}

.page-about .trace__year {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--amber);
}

.page-about .trace__head {
  display: block;
  min-width: 0;
}

.page-about .trace__title {
  display: block;
  color: var(--ice);
  font-size: 15px;
  font-weight: 700;
  line-height: 1.5;
}

.page-about .trace__note {
  display: inline-block;
  margin-top: 5px;
  padding: 1px 7px;
  border: 1px solid var(--steel);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--violet);
  filter: brightness(1.7);
}

.page-about .trace__card[open] .trace__note {
  color: var(--cyan);
}

.page-about .trace__body {
  margin: 0 15px 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--about-line);
  color: var(--haze);
  font-size: 14px;
  line-height: 1.85;
}

/* ---------- 团队卡 ---------- */
.page-about .crew {
  display: grid;
  gap: 12px;
}

.page-about .crew__card {
  padding: 16px;
  border: 1px solid var(--steel);
  border-left: 3px solid rgba(0, 229, 255, 0.7);
  border-radius: 4px;
  background: rgba(13, 21, 38, 0.72);
}

.page-about .crew__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
}

.page-about .crew__name {
  margin: 8px 0 6px;
  font-size: 15px;
  color: var(--ice);
  letter-spacing: 0.01em;
}

.page-about .crew__desc {
  margin: 0;
  color: var(--haze);
  font-size: 13.5px;
  line-height: 1.8;
}

/* ---------- 图文分栏 ---------- */
.page-about .split {
  display: grid;
  gap: 18px;
}

.page-about .split__body p {
  margin: 0 0 12px;
  color: var(--haze);
  font-size: 14.5px;
  line-height: 1.85;
}

.page-about .split__media {
  margin: 0;
  border-radius: 4px;
}

.page-about .split__link {
  margin: 16px 0 0;
}

/* ---------- 步骤 ---------- */
.page-about .steps {
  counter-reset: steps;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.page-about .steps li {
  position: relative;
  padding-left: 34px;
  color: var(--haze);
  font-size: 14px;
  line-height: 1.78;
}

.page-about .steps li::before {
  counter-increment: steps;
  content: counter(steps, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 1px;
  padding: 1px 5px;
  border: 1px solid var(--steel);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--cyan);
}

/* ---------- 数字 ---------- */
.page-about .stat-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 30px;
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px dashed var(--about-line);
}

.page-about .stat {
  min-width: 104px;
}

.page-about .stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 25px;
  font-weight: 700;
  line-height: 1.15;
  color: var(--cyan);
}

.page-about .stat__label {
  display: block;
  margin-top: 3px;
  font-size: 12.5px;
  color: var(--haze);
}

/* ---------- 移动优先条目 ---------- */
.page-about .rules {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.page-about .rules li {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  padding: 12px 14px;
  border: 1px solid var(--steel);
  border-radius: 4px;
  background: linear-gradient(120deg, rgba(123, 47, 247, 0.12), rgba(17, 26, 46, 0.5));
}

.page-about .rules__k {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--pink);
  padding-top: 2px;
}

.page-about .rules__v {
  color: var(--haze);
  font-size: 14px;
  line-height: 1.78;
}

/* ---------- 共建生态 ---------- */
.page-about .partner-list {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .partner-list li {
  position: relative;
  padding: 10px 14px 10px 30px;
  border: 1px solid var(--steel);
  border-radius: 3px;
  background: rgba(13, 21, 38, 0.68);
  color: var(--haze);
  font-size: 13.5px;
  line-height: 1.7;
}

.page-about .partner-list li::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 17px;
  width: 6px;
  height: 6px;
  border-radius: 1px;
  background: var(--violet);
  filter: brightness(1.6);
}

/* ---------- 下一步入口 ---------- */
.page-about .dossier--next::before {
  background: linear-gradient(90deg, var(--pink), var(--violet) 55%, transparent 90%);
}

.page-about .next {
  display: grid;
  gap: 12px;
}

.page-about .next__card {
  display: grid;
  gap: 6px;
  padding: 16px;
  border: 1px solid var(--steel);
  border-radius: 4px;
  background: linear-gradient(150deg, rgba(0, 229, 255, 0.09), rgba(123, 47, 247, 0.12));
  text-decoration: none;
  transition: transform 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .next__card:hover,
.page-about .next__card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--cyan);
}

.page-about .next__title {
  color: var(--ice);
  font-size: 15px;
  font-weight: 700;
}

.page-about .next__text {
  color: var(--haze);
  font-size: 13.5px;
  line-height: 1.75;
}

.page-about .next__arrow {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .crew {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

@media (min-width: 820px) {
  .page-about .split {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
    align-items: center;
    gap: 26px;
  }

  .page-about .split--flip .split__media {
    order: -1;
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 52px);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: 3px;
    overflow: visible;
    padding: 14px 0 0;
  }

  .page-about .rail-link {
    width: 100%;
    justify-content: flex-start;
    padding: 9px 10px;
    border: 0;
    border-left: 2px solid var(--steel);
    border-radius: 0;
    background: transparent;
    font-size: 13.5px;
  }

  .page-about .rail-link.is-active,
  .page-about .rail-link[aria-current="location"] {
    background: rgba(0, 229, 255, 0.14);
    border-left-color: var(--cyan);
    color: var(--ice);
  }

  .page-about .rail-link.is-active .mono,
  .page-about .rail-link[aria-current="location"] .mono {
    color: var(--cyan);
  }
}

@media (min-width: 1040px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: center;
    gap: clamp(28px, 4vw, 52px);
  }

  .page-about .about-hero__figure {
    align-self: stretch;
  }
}
</