.page-about {
  --about-rail: 216px;
  display: block;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(24px, 5vw, 52px) clamp(28px, 5vw, 56px);
  border-bottom: 3px solid var(--line);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-cond);
  font-weight: 800;
  font-size: clamp(31px, 6.4vw, 62px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--ink);
  max-width: 22ch;
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.55vw, 17px);
  line-height: 1.85;
  color: var(--body-ink);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .afact {
  border: 2px solid var(--line);
  background: var(--panel);
  padding: 12px 14px 13px;
}

.page-about .afact__num {
  display: block;
  font-size: clamp(24px, 3.2vw, 34px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .afact__label {
  display: block;
  margin-top: 5px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

/* ---------- 侧栏 + 正文 ---------- */
.page-about .about-flow {
  padding-block: clamp(28px, 4.5vw, 56px) clamp(40px, 6vw, 80px);
}

.page-about .about-flow__rail {
  border: 2px solid var(--line);
  background: var(--panel);
  padding: 14px 12px 10px;
  margin-bottom: 26px;
}

.page-about .rail-line {
  list-style: none;
  margin: 10px 0 0;
  padding: 0;
  display: flex;
  gap: 4px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .rail-line__item {
  flex: none;
}

.page-about .rail-line__link {
  display: flex;
  align-items: center;
  gap: 9px;
  min-height: 44px;
  padding: 10px 10px;
  font-size: 14px;
  white-space: nowrap;
  text-decoration: none;
  color: var(--muted);
  border-left: 3px solid transparent;
  transition: color 0.2s var(--ease-out), border-color 0.2s var(--ease-out);
}

.page-about .rail-line__link:hover,
.page-about .rail-line__link:focus-visible {
  color: var(--ink);
  border-left-color: var(--cyan);
}

.page-about .rail-line__dot {
  flex: none;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 2px solid var(--line);
}

.page-about .rail-line__link:hover .rail-line__dot,
.page-about .rail-line__link:focus-visible .rail-line__dot {
  border-color: var(--cyan);
  background: var(--cyan);
}

.page-about .rail-line__num {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--muted);
  opacity: 0.6;
}

/* ---------- 段落通用 ---------- */
.page-about .about-sec {
  padding-block: clamp(36px, 5.5vw, 76px);
  border-top: 2px solid var(--line);
}

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

.page-about .about-sec h2 {
  margin: 10px 0 0;
  font-size: clamp(23px, 3.3vw, 38px);
  line-height: 1.22;
  letter-spacing: -0.015em;
  font-weight: 800;
  color: var(--ink);
  max-width: 24ch;
}

.page-about .about-sec p {
  line-height: 1.85;
  color: var(--body-ink);
}

.page-about .about-sec__lead {
  margin: 14px 0 0;
  max-width: 62ch;
  font-size: 16px;
}

.page-about .about-sec__foot {
  margin: 22px 0 0;
  max-width: 62ch;
  font-size: 15px;
  color: var(--muted);
}

.page-about .about-sec a {
  color: var(--ink);
  text-decoration: none;
  box-shadow: inset 0 -2px 0 var(--cyan);
}

.page-about .about-sec a:hover,
.page-about .about-sec a:focus-visible {
  color: var(--cyan);
}

/* ---------- 起点分栏 ---------- */
.page-about .about-split {
  margin-top: 26px;
  display: grid;
  gap: 22px;
}

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

.page-about .about-split__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 2px solid var(--line);
}

.page-about .about-split__text p {
  margin: 0 0 14px;
  font-size: 15.5px;
}

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

/* ---------- 版本时间线 ---------- */
.page-about .verline {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  position: relative;
}

.page-about .verline::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 10px;
  bottom: 24px;
  width: 2px;
  background: linear-gradient(180deg, var(--line) 0%, var(--line) 74%, rgba(27, 36, 64, 0) 100%);
}

.page-about .verline__item {
  position: relative;
  padding-left: 36px;
}

.page-about .ver {
  border: 2px solid var(--line);
  background: var(--panel);
  margin-bottom: 14px;
}

.page-about .ver__sum {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 14px 14px;
  min-height: 44px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ver__dot {
  position: absolute;
  left: 4px;
  top: 20px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  border: 2px solid var(--cyan);
  background: var(--bg);
}

.page-about .ver[open] .ver__dot {
  border-color: var(--orange);
  background: var(--orange);
  box-shadow: 0 0 0 5px rgba(255, 122, 46, 0.16);
}

.page-about .ver__ver {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .ver__name {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ver__stage {
  margin-left: auto;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--orange);
  border: 1px solid var(--line);
  padding: 3px 8px;
  white-space: nowrap;
}

.page-about .ver__body {
  padding: 2px 16px 16px;
  border-top: 2px dashed var(--line);
}

.page-about .ver__body p {
  margin: 14px 0 0;
  font-size: 15px;
  color: var(--muted);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  margin-top: 28px;
  display: grid;
  gap: 26px;
}

.page-about .team-ring svg {
  display: block;
  width: 100%;
  max-width: 268px;
  height: auto;
  margin: 0 auto;
}

.page-about .ring-arc {
  fill: none;
  stroke-width: 18;
  transition: opacity 0.22s var(--ease-out);
}

.page-about .ring-arc--a { stroke: var(--cyan); }
.page-about .ring-arc--b { stroke: var(--orange); }
.page-about .ring-arc--c { stroke: var(--violet); }
.page-about .ring-arc--d { stroke: var(--muted); }

.page-about .team-ring svg:hover .ring-arc {
  opacity: 0.55;
}

.page-about .team-ring svg .ring-arc:hover {
  opacity: 1;
}

.page-about .ring-core {
  font-family: var(--font-mono);
  font-size: 42px;
  font-weight: 700;
  fill: var(--ink);
}

.page-about .ring-core-sub {
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.12em;
  fill: var(--muted);
}

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

.page-about .team-item {
  border: 2px solid var(--line);
  background: var(--panel);
  padding: 15px 16px 17px;
}

.page-about .team-item--a { border-top: 3px solid var(--cyan); }
.page-about .team-item--b { border-top: 3px solid var(--orange); }
.page-about .team-item--c { border-top: 3px solid var(--violet); }
.page-about .team-item--d { border-top: 3px solid var(--muted); }

.page-about .team-item__num {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.page-about .team-item__name {
  margin: 6px 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .team-item__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-team__media {
  margin: 26px 0 0;
}

.page-about .about-team__media img,
.page-about .about-sources__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 2px solid var(--line);
}

/* ---------- 来源 ---------- */
.page-about .source-grid {
  margin-top: 26px;
  display: grid;
  gap: 14px;
}

.page-about .source-card {
  border: 2px solid var(--line);
  background: var(--panel);
  padding: 17px 16px 19px;
}

.page-about .source-card__num {
  margin: 0;
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--orange);
}

.page-about .source-card h3 {
  margin: 10px 0 8px;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .source-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-sources__media {
  margin: 26px 0 0;
}

/* ---------- 覆盖 ---------- */
.page-about .reach-grid {
  margin-top: 26px;
  display: grid;
  gap: 22px;
}

.page-about .cover-grid {
  display: block;
  width: 100%;
  height: auto;
  border: 2px solid var(--line);
  background: var(--bg);
}

.page-about .cover-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .cstat {
  border: 2px solid var(--line);
  background: var(--panel);
  padding: 14px 14px 15px;
}

.page-about .cstat__num {
  display: block;
  font-size: clamp(22px, 2.9vw, 30px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .cstat__label {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  color: var(--muted);
  letter-spacing: 0.06em;
}

/* ---------- 主体信息 ---------- */
.page-about .info-card {
  margin-top: 26px;
  border: 3px solid var(--line);
  background: var(--panel);
}

.page-about .info-row {
  display: grid;
  gap: 5px;
  padding: 14px 16px;
  border-bottom: 2px solid var(--line);
}

.page-about .info-row:last-child {
  border-bottom: 0;
}

.page-about .info-row__k {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .info-row__v {
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink);
  overflow-wrap: anywhere;
}

/* ---------- 中屏及以上 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
  }

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

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

  .page-about .cover-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .info-row {
    grid-template-columns: 148px minmax(0, 1fr);
    align-items: baseline;
    gap: 18px;
    padding: 15px 18px;
  }
}

@media (min-width: 820px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: start;
    gap: 30px;
  }

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

@media (min-width: 960px) {
  .page-about .about-flow {
    display: grid;
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 60px);
    align-items: start;
  }

  .page-about .about-flow__rail {
    position: sticky;
    top: 92px;
    margin-bottom: 0;
  }

  .page-about .rail-line {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    margin-top: 12px;
  }

  .page-about .rail-line__link {
    width: 100%;
    padding: 9px 8px 9px 10px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    gap: 36px;
  }

  .page-about .team-grid {
    grid-template-columns: 268px minmax(0, 1fr);
    align-items: center;
    gap: 34px;
  }

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

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

@media (min-width: 1180px) {
  .page-about .about-split__text p {
    font-size: 16px;
  }

  .page-about .ver__body {
    padding: 2px 20px 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-line__link,
  .page-about .ring-arc {
    transition: none;
  }

  .page-about .ver[open] .ver__dot {
    box-shadow: none;
  }
}