.page-about {
  --about-rule: 2px;
  background: var(--night);
  color: var(--cream);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(26px, 4.6vw, 52px) 0 clamp(40px, 6vw, 76px);
  background:
    radial-gradient(120% 82% at 90% 0%, rgba(27, 107, 255, 0.24), transparent 62%),
    radial-gradient(88% 58% at 6% 102%, rgba(182, 255, 60, 0.1), transparent 60%),
    var(--night);
}

.page-about .about-hero__shell {
  position: relative;
}

.page-about .breadcrumbs ol {
  list-style: none;
  margin: 0 0 clamp(20px, 3.4vw, 34px);
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .breadcrumbs li {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.page-about .breadcrumbs li + li::before {
  content: "/";
  color: rgba(159, 179, 174, 0.5);
}

.page-about .breadcrumbs a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

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

.page-about .breadcrumbs [aria-current="page"] {
  color: var(--cream);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 48px);
}

.page-about .about-hero__kicker {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--lime);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(36px, 7.2vw, 84px);
  line-height: 1.04;
  letter-spacing: -0.03em;
  max-width: 16ch;
  color: var(--cream);
}

.page-about .about-hero__lede {
  margin: 0 0 clamp(24px, 3.4vw, 34px);
  max-width: 44ch;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.78;
  color: rgba(244, 239, 228, 0.78);
}

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

.page-about .about-hero__figure {
  margin: 0;
  border-radius: var(--radius-l);
  border: var(--about-rule) solid rgba(182, 255, 60, 0.24);
  box-shadow: 0 0 0 1px rgba(226, 217, 198, 0.06), 0 24px 60px -32px rgba(0, 0, 0, 0.9);
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}

.page-about .about-hero__stats {
  list-style: none;
  margin: clamp(34px, 5.6vw, 62px) 0 0;
  padding: clamp(20px, 3vw, 30px) 0 0;
  border-top: var(--about-rule) solid rgba(226, 217, 198, 0.18);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 22px;
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.6vw, 42px);
  font-weight: 600;
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--lime);
}

.page-about .about-hero__stats li:nth-child(2) .stat-num {
  color: var(--ember);
}

.page-about .stat-cap {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--mist);
}

/* ---------- 长廊骨架 ---------- */
.page-about .about-corridor {
  padding: clamp(40px, 7vw, 92px) 0 clamp(48px, 8vw, 100px);
  background: linear-gradient(180deg, var(--night) 0%, #071613 46%, var(--night) 100%);
}

.page-about .about-corridor__shell {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 46px);
}

.page-about .about-rail__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 14px;
  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-flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 2px;
  white-space: nowrap;
  font-size: 14px;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

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

.page-about .about-rail__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--ember);
}

.page-about .about-track {
  display: flex;
  flex-direction: column;
  gap: clamp(24px, 4vw, 48px);
  min-width: 0;
}

/* ---------- 画板 ---------- */
.page-about .board {
  position: relative;
  border-radius: var(--radius-l);
  padding: clamp(22px, 3.4vw, 42px);
  border: var(--about-rule) solid transparent;
  scroll-margin-top: 96px;
}

.page-about .board--night {
  background: var(--panel-teal);
  border-color: rgba(226, 217, 198, 0.13);
  color: var(--cream);
}

.page-about .board--cream {
  background: var(--cream);
  border-color: var(--edge);
  color: var(--ink);
}

.page-about .board__head {
  margin-bottom: clamp(18px, 2.6vw, 30px);
}

.page-about .about-tag {
  display: inline-flex;
  align-items: center;
  margin: 0 0 16px;
  padding: 5px 12px;
  border: 1px solid currentColor;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ember);
  opacity: 0.9;
}

.page-about .board--cream .about-tag {
  color: var(--blue-deep);
}

.page-about .board h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(25px, 3.8vw, 46px);
  line-height: 1.12;
  letter-spacing: -0.028em;
  max-width: 24ch;
}

.page-about .board__body {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(20px, 3vw, 34px);
}

.page-about .board .prose p {
  margin: 0 0 16px;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.82;
}

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

.page-about .board--cream .prose p {
  color: #2b3933;
}

.page-about .board--night .prose p {
  color: rgba(244, 239, 228, 0.8);
}

.page-about .about-note {
  align-self: start;
  padding: clamp(18px, 2.4vw, 24px);
  border-radius: var(--radius-m);
  border: var(--about-rule) solid var(--edge);
  background: rgba(255, 255, 255, 0.6);
  font-size: 14px;
  line-height: 1.72;
  color: #3a463f;
}

.page-about .about-note__k {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ember);
}

.page-about .about-note p {
  margin: 0 0 12px;
}

.page-about .about-note__link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--blue-deep);
  text-decoration: none;
  border-bottom: 2px solid var(--blue);
  padding-bottom: 2px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-note__link:hover,
.page-about .about-note__link:focus-visible {
  color: var(--ember);
  border-bottom-color: var(--ember);
}

/* ---------- 通栏口号 ---------- */
.page-about .about-quote {
  margin: 0;
  padding: clamp(6px, 2vw, 18px) 0 clamp(6px, 2vw, 18px) clamp(14px, 3vw, 34px);
  border-left: var(--about-rule) solid var(--lime);
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(28px, 5.6vw, 68px);
  line-height: 1.08;
  letter-spacing: -0.03em;
  color: rgba(244, 239, 228, 0.52);
}

/* ---------- 版本时间轴 ---------- */
.page-about .about-versions__figure {
  margin: 0 0 clamp(22px, 3vw, 34px);
  border-radius: var(--radius-m);
  opacity: 0.62;
}

.page-about .about-versions__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

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

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--ember) 0%, rgba(226, 217, 198, 0.2) 52%, var(--lime) 100%);
}

.page-about .timeline__item {
  position: relative;
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 19px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--ember);
  box-shadow: 0 0 0 4px rgba(255, 122, 26, 0.14);
}

.page-about .timeline__item--now::before {
  border-color: var(--lime);
  box-shadow: 0 0 0 4px rgba(182, 255, 60, 0.18);
}

.page-about .timeline details {
  border-radius: var(--radius-m);
  border: var(--about-rule) solid rgba(226, 217, 198, 0.14);
  background: rgba(10, 30, 26, 0.46);
  transition: border-color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .timeline details[open] {
  border-color: rgba(182, 255, 60, 0.5);
  background: rgba(10, 30, 26, 0.86);
}

.page-about .timeline summary,
.page-about .principles summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
}

.page-about .timeline summary::-webkit-details-marker,
.page-about .principles summary::-webkit-details-marker {
  display: none;
}

.page-about .timeline summary {
  padding: 15px 18px;
}

.page-about .timeline summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--lime);
}

.page-about .timeline details[open] summary::after {
  content: "–";
}

.page-about .timeline__ver {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ember);
}

.page-about .timeline__name {
  font-size: clamp(16px, 1.7vw, 19px);
  font-weight: 600;
  color: var(--cream);
}

.page-about .timeline__brief {
  flex: 1 1 100%;
  font-size: 14px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .timeline__detail {
  padding: 0 18px 18px;
}

.page-about .timeline__detail p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: rgba(244, 239, 228, 0.78);
}

/* ---------- 城市看台上线四步 ---------- */
.page-about .about-steps {
  align-self: start;
  padding: clamp(18px, 2.4vw, 26px);
  border-radius: var(--radius-m);
  border: var(--about-rule) solid var(--edge);
  background: rgba(226, 217, 198, 0.36);
}

.page-about .about-steps__title {
  margin: 0 0 16px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-steps__list {
  list-style: none;
  margin: 0 0 18px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .about-steps__list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  font-size: 14px;
  line-height: 1.65;
  color: #3a463f;
}

.page-about .about-steps__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: #fff;
  background: var(--blue-deep);
  border-radius: 4px;
  padding: 3px 6px;
}

.page-about .about-steps__link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--blue-deep);
  text-decoration: none;
  border-bottom: 2px solid var(--blue);
  padding-bottom: 2px;
}

.page-about .about-steps__link:hover,
.page-about .about-steps__link:focus-visible {
  color: var(--ember);
  border-bottom-color: var(--ember);
}

/* ---------- 团队 ---------- */
.page-about .about-team__aside {
  display: flex;
  flex-direction: column;
  gap: clamp(18px, 2.4vw, 26px);
}

.page-about .about-team__figure {
  margin: 0;
  border-radius: var(--radius-m);
  border: var(--about-rule) solid rgba(226, 217, 198, 0.16);
}

.page-about .about-team__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .about-ring {
  display: flex;
  align-items: center;
  gap: clamp(16px, 2.4vw, 26px);
  padding: clamp(18px, 2.4vw, 24px);
  border-radius: var(--radius-m);
  border: var(--about-rule) solid rgba(182, 255, 60, 0.24);
  background: rgba(10, 30, 26, 0.5);
}

.page-about .about-ring__svg {
  width: clamp(84px, 14vw, 118px);
  height: auto;
  flex: 0 0 auto;
}

.page-about .about-ring__legend {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
  font-size: 14px;
  line-height: 1.5;
  color: rgba(244, 239, 228, 0.86);
}

.page-about .about-ring__legend li {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .about-ring__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex: 0 0 auto;
  transform: translateY(1px);
}

.page-about .about-ring__dot--lime {
  background: var(--lime);
}

.page-about .about-ring__dot--ember {
  background: var(--ember);
}

/* ---------- 协作生态 ---------- */
.page-about .about-coop {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(14px, 2vw, 22px);
}

.page-about .about-coop__item {
  padding: clamp(18px, 2.4vw, 26px);
  border-radius: var(--radius-m);
  border: var(--about-rule) solid var(--edge);
  background: rgba(255, 255, 255, 0.58);
  transition: border-color 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .about-coop__item:hover {
  border-color: var(--blue);
  transform: translateY(-3px);
}

.page-about .about-coop__item--accent {
  background: linear-gradient(150deg, rgba(182, 255, 60, 0.22), rgba(255, 122, 26, 0.16));
  border-color: rgba(255, 122, 26, 0.4);
}

.page-about .about-coop__type {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--blue-deep);
}

.page-about .about-coop__item--accent .about-coop__type {
  color: var(--ember);
}

.page-about .about-coop__num {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .about-coop__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: #3a463f;
}

/* ---------- 三条做法 ---------- */
.page-about .principles {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .principles details {
  border-radius: var(--radius-m);
  border: var(--about-rule) solid rgba(226, 217, 198, 0.14);
  background: rgba(10, 30, 26, 0.44);
  overflow: hidden;
  transition: border-color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .principles details[open] {
  border-color: rgba(255, 122, 26, 0.55);
  background: rgba(10, 30, 26, 0.84);
}

.page-about .principles summary {
  padding: 16px 20px;
}

.page-about .principles__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--lime);
}

.page-about .principles__name {
  font-size: clamp(17px, 1.9vw, 21px);
  font-weight: 600;
  color: var(--cream);
}

.page-about .principles__hint {
  flex: 1 1 100%;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .principles__body {
  padding: 0 20px 20px;
}

.page-about .principles__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(244, 239, 228, 0.78);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding: clamp(44px, 7vw, 96px) 0 clamp(56px, 8vw, 108px);
  background:
    radial-gradient(90% 70% at 12% 0%, rgba(27, 107, 255, 0.22), transparent 64%),
    var(--night);
}

.page-about .about-cta__inner h2 {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(28px, 4.6vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--cream);
}

.page-about .about-cta__inner p {
  margin: 0 0 clamp(22px, 3vw, 32px);
  max-width: 48ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.78;
  color: rgba(244, 239, 228, 0.74);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .about-coop__item--accent {
    grid-column: 1 / -1;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: end;
  }

  .page-about .board__body--split {
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 0.86fr);
  }

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

  .page-about .about-coop__item--accent {
    grid-column: auto;
  }
}

@media (min-width: 1040px) {
  .page-about .about-corridor__shell {
    grid-template-columns: 176px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-left: var(--about-rule) solid rgba(226, 217, 198, 0.16);
    padding-left: 0;
  }

  .page-about .about-rail__list a {
    display: flex;
    white-space: normal;
    margin-left: calc(-1 * var(--about-rule));
    padding: 11px 4px 11px 14px;
    border-bottom: none;
    border-left: var(--about-rule) solid transparent;
    line-height: 1.45;
  }

  .page-about .about-rail__list a:hover,
  .page-about .about-rail__list a:focus-visible {
    border-bottom-color: transparent;
    border-left-color: var(--lime);
  }

  .page-about .board--offset {
    margin-left: clamp(0px, 4%, 56px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-coop__item,
  .page-about .breadcrumbs a,
  .page-about .about-rail__list a {
    transition: none;
  }

  .page-about .about-coop__item:hover {
    transform: none;
  }
}