.page-about {
  --about-line: var(--rail-line);
  --about-panel: var(--ink-2);
  --about-gap: 1.25rem;
  padding-bottom: 4rem;
  color: var(--trace-light);
}

.page-about h2 {
  font-size: clamp(1.5rem, 1.15rem + 1.6vw, 2.25rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--white);
  margin: 0.4rem 0 0.85rem;
}

.page-about h3 {
  color: var(--white);
  letter-spacing: -0.005em;
}

.page-about p {
  margin: 0 0 0.9rem;
  line-height: 1.75;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 2rem;
  padding: 2rem 0 2.75rem;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-hero__lead {
  font-size: 1.0625rem;
  color: var(--trace-light);
  max-width: 46ch;
}

.page-about .about-hero__sub {
  font-size: 0.9375rem;
  color: var(--trace);
  max-width: 44ch;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.page-about .about-hero__panel {
  position: relative;
  background: var(--about-panel);
  border: 1px solid var(--about-line);
  border-radius: var(--r-lg);
  padding: 1.25rem 1.25rem 1rem;
  box-shadow: inset 0 0 0 1px rgba(57, 224, 208, 0.06);
}

.page-about .about-hero__panel::before {
  content: "";
  position: absolute;
  top: 1.35rem;
  left: -1px;
  width: 3px;
  height: 34px;
  border-radius: 0 3px 3px 0;
  background: linear-gradient(180deg, var(--cyan), var(--signal));
}

.page-about .about-hero__panel-title {
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
  margin: 0 0 1rem;
}

.page-about .stat-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .stat-list__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.55rem 0;
  border-bottom: 1px dashed var(--about-line);
}

.page-about .stat-list__row:last-child {
  border-bottom: 0;
}

.page-about .stat-list__k {
  font-size: 0.875rem;
  color: var(--trace);
}

.page-about .stat-list__v {
  font-size: 0.9375rem;
  color: var(--white);
  white-space: nowrap;
}

.page-about .about-hero__panel-note {
  margin: 1rem 0 0;
  font-size: 0.75rem;
  color: var(--trace);
  padding-top: 0.75rem;
  border-top: 1px solid var(--about-line);
}

/* ---------- 通用章节 ---------- */
.page-about section {
  padding: 3rem 0 0;
}

.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--about-line);
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--about-panel);
}

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

.page-about .about-figure--roles { aspect-ratio: 4 / 3; }
.page-about .about-figure--flow { aspect-ratio: 2 / 1; margin: 1.75rem 0 2rem; }
.page-about .about-figure--history { aspect-ratio: 8 / 3; margin: 0 0 2rem; }

/* ---------- 团队构成 ---------- */
.page-about .about-roles__intro {
  max-width: 56ch;
  margin-bottom: 1.75rem;
}

.page-about .about-roles__grid {
  display: grid;
  gap: 1.5rem;
}

.page-about .role-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.page-about .role-card {
  position: relative;
  background: var(--about-panel);
  border: 1px solid var(--about-line);
  border-radius: var(--r-md);
  padding: 1.15rem 1.15rem 1rem 3.25rem;
  transition: border-color 0.2s var(--ease-out), transform 0.2s var(--ease-out);
}

.page-about .role-card:hover,
.page-about .role-card:focus-within {
  border-color: rgba(57, 224, 208, 0.5);
  transform: translateX(3px);
}

.page-about .role-card__idx {
  position: absolute;
  top: 1.2rem;
  left: 1.15rem;
  font-size: 0.8125rem;
  color: var(--signal);
}

.page-about .role-card__name {
  margin: 0 0 0.5rem;
  font-size: 1.0625rem;
  font-weight: 700;
}

.page-about .role-card__desc {
  font-size: 0.9375rem;
  color: var(--trace-light);
  margin-bottom: 0.75rem;
}

.page-about .role-card__duties {
  list-style: none;
  margin: 0 0 0.85rem;
  padding: 0;
  font-size: 0.875rem;
  color: var(--trace);
}

.page-about .role-card__duties li {
  position: relative;
  padding-left: 0.95rem;
  line-height: 1.7;
}

.page-about .role-card__duties li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 5px;
  height: 1px;
  background: var(--cyan);
}

.page-about .role-card__meter {
  margin: 0;
  padding-top: 0.7rem;
  border-top: 1px dashed var(--about-line);
  font-size: 0.8125rem;
  color: var(--trace);
  transition: color 0.2s var(--ease-out), opacity 0.2s var(--ease-out);
}

.page-about .role-card__meter .mono {
  color: var(--ok);
  font-size: 0.9375rem;
}

@media (hover: hover) {
  .page-about .role-card__meter { opacity: 0.5; }
  .page-about .role-card:hover .role-card__meter,
  .page-about .role-card:focus-within .role-card__meter {
    opacity: 1;
    color: var(--trace-light);
  }
}

/* ---------- 索引维护流程 ---------- */
.page-about .about-audit__intro {
  max-width: 60ch;
}

.page-about .flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  position: relative;
}

.page-about .flow-list::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), var(--about-line));
}

.page-about .flow-step {
  position: relative;
  padding-left: 2.25rem;
}

.page-about .flow-step__item {
  border-bottom: 1px solid var(--about-line);
}

.page-about .flow-step:first-child .flow-step__item {
  border-top: 1px solid var(--about-line);
}

.page-about .flow-step__summary {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.95rem 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .flow-step__summary::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 1.35rem;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  transition: background 0.2s var(--ease-out);
}

.page-about .flow-step__item[open] .flow-step__summary::before {
  background: var(--cyan);
}

.page-about .flow-step__no {
  font-size: 0.8125rem;
  color: var(--trace);
  flex: 0 0 auto;
}

.page-about .flow-step__item[open] .flow-step__no {
  color: var(--cyan);
}

.page-about .flow-step__name {
  flex: 1 1 auto;
  font-size: 1rem;
  font-weight: 600;
  color: var(--white);
}

.page-about .flow-step__sign {
  flex: 0 0 auto;
  width: 12px;
  height: 12px;
  position: relative;
}

.page-about .flow-step__sign::before,
.page-about .flow-step__sign::after {
  content: "";
  position: absolute;
  background: var(--trace);
  transition: transform 0.22s var(--ease-out);
}

.page-about .flow-step__sign::before {
  left: 0; top: 5px; width: 12px; height: 1.5px;
}

.page-about .flow-step__sign::after {
  left: 5px; top: 0; width: 1.5px; height: 12px;
}

.page-about .flow-step__item[open] .flow-step__sign::after {
  transform: scaleY(0);
}

.page-about .flow-step__detail {
  padding: 0 0 1.05rem 0;
}

.page-about .flow-step__detail p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--trace);
  max-width: 68ch;
}

/* ---------- 时间线 ---------- */
.page-about .about-history__intro {
  max-width: 60ch;
  margin-bottom: 1.75rem;
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.1rem;
  position: relative;
}

.page-about .timeline__item {
  position: relative;
  padding-left: 1.75rem;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 1.65rem;
  bottom: -1.1rem;
  width: 1px;
  background: var(--about-line);
}

.page-about .timeline__item:last-child::before { display: none; }

.page-about .timeline__dot {
  position: absolute;
  left: 0;
  top: 1.1rem;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(57, 224, 208, 0.12);
}

.page-about .tl-node {
  background: var(--about-panel);
  border: 1px solid var(--about-line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .tl-node__summary {
  display: grid;
  gap: 0.3rem;
  padding: 0.9rem 2.5rem 0.9rem 1rem;
  cursor: pointer;
  list-style: none;
  position: relative;
}

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

.page-about .tl-node__phase {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--signal);
}

.page-about .tl-node__phase.now {
  color: var(--ok);
}

.page-about .tl-node__title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--white);
}

.page-about .tl-node__sign {
  position: absolute;
  right: 1rem;
  top: 1.2rem;
  width: 12px;
  height: 12px;
}

.page-about .tl-node__sign::before,
.page-about .tl-node__sign::after {
  content: "";
  position: absolute;
  background: var(--trace);
  transition: transform 0.22s var(--ease-out);
}

.page-about .tl-node__sign::before {
  left: 0; top: 5px; width: 12px; height: 1.5px;
}

.page-about .tl-node__sign::after {
  left: 5px; top: 0; width: 1.5px; height: 12px;
}

.page-about .tl-node[open] .tl-node__sign::after {
  transform: scaleY(0);
}

.page-about .tl-node__panel {
  padding: 0 1rem 1rem;
  border-top: 1px dashed var(--about-line);
  margin-top: 0.15rem;
}

.page-about .tl-node__panel p {
  font-size: 0.9375rem;
  color: var(--trace);
  margin: 0.85rem 0 0;
  max-width: 60ch;
}

.page-about .tl-node__metric {
  margin: 0.85rem 0 0;
  font-size: 0.8125rem;
  color: var(--cyan);
  padding-top: 0.7rem;
  border-top: 1px solid var(--about-line);
}

/* ---------- 版本比对小组 ---------- */
.page-about .about-compare__intro {
  max-width: 62ch;
  margin-bottom: 1.75rem;
}

.page-about .compare-cards {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.page-about .compare-card {
  position: relative;
  background: var(--about-panel);
  border: 1px solid var(--about-line);
  border-radius: var(--r-md);
  padding: 1.25rem;
  overflow: hidden;
}

.page-about .compare-card::after {
  content: "";
  position: absolute;
  right: -28px;
  bottom: -28px;
  width: 90px;
  height: 90px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 122, 47, 0.16), transparent 68%);
}

.page-about .compare-card__k {
  display: inline-block;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
  margin-bottom: 0.6rem;
}

.page-about .compare-card__t {
  margin: 0 0 0.55rem;
  font-size: 1.0625rem;
  font-weight: 700;
}

.page-about .compare-card p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--trace);
  position: relative;
  z-index: 1;
}

/* ---------- 与服务清单配合 ---------- */
.page-about .about-collab {
  display: grid;
  gap: 1.75rem;
}

.page-about .about-collab__body p {
  max-width: 58ch;
}

.page-about .about-collab__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.page-about .review-panel {
  background: linear-gradient(160deg, rgba(18, 36, 59, 0.95), rgba(11, 23, 41, 0.95));
  border: 1px solid var(--about-line);
  border-radius: var(--r-lg);
  padding: 1.35rem 1.25rem 1.15rem;
}

.page-about .review-panel__kicker {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--signal);
  margin: 0 0 1.1rem;
}

.page-about .review-panel__steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  position: relative;
}

.page-about .review-panel__steps::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 12px;
  bottom: 12px;
  width: 1px;
  background: var(--about-line);
}

.page-about .review-panel__step {
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  padding: 0.5rem 0;
}

.page-about .review-panel__no {
  flex: 0 0 auto;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--about-line);
  color: var(--cyan);
  font-size: 0.6875rem;
  display: grid;
  place-items: center;
  position: relative;
  z-index: 1;
}

.page-about .review-panel__txt {
  font-size: 0.9375rem;
  color: var(--trace-light);
  padding-top: 0.15rem;
  line-height: 1.5;
}

.page-about .review-panel__foot {
  margin: 1.1rem 0 0;
  padding-top: 0.85rem;
  border-top: 1px solid var(--about-line);
  font-size: 0.75rem;
  color: var(--trace);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding: 3rem 0 0;
}

.page-about .about-cta__inner {
  position: relative;
  border: 1px solid var(--about-line);
  border-radius: var(--r-lg);
  background:
    radial-gradient(120% 160% at 0% 0%, rgba(57, 224, 208, 0.12), transparent 55%),
    radial-gradient(90% 140% at 100% 100%, rgba(255, 122, 47, 0.14), transparent 55%),
    var(--ink-2);
  padding: 1.75rem 1.35rem;
  overflow: hidden;
}

.page-about .about-cta__inner h2 {
  margin-bottom: 0.7rem;
}

.page-about .about-cta__inner p {
  max-width: 56ch;
  color: var(--trace-light);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.4rem;
}

/* ---------- 平板 ---------- */
@media (min-width: 680px) {
  .page-about .compare-cards {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .role-card:first-child {
    grid-column: 1 / -1;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 900px) {
  .page-about {
    --about-gap: 1.5rem;
  }

  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.45fr) minmax(280px, 0.85fr);
    gap: 3.5rem;
    align-items: start;
    padding: 3rem 0 3.5rem;
  }

  .page-about .about-hero__panel {
    margin-top: 2.5rem;
  }

  .page-about .about-roles__grid {
    grid-template-columns: minmax(0, 1.5fr) minmax(240px, 0.75fr);
    gap: 2rem;
    align-items: start;
  }

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

  .page-about .role-card:first-child {
    grid-column: 1 / -1;
  }

  .page-about .about-figure--roles {
    margin-top: 2.75rem;
  }

  .page-about .about-collab {
    grid-template-columns: minmax(0, 1.55fr) minmax(280px, 0.85fr);
    gap: 3rem;
    align-items: start;
  }

  .page-about .review-panel {
    margin-top: 2.25rem;
  }

  .page-about .about-cta__inner {
    padding: 2.75rem 2.5rem;
  }

  /* 时间线：左右交替 */
  .page-about .timeline {
    grid-template-columns: 1fr 1fr;
    column-gap: 0;
    row-gap: 1.5rem;
  }

  .page-about .timeline::before {
    content: "";
    position: absolute;
    left: 50%;
    top: 10px;
    bottom: 10px;
    width: 1px;
    transform: translateX(-50%);
    background: linear-gradient(180deg, transparent, var(--about-line) 10%, var(--about-line) 90%, transparent);
  }

  .page-about .timeline__item {
    padding-left: 0;
  }

  .page-about .timeline__item::before { display: none; }

  .page-about .timeline__item:nth-child(odd) {
    grid-column: 1;
    padding-right: 2.75rem;
  }

  .page-about .timeline__item:nth-child(even) {
    grid-column: 2;
    padding-left: 2.75rem;
  }

  .page-about .timeline__dot {
    top: 1.35rem;
  }

  .page-about .timeline__item:nth-child(odd) .timeline__dot {
    left: auto;
    right: -6px;
  }

  .page-about .timeline__item:nth-child(even) .timeline__dot {
    left: -6px;
  }
}

@media (min-width: 1100px) {
  .page-about .about-audit__intro,
  .page-about .about-compare__intro,
  .page-about .about-history__intro {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .flow-list {
    max-width: 900px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .role-card,
  .page-about .role-card__meter,
  .page-about .flow-step__sign::before,
  .page-about .flow-step__sign::after,
  .page-about .tl-node__sign::before,
  .page-about .tl-node__sign::after {
    transition: none !important;
  }
}
</main>