.page-about {
  --about-rail-w: 88px;
  --about-row-gap: 24px;
}

/* ---------- 首屏 ---------- */
.page-about .about-intro {
  padding: 34px 0 30px;
  border-bottom: 1px solid var(--rule);
}

.page-about .about-intro__title {
  font-family: var(--font-head);
  font-size: clamp(30px, 7.4vw, 58px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin: 12px 0 18px;
  max-width: 24ch;
}

.page-about .page-head__kicker {
  color: var(--copper);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.page-about .page-head__lead {
  max-width: 64ch;
  color: var(--ink);
  opacity: 0.86;
  line-height: 1.8;
}

/* ---------- 数字带 ---------- */
.page-about .about-band {
  margin: 26px 0 0;
}

.page-about .about-band .band__item {
  border-left: 1px solid var(--rule);
  padding-left: 14px;
}

.page-about .about-band .band__value {
  color: var(--cinnabar);
  font-size: 22px;
  display: block;
}

.page-about .about-band .band__label {
  color: var(--muted);
  font-size: 12px;
  display: block;
  margin-top: 4px;
}

/* ---------- 通用章节 ---------- */
.page-about .section {
  padding: 44px 0;
  border-top: 1px solid var(--rule);
}

.page-about .section__kicker {
  color: var(--copper);
  font-size: 12px;
  letter-spacing: 0.1em;
  margin: 0 0 10px;
}

.page-about .section__title {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: clamp(22px, 4.6vw, 34px);
  line-height: 1.28;
  color: var(--ink);
  margin: 0 0 14px;
}

.page-about .section__desc {
  color: var(--muted);
  max-width: 56ch;
  line-height: 1.8;
  margin: 0 0 22px;
}

.page-about .section p {
  line-height: 1.8;
  max-width: 62ch;
}

/* ---------- 01 缘起 ---------- */
.page-about .about-origin__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

.page-about .about-origin__note {
  border-left: 3px solid var(--cinnabar);
  background: var(--cinnabar-tint);
  padding: 12px 16px;
  margin-top: 18px;
  font-size: 14px;
  max-width: 56ch;
}

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

.page-about .figure__frame {
  background: var(--paper-2);
  border: 1px solid var(--rule);
  overflow: hidden;
}

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

.page-about .figure__caption {
  margin-top: 10px;
  font-size: 12px;
  color: var(--muted);
  line-height: 1.7;
}

/* ---------- 02 时间线 ---------- */
.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 22px;
  border-left: 1px solid var(--rule);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 20px 0 22px;
}

.page-about .about-timeline__item + .about-timeline__item {
  border-top: 1px solid var(--rule);
}

.page-about .about-timeline__dot {
  position: absolute;
  left: -27px;
  top: 26px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--rule);
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .about-timeline__item:hover .about-timeline__dot,
.page-about .about-timeline__item:focus-within .about-timeline__dot {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
}

.page-about .about-timeline__year {
  display: block;
  font-size: 20px;
  color: var(--muted);
  letter-spacing: 0.04em;
  transition: color var(--t-fast) var(--ease);
}

.page-about .about-timeline__item:hover .about-timeline__year,
.page-about .about-timeline__item:focus-within .about-timeline__year {
  color: var(--cinnabar);
}

.page-about .about-timeline__title {
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 600;
  color: var(--ink);
  margin: 0 0 8px;
  line-height: 1.5;
}

.page-about .about-timeline__desc {
  color: var(--muted);
  font-size: 14px;
  margin: 0 0 10px;
  max-width: 58ch;
}

.page-about .about-timeline__key {
  margin: 0;
  font-size: 12px;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.page-about .about-timeline__key .tag {
  background: var(--copper-tint);
  color: var(--copper);
  padding: 2px 8px;
  font-size: 11px;
  letter-spacing: 0.06em;
}

.page-about .about-timeline__foot {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: 30px;
  padding-top: 26px;
  border-top: 1px solid var(--rule);
}

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

.page-about .about-timeline__aside p {
  font-size: 14px;
  color: var(--muted);
  margin: 0 0 12px;
  max-width: 52ch;
}

.page-about .about-timeline__link a {
  color: var(--cinnabar);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 2px;
  font-size: 14px;
}

.page-about .about-timeline__link a:hover {
  color: var(--cinnabar-dark);
}

/* ---------- 03 分工 ---------- */
.page-about .about-team__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

.page-about .about-team .chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 20px;
}

.page-about .about-team .chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--ink);
  background: transparent;
  border: 1px solid var(--rule);
  padding: 7px 13px;
  cursor: pointer;
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .about-team .chip:hover {
  background: var(--cinnabar-tint);
  border-color: var(--cinnabar);
}

.page-about .about-team .chip:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 2px;
}

.page-about .about-team .chip[aria-pressed="true"] {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

.page-about .about-team .chip__count {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--copper);
}

.page-about .about-team .chip[aria-pressed="true"] .chip__count {
  color: var(--paper-2);
}

.page-about .about-team__rows {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--rule);
}

.page-about .about-team__row {
  display: grid;
  grid-template-columns: 40px 1fr auto;
  grid-template-areas:
    "no name size"
    "duty duty duty";
  gap: 8px 12px;
  align-items: baseline;
  padding: 16px 0;
  border-bottom: 1px solid var(--rule);
  transition: background var(--t-fast) var(--ease);
}

.page-about .about-team__row:hover {
  background: var(--copper-tint);
}

.page-about .about-team__row[hidden] {
  display: none;
}

.page-about .about-team__no {
  grid-area: no;
  font-size: 12px;
  color: var(--muted);
}

.page-about .about-team__name {
  grid-area: name;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .about-team__size {
  grid-area: size;
  font-size: 13px;
  color: var(--cinnabar);
}

.page-about .about-team__duty {
  grid-area: duty;
  margin: 0;
  font-size: 14px;
  color: var(--muted);
  max-width: 58ch;
}

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

/* ---------- 04 标准 ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 0 0 26px;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .about-flow__step {
  position: relative;
  padding: 18px 0 18px 22px;
  border-top: 1px solid var(--rule);
}

.page-about .about-flow__step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 26px;
  width: 10px;
  height: 1px;
  background: var(--cinnabar);
  transition: width var(--t-mid) var(--ease);
}

.page-about .about-flow__step:hover::before {
  width: 18px;
}

.page-about .about-flow__no {
  font-size: 12px;
  color: var(--copper);
  letter-spacing: 0.08em;
}

.page-about .about-flow__title {
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink);
  margin: 6px 0 8px;
}

.page-about .about-flow__desc {
  margin: 0;
  font-size: 14px;
  color: var(--muted);
  max-width: 48ch;
}

.page-about .about-fold {
  border: 1px solid var(--rule);
  border-left: 3px solid var(--copper);
  background: var(--paper-2);
}

.page-about .about-fold__sum {
  cursor: pointer;
  padding: 14px 18px;
  font-size: 15px;
  color: var(--ink);
  font-weight: 600;
  list-style: none;
}

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

.page-about .about-fold__sum::after {
  content: "＋";
  float: right;
  font-family: var(--font-mono);
  color: var(--cinnabar);
}

.page-about .about-fold[open] .about-fold__sum::after {
  content: "－";
}

.page-about .about-fold__sum:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: -2px;
}

.page-about .about-fold__body {
  padding: 0 18px 16px;
  border-top: 1px solid var(--rule);
}

.page-about .about-fold__body p {
  font-size: 14px;
  color: var(--muted);
  margin: 14px 0 0;
  max-width: 60ch;
}

/* ---------- 05 覆盖与主体 ---------- */
.page-about .about-reach__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

.page-about .about-reach__bars {
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
}

.page-about .about-reach__bar {
  display: grid;
  grid-template-columns: 1fr auto;
  grid-template-areas:
    "label val"
    "track track";
  gap: 6px 12px;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid var(--rule);
}

.page-about .about-reach__label {
  grid-area: label;
  font-size: 14px;
  color: var(--ink);
}

.page-about .about-reach__val {
  grid-area: val;
  font-size: 13px;
  color: var(--muted);
}

.page-about .about-reach__track {
  grid-area: track;
  display: block;
  height: 8px;
  background: var(--paper-2);
  overflow: hidden;
}

.page-about .about-reach__fill {
  display: block;
  height: 100%;
  transition: width var(--t-slow) var(--ease);
}

.page-about .about-reach__fill--a {
  width: 40%;
  background: var(--cinnabar);
}

.page-about .about-reach__fill--b {
  width: 60%;
  background: var(--copper);
}

.page-about .about-reach__note {
  font-size: 13px;
  color: var(--muted);
  max-width: 52ch;
}

.page-about .about-reach__side {
  border: 1px solid var(--rule);
  background: var(--paper-2);
  padding: 18px;
}

.page-about .about-registry {
  margin: 0;
  display: grid;
  gap: 0;
}

.page-about .about-registry__item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 11px 0;
  border-bottom: 1px solid var(--rule);
}

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

.page-about .about-registry dt {
  font-size: 13px;
  color: var(--muted);
}

.page-about .about-registry dd {
  margin: 0;
  font-size: 14px;
  color: var(--ink);
  text-align: right;
}

.page-about .about-registry__hint {
  margin: 14px 0 0;
  font-size: 12px;
  line-height: 1.7;
}

/* ---------- 收尾操作 ---------- */
.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
  padding-top: 26px;
  border-top: 1px solid var(--rule);
}

.page-about .about-actions .btn {
  display: inline-block;
  font-size: 14px;
  padding: 11px 22px;
  text-decoration: none;
  border: 1px solid transparent;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .about-actions .btn--primary {
  background: var(--cinnabar);
  color: var(--paper);
}

.page-about .about-actions .btn--primary:hover {
  background: var(--cinnabar-dark);
}

.page-about .about-actions .btn--ghost {
  background: transparent;
  border-color: var(--rule);
  color: var(--ink);
}

.page-about .about-actions .btn--ghost:hover {
  border-color: var(--ink);
  background: var(--paper-2);
}

.page-about .about-actions .btn--copper {
  background: transparent;
  border-color: var(--copper);
  color: var(--copper);
}

.page-about .about-actions .btn--copper:hover {
  background: var(--copper-tint);
}

.page-about .about-actions .btn:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-timeline__item {
    display: grid;
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: var(--about-row-gap);
    align-items: start;
  }

  .page-about .about-timeline__year {
    font-size: 22px;
    padding-top: 2px;
  }

  .page-about .about-timeline__body {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .about-timeline__list {
    padding-left: 26px;
  }

  .page-about .about-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 32px;
  }

  .page-about .about-timeline__foot {
    grid-template-columns: minmax(0, 5fr) minmax(0, 4fr);
    align-items: start;
  }

  .page-about .about-reach__bar {
    grid-template-columns: 160px minmax(0, 1fr) 96px;
    grid-template-areas: "label track val";
    gap: 14px;
  }

  .page-about .about-reach__val {
    text-align: right;
  }
}

@media (min-width: 960px) {
  .page-about .about-intro {
    padding: 48px 0 40px;
  }

  .page-about .section {
    padding: 60px 0;
  }

  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 40px;
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 40px;
    align-items: start;
  }

  .page-about .about-team__row {
    grid-template-columns: 48px 150px 1fr auto;
    grid-template-areas: "no name duty size";
    align-items: baseline;
    gap: 0 18px;
  }

  .page-about .about-team__duty {
    padding-right: 16px;
  }

  .page-about .about-reach__grid {
    grid-template-columns: minmax(0, 1fr) 320px;
    gap: 40px;
    align-items: start;
  }

  .page-about .about-flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    column-gap: 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__dot,
  .page-about .about-timeline__year,
  .page-about .about-flow__step::before,
  .page-about .about-reach__fill,
  .page-about .about-actions .btn,
  .page-about .about-team .chip {
    transition: none;
  }
}