.page-about {
  --about-shadow: 0 18px 42px rgba(0, 0, 0, 0.36);
  --about-gap: clamp(18px, 3vw, 30px);
  background-color: var(--ink);
  color: var(--paper);
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .about-hero {
  padding-block: clamp(22px, 4vw, 40px) clamp(24px, 4vw, 44px);
  border-bottom: 1px solid var(--line-dim);
}

.page-about .about-hero h1 {
  margin: 10px 0 16px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 5.2vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lead {
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-hero__chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-hero__chips li {
  padding: 6px 12px;
  font-size: 13px;
  color: var(--paper);
  background-color: var(--panel);
  border: 1px solid var(--line-warm);
  clip-path: var(--clip-cut);
}

.page-about .about-shell {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  margin-top: clamp(24px, 4vw, 44px);
}

/* ---------- 章节索引 ---------- */
.page-about .about-index {
  align-self: start;
}

.page-about .about-index__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
  text-transform: uppercase;
}

.page-about .about-index__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

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

.page-about .about-index__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px 8px 14px;
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  background-color: var(--panel-deep);
  border-left: 3px solid var(--line-warm);
  clip-path: var(--clip-cut);
  transition: color 160ms ease-out, border-color 160ms ease-out, background-color 160ms ease-out;
}

.page-about .about-index__link .num {
  color: var(--cyan);
  font-size: 12px;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--paper);
  background-color: var(--panel);
  border-left-color: var(--orange);
}

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

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding-block: clamp(22px, 3.4vw, 36px) 0;
}

.page-about .about-sec__num {
  margin: 0;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--orange);
}

.page-about .about-sec__h {
  margin: 8px 0 16px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 3.4vw, 30px);
  line-height: 1.22;
  letter-spacing: -0.01em;
}

.page-about .about-sec__lead {
  max-width: 60ch;
  margin: 0 0 18px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-sec__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .about-sec__grid p {
  margin: 0;
  padding: 14px 16px;
  font-size: 15.5px;
  line-height: 1.8;
  background-color: var(--panel);
  border-left: 3px solid var(--line-cool);
  clip-path: var(--clip-cut);
}

.page-about .about-sec a {
  color: var(--orange-soft);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

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

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0;
  position: relative;
  border: 1px solid var(--line-warm);
  clip-path: var(--clip-cut);
  background-color: var(--panel-deep);
  box-shadow: var(--about-shadow);
}

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

.page-about .about-figure figcaption {
  padding: 10px 14px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
  background-color: var(--panel);
  border-top: 1px solid var(--line-dim);
}

.page-about .about-figure--band {
  margin-bottom: 22px;
}

/* ---------- 时间轴 ---------- */
.page-about .tl {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .tl-node {
  position: relative;
  padding-left: 22px;
  border-left: 2px solid var(--line-warm);
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 20px;
  width: 12px;
  height: 12px;
  background: var(--grad-warm);
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(255, 122, 24, 0.16);
}

.page-about .tl-node details {
  background-color: var(--panel);
  border: 1px solid var(--line-dim);
  clip-path: var(--clip-cut);
  transition: border-color 180ms ease-out;
}

.page-about .tl-node details[open] {
  border-color: var(--line-warm);
}

.page-about .tl-node summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .tl-node summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

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

.page-about .tl-node__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  color: var(--paper);
}

.page-about .tl-node__body {
  padding: 0 16px 16px;
  border-top: 1px solid var(--line-dim);
  margin-top: 2px;
  padding-top: 12px;
}

.page-about .tl-node__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .tl-node details[open] .tl-node__name {
  color: var(--orange-soft);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.page-about .about-team__h {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 17px;
  color: var(--paper);
}

.page-about .about-team__text p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-list {
  margin: 0 0 18px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.page-about .about-list li {
  padding: 10px 14px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
  background-color: var(--panel-deep);
  border-left: 3px solid var(--purple);
}

.page-about .about-list strong {
  color: var(--paper);
  font-weight: 500;
}

.page-about .about-team__link {
  padding: 12px 14px;
  background: linear-gradient(100deg, rgba(75, 46, 158, 0.34), rgba(18, 41, 31, 0.9));
  border-left: 3px solid var(--orange);
  font-size: 14.5px;
  line-height: 1.75;
}

/* ---------- 数据一览 ---------- */
.page-about .about-statwrap {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .about-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.page-about .about-chip {
  padding: 6px 14px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--paper);
  text-decoration: none;
  background-color: var(--panel);
  border: 1px solid var(--line-cool);
  clip-path: var(--clip-cut);
  transition: color 160ms ease-out, border-color 160ms ease-out;
}

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

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

.page-about .about-statgroup {
  margin-bottom: 16px;
  padding: 14px 16px 6px;
  background-color: var(--panel);
  border-top: 2px solid var(--orange);
  clip-path: var(--clip-cut);
  scroll-margin-top: 90px;
}

.page-about .about-statgroup:nth-of-type(3) {
  border-top-color: var(--purple);
}

.page-about .about-statgroup:nth-of-type(4) {
  border-top-color: var(--cyan);
}

.page-about .about-statgroup__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .about-statgroup__title .num {
  color: var(--orange);
  margin-right: 8px;
}

.page-about .about-stats {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-bottom: 10px;
  border-bottom: 1px dashed var(--line-dim);
}

.page-about .about-stats__v {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(22px, 3.6vw, 28px);
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-stats__k {
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 合作 ---------- */
.page-about .about-cols {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .about-cols__item {
  padding: 16px;
  background-color: var(--panel-deep);
  border: 1px solid var(--line-dim);
  clip-path: var(--clip-cut);
}

.page-about .about-cols__item p {
  margin: 0 0 12px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-steps {
  margin: 0 0 14px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
  counter-reset: step;
}

.page-about .about-steps li {
  display: grid;
  grid-template-columns: 26px 1fr;
  gap: 10px;
  align-items: start;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-steps li .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  font-size: 12.5px;
  color: var(--ink);
  background: var(--grad-warm);
  clip-path: polygon(0 0, 100% 0, 100% 70%, 70% 100%, 0 100%);
}

/* ---------- 承诺与联系 ---------- */
.page-about .about-promise {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
}

.page-about .about-promise__card {
  padding: 16px;
  background-color: var(--panel);
  border-top: 2px solid var(--orange);
  clip-path: var(--clip-cut);
}

.page-about .about-promise__card:nth-child(2) {
  border-top-color: var(--purple);
}

.page-about .about-promise__card:nth-child(3) {
  border-top-color: var(--cyan);
}

.page-about .about-promise__tag {
  display: inline-block;
  margin-bottom: 8px;
  padding: 3px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--paper);
  background-color: var(--purple-deep);
  clip-path: var(--clip-cut);
}

.page-about .about-promise__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-contact {
  padding: 18px;
  background:
    var(--tiger),
    linear-gradient(120deg, rgba(75, 46, 158, 0.42), rgba(18, 41, 31, 0.94) 64%);
  border: 1px solid var(--line-warm);
  clip-path: var(--clip-cut);
}

.page-about .about-contact__main p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--paper);
}

.page-about .about-contact__list {
  margin: 0 0 16px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.page-about .about-contact__list li {
  display: grid;
  gap: 2px;
  padding-bottom: 8px;
  border-bottom: 1px dashed var(--line-dim);
}

.page-about .about-contact__k {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--orange-soft);
}

.page-about .about-contact__v {
  font-size: 15px;
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .about-sec__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .page-about .about-promise__card:nth-child(1) {
    transform: translateY(0);
  }

  .page-about .about-promise__card:nth-child(2) {
    transform: translateY(10px);
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
    gap: 24px;
  }

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

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: clamp(24px, 3.4vw, 48px);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: 88px;
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 4px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-index__link {
    display: flex;
    width: 100%;
    padding: 9px 12px 9px 13px;
    white-space: normal;
    background-color: transparent;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    background-color: var(--panel);
  }

  .page-about .about-statwrap {
    grid-template-columns: minmax(0, 0.86fr) minmax(0, 1.14fr);
    align-items: start;
    gap: 24px;
  }

  .page-about .about-figure--stat {
    position: sticky;
    top: 88px;
  }

  /* 时间轴：中心轨道 + 左右交错 */
  .page-about .tl {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 56px;
    row-gap: 14px;
  }

  .page-about .tl::before {
    content: "";
    position: absolute;
    left: 50%;
    top: 6px;
    bottom: 6px;
    width: 2px;
    transform: translateX(-1px);
    background: linear-gradient(180deg, var(--orange), var(--purple) 58%, var(--cyan));
    opacity: 0.55;
  }

  .page-about .tl-node {
    padding-left: 0;
    border-left: 0;
  }

  .page-about .tl-node:nth-child(odd) {
    grid-column: 1;
    padding-right: 8px;
  }

  .page-about .tl-node:nth-child(even) {
    grid-column: 2;
    padding-left: 8px;
    margin-top: 26px;
  }

  .page-about .tl-node:nth-child(7) {
    margin-top: 8px;
  }

  .page-about .tl-node::before {
    top: 22px;
    left: auto;
    right: -6px;
  }

  .page-about .tl-node:nth-child(even)::before {
    right: auto;
    left: -6px;
  }

  .page-about .tl-node::after {
    content: "";
    position: absolute;
    top: 26px;
    right: -26px;
    width: 26px;
    height: 1px;
    background: var(--line-warm);
    transform: rotate(-22deg);
    transform-origin: right center;
  }

  .page-about .tl-node:nth-child(even)::after {
    right: auto;
    left: -26px;
    transform: rotate(22deg);
    transform-origin: left center;
  }

  .page-about .about-sec__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .about-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px 20px;
  }

  .page-about .about-promise__card:nth-child(3) {
    transform: translateY(20px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .tl-node details,
  .page-about .about-chip {
    transition: none;
  }
}