.page-about {
  --about-line: rgba(92, 107, 103, 0.28);
  --about-line-soft: rgba(92, 107, 103, 0.16);
  padding-bottom: clamp(48px, 8vw, 120px);
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
  list-style: none;
  margin: 0;
  padding: clamp(16px, 3vw, 28px) 0 0;
  font-size: 12px;
  color: var(--rule);
  letter-spacing: 0.06em;
}

.page-about .breadcrumb li + li::before {
  content: "/";
  margin-right: 12px;
  color: var(--rule);
}

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

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: clamp(24px, 4vw, 48px);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.page-about .about-hero__frame {
  position: relative;
  background: var(--panel);
  border: var(--hair);
  padding: clamp(24px, 4vw, 48px) clamp(20px, 4vw, 44px);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

.page-about .about-hero__corner {
  position: absolute;
  width: 14px;
  height: 14px;
  border: 1px solid var(--accent);
  opacity: 0.7;
}

.page-about .about-hero__corner--tl { top: 10px; left: 10px; border-right: 0; border-bottom: 0; }
.page-about .about-hero__corner--tr { top: 10px; right: 10px; border-left: 0; border-bottom: 0; }
.page-about .about-hero__corner--bl { bottom: 10px; left: 10px; border-right: 0; border-top: 0; }
.page-about .about-hero__corner--br { bottom: 10px; right: 10px; border-left: 0; border-top: 0; }

.page-about .about-hero__title {
  margin: 18px 0 0;
  font-family: var(--font-head);
  font-weight: 200;
  font-size: clamp(40px, 8vw, 92px);
  line-height: 0.96;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.page-about .about-hero__title em {
  font-style: normal;
  color: var(--accent);
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 56ch;
  color: var(--silver);
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
}

.page-about .about-hero__keys {
  list-style: none;
  margin: 32px 0 0;
  padding: 18px 0 0;
  border-top: var(--hair);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 20px;
}

.page-about .about-hero__keys li {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .about-hero__keys .mono {
  font-family: var(--font-num);
  font-size: 34px;
  font-weight: 600;
  line-height: 1;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

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

.page-about .about-hero__media {
  margin: 0;
  position: relative;
  border: var(--hair);
  background: var(--deep);
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  filter: saturate(0.85) contrast(1.05);
}

.page-about .about-hero__caption {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 12px 16px;
  border-top: var(--hair);
  font-size: 12px;
  color: var(--rule);
  letter-spacing: 0.04em;
}

/* ---------- 页内索引 ---------- */

.page-about .about-toc {
  margin-top: clamp(32px, 5vw, 56px);
  border-top: var(--hair);
  padding-top: 18px;
}

.page-about .about-toc ol {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--about-line-soft);
}

.page-about .about-toc li {
  background: var(--bg);
}

.page-about .about-toc a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 14px;
  color: var(--silver);
  text-decoration: none;
  font-size: 13px;
  border-left: 2px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-toc a .mono {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--rule);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--ink);
  border-left-color: var(--accent);
  background: var(--panel);
}

.page-about .about-toc a:hover .mono,
.page-about .about-toc a:focus-visible .mono {
  color: var(--warn);
}

/* ---------- 章节骨架 ---------- */

.page-about .about-sec {
  position: relative;
  padding: clamp(52px, 8vw, 104px) 0;
  border-top: var(--hair-soft);
}

.page-about .about-sec::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: clamp(56px, 14%, 190px);
  height: 2px;
  background: var(--accent);
  opacity: 0.6;
}

.page-about .about-sec--band {
  background: var(--panel);
}

.page-about .about-sec--timeline {
  background: var(--bg);
}

.page-about .about-sec--end {
  background: var(--deep);
}

.page-about .about-sec__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  border-left: 2px solid var(--accent);
  padding-left: 14px;
}

.page-about .about-sec__index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--warn);
}

.page-about .about-sec__title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 300;
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1.2;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.page-about .about-sec__body {
  max-width: 72ch;
}

.page-about .about-sec__lead {
  margin: 0 0 24px;
  color: var(--silver);
  font-size: 16px;
  line-height: 1.8;
  border-left: 1px solid var(--about-line);
  padding-left: 16px;
}

.page-about .about-sec__body.prose p {
  margin: 0 0 18px;
  color: var(--silver);
  font-size: 15.5px;
  line-height: 1.85;
}

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

.page-about .about-sec__aside {
  margin-top: 28px !important;
  padding-top: 16px;
  border-top: var(--hair-soft);
  font-size: 14px;
  color: var(--rule);
}

.page-about .about-sec__aside .eyebrow {
  display: block;
  margin-bottom: 8px;
}

/* ---------- 字段清单 ---------- */

.page-about .about-fields {
  list-style: none;
  margin: 24px 0;
  padding: 0;
  border-top: var(--hair);
}

.page-about .about-fields li {
  display: grid;
  grid-template-columns: minmax(0, 96px) 1fr;
  gap: 12px;
  padding: 12px 0;
  border-bottom: var(--hair-soft);
  font-size: 14px;
  color: var(--silver);
  line-height: 1.7;
}

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

/* ---------- 流程步骤条 ---------- */

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--about-line-soft);
  counter-reset: step;
}

.page-about .about-steps__item {
  position: relative;
  background: var(--panel-2);
  padding: 20px 20px 22px 34px;
  transition: background-color var(--dur) var(--ease);
}

.page-about .about-steps__dot {
  position: absolute;
  left: 10px;
  top: 24px;
  width: 8px;
  height: 8px;
  background: var(--warn);
  transition: background-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-steps__item::before {
  content: "";
  position: absolute;
  left: 13.5px;
  top: 32px;
  bottom: -1px;
  width: 1px;
  background: var(--about-line);
}

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

.page-about .about-steps__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--rule);
}

.page-about .about-steps__name {
  margin: 8px 0 6px;
  font-family: var(--font-head);
  font-weight: 500;
  font-size: 17px;
  color: var(--ink);
  letter-spacing: 0.02em;
}

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

.page-about .about-steps__item:hover,
.page-about .about-steps__item:focus-within {
  background: #16402f;
}

.page-about .about-steps__item:hover .about-steps__dot,
.page-about .about-steps__item:focus-within .about-steps__dot {
  background: var(--accent);
  transform: scale(1.35);
}

/* ---------- 图片说明牌 ---------- */

.page-about .about-process-fig,
.page-about .about-stand-fig {
  margin: 34px 0 0;
  border: var(--hair);
  background: var(--deep);
}

.page-about .about-process-fig img,
.page-about .about-stand-fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  filter: saturate(0.8) brightness(0.92);
}

.page-about .about-stand-fig img {
  aspect-ratio: 16 / 7;
}

.page-about .about-process-fig .media__caption,
.page-about .about-stand-fig .media__caption {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 12px 16px;
  border-top: var(--hair);
  font-size: 12px;
  color: var(--rule);
  letter-spacing: 0.04em;
}

/* ---------- 沿革刻度带 ---------- */

.page-about .about-timeline {
  margin-top: 24px;
  border-top: var(--hair-strong);
  border-bottom: var(--hair-strong);
  padding: 18px 0 24px;
  position: relative;
}

.page-about .about-timeline__axis {
  display: flex;
  justify-content: space-between;
  padding: 0 4px 12px;
  border-bottom: var(--hair-soft);
}

.page-about .about-timeline__tick {
  width: 1px;
  height: 10px;
  background: var(--accent);
  opacity: 0.55;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 18px 0 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--about-line-soft);
}

.page-about .about-timeline__item {
  background: var(--bg);
  padding: 18px 16px;
  position: relative;
  border-left: 2px solid transparent;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
  outline-offset: -2px;
}

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

.page-about .about-timeline__phase {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--rule);
  transition: color var(--dur) var(--ease);
}

.page-about .about-timeline__item:hover .about-timeline__phase,
.page-about .about-timeline__item:focus-visible .about-timeline__phase {
  color: var(--warn);
}

.page-about .about-timeline__name {
  margin: 8px 0 6px;
  font-family: var(--font-head);
  font-weight: 500;
  font-size: 16px;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.page-about .about-timeline__item p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--silver);
}

/* ---------- 团队表 ---------- */

.page-about .about-team caption {
  text-align: left;
  padding: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--rule);
}

.page-about .about-team th,
.page-about .about-team td {
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  letter-spacing: 0.02em;
}

.page-about .about-team tbody th {
  color: var(--ink);
  font-weight: 500;
}

.page-about .about-team tbody td:nth-child(2) {
  color: var(--accent);
  font-weight: 600;
  white-space: nowrap;
}

/* ---------- 折叠区 ---------- */

.page-about .about-fold {
  margin-top: 14px;
  border: var(--hair);
  background: var(--panel);
}

.page-about .about-fold summary {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  align-items: baseline;
  justify-content: space-between;
  padding: 14px 18px;
  cursor: pointer;
  font-size: 14px;
  color: var(--ink);
  list-style: none;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

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

.page-about .about-fold summary::before {
  content: "+";
  display: inline-block;
  margin-right: 10px;
  color: var(--accent);
  font-family: var(--font-mono);
}

.page-about .about-fold[open] summary::before {
  content: "−";
}

.page-about .about-fold summary:hover,
.page-about .about-fold summary:focus-visible {
  background: var(--panel-2);
}

.page-about .about-fold .fold__count {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--rule);
}

.page-about .about-fold .fold__body {
  padding: 4px 18px 18px 42px;
}

.page-about .about-fold .fold__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--silver);
}

/* ---------- 联系表 ---------- */

.page-about .about-contact {
  margin: 26px 0;
  border-top: var(--hair);
}

.page-about .about-contact__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 14px 0;
  border-bottom: var(--hair-soft);
}

.page-about .about-contact__key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--warn);
}

.page-about .about-contact__val {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--ink);
  letter-spacing: 0.02em;
  word-break: break-word;
}

.page-about .about-contact__note {
  font-size: 12.5px;
  color: var(--rule);
  line-height: 1.7;
}

/* ---------- 响应式 ---------- */

@media (min-width: 700px) {
  .page-about .about-toc ol {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-contact__row {
    grid-template-columns: 64px minmax(0, 1fr) minmax(0, 1fr);
    align-items: baseline;
    gap: 14px;
  }

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

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

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 32px;
    align-items: stretch;
  }

  .page-about .about-hero__keys {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-sec__grid {
    grid-template-columns: 92px minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .about-sec__head {
    position: sticky;
    top: 32px;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    border-left: 0;
    padding-left: 0;
    border-top: 2px solid var(--accent);
    padding-top: 16px;
  }

  .page-about .about-sec__title {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    font-size: clamp(20px, 2vw, 26px);
    letter-spacing: 0.16em;
    line-height: 1;
  }

  .page-about .about-toc ol {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-steps__item::before {
    left: auto;
    right: -1px;
    top: 27px;
    bottom: auto;
    width: 1px;
    height: calc(100% + 1px);
    left: 13.5px;
    right: auto;
  }

  .page-about .about-timeline__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1200px) {
  .page-about .about-timeline__list {
    grid-template-columns: repeat(7, minmax(0, 1fr));
  }

  .page-about .about-toc ol {
    grid-template-columns: repeat(7, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc a,
  .page-about .about-steps__item,
  .page-about .about-steps__dot,
  .page-about .about-timeline__item,
  .page-about .about-timeline__phase,
  .page-about .about-fold summary {
    transition: none;
  }
}
</main>