.page-about {
  --about-line: var(--line);
  --about-line-strong: var(--line-strong);
  position: relative;
  background:
    radial-gradient(960px 460px at 86% -6%, rgba(52, 225, 214, 0.11), transparent 62%),
    radial-gradient(720px 420px at -12% 34%, rgba(255, 111, 94, 0.07), transparent 66%),
    linear-gradient(180deg, var(--ink) 0%, var(--ink-deep) 58%, var(--ink) 100%);
  color: var(--paper);
  padding: 26px 0 92px;
  overflow-x: clip;
}

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

.page-about .about-shell {
  width: 100%;
  max-width: 1220px;
  margin-inline: auto;
  padding-inline: 18px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  max-width: 900px;
  padding-block: clamp(22px, 4.5vw, 52px) 6px;
}

.page-about .eyebrow {
  margin: 16px 0 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.22em;
  color: var(--cyan);
  text-transform: uppercase;
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-size: clamp(29px, 5.6vw, 54px);
  line-height: 1.16;
  font-weight: 900;
  letter-spacing: 0.03em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: 0 0 26px;
  max-width: 36em;
  font-size: clamp(16px, 1.35vw, 18.5px);
  line-height: 1.85;
  color: rgba(242, 239, 230, 0.8);
}

.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .about-stats li {
  background: rgba(19, 41, 74, 0.72);
  padding: 15px 15px 17px;
  transition: background 0.2s ease;
}

.page-about .about-stats li:hover {
  background: rgba(19, 41, 74, 0.95);
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.4vw, 33px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

/* ---------- 图片框 ---------- */
.page-about .image-frame {
  margin: 0;
}

.page-about .about-hero__media {
  margin-top: 32px;
}

.page-about .image-frame__media {
  overflow: hidden;
  border: 1px solid var(--about-line);
  background: var(--ink-deep);
}

.page-about .about-hero__media .image-frame__media img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.page-about .image-frame__caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 章节索引 ---------- */
.page-about .about-index {
  margin: 42px 0 6px;
  border-top: 1px solid var(--about-line);
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-index__head {
  margin: 0;
  padding: 12px 0 4px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px 18px;
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 0;
  font-size: 14px;
  color: rgba(242, 239, 230, 0.72);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--coral);
  outline: none;
}

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

/* ---------- 主体布局 ---------- */
.page-about .about-body {
  margin-top: 38px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 40px;
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding-block: 32px 6px;
  border-top: 1px solid var(--about-line);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 4px;
}

.page-about .section-kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .about-section h2 {
  margin: 13px 0 15px;
  font-size: clamp(22px, 2.9vw, 33px);
  line-height: 1.34;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.page-about .about-section p {
  margin: 0 0 14px;
  max-width: 38em;
  font-size: 17px;
  line-height: 1.8;
  color: rgba(242, 239, 230, 0.76);
}

/* ---------- 折叠细节 ---------- */
.page-about .about-more {
  margin: 20px 0 6px;
  max-width: 44em;
  border: 1px solid var(--about-line);
  background: rgba(19, 41, 74, 0.5);
  padding: 0 18px;
  transition: border-color 0.2s ease;
}

.page-about .about-more:hover {
  border-color: var(--about-line-strong);
}

.page-about .about-more summary {
  cursor: pointer;
  list-style: none;
  padding: 14px 0;
  font-size: 14.5px;
  letter-spacing: 0.03em;
  color: var(--cyan);
}

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

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

.page-about .about-more[open] summary::before {
  content: "\2013";
}

.page-about .about-more summary:focus-visible {
  outline: 1px solid var(--coral);
  outline-offset: 3px;
}

.page-about .about-more p {
  padding-bottom: 14px;
  margin: 0;
  font-size: 15.5px;
  color: rgba(242, 239, 230, 0.72);
}

/* ---------- 四条主线 ---------- */
.page-about .about-threads {
  margin-top: 10px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .thread-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .thread {
  position: relative;
  padding: 18px 18px 18px 22px;
  border: 1px solid var(--about-line);
  background: rgba(11, 26, 46, 0.72);
  transition: border-color 0.2s ease;
}

.page-about .thread::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--thread-color, var(--cyan));
}

.page-about .thread--cyan {
  --thread-color: var(--cyan);
}

.page-about .thread--moss {
  --thread-color: var(--moss);
}

.page-about .thread--gold {
  --thread-color: var(--gold);
}

.page-about .thread--coral {
  --thread-color: var(--coral);
}

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

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

.page-about .thread__title {
  margin: 8px 0 8px;
  font-size: 19px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.page-about .thread__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: rgba(242, 239, 230, 0.7);
}

.page-about .thread__fit {
  display: inline-block;
  margin-top: 11px;
  padding: 3px 9px;
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--cyan);
  border: 1px solid rgba(52, 225, 214, 0.34);
}

.page-about .about-threads__media .image-frame__media img {
  width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

/* ---------- 阶段演进 ---------- */
.page-about .phase-track {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .phase {
  position: relative;
  padding: 0 0 0 20px;
  border-left: 1px solid var(--about-line);
}

.page-about .phase__node {
  display: inline-block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 21px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--coral);
}

.page-about .phase__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.page-about .phase__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(242, 239, 230, 0.68);
}

/* ---------- 团队与覆盖 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.page-about .about-split__media {
  margin-top: 4px;
}

.page-about .about-split__media .image-frame__media img {
  width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .team-figures {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .figure-cell {
  border: 1px solid var(--about-line);
  background: rgba(19, 41, 74, 0.45);
  padding: 15px 14px 17px;
  transition: border-color 0.2s ease;
}

.page-about .figure-cell:hover {
  border-color: var(--about-line-strong);
}

.page-about .figure-cell .data-number {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(23px, 3vw, 31px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--gold);
}

.page-about .figure-cell .data-number--coral {
  color: var(--coral);
}

.page-about .figure-cell__label {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

/* ---------- 迭代节奏 ---------- */
.page-about .cadence-list {
  list-style: none;
  margin: 24px 0 20px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(1, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .cadence-list li {
  background: rgba(11, 26, 46, 0.78);
  padding: 16px 16px 18px;
}

.page-about .cadence-list .data-number {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.2vw, 32px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .cadence-list .data-number--coral {
  color: var(--coral);
}

.page-about .cadence-list__label {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

.page-about .further {
  margin: 0 0 8px;
}

.page-about .further__link {
  display: inline-block;
  font-size: 15px;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(52, 225, 214, 0.35);
  padding-bottom: 2px;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .further__link:hover,
.page-about .further__link:focus-visible {
  color: var(--coral);
  border-bottom-color: var(--coral);
  outline: none;
}

/* ---------- 入口对照表 ---------- */
.page-about .table-wrap {
  margin-top: 22px;
  overflow-x: auto;
  border: 1px solid var(--about-line);
}

.page-about .chooser-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .chooser-table caption {
  caption-side: top;
  text-align: left;
  padding: 13px 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--mist);
  border-bottom: 1px solid var(--about-line);
}

.page-about .chooser-table th,
.page-about .chooser-table td {
  padding: 14px 16px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--about-line);
}

.page-about .chooser-table thead th {
  background: var(--rock);
  color: var(--paper);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.page-about .chooser-table tbody tr {
  background: rgba(11, 26, 46, 0.62);
  transition: background 0.18s ease;
}

.page-about .chooser-table tbody tr:hover {
  background: rgba(52, 225, 214, 0.08);
}

.page-about .chooser-table tbody td {
  color: rgba(242, 239, 230, 0.78);
  line-height: 1.7;
}

.page-about .chooser-table tbody td:first-child {
  color: var(--paper);
}

.page-about .chooser-table a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(52, 225, 214, 0.32);
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .chooser-table a:hover,
.page-about .chooser-table a:focus-visible {
  color: var(--coral);
  border-bottom-color: var(--coral);
  outline: none;
}

/* ---------- 下一步 ---------- */
.page-about .about-next {
  margin-top: 44px;
  padding: 30px 22px 26px;
  border: 1px solid var(--about-line);
  background:
    linear-gradient(115deg, rgba(255, 111, 94, 0.1) 0%, rgba(11, 26, 46, 0) 46%),
    rgba(19, 41, 74, 0.62);
}

.page-about .about-next h2 {
  margin: 13px 0 14px;
  font-size: clamp(21px, 2.6vw, 29px);
  font-weight: 800;
  letter-spacing: 0.03em;
  color: var(--paper);
}

.page-about .about-next p {
  margin: 0 0 22px;
  max-width: 40em;
  font-size: 16.5px;
  line-height: 1.8;
  color: rgba(242, 239, 230, 0.76);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 右侧旁注 ---------- */
.page-about .about-rail {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .about-rail .aside-note {
  position: relative;
  background: rgba(19, 41, 74, 0.74);
  padding: 14px 15px 16px;
  transition: background 0.2s ease;
}

.page-about .about-rail .aside-note:hover,
.page-about .about-rail .aside-note:focus-within {
  background: rgba(19, 41, 74, 0.98);
}

.page-about .aside-note__label {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--mist);
}

.page-about .aside-note__value {
  display: block;
  font-family: var(--font-mono);
  font-size: 25px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--cyan);
  transition: color 0.18s ease;
}

.page-about .about-rail .aside-note:hover .aside-note__value,
.page-about .about-rail .aside-note:focus-within .aside-note__value {
  color: var(--coral);
}

.page-about .aside-note__extra {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .about-index__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

@media (min-width: 700px) {
  .page-about .about-shell {
    padding-inline: 26px;
  }

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

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

  .page-about .about-next {
    padding: 34px 30px 30px;
  }
}

@media (min-width: 760px) {
  .page-about .phase-track {
    border-top: 1px solid var(--about-line);
  }

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

@media (min-width: 900px) {
  .page-about .about-threads {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.78fr);
    gap: 34px;
    align-items: start;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.72fr);
    gap: 34px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    padding-inline: 32px;
  }

  .page-about .about-body {
    grid-template-columns: minmax(0, 1fr) 232px;
    gap: 52px;
    align-items: start;
  }

  .page-about .about-rail {
    grid-template-columns: minmax(0, 1fr);
    position: sticky;
    top: 92px;
  }

  .page-about .aside-note__extra {
    position: absolute;
    left: 8px;
    right: 8px;
    top: calc(100% - 4px);
    z-index: 6;
    margin-top: 0;
    padding: 10px 12px;
    background: var(--rock);
    border: 1px solid var(--about-line-strong);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
  }

  .page-about .about-rail .aside-note:hover .aside-note__extra,
  .page-about .about-rail .aside-note:focus-within .aside-note__extra {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

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

  .page-about .phase {
    padding: 24px 22px 6px 0;
  }

  .page-about .phase + .phase {
    padding-left: 22px;
    box-shadow: inset 1px 0 0 var(--about-line);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__list a,
  .page-about .about-more,
  .page-about .thread,
  .page-about .figure-cell,
  .page-about .further__link,
  .page-about .chooser-table a,
  .page-about .chooser-table tbody tr,
  .page-about .aside-note,
  .page-about .aside-note__value,
  .page-about .aside-note__extra {
    transition: none;
  }
}