.page-about {
  background: var(--abyss);
  color: var(--ice);
  font-family: var(--font-body);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--hairline);
  background: var(--abyss);
}

.page-about .about-hero-visual {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-about .about-hero-visual img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.4;
}

.page-about .about-hero-visual::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(5, 10, 22, 0.55) 0%, rgba(5, 10, 22, 0.86) 58%, var(--abyss) 100%);
}

.page-about .about-hero-cut {
  position: absolute;
  right: -8%;
  top: -10%;
  width: 62%;
  height: 130%;
  background: linear-gradient(155deg, rgba(92, 27, 55, 0.8), rgba(22, 28, 74, 0.25) 55%, transparent 78%);
  clip-path: polygon(34% 0, 100% 0, 100% 100%, 0 100%);
  transform: rotate(-5deg);
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
  padding-top: 6.5rem;
  padding-bottom: 3rem;
}

.page-about .about-hero-inner .breadcrumb {
  margin-bottom: 1.75rem;
}

.page-about .about-hero-inner h1 {
  margin: 0.5rem 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2rem, 7vw, 3.6rem);
  line-height: 1.18;
  letter-spacing: -0.02em;
  color: var(--ice);
  max-width: 18em;
}

.page-about .about-hero-lead {
  margin: 1.25rem 0 0;
  max-width: 34em;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-hero-stats {
  list-style: none;
  margin: 2.25rem 0 0;
  padding: 1.5rem 0 0;
  border-top: 1px solid var(--hairline);
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.page-about .about-hero-stats li {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.page-about .about-stat-num {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--cyan);
  line-height: 1;
}

.page-about .about-stat-label {
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--mist);
  letter-spacing: 0.02em;
}

/* ---------- 双栏骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2.5rem;
  padding-block: 2.75rem 4rem;
}

/* ---------- 章节索引 ---------- */
.page-about .about-side {
  border-left: 1px solid var(--hairline);
  padding-left: 1rem;
}

.page-about .about-side-title {
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--mist);
  text-transform: uppercase;
}

.page-about .about-side-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.page-about .about-side-list a {
  display: block;
  font-size: 0.875rem;
  line-height: 1.5;
  color: var(--mist);
  text-decoration: none;
  padding-left: 0.75rem;
  border-left: 2px solid transparent;
  margin-left: -1rem;
  padding-top: 0.15rem;
  padding-bottom: 0.15rem;
  transition: color 180ms ease, border-color 180ms ease;
}

.page-about .about-side-list a:hover,
.page-about .about-side-list a:focus-visible {
  color: var(--cyan);
  border-left-color: var(--cyan);
}

.page-about .about-side-scale {
  display: none;
  align-items: flex-end;
  gap: 0.3rem;
  height: 2.75rem;
  margin-top: 1.75rem;
}

.page-about .about-scale-bar {
  width: 0.4rem;
  background: var(--hairline);
}

.page-about .about-side-scale .about-scale-bar:nth-child(1) { height: 28%; }
.page-about .about-side-scale .about-scale-bar:nth-child(2) { height: 45%; }
.page-about .about-side-scale .about-scale-bar:nth-child(3) { height: 62%; }
.page-about .about-side-scale .about-scale-bar:nth-child(4) { height: 78%; }
.page-about .about-side-scale .about-scale-bar:nth-child(5) { height: 100%; background: var(--cyan); }

.page-about .about-side-meta {
  margin: 0.6rem 0 0;
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--mist);
}

/* ---------- 章节通用 ---------- */
.page-about .about-chapter + .about-chapter {
  margin-top: 3rem;
}

.page-about .about-chapter-head {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--hairline);
  margin-bottom: 1.5rem;
}

.page-about .about-chapter-head::before {
  content: "";
  flex: none;
  width: 0.55rem;
  height: 1.5rem;
  background: var(--orange);
  clip-path: polygon(0 0, 100% 0, 100% 76%, 0 100%);
  transform: translateY(0.1rem);
}

.page-about .about-chapter-num {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .about-chapter-head h2 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(1.375rem, 4.4vw, 1.875rem);
  line-height: 1.4;
  color: var(--ice);
  letter-spacing: 0.01em;
  transition: color 220ms ease;
}

.page-about .about-chapter:target .about-chapter-head h2 {
  color: var(--cyan);
}

.page-about .about-chapter-body > p {
  margin: 0 0 1.2em;
  max-width: 36em;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-chapter-body > p:last-child {
  margin-bottom: 0;
}

/* 带色温的分区 */
.page-about .about-chapter--indigo {
  background: linear-gradient(170deg, rgba(22, 28, 74, 0.92), rgba(22, 28, 74, 0.4) 85%);
  padding: 1.5rem 1.15rem 1.75rem;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

.page-about .about-chapter--teal {
  background: linear-gradient(170deg, rgba(6, 42, 46, 0.95), rgba(6, 42, 46, 0.45) 85%);
  padding: 1.5rem 1.15rem 1.75rem;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 22px 100%, 0 calc(100% - 22px));
}

.page-about .about-chapter--indigo .about-chapter-head::before,
.page-about .about-chapter--teal .about-chapter-head::before {
  background: var(--amber);
}

/* ---------- 三项能力 ---------- */
.page-about .about-capabilities {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.5rem;
}

.page-about .about-capabilities li {
  padding-top: 1rem;
  border-top: 2px solid var(--hairline);
}

.page-about .about-capabilities li:first-child {
  border-top-color: var(--orange);
}

.page-about .about-capabilities h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
  color: var(--ice);
}

.page-about .about-capabilities p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 版本时间轴 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0 0 0 1.4rem;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.6rem;
  bottom: 0.6rem;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), var(--hairline) 70%);
}

.page-about .about-ver {
  position: relative;
  padding-bottom: 1.1rem;
}

.page-about .about-ver::before {
  content: "";
  position: absolute;
  left: -1.4rem;
  top: 0.55rem;
  width: 8px;
  height: 8px;
  background: var(--cyan);
  transform: translateX(-50%) rotate(45deg);
}

.page-about .about-ver:last-child {
  padding-bottom: 0;
}

.page-about .about-ver:last-child::before {
  background: var(--orange);
}

.page-about .about-ver summary {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  cursor: pointer;
  list-style: none;
  padding: 0.5rem 1.9rem 0.5rem 0;
  position: relative;
  border-bottom: 1px solid var(--hairline);
}

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

.page-about .about-ver summary::after {
  content: "＋";
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--cyan);
}

.page-about .about-ver[open] summary::after {
  content: "－";
}

.page-about .about-ver-tag {
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--cyan);
  letter-spacing: 0.04em;
  line-height: 1.2;
}

.page-about .about-ver:nth-child(1) .about-ver-tag { font-size: 1rem; }
.page-about .about-ver:nth-child(2) .about-ver-tag { font-size: 1.15rem; }
.page-about .about-ver:nth-child(3) .about-ver-tag { font-size: 1.3rem; }
.page-about .about-ver:nth-child(4) .about-ver-tag { font-size: 1.5rem; }
.page-about .about-ver:nth-child(5) .about-ver-tag { font-size: 1.75rem; color: var(--orange); }

.page-about .about-ver-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9375rem;
  line-height: 1.5;
  color: var(--ice);
  letter-spacing: 0.01em;
}

.page-about .about-ver details p {
  margin: 0.65rem 0 0.35rem;
  padding-left: 0.15rem;
  max-width: 34em;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--mist);
}

/* ---------- 团队分工 ---------- */
.page-about .about-team {
  margin: 1.75rem 0 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.1rem;
}

.page-about .about-team-row {
  padding-top: 0.9rem;
  border-top: 1px solid var(--hairline);
}

.page-about .about-team-row dt {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9375rem;
  color: var(--ice);
  letter-spacing: 0.02em;
}

.page-about .about-team-count {
  font-family: var(--font-mono);
  font-size: 1.375rem;
  font-weight: 500;
  color: var(--orange);
  line-height: 1;
}

.page-about .about-team-row dd {
  margin: 0.45rem 0 0;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--mist);
  max-width: 34em;
}

.page-about .about-quote {
  margin: 2rem 0 0;
  padding-left: 1.1rem;
  border-left: 2px solid var(--cyan);
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(1.125rem, 3.4vw, 1.5rem);
  line-height: 1.65;
  color: var(--ice);
}

/* ---------- 数据章节 ---------- */
.page-about .about-chapter-body--split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.75rem;
  align-items: start;
}

.page-about .about-chapter-text p {
  margin: 0 0 1.1em;
  max-width: 34em;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-chapter-text p:last-child {
  margin-bottom: 0;
}

/* ---------- 图版 ---------- */
.page-about .about-figure {
  margin: 0;
}

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

.page-about .about-figure--cut img {
  clip-path: polygon(0 0, 100% 0, 100% 100%, 26px 100%, 0 calc(100% - 26px));
}

.page-about .about-figure--wide {
  margin-top: 1.75rem;
}

.page-about .about-figure .media-caption {
  margin-top: 0.65rem;
  font-size: 0.75rem;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 标准清单 ---------- */
.page-about .about-standards {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.15rem;
}

.page-about .about-standards li {
  display: grid;
  gap: 0.35rem;
  padding-left: 0.9rem;
  border-left: 2px solid var(--hairline);
}

.page-about .about-standards li:nth-child(2) {
  border-left-color: var(--cyan);
}

.page-about .about-standards strong {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9375rem;
  color: var(--ice);
  letter-spacing: 0.02em;
}

.page-about .about-standards span {
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--mist);
  max-width: 34em;
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  margin-top: 3rem;
  padding: 1.75rem 1.15rem;
  background: var(--panel);
  border-top: 2px solid var(--orange);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 22px 100%, 0 calc(100% - 22px));
}

.page-about .about-cta h2 {
  margin: 0 0 0.75rem;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(1.25rem, 4vw, 1.625rem);
  line-height: 1.4;
  color: var(--ice);
}

.page-about .about-cta p {
  margin: 0;
  max-width: 34em;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-cta-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.85rem 1.25rem;
  margin-top: 1.5rem;
}

.page-about .about-textlink {
  font-size: 0.875rem;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 180ms ease;
}

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

.page-about .about-toplink-row {
  margin-top: 1.5rem;
}

.page-about .about-toplink {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px dashed var(--hairline);
}

.page-about .about-toplink:hover,
.page-about .about-toplink:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 窄屏收口 ---------- */
@media (max-width: 359px) {
  .page-about .about-hero-inner h1 {
    font-size: 1.75rem;
  }

  .page-about .about-cta {
    padding-left: 0.9rem;
    padding-right: 0.9rem;
  }
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero-inner {
    padding-top: 7.5rem;
    padding-bottom: 3.75rem;
  }

  .page-about .about-hero-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
  }

  .page-about .about-capabilities {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
  }

  .page-about .about-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.35rem 2rem;
  }

  .page-about .about-standards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.5rem 2rem;
  }

  .page-about .about-chapter--indigo,
  .page-about .about-chapter--teal {
    padding: 2rem 1.75rem 2.25rem;
  }

  .page-about .about-cta {
    padding: 2.25rem 2rem;
  }
}

/* ---------- 桌面：双栏错位长文 ---------- */
@media (min-width: 960px) {
  .page-about .about-layout {
    grid-template-columns: 216px minmax(0, 1fr);
    gap: 4rem;
    padding-block: 4.25rem 5.5rem;
  }

  .page-about .about-side {
    position: sticky;
    top: 5.5rem;
    align-self: start;
    padding-left: 1.15rem;
  }

  .page-about .about-side-scale {
    display: flex;
  }

  .page-about .about-chapter + .about-chapter {
    margin-top: 4rem;
  }

  .page-about .about-chapter--indigo {
    margin-left: -1.5rem;
    padding: 2.25rem 2rem 2.5rem;
  }

  .page-about .about-chapter--teal {
    margin-right: -1.5rem;
    padding: 2.25rem 2rem 2.5rem;
  }

  .page-about .about-chapter-body--split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 2.5rem;
    align-items: start;
  }

  .page-about .about-chapter-body > p {
    font-size: 1.0625rem;
  }

  .page-about .about-cta {
    margin-left: -1.5rem;
    padding: 2.5rem 2.25rem;
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero-inner h1 {
    font-size: 3.6rem;
  }

  .page-about .about-hero-lead {
    font-size: 1.0625rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-side-list a,
  .page-about .about-chapter-head h2,
  .page-about .about-textlink {
    transition: none;
  }
}