.page-about {
  --about-shadow: 8px 8px 0 0 var(--navy-800);
  --about-rule: 1px solid var(--haze);
  background: var(--navy-950);
}

/* ---------- 首屏封面 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(2rem, 7vw, 4.5rem) 0 clamp(2.25rem, 6vw, 3.5rem);
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(0, 229, 255, 0.16), transparent 58%),
    linear-gradient(158deg, var(--navy-900), var(--navy-950) 64%);
  border-bottom: 1px solid var(--navy-700);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(27, 69, 102, 0.35) 1px, transparent 1px),
    linear-gradient(90deg, rgba(27, 69, 102, 0.35) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.55), transparent 78%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.55), transparent 78%);
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .breadcrumb-list {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--steel);
}

.page-about .about-hero .breadcrumb-list a {
  color: var(--cyan-300);
}

.page-about .about-kicker {
  margin: 1.25rem 0 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.22em;
  color: var(--amber-500);
}

.page-about .about-title {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: clamp(2rem, 6.4vw, 4rem);
  line-height: 1.06;
  letter-spacing: -0.035em;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .about-lead {
  margin: 1.25rem 0 0;
  max-width: 62ch;
  font-size: clamp(0.98rem, 1.9vw, 1.1rem);
  line-height: 1.85;
  color: var(--steel);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.25rem;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--navy-700);
}

.page-about .about-fact {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  min-width: 0;
}

.page-about .about-fact-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  color: var(--amber-300);
  letter-spacing: -0.02em;
}

.page-about .about-fact-label {
  font-size: 0.8rem;
  line-height: 1.5;
  color: var(--steel);
}

/* ---------- 主体布局 ---------- */
.page-about .about-layout {
  display: grid;
  gap: 1.5rem;
  padding-top: clamp(1.75rem, 5vw, 3rem);
  padding-bottom: clamp(2.5rem, 7vw, 5rem);
}

/* ---------- 章节索引 ---------- */
.page-about .about-toc {
  padding: 0.75rem;
  background: rgba(10, 27, 46, 0.72);
  border: var(--edge);
  border-radius: var(--radius);
}

.page-about .about-toc-title {
  margin: 0 0 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  color: var(--steel);
}

.page-about .about-toc-list {
  display: flex;
  gap: 0.5rem;
  margin: 0;
  padding: 0 0 0.25rem;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-toc-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.65rem;
  white-space: nowrap;
  font-size: 0.85rem;
  color: var(--steel);
  text-decoration: none;
  border: 1px solid var(--navy-700);
  border-radius: var(--radius);
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background-color 0.2s var(--ease);
}

.page-about .about-toc-num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--amber-500);
}

.page-about .about-toc-link:hover,
.page-about .about-toc-link:focus-visible {
  color: var(--cyan-300);
  border-color: var(--cyan-500);
  background: rgba(0, 229, 255, 0.08);
  outline: none;
}

.page-about .about-toc-link[aria-current="true"],
.page-about .about-toc-link[aria-current="location"] {
  color: var(--cyan-300);
  border-color: var(--cyan-500);
  background: rgba(0, 229, 255, 0.1);
}

/* ---------- 章节块 ---------- */
.page-about .about-content {
  display: grid;
  gap: clamp(1.25rem, 3.5vw, 2rem);
  min-width: 0;
}

.page-about .about-block {
  position: relative;
  padding: clamp(1.25rem, 4.5vw, 2.75rem);
  border-radius: var(--radius);
  scroll-margin-top: 1.5rem;
}

.page-about .about-block--paper {
  background: var(--paper);
  color: var(--navy-900);
  border: 2px solid var(--haze);
  box-shadow: var(--about-shadow);
}

.page-about .about-block--paper::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 0;
  height: 0;
  border-top: 26px solid var(--haze);
  border-left: 26px solid transparent;
}

.page-about .about-block--dark {
  background: linear-gradient(152deg, var(--navy-900), var(--navy-800));
  color: var(--paper);
  border: var(--edge);
  box-shadow: 6px 6px 0 0 rgba(0, 229, 255, 0.12);
}

.page-about .chapter-head {
  display: grid;
  gap: 0.7rem;
  justify-items: start;
  margin-bottom: 1.25rem;
}

.page-about .chapter-num {
  display: inline-block;
  padding: 0.15rem 0.45rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--navy-950);
  background: var(--amber-500);
  border-radius: 2px;
}

.page-about .chapter-title {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: clamp(1.35rem, 3.6vw, 2rem);
  line-height: 1.2;
  letter-spacing: -0.025em;
}

.page-about .about-text p {
  margin: 0 0 1rem;
  font-size: 1rem;
  line-height: 1.85;
}

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

.page-about .about-text--onDark {
  margin: 0 0 1.25rem;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--steel);
  max-width: 66ch;
}

.page-about .about-inline-link {
  color: var(--navy-700);
  text-decoration: underline;
  text-decoration-color: var(--amber-500);
  text-underline-offset: 3px;
  font-weight: 700;
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  color: var(--navy-950);
  text-decoration-color: var(--cyan-500);
  outline: 2px solid var(--cyan-500);
  outline-offset: 2px;
}

.page-about .about-inline-link--onDark {
  color: var(--cyan-300);
  text-decoration-color: var(--cyan-500);
}

.page-about .about-inline-link--onDark:hover,
.page-about .about-inline-link--onDark:focus-visible {
  color: var(--paper);
}

/* ---------- 图文排布 ---------- */
.page-about .about-split {
  display: grid;
  gap: 1.5rem;
  align-items: start;
}

.page-about .about-figure {
  margin: 0;
  border-radius: var(--radius);
  overflow: hidden;
}

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

.page-about .about-figure figcaption {
  padding: 0.55rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.5;
  letter-spacing: 0.02em;
}

.page-about .about-figure--paper {
  background: var(--navy-900);
  border: 2px solid var(--haze);
}

.page-about .about-figure--paper figcaption {
  color: var(--steel);
  border-top: 1px solid var(--navy-700);
}

.page-about .about-figure--dark {
  margin-top: 1.75rem;
  border: var(--edge);
  background: var(--navy-950);
}

.page-about .about-figure--dark figcaption {
  color: var(--steel);
  border-top: 1px solid var(--navy-700);
}

/* ---------- 服务原则 ---------- */
.page-about .about-principles {
  margin: 1.25rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1.1rem;
  counter-reset: principle;
}

.page-about .about-principle {
  position: relative;
  padding-left: 1rem;
  border-left: 3px solid var(--amber-500);
}

.page-about .about-principle h3 {
  margin: 0 0 0.35rem;
  font-family: var(--font-heading);
  font-size: 1.02rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .about-principle p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.8;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan-500), rgba(27, 69, 102, 0.85));
}

.page-about .about-timeline li {
  position: relative;
  padding: 0 0 1.5rem 2rem;
}

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

.page-about .about-timeline li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.35rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--navy-950);
  border: 2px solid var(--cyan-500);
  transition: background-color 0.2s var(--ease), box-shadow 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-timeline li:hover::before,
.page-about .about-timeline li:focus-within::before {
  background: var(--amber-500);
  border-color: var(--amber-300);
  box-shadow: 0 0 0 4px rgba(255, 176, 32, 0.18);
}

.page-about .tl-year {
  margin: 0 0 0.15rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  color: var(--amber-300);
}

.page-about .tl-title {
  margin: 0 0 0.3rem;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--paper);
  letter-spacing: -0.01em;
}

.page-about .tl-desc {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--steel);
  max-width: 60ch;
}

/* ---------- 团队角色 ---------- */
.page-about .about-figure--wide {
  margin-top: 1.25rem;
}

.page-about .about-roles {
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0;
}

.page-about .about-role {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 0.85rem;
  padding: 1rem 0;
  border-top: var(--about-rule);
}

.page-about .about-role:last-child {
  border-bottom: var(--about-rule);
}

.page-about .about-role-num {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--navy-950);
  background: var(--amber-300);
  border-radius: 2px;
  padding: 0.1rem 0.35rem;
  height: fit-content;
}

.page-about .about-role h3 {
  margin: 0 0 0.3rem;
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .about-role p {
  margin: 0;
  font-size: 0.93rem;
  line-height: 1.8;
}

/* ---------- 认证折叠面板 ---------- */
.page-about .about-certs {
  display: grid;
  gap: 0.7rem;
  margin-bottom: 1.5rem;
}

.page-about .about-cert {
  background: rgba(5, 13, 26, 0.62);
  border: var(--edge);
  border-radius: var(--radius);
  transition: border-color 0.2s var(--ease);
}

.page-about .about-cert[open] {
  border-color: var(--cyan-500);
}

.page-about .about-cert summary {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-heading);
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--paper);
}

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

.page-about .about-cert summary:focus-visible {
  outline: 2px solid var(--cyan-500);
  outline-offset: -2px;
}

.page-about .about-cert-mark {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--amber-500);
}

.page-about .about-cert-name {
  flex: 1 1 auto;
  min-width: 0;
}

.page-about .about-cert-sign {
  position: relative;
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
}

.page-about .about-cert-sign::before,
.page-about .about-cert-sign::after {
  content: "";
  position: absolute;
  background: var(--cyan-500);
  transition: transform 0.22s var(--ease), opacity 0.22s var(--ease);
}

.page-about .about-cert-sign::before {
  top: 6px;
  left: 0;
  width: 14px;
  height: 2px;
}

.page-about .about-cert-sign::after {
  top: 0;
  left: 6px;
  width: 2px;
  height: 14px;
}

.page-about .about-cert[open] .about-cert-sign::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .about-cert-body {
  padding: 0 1rem 1rem 1rem;
  font-size: 0.92rem;
  line-height: 1.85;
  color: var(--steel);
}

/* ---------- 联系路径 ---------- */
.page-about .about-links {
  display: grid;
  gap: 0.6rem;
  margin: 1.35rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-links a {
  display: grid;
  gap: 0.2rem;
  padding: 0.85rem 1rem;
  text-decoration: none;
  color: var(--navy-900);
  border: var(--about-rule);
  border-left: 3px solid var(--cyan-500);
  transition: background-color 0.2s var(--ease), border-left-color 0.2s var(--ease), transform 0.2s var(--ease);
}

.page-about .about-links a:hover,
.page-about .about-links a:focus-visible {
  background: rgba(0, 229, 255, 0.09);
  border-left-color: var(--amber-500);
  transform: translateX(2px);
  outline: none;
}

.page-about .about-link-label {
  font-family: var(--font-heading);
  font-size: 0.96rem;
  font-weight: 800;
}

.page-about .about-link-goal {
  font-size: 0.85rem;
  color: var(--navy-700);
}

.page-about .about-cta {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.5rem;
  padding-top: 1.25rem;
  border-top: var(--about-rule);
}

.page-about .about-cta-note {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.75;
  color: var(--navy-700);
}

.page-about .about-cta .cta {
  justify-self: start;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 1.75rem;
  }

  .page-about .about-role:nth-last-child(2) {
    border-bottom: var(--about-rule);
  }
}

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    gap: 2rem;
  }

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

  .page-about .about-links a {
    height: 100%;
  }
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: 196px minmax(0, 1fr);
    gap: 2.25rem;
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 1.5rem;
    padding: 1rem;
  }

  .page-about .about-toc-list {
    flex-direction: column;
    overflow-x: visible;
    padding-bottom: 0;
  }

  .page-about .about-toc-link {
    width: 100%;
    white-space: normal;
    padding: 0.5rem 0.6rem;
    border-color: transparent;
    border-left: 2px solid var(--navy-700);
    border-radius: 0;
  }

  .page-about .about-toc-link:hover,
  .page-about .about-toc-link:focus-visible,
  .page-about .about-toc-link[aria-current="true"],
  .page-about .about-toc-link[aria-current="location"] {
    border-left-color: var(--amber-500);
    border-top-color: transparent;
    border-right-color: transparent;
    border-bottom-color: transparent;
  }

  .page-about .about-timeline li {
    padding-left: 8.5rem;
  }

  .page-about .tl-year {
    position: absolute;
    left: 2rem;
    top: 0.1rem;
    margin: 0;
    text-align: right;
  }

  .page-about .about-timeline::before {
    left: 6.85rem;
  }

  .page-about .about-timeline li::before {
    left: 6.35rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc-link,
  .page-about .about-links a,
  .page-about .about-timeline li::before,
  .page-about .about-cert-sign::before,
  .page-about .about-cert-sign::after {
    transition: none;
  }

  .page-about .about-links a:hover,
  .page-about .about-links a:focus-visible {
    transform: none;
  }
}