.page-about {
  background: var(--c-bg);
  color: var(--c-white);
}

/* ===== 品牌档案封面 ===== */
.page-about__cover {
  position: relative;
  overflow: hidden;
  padding-top: 2rem;
  padding-bottom: var(--space-12);
}

.page-about__cover::before {
  content: '';
  position: absolute;
  top: 0;
  right: -12%;
  width: 58%;
  height: 100%;
  background: linear-gradient(135deg, transparent 0%, rgba(100, 255, 218, 0.05) 100%);
  clip-path: polygon(18% 0, 100% 0, 82% 100%, 0 100%);
  pointer-events: none;
}

.page-about__cover::after {
  content: '01';
  position: absolute;
  right: 4%;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: clamp(6rem, 16vw, 12rem);
  font-weight: 700;
  line-height: 1;
  color: rgba(100, 255, 218, 0.045);
  pointer-events: none;
}

.page-about__cover-grid {
  display: grid;
  gap: var(--space-8);
  position: relative;
  z-index: 1;
}

.page-about__code {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  color: var(--c-neon);
  margin-bottom: var(--space-6);
}

.page-about__code::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c-neon);
  box-shadow: 0 0 0 4px rgba(100, 255, 218, 0.15);
}

.page-about h1 {
  margin: 0 0 var(--space-6);
  font-family: var(--font-heading);
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.page-about__h1-sub {
  display: block;
  margin-top: var(--space-5);
  font-size: 1rem;
  line-height: 1.55;
  font-weight: 400;
  letter-spacing: 0;
  color: var(--c-gray);
  max-width: 34rem;
}

.page-about__summary {
  font-size: 1rem;
  line-height: 1.85;
  color: var(--c-white);
  max-width: 40rem;
  margin: 0 0 var(--space-6);
}

.page-about__loc {
  margin: 0 0 var(--space-6);
  padding-left: var(--space-4);
  border-left: 2px solid var(--c-neon);
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--c-gray);
  max-width: 36rem;
}

.page-about__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

/* 档案卡 */
.page-about__file {
  position: relative;
  background: var(--c-bg-alt);
  border: 2px solid var(--c-line);
  box-shadow: 6px 6px 0 rgba(2, 12, 27, 0.5);
  padding: var(--space-6) var(--space-6) var(--space-4);
}

.page-about__file::before {
  content: '';
  position: absolute;
  top: -2px;
  left: var(--space-6);
  width: 58px;
  height: 6px;
  background: var(--c-neon);
  border-radius: 0 0 3px 3px;
}

.page-about__file-tag {
  display: inline-block;
  background: var(--c-neon);
  color: var(--c-bg-deep);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  padding: 0.25rem 0.75rem;
  border-radius: 2px;
  margin-bottom: var(--space-5);
}

.page-about__file-list {
  margin: 0;
}

.page-about__file-list > div {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--c-line);
}

.page-about__file-list > div:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.page-about__file-list dt {
  font-size: 0.8125rem;
  color: var(--c-gray);
}

.page-about__file-list dd {
  margin: 0;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--c-white);
  word-break: break-word;
}

/* ===== 发展历程 ===== */
.page-about__milestones {
  padding-bottom: var(--space-12);
}

.page-about__milestones-head {
  display: grid;
  gap: var(--space-6);
  margin-bottom: var(--space-8);
}

.page-about__milestones-copy h2,
.page-about__capacity-copy h2,
.page-about__compliance-copy h2,
.page-about__team-head h2 {
  font-family: var(--font-heading);
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  line-height: 1.25;
  margin: var(--space-4) 0 var(--space-4);
}

.page-about__milestones-copy p,
.page-about__capacity-copy p,
.page-about__compliance-copy p,
.page-about__team-head p {
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--c-gray);
  margin: 0;
  max-width: 40rem;
}

.page-about__milestones-img {
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 2px solid var(--c-line);
  box-shadow: var(--shadow);
}

.page-about__track {
  position: relative;
  display: grid;
  gap: var(--space-5);
  margin-top: var(--space-8);
}

.page-about__milestone {
  position: relative;
  background: var(--c-bg-alt);
  border: 2px solid var(--c-line);
  box-shadow: var(--shadow);
  z-index: 1;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.page-about__milestone[open] {
  border-color: var(--c-neon);
}

.page-about__milestone:hover,
.page-about__milestone:focus-within {
  border-color: var(--c-neon);
  box-shadow: 6px 6px 0 rgba(2, 12, 27, 0.55);
}

.page-about__milestone summary {
  position: relative;
  list-style: none;
  cursor: pointer;
  padding: var(--space-5);
  display: grid;
  gap: var(--space-3);
}

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

.page-about__milestone summary::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--c-neon) 0%, var(--c-neon) 35%, transparent 35%);
  opacity: 0.7;
}

.page-about__milestone p {
  padding: 0 var(--space-5) var(--space-5);
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--c-gray);
}

.page-about__year {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--c-neon);
}

.page-about__milestone-title {
  font-family: var(--font-heading);
  font-size: 1rem;
  line-height: 1.45;
  font-weight: 600;
  color: var(--c-white);
  padding-right: 1.5rem;
}

.page-about__milestone-mark {
  position: absolute;
  right: var(--space-5);
  top: var(--space-5);
  font-family: var(--font-mono);
  font-size: 1.125rem;
  color: var(--c-gray);
  transition: transform 0.2s ease, color 0.2s ease;
}

.page-about__milestone[open] .page-about__milestone-mark {
  transform: rotate(45deg);
  color: var(--c-neon);
}

/* ===== 服务能力 ===== */
.page-about__capacity {
  padding-bottom: var(--space-12);
}

.page-about__capacity-head {
  display: grid;
  gap: var(--space-6);
  margin-bottom: var(--space-6);
}

.page-about__capacity-img {
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border: 2px solid var(--c-line);
  box-shadow: var(--shadow);
}

.page-about__ruler {
  display: grid;
  gap: var(--space-6);
  border-top: 2px solid var(--c-line);
  border-bottom: 8px solid var(--c-bg-deep);
  padding-top: var(--space-5);
  padding-bottom: var(--space-5);
  margin-top: var(--space-8);
  background: rgba(2, 12, 27, 0.18);
}

.page-about__stat {
  padding: var(--space-4) 0;
  border-left: 2px solid var(--c-neon);
  padding-left: var(--space-5);
  display: grid;
  gap: var(--space-2);
  min-width: 0;
}

.page-about__stat-num {
  font-size: clamp(2rem, 5vw, 2.75rem);
  font-weight: 700;
  line-height: 1;
  color: var(--c-neon);
}

.page-about__stat-label {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  color: var(--c-white);
}

.page-about__stat-desc {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--c-gray);
}

.page-about__capacity-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-3);
  margin: var(--space-6) 0 0;
  padding: var(--space-4) var(--space-6);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--c-gray);
  background: rgba(2, 12, 27, 0.35);
  border: 1px solid var(--c-line);
  border-left: 3px solid var(--c-neon);
}

.page-about__capacity-meta a {
  color: var(--c-neon);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about__capacity-meta a:hover,
.page-about__capacity-meta a:focus-visible {
  color: var(--c-white);
}

/* ===== 安全与合规 ===== */
.page-about__compliance {
  padding-bottom: var(--space-12);
}

.page-about__compliance-grid {
  display: grid;
  gap: var(--space-8);
}

.page-about__checks {
  display: grid;
  gap: var(--space-5);
}

.page-about__check {
  display: grid;
  gap: var(--space-3);
  background: var(--c-bg-alt);
  border: 2px solid var(--c-line);
  border-left: 4px solid var(--c-orange);
  box-shadow: 4px 4px 0 rgba(2, 12, 27, 0.35);
  padding: var(--space-5);
  min-width: 0;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.page-about__check:hover,
.page-about__check:focus-within {
  border-color: var(--c-orange);
  box-shadow: 5px 5px 0 rgba(2, 12, 27, 0.45);
}

.page-about__check span {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--c-orange);
}

.page-about__check strong {
  font-family: var(--font-heading);
  font-size: 1.0625rem;
  color: var(--c-white);
}

.page-about__check p {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--c-gray);
}

/* ===== 团队构成 ===== */
.page-about__team {
  padding-bottom: var(--space-12);
}

.page-about__team-layout {
  display: grid;
  gap: var(--space-8);
}

.page-about__team-groups {
  display: grid;
  gap: var(--space-5);
  align-content: start;
}

.page-about__team-item {
  position: relative;
  background: var(--c-bg-deep);
  border: 2px solid var(--c-line);
  padding: var(--space-5);
  cursor: default;
  min-width: 0;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.page-about__team-item::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  height: 4px;
  width: 0;
  background: var(--c-orange);
  transition: width 0.25s ease;
}

.page-about__team-item:hover,
.page-about__team-item:focus-visible {
  border-color: var(--c-neon);
  transform: translateX(4px);
}

.page-about__team-item:hover::after,
.page-about__team-item:focus-visible::after {
  width: 100%;
}

.page-about__team-head-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-4);
  margin-bottom: var(--space-3);
}

.page-about__team-head-row span {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--c-neon);
}

.page-about__team-head-row strong {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  color: var(--c-white);
}

.page-about__team-summary {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--c-gray);
}

.page-about__team-visual {
  position: relative;
}

.page-about__team-visual::before {
  content: '';
  position: absolute;
  inset: -10px -10px 10px 10px;
  border: 2px solid rgba(100, 255, 218, 0.35);
  pointer-events: none;
}

.page-about__team-visual img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  border: 2px solid var(--c-line);
  box-shadow: var(--shadow);
}

/* 键盘焦点 */
.page-about__team-item:focus-visible,
.page-about__milestone summary:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 3px;
}

/* ===== 桌面端增强 ===== */
@media (min-width: 960px) {
  .page-about__cover {
    padding-top: 3.5rem;
    padding-bottom: 7rem;
  }

  .page-about__cover-grid {
    grid-template-columns: 3fr 2fr;
    gap: var(--space-12);
    align-items: start;
  }

  .page-about__file {
    margin-top: var(--space-4);
  }

  .page-about__milestones-head {
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: var(--space-10);
  }

  .page-about__track {
    grid-template-columns: repeat(5, 1fr);
    gap: var(--space-4);
    margin-top: var(--space-10);
  }

  .page-about__track::before {
    content: '';
    position: absolute;
    top: 34px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--c-line);
    z-index: 0;
  }

  .page-about__capacity-head {
    grid-template-columns: 1fr minmax(0, 620px);
    align-items: center;
    gap: var(--space-10);
  }

  .page-about__ruler {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-6);
    margin-top: var(--space-10);
  }

  .page-about__compliance-grid {
    grid-template-columns: 2fr 3fr;
    gap: var(--space-10);
    align-items: start;
  }

  .page-about__checks {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-5);
  }

  .page-about__team-layout {
    grid-template-columns: 3fr 2fr;
    gap: var(--space-10);
    align-items: stretch;
  }

  .page-about__team-visual {
    display: flex;
    align-items: flex-start;
  }
}