.page-about {
  --about-gold-line: linear-gradient(135deg, var(--gold) 0%, var(--red) 60%, var(--red-dark) 100%);
  background: var(--blue-black);
  color: var(--white);
  font-family: var(--font-body);
  line-height: 1.6;
  overflow-x: hidden;
}

/* ===== 首屏 ===== */
.about-hero {
  display: grid;
  grid-template-columns: 1fr;
  background:
    radial-gradient(circle at 82% 22%, rgba(230, 57, 70, 0.14) 0, transparent 42%),
    linear-gradient(125deg, var(--blue-black) 0%, var(--blue) 72%, var(--red-dark) 130%);
  padding: calc(var(--header-height) + 36px) 0 56px;
  overflow: hidden;
}

.about-hero__media {
  position: relative;
  order: 2;
  min-height: 240px;
  margin: 20px 0 0;
}

.about-hero__media img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.about-hero__content {
  order: 1;
  width: min(100% - 32px, 760px);
  margin-inline: auto;
  padding-inline: var(--space-1);
}

.about-hero__kicker {
  margin: 18px 0 8px;
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--gold);
  text-transform: uppercase;
}

.about-hero h1 {
  margin: 0 0 18px;
  font-family: var(--font-heading);
  font-size: clamp(34px, 6.5vw, 72px);
  line-height: 1.05;
  letter-spacing: 0.01em;
  color: var(--light);
  text-transform: none;
}

.about-hero__lead {
  margin: 0 0 28px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--steel);
  max-width: 640px;
}

.about-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  padding-top: 20px;
  border-top: 2px solid rgba(230, 57, 70, 0.55);
}

.hero-fact {
  font-size: 14px;
  color: var(--steel);
}

.hero-fact strong {
  display: block;
  font-family: var(--font-data);
  font-size: 24px;
  font-weight: 700;
  color: var(--white);
  line-height: 1.2;
}

/* ===== 分屏主体 ===== */
.about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px 0;
  width: min(100% - 32px, 1280px);
  margin-inline: auto;
  padding: 48px 0 80px;
}

.about-timeline-panel {
  position: relative;
}

.about-timeline-inner {
  background: rgba(11, 29, 46, 0.72);
  border: 1px solid rgba(201, 162, 39, 0.18);
  border-left: 4px solid var(--gold);
  border-radius: var(--radius);
  padding: 24px 20px 28px;
}

.about-kicker,
.section-kicker {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--red);
  text-transform: uppercase;
}

.about-timeline-inner h2,
.section-heading h2 {
  margin: 6px 0 8px;
  font-family: var(--font-heading);
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.1;
  color: var(--light);
}

.about-timeline-intro,
.section-sub {
  margin: 0 0 18px;
  font-size: 14px;
  color: var(--steel);
  line-height: 1.7;
}

/* ===== 时间轴 ===== */
.timeline-list {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.timeline-item {
  position: relative;
  padding-left: 40px;
  margin-bottom: 14px;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 26px;
  bottom: -12px;
  width: 2px;
  background: linear-gradient(180deg, var(--gold) 0%, var(--red) 60%, var(--red-dark) 100%);
  opacity: 0.65;
}

.timeline-item:last-child::before {
  display: none;
}

.timeline-node {
  position: absolute;
  left: 0;
  top: 14px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--red);
  border: 3px solid var(--gold);
  z-index: 1;
  box-shadow: 0 0 0 5px rgba(201, 162, 39, 0.14), 0 0 0 9px rgba(230, 57, 70, 0.08);
}

.timeline-card {
  background: rgba(16, 42, 60, 0.62);
  border: 1px solid rgba(241, 244, 248, 0.1);
  border-radius: var(--radius);
  padding: 12px 14px;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}

.timeline-card:hover,
.timeline-card[open] {
  border-color: rgba(230, 57, 70, 0.5);
  background: rgba(16, 42, 60, 0.85);
}

.timeline-card summary {
  display: flex;
  align-items: baseline;
  gap: 11px;
  list-style: none;
  cursor: pointer;
}

.timeline-card summary::-webkit-details-marker {
  display: none;
}

.timeline-card summary::after {
  content: '+';
  margin-left: auto;
  font-family: var(--font-data);
  font-size: 18px;
  color: var(--gold);
  line-height: 1;
}

.timeline-card[open] summary::after {
  content: '−';
}

.timeline-year {
  font-family: var(--font-data);
  font-size: 18px;
  font-weight: 700;
  color: var(--gold);
  white-space: nowrap;
}

.timeline-title {
  font-family: var(--font-heading);
  font-size: 16px;
  color: var(--white);
  letter-spacing: 0.02em;
}

.timeline-card p {
  margin: 10px 0 0;
  padding-top: 10px;
  border-top: 1px solid rgba(241, 244, 248, 0.08);
  font-size: 13px;
  line-height: 1.7;
  color: var(--steel);
}

.timeline-footnote {
  margin: 20px 0 0;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--gold);
  opacity: 0.85;
  line-height: 1.5;
}

/* ===== 右侧内容面板 ===== */
.about-content-panel {
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.about-section {
  position: relative;
  background: rgba(16, 42, 60, 0.5);
  border: 1px solid rgba(241, 244, 248, 0.09);
  border-radius: 4px;
  padding: 26px 20px 22px;
  overflow: hidden;
  transition: border-color var(--transition);
}

.about-section:hover {
  border-color: rgba(230, 57, 70, 0.35);
}

.section-num {
  position: absolute;
  top: 10px;
  right: 14px;
  margin: 0;
  font-family: var(--font-heading);
  font-size: 84px;
  line-height: 1;
  color: var(--gold);
  opacity: 0.13;
  pointer-events: none;
  user-select: none;
}

.section-heading {
  position: relative;
  z-index: 1;
}

.section-sub {
  max-width: 520px;
}

/* ===== 团队 ===== */
.team-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin: 18px 0 0;
}

.team-cell {
  position: relative;
  background: rgba(11, 29, 46, 0.72);
  border: 1px solid rgba(241, 244, 248, 0.09);
  border-radius: var(--radius);
  padding: 16px 12px 12px;
  text-align: center;
  transition: transform var(--transition), border-color var(--transition);
}

.team-cell:hover {
  transform: translateY(-2px);
  border-color: var(--red);
}

.team-cell--total {
  border-color: rgba(201, 162, 39, 0.45);
}

.team-cell--total:hover {
  border-color: var(--gold);
}

.team-num {
  display: block;
  font-family: var(--font-data);
  font-size: 32px;
  font-weight: 700;
  color: var(--white);
  line-height: 1.15;
}

.team-label {
  display: block;
  margin-top: 3px;
  font-size: 13px;
  color: var(--steel);
}

.team-detail {
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.45;
  color: var(--steel);
}

@media (hover: hover) {
  .team-detail {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.2s ease, opacity 0.2s ease, margin-top 0.2s ease, color 0.2s ease;
  }

  .team-cell:hover .team-detail,
  .team-cell:focus-within .team-detail {
    max-height: 60px;
    margin-top: 8px;
    opacity: 1;
    color: var(--light);
  }
}

.team-capability {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.capability-item {
  background: rgba(29, 53, 87, 0.55);
  border-left: 3px solid var(--blue-light);
  padding: 10px 14px;
  display: grid;
  grid-template-columns: auto auto 1fr;
  align-items: baseline;
  gap: 8px 12px;
}

.capability-label {
  font-size: 13px;
  color: var(--steel);
}

.capability-value {
  font-family: var(--font-data);
  font-size: 17px;
  font-weight: 700;
  color: var(--gold);
  white-space: nowrap;
}

.capability-desc {
  font-size: 12px;
  color: var(--steel);
}

.section-link {
  margin: 18px 0 0;
  font-size: 14px;
}

.section-link a {
  color: var(--blue-light);
  text-decoration: none;
  border-bottom: 1px solid rgba(69, 123, 157, 0.4);
  transition: color var(--transition), border-color var(--transition);
}

.section-link a:hover {
  color: var(--light);
  border-color: var(--red);
}

/* ===== 数据面板 ===== */
.panel-figure {
  margin: 18px 0 0;
  border: 1px solid rgba(69, 123, 157, 0.38);
  background: var(--blue-black);
  border-radius: var(--radius);
  overflow: hidden;
}

.panel-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.panel-figure figcaption {
  padding: 9px 14px;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--steel);
  background: rgba(11, 29, 46, 0.7);
}

.path-list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.path-step {
  background: rgba(11, 29, 46, 0.7);
  border-top: 3px solid var(--gold);
  border-radius: var(--radius);
  padding: 16px 16px 12px;
  transition: transform var(--transition), border-color var(--transition);
}

.path-step:hover {
  transform: translateY(-2px);
  border-top-color: var(--red);
}

.path-index {
  display: block;
  font-family: var(--font-data);
  font-size: 13px;
  font-weight: 700;
  color: var(--red);
}

.path-body h3 {
  margin: 4px 0 4px;
  font-family: var(--font-heading);
  font-size: 19px;
  color: var(--white);
}

.path-body p {
  margin: 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--steel);
}

.section-note {
  margin: 16px 0 0;
  padding: 12px 14px;
  border-left: 3px solid var(--red);
  background: rgba(230, 57, 70, 0.08);
  font-size: 13px;
  line-height: 1.7;
  color: var(--steel);
}

/* ===== 资料库 ===== */
.library-stat-block {
  margin: 18px 0 0;
  background: linear-gradient(135deg, var(--blue) 0%, var(--blue-black) 78%);
  border: 1px solid rgba(201, 162, 39, 0.28);
  border-radius: var(--radius);
  padding: 24px 18px;
  text-align: center;
}

.library-stat-num {
  display: block;
  font-family: var(--font-data);
  font-size: clamp(44px, 6vw, 72px);
  font-weight: 700;
  line-height: 1.05;
  color: var(--gold);
}

.library-stat-label {
  display: block;
  margin-top: 6px;
  font-size: 14px;
  color: var(--steel);
}

.format-list {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.format-list li {
  background: rgba(69, 123, 157, 0.16);
  border: 1px solid rgba(69, 123, 157, 0.4);
  border-radius: 99px;
  padding: 6px 14px;
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--white);
}

.library-desc,
.library-meta {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--steel);
}

.library-meta {
  font-size: 13px;
  color: var(--blue-light);
}

/* ===== 认证联系 ===== */
.cert-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 18px;
}

.cert-info {
  background: rgba(11, 29, 46, 0.72);
  border: 1px solid rgba(201, 162, 39, 0.18);
  border-radius: var(--radius);
  padding: 18px 16px;
}

.cert-row {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 6px 10px;
  padding: 10px 0;
  border-bottom: 1px solid rgba(241, 244, 248, 0.07);
}

.cert-row:last-of-type {
  border-bottom: none;
}

.cert-label {
  flex: 0 0 76px;
  font-size: 12px;
  color: var(--steel);
  line-height: 1.5;
}

.cert-value {
  flex: 1 1 200px;
  font-size: 14px;
  color: var(--white);
  word-break: break-word;
}

.cert-copy-btn {
  margin-left: auto;
  background: transparent;
  border: 1px solid var(--gold);
  color: var(--gold);
  border-radius: var(--radius);
  padding: 4px 10px;
  font-size: 12px;
  font-family: var(--font-body);
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
}

.cert-copy-btn:hover {
  background: var(--gold);
  color: var(--blue-black);
}

.cert-copy-btn:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 2px;
}

.cert-note {
  margin: 14px 0 0;
  padding: 12px 14px;
  background: rgba(201, 162, 39, 0.08);
  border-left: 3px solid var(--gold);
  font-size: 13px;
  line-height: 1.7;
  color: var(--steel);
}

.cert-figure {
  margin: 0;
  border: 1px solid rgba(241, 244, 248, 0.1);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--blue);
}

.cert-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.cert-figure figcaption {
  padding: 8px 12px;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--steel);
  background: rgba(11, 29, 46, 0.72);
}

/* ===== 桌面端增强 ===== */
@media (min-width: 720px) {
  .about-hero__media {
    min-height: 320px;
  }

  .team-capability {
    grid-template-columns: repeat(3, 1fr);
  }

  .capability-item {
    grid-template-columns: 1fr;
    gap: 4px 0;
  }

  .capability-value {
    font-size: 19px;
  }

  .path-list {
    grid-template-columns: repeat(3, 1fr);
  }

  .cert-grid {
    grid-template-columns: 1.1fr 0.9fr;
  }

  .cert-figure {
    align-self: start;
  }

  .cert-note {
    margin-top: 18px;
  }
}

@media (min-width: 960px) {
  .about-hero {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: center;
    padding: calc(var(--header-height) + 56px) 0 72px;
  }

  .about-hero__media {
    order: 0;
    min-height: 520px;
    margin: 0;
  }

  .about-hero__content {
    order: 0;
    width: 100%;
    max-width: 680px;
    padding-block: 20px;
  }

  .about-split {
    grid-template-columns: minmax(320px, 0.75fr) minmax(0, 1.5fr);
    gap: 0 56px;
    padding: 64px 0 96px;
  }

  .about-timeline-panel::after {
    content: '';
    position: absolute;
    top: 0;
    right: -34px;
    width: 18px;
    height: 100%;
    background: repeating-linear-gradient(
      -45deg,
      transparent 0 7px,
      rgba(230, 57, 70, 0.28) 7px 9px,
      transparent 9px 16px
    );
    pointer-events: none;
  }

  .about-timeline-inner {
    position: sticky;
    top: calc(var(--header-height) + 24px);
  }

  .about-section {
    padding: 34px 32px 28px;
  }

  .team-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
  }

  .team-num {
    font-size: 36px;
  }

  .hero-fact {
    font-size: 15px;
  }

  .hero-fact strong {
    font-size: 28px;
  }
}

@media (min-width: 1200px) {
  .about-split {
    width: min(100% - 48px, 1320px);
  }

  .about-hero__content {
    max-width: 760px;
    padding-left: 0;
  }

  .section-num {
    font-size: 96px;
  }
}