.page-about {
  --about-gold-soft: rgba(201, 162, 75, 0.16);
  --about-cyan-soft: rgba(40, 209, 204, 0.12);
  --about-purple-soft: rgba(139, 124, 246, 0.14);
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: no-preference) {
  .page-about {
    scroll-behavior: smooth;
  }
}

/* ===== 首屏：金色曲线横跨页宽 ===== */
.page-about .about-hero {
  position: relative;
  min-height: 440px;
  display: flex;
  align-items: flex-end;
  background: var(--deep-navy);
  overflow: hidden;
  isolation: isolate;
}

.page-about .about-hero-media,
.page-about .about-hero-shade {
  position: absolute;
  inset: 0;
}

.page-about .about-hero-media {
  z-index: -2;
}

.page-about .about-hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.52;
}

.page-about .about-hero-shade {
  z-index: -1;
  background: linear-gradient(180deg, rgba(10, 27, 42, 0.72) 0%, rgba(10, 27, 42, 0.35) 52%, rgba(10, 27, 42, 0.78) 100%);
}

.page-about .about-hero-arc {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 140px;
  z-index: 0;
}

.page-about .about-hero-body {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 88px 24px 72px;
}

.page-about .about-breadcrumb-sep {
  margin: 0 8px;
  color: var(--gold);
}

.page-about .about-page-title {
  font-family: var(--font-title);
  font-size: 2rem;
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--soft-white);
  margin: 18px 0 12px;
  max-width: 18em;
}

.page-about .about-page-excerpt {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--mist-blue);
  max-width: 36em;
  margin: 0 0 22px;
}

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

.page-about .about-hero-tag {
  display: inline-flex;
  align-items: center;
  padding: 7px 14px;
  border-radius: 999px;
  border: 1px solid rgba(245, 247, 250, 0.2);
  background: rgba(10, 27, 42, 0.55);
  color: var(--soft-white);
  font-size: 0.86rem;
  text-decoration: none;
  transition: border-color 0.3s ease, background 0.3s ease, color 0.3s ease;
}

.page-about .about-hero-tag--gold:hover,
.page-about .about-hero-tag--gold:focus-visible {
  border-color: var(--gold);
  color: var(--gold);
}

.page-about .about-hero-tag--cyan:hover,
.page-about .about-hero-tag--cyan:focus-visible {
  border-color: var(--bright-cyan);
  color: var(--bright-cyan);
}

.page-about .about-hero-tag--purple:hover,
.page-about .about-hero-tag--purple:focus-visible {
  border-color: var(--electric-purple);
  color: var(--electric-purple);
}

.page-about .about-hero-tag--orange:hover,
.page-about .about-hero-tag--orange:focus-visible {
  border-color: var(--orange-red);
  color: var(--orange-red);
}

/* ===== 左右分置：目录 + 主内容 ===== */
.page-about .about-layout {
  display: grid;
  gap: 36px;
  padding: 48px 24px 72px;
}

.page-about .about-dir-inner {
  position: sticky;
  top: calc(var(--header-h) + 24px);
}

.page-about .about-dir-kicker {
  font-size: 0.8rem;
  letter-spacing: 0.18em;
  color: var(--mid-gray);
  margin: 0 0 14px;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 10px;
}

.page-about .about-dir-kicker::before {
  content: "";
  width: 24px;
  height: 3px;
  background: linear-gradient(90deg, var(--gold), transparent);
  border-radius: 999px;
}

.page-about .about-dir-nav {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 28px;
}

.page-about .about-dir-link {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 12px;
  border-radius: var(--radius-s);
  color: var(--mist-blue);
  font-size: 0.92rem;
  line-height: 1.5;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.page-about .about-dir-link .about-dir-num {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 0.78rem;
  color: var(--gold);
}

.page-about .about-dir-link:hover,
.page-about .about-dir-link:focus-visible {
  background: var(--about-gold-soft);
  color: var(--soft-white);
  border-left-color: var(--gold);
}

.page-about .about-dir-card {
  border: 1px solid rgba(201, 162, 75, 0.32);
  background: rgba(22, 50, 79, 0.5);
  border-radius: var(--radius-m);
  padding: 18px;
}

.page-about .about-dir-card-title {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--gold);
  margin: 0 0 10px;
}

.page-about .about-dir-card-link {
  display: block;
  padding: 6px 0;
  color: var(--mist-blue);
  text-decoration: none;
  font-size: 0.9rem;
  border-bottom: 1px dashed rgba(214, 229, 240, 0.14);
  transition: color 0.3s ease, padding-left 0.3s ease;
}

.page-about .about-dir-card-link:hover,
.page-about .about-dir-card-link:focus-visible {
  color: var(--bright-cyan);
  padding-left: 6px;
}

/* ===== 通用 section ===== */
.page-about .about-section {
  scroll-margin-top: calc(var(--header-h) + 24px);
  padding: 8px 0 8px;
}

.page-about .about-section + .about-section {
  margin-top: 48px;
}

.page-about .about-section-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 14px;
}

.page-about .about-section-title {
  font-family: var(--font-title);
  font-size: 1.5rem;
  font-weight: 900;
  line-height: 1.3;
  color: var(--soft-white);
  margin: 0;
}

.page-about .about-section-title::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 1.1em;
  margin-right: 12px;
  border-radius: 999px;
  background: linear-gradient(180deg, var(--gold), var(--bright-cyan));
  vertical-align: -0.2em;
}

.page-about .about-section-index {
  margin-left: auto;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: 1.6rem;
  color: rgba(201, 162, 75, 0.24);
  line-height: 1;
}

.page-about .about-section-lead {
  color: var(--mid-gray);
  line-height: 1.7;
  font-size: 0.96rem;
  margin: 0 0 26px;
  max-width: 48em;
}

/* ===== 品牌档案：三桥卡片 ===== */
.page-about .about-bridge-grid {
  display: grid;
  gap: 18px;
}

.page-about .about-bridge-card {
  position: relative;
  overflow: hidden;
  padding: 26px 22px 22px;
  border-color: rgba(201, 162, 75, 0.24);
  transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.page-about .about-bridge-card .about-bridge-cable {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--gold), var(--bright-cyan), transparent 78%);
  opacity: 0.7;
}

.page-about .about-bridge-card:hover,
.page-about .about-bridge-card:focus-within {
  border-color: var(--gold);
  transform: translateY(-3px);
  box-shadow: var(--shadow-float);
}

.page-about .about-bridge-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 14px;
}

.page-about .about-bridge-name {
  font-family: var(--font-title);
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--gold);
  letter-spacing: 0.04em;
}

.page-about .about-bridge-title {
  font-family: var(--font-title);
  font-size: 1rem;
  font-weight: 700;
  color: var(--soft-white);
  margin: 0 0 8px;
}

.page-about .about-bridge-text {
  font-size: 0.92rem;
  line-height: 1.75;
  color: var(--mist-blue);
  margin: 0 0 16px;
}

.page-about .about-inline-link {
  color: var(--bright-cyan);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  color: var(--gold);
  text-decoration: underline;
}

.page-about .about-brand-visual {
  margin-top: 30px;
}

.page-about .about-brand-visual img,
.page-about .about-num-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-l);
  border: 1px solid rgba(201, 162, 75, 0.28);
  box-shadow: var(--shadow-card);
}

.page-about .about-visual-caption,
.page-about .about-media-caption {
  color: var(--mid-gray);
  font-size: 0.86rem;
  line-height: 1.65;
  margin: 10px 0 0;
}

/* ===== 关键数字：Bento 数字墙 ===== */
.page-about .about-num-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

.page-about .about-num-card {
  position: relative;
  background: linear-gradient(140deg, var(--royal-blue), var(--deep-navy));
  border: 1px solid rgba(214, 229, 240, 0.12);
  border-radius: var(--radius-m);
  padding: 18px 16px;
  min-height: 140px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  transition: border-color 0.3s ease, box-shadow 0.3s ease, transform 0.3s ease;
}

.page-about .about-num-card:hover,
.page-about .about-num-card:focus-within {
  border-color: var(--gold);
  box-shadow: var(--shadow-float);
  transform: translateY(-2px);
}

.page-about .about-num-card--large {
  grid-column: span 2;
  background: linear-gradient(135deg, rgba(201, 162, 75, 0.14), rgba(10, 27, 42, 0.9) 55%), linear-gradient(140deg, var(--royal-blue), var(--deep-navy));
  border-color: rgba(201, 162, 75, 0.5);
}

.page-about .about-num-card--large .about-num {
  font-size: 4rem;
}

.page-about .about-num {
  font-family: var(--font-title);
  font-weight: 900;
  font-size: 2.6rem;
  line-height: 1.05;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.page-about .about-num-label {
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--soft-white);
  margin-top: 6px;
}

.page-about .about-num-source {
  font-size: 0.78rem;
  color: var(--mid-gray);
  margin-top: 4px;
  line-height: 1.5;
}

.page-about .about-num-caption {
  font-size: 0.86rem;
  line-height: 1.7;
  color: var(--mist-blue);
  margin: 12px 0 0;
  max-width: 26em;
}

.page-about .about-num-media {
  grid-column: span 2;
  align-self: stretch;
  background: rgba(22, 50, 79, 0.4);
  border: 1px solid rgba(214, 229, 240, 0.1);
  border-radius: var(--radius-m);
  padding: 12px;
}

.page-about .about-num-media img {
  height: auto;
  max-height: 260px;
  object-fit: cover;
  border: none;
  box-shadow: none;
  border-radius: var(--radius-s);
}

/* ===== 发展时间轴 ===== */
.page-about .about-timeline {
  position: relative;
  margin-top: 34px;
  padding-left: 40px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 10px;
  width: 3px;
  background: linear-gradient(180deg, var(--gold) 0%, var(--electric-purple) 52%, var(--bright-cyan) 100%);
  border-radius: 999px;
  opacity: 0.75;
}

.page-about .about-tl-item {
  position: relative;
  margin-bottom: 26px;
}

.page-about .about-tl-dot {
  position: absolute;
  left: -39px;
  top: 20px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 4px rgba(201, 162, 75, 0.18), 0 0 0 8px rgba(201, 162, 75, 0.05);
  transition: transform 0.3s ease, background 0.3s ease;
}

.page-about .about-tl-item:hover .about-tl-dot {
  transform: scale(1.2);
  background: var(--bright-cyan);
  box-shadow: 0 0 0 4px rgba(40, 209, 204, 0.2), 0 0 0 8px rgba(40, 209, 204, 0.06);
}

.page-about .about-tl-card {
  padding: 20px 20px 16px;
  border-color: rgba(214, 229, 240, 0.12);
  transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.page-about .about-tl-card:hover,
.page-about .about-tl-card:focus-within {
  transform: translateY(-3px);
  border-color: rgba(201, 162, 75, 0.5);
  box-shadow: var(--shadow-float);
}

.page-about .about-tl-title {
  font-family: var(--font-title);
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--soft-white);
  margin: 12px 0 8px;
}

.page-about .about-tl-text {
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--mist-blue);
  margin: 0;
}

.page-about .about-tl-details {
  margin-top: 12px;
  border-top: 1px dashed rgba(214, 229, 240, 0.16);
  padding-top: 10px;
}

.page-about .about-tl-details summary {
  list-style: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--gold);
  transition: color 0.3s ease;
}

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

.page-about .about-tl-details summary::before {
  content: "+";
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  border: 1px solid currentColor;
  border-radius: 4px;
  font-size: 0.9rem;
  line-height: 1;
  transition: transform 0.3s ease;
}

.page-about .about-tl-details[open] summary::before {
  content: "–";
  transform: rotate(180deg);
}

.page-about .about-tl-details summary:hover,
.page-about .about-tl-details summary:focus-visible {
  color: var(--bright-cyan);
}

.page-about .about-tl-details p {
  font-size: 0.86rem;
  line-height: 1.7;
  color: var(--mid-gray);
  margin: 10px 0 0;
}

/* ===== 服务理念 ===== */
.page-about .about-service-grid {
  display: grid;
  gap: 18px;
}

.page-about .about-service-card {
  padding: 24px 22px;
  border-color: rgba(201, 162, 75, 0.26);
}

.page-about .about-service-title {
  font-family: var(--font-title);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--soft-white);
  margin: 14px 0 8px;
}

.page-about .about-service-text {
  font-size: 0.92rem;
  line-height: 1.75;
  color: var(--mist-blue);
  margin: 0 0 16px;
}

.page-about .about-contact-list {
  margin: 0;
  padding: 0;
  border-top: 1px solid rgba(214, 229, 240, 0.12);
}

.page-about .about-contact-row {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 12px 0;
  border-bottom: 1px dashed rgba(214, 229, 240, 0.14);
}

.page-about .about-contact-row dt {
  font-size: 0.78rem;
  color: var(--mid-gray);
  letter-spacing: 0.04em;
}

.page-about .about-contact-row dd {
  margin: 0;
  font-family: var(--font-title);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--soft-white);
  word-break: break-all;
}

.page-about .about-service-note {
  color: var(--ink);
}

.page-about .about-service-note .about-service-title {
  color: var(--ink);
}

.page-about .about-service-note .about-service-text {
  color: #314554;
}

.page-about .about-service-links {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-service-links a {
  display: inline-block;
  padding: 7px 14px;
  border: 1px solid var(--gold);
  border-radius: 999px;
  color: var(--ink);
  font-size: 0.84rem;
  text-decoration: none;
  transition: background 0.3s ease, color 0.3s ease;
}

.page-about .about-service-links a:hover,
.page-about .about-service-links a:focus-visible {
  background: var(--gold);
  color: var(--deep-navy);
}

/* ===== 底部桥墩分隔线 ===== */
.page-about .about-pier {
  margin-top: 44px;
  overflow: hidden;
  opacity: 0.7;
}

.page-about .about-pier svg {
  display: block;
  width: 100%;
  height: 100px;
}

/* ===== 响应式适配 ===== */
@media (min-width: 720px) {
  .page-about .about-page-title {
    font-size: 2.6rem;
  }

  .page-about .about-bridge-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .page-about .about-num-card--large {
    grid-column: span 2;
    grid-row: span 2;
  }

  .page-about .about-num-media {
    grid-column: span 2;
  }

  .page-about .about-service-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    min-height: 560px;
  }

  .page-about .about-hero-body {
    padding: 120px 24px 92px;
  }

  .page-about .about-page-title {
    font-size: 3.2rem;
  }

  .page-about .about-page-excerpt {
    font-size: 1.1rem;
  }

  .page-about .about-layout {
    grid-template-columns: 260px minmax(0, 1fr);
    gap: 56px;
    max-width: calc(var(--container-w) + 48px);
  }

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

  .page-about .about-section-title {
    font-size: 1.8rem;
  }

  .page-about .about-num-card--large .about-num {
    font-size: 5rem;
  }

  .page-about .about-num-card {
    min-height: 150px;
    padding: 20px 18px;
  }

  .page-about .about-tl-card {
    padding: 24px 24px 18px;
  }

  .page-about .about-tl-card {
    width: calc(100% - 64px);
  }

  .page-about .about-tl-item:nth-child(even) .about-tl-card {
    margin-left: auto;
  }

  .page-about .about-service-card,
  .page-about .about-service-note {
    padding: 28px 26px;
  }

  .page-about .about-pier svg {
    height: 120px;
  }
}

@media (hover: hover) {
  .page-about .about-num-source {
    opacity: 0.7;
    transform: translateY(2px);
    transition: opacity 0.3s ease, transform 0.3s ease;
  }

  .page-about .about-num-card:hover .about-num-source,
  .page-about .about-num-card:focus-within .about-num-source {
    opacity: 1;
    transform: translateY(0);
    color: var(--bright-cyan);
  }
}