.page-about {
  background-color: var(--c-cream);
  color: var(--c-blue);
  overflow-x: hidden;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about a {
  color: inherit;
}

/* ===== 平台定位 / 英雄区 ===== */
.page-about .about-hero {
  position: relative;
  background-color: var(--c-blue);
  background-image: linear-gradient(135deg, rgba(13, 27, 42, 0.96) 0%, rgba(20, 33, 61, 0.9) 58%, rgba(29, 53, 87, 0.82) 100%);
  color: var(--c-white);
  padding-top: var(--space-12);
  padding-bottom: var(--space-16);
  border-bottom: 8px solid var(--c-red);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 36%;
  height: 100%;
  background: linear-gradient(135deg, transparent 0%, transparent 42%, rgba(230, 57, 70, 0.42) 42%, rgba(230, 57, 70, 0.42) 58%, transparent 58%);
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: var(--space-12);
  align-items: center;
}

.page-about .about-hero-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.page-about .about-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.7);
  margin-bottom: var(--space-6);
}

.page-about .about-breadcrumb a {
  color: var(--c-yellow);
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.page-about .about-breadcrumb a:hover,
.page-about .about-breadcrumb a:focus-visible {
  border-bottom-color: var(--c-yellow);
}

.page-about .about-breadcrumb-sep {
  opacity: 0.5;
}

.page-about .about-breadcrumb [aria-current="page"] {
  color: var(--c-white);
}

.page-about .about-hero-pageindex {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.34em;
  color: var(--c-yellow);
  text-transform: uppercase;
  border: 2px solid rgba(255, 255, 255, 0.28);
  padding: 0.4rem 0.8rem;
  margin-bottom: var(--space-8);
  transform: rotate(-1.2deg);
}

.page-about .about-hero-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.2rem, 6vw, 5rem);
  line-height: 1.06;
  letter-spacing: 0.01em;
  text-transform: uppercase;
  margin: 0 0 var(--space-8);
  max-width: 15ch;
}

.page-about .about-hero-title em {
  font-style: normal;
  color: var(--c-yellow);
}

.page-about .about-lede {
  font-size: 1rem;
  line-height: 1.85;
  max-width: 56ch;
  color: rgba(255, 255, 255, 0.86);
  margin: 0 0 var(--space-8);
}

.page-about .about-lede strong {
  color: var(--c-white);
  font-weight: 700;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-12);
}

.page-about .about-hero-actions .btn {
  margin: 0;
}

.page-about .about-hero-actions .btn-primary {
  background: var(--c-red);
  border-color: var(--c-white);
  color: var(--c-white);
  box-shadow: 5px 5px 0 rgba(0, 0, 0, 0.24);
}

.page-about .about-hero-actions .btn-outline {
  border-color: rgba(255, 255, 255, 0.7);
  color: var(--c-white);
  background: transparent;
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: 1fr;
  border-top: 3px solid rgba(255, 255, 255, 0.3);
  border-bottom: 3px solid rgba(255, 255, 255, 0.3);
  width: 100%;
}

.page-about .about-fact {
  padding: var(--space-6) var(--space-4);
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.page-about .about-fact + .about-fact {
  border-top: 3px solid rgba(255, 255, 255, 0.3);
}

.page-about .about-fact-num {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2rem, 3vw, 3.2rem);
  color: var(--c-yellow);
  line-height: 1;
}

.page-about .about-fact-label {
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: rgba(255, 255, 255, 0.78);
}

.page-about .about-hero-visual {
  position: relative;
  margin-top: var(--space-8);
}

.page-about .about-hero-media {
  position: relative;
  border: 4px solid var(--c-white);
  background: var(--c-gray-light);
  box-shadow: 10px 10px 0 var(--c-blue-dark);
  transform: rotate(-1.2deg);
}

.page-about .about-hero-media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  object-position: center;
}

.page-about .about-hero-slashed {
  position: absolute;
  top: -12px;
  right: 24px;
  width: 44%;
  height: 20px;
  background: var(--c-yellow);
  border: 3px solid var(--c-white);
  z-index: 2;
  transform: rotate(4deg);
}

.page-about .about-hero-sticker {
  position: absolute;
  left: 14px;
  bottom: 28px;
  background: var(--c-blue);
  color: var(--c-white);
  border: 3px solid var(--c-white);
  box-shadow: 6px 6px 0 var(--c-red);
  padding: var(--space-4) var(--space-6);
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  line-height: 1.3;
}

.page-about .about-hero-sticker strong {
  display: block;
  color: var(--c-yellow);
  font-size: 1.3rem;
}

.page-about .about-hero-sticker span {
  font-size: 0.7rem;
  letter-spacing: 0.3em;
}

/* ===== 发展里程碑 ===== */
.page-about .about-milestones {
  position: relative;
  padding: var(--space-16) 0;
  background-color: var(--c-cream);
}

.page-about .about-milestones::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 14px;
  background: repeating-linear-gradient(135deg, var(--c-cream) 0px, var(--c-cream) 8px, var(--c-gray-light) 8px, var(--c-gray-light) 10px);
}

.page-about .about-milestone-layout {
  display: grid;
  gap: var(--space-16);
}

.page-about .about-milestone-intro {
  align-self: start;
}

.page-about .about-milestone-intro .section-head {
  margin-bottom: var(--space-6);
}

.page-about .about-milestone-desc {
  font-size: 1rem;
  line-height: 1.85;
  color: var(--c-gray);
  margin: 0 0 var(--space-8);
}

.page-about .about-milestone-points {
  list-style: none;
  padding: 0;
  margin: 0 0 var(--space-8);
  border-top: 3px solid var(--c-blue);
}

.page-about .about-milestone-points li {
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--c-gray-light);
  display: flex;
  gap: var(--space-4);
  align-items: baseline;
  font-size: 0.95rem;
}

.page-about .about-milestone-points li::before {
  content: "▸";
  color: var(--c-red);
  font-weight: 700;
  flex: 0 0 auto;
}

.page-about .about-timeline {
  position: relative;
  margin: 0;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 6px;
  left: 10px;
  width: 4px;
  background: var(--c-blue);
}

.page-about .about-timeline-item {
  position: relative;
  margin-bottom: var(--space-6);
  padding-left: calc(2.2rem + 14px);
  background: none;
  border: 0;
  box-shadow: none;
}

.page-about .about-timeline-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 24px;
  height: 24px;
  background: var(--c-yellow);
  border: 4px solid var(--c-blue);
  transform: rotate(45deg);
  z-index: 2;
}

.page-about .about-timeline-head {
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  cursor: pointer;
  padding: var(--space-4) var(--space-6);
  border: 3px solid var(--c-blue);
  background: var(--c-white);
  box-shadow: 6px 6px 0 var(--c-blue-dark);
}

.page-about .about-timeline-head::-webkit-details-marker {
  display: none;
}

.page-about .about-timeline-head:hover {
  background: var(--c-cream);
}

.page-about .about-timeline-index {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  background: var(--c-red);
  color: var(--c-white);
  padding: 0.35rem 0.6rem;
  border: 2px solid var(--c-blue);
  box-shadow: 3px 3px 0 var(--c-yellow);
  line-height: 1;
  flex: 0 0 auto;
}

.page-about .about-timeline-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1rem, 2vw, 1.4rem);
  text-transform: uppercase;
  letter-spacing: 0.02em;
  line-height: 1.2;
  flex: 1;
}

.page-about .about-timeline-caret {
  width: 10px;
  height: 10px;
  border-right: 3px solid var(--c-blue);
  border-bottom: 3px solid var(--c-blue);
  transform: rotate(45deg);
  flex: 0 0 auto;
  transition: transform 0.2s ease, margin-top 0.2s ease;
}

.page-about .about-timeline-item[open] .about-timeline-caret {
  transform: rotate(225deg);
  margin-top: 8px;
}

.page-about .about-timeline-body {
  padding: var(--space-6);
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--c-gray);
  background: var(--c-cream);
  border: 3px solid var(--c-blue);
  border-top: 0;
  box-shadow: 6px 6px 0 var(--c-blue-dark);
}

.page-about .about-timeline-body p {
  margin: 0;
}

/* ===== 内容体系 ===== */
.page-about .about-system {
  position: relative;
  background-color: var(--c-blue-dark);
  background-image: radial-gradient(circle at 92% 12%, rgba(255, 195, 0, 0.12) 0px, transparent 160px);
  color: var(--c-white);
  padding: var(--space-16) 0 var(--space-24);
  border-top: 6px solid var(--c-black);
}

.page-about .about-system::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 12px;
  background: linear-gradient(90deg, var(--c-red), var(--c-yellow), var(--c-red), var(--c-yellow), var(--c-red), var(--c-yellow));
}

.page-about .about-system .section-label {
  color: var(--c-yellow);
}

.page-about .about-system .section-title {
  color: var(--c-white);
}

.page-about .about-system-grid {
  display: grid;
  gap: var(--space-6);
  margin-top: var(--space-12);
}

.page-about .about-system-item {
  position: relative;
  background: var(--c-white);
  color: var(--c-blue);
  border: 4px solid var(--c-black);
  padding: var(--space-8);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  clip-path: polygon(100% 0%, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0% 100%, 0% 0%);
}

.page-about .system-video {
  box-shadow: 8px 8px 0 var(--c-red);
}

.page-about .system-nav {
  box-shadow: 8px 8px 0 var(--c-blue-2);
}

.page-about .system-column {
  box-shadow: 8px 8px 0 var(--c-yellow);
}

.page-about .system-analysis {
  box-shadow: 8px 8px 0 var(--c-green);
}

.page-about .about-system-index {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.88rem;
  display: inline-block;
  width: max-content;
  padding: 0.35rem 0.75rem;
  border: 2px solid var(--c-blue);
  transform: rotate(-2deg);
}

.page-about .system-video .about-system-index {
  background: var(--c-red);
  color: var(--c-white);
}

.page-about .system-nav .about-system-index {
  background: var(--c-yellow);
  color: var(--c-blue);
}

.page-about .system-column .about-system-index {
  background: var(--c-blue);
  color: var(--c-white);
  border-color: var(--c-yellow);
}

.page-about .system-analysis .about-system-index {
  background: var(--c-green);
  color: var(--c-blue);
}

.page-about .about-system-item h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  text-transform: uppercase;
  margin: var(--space-4) 0 0;
  line-height: 1.15;
}

.page-about .about-system-item p {
  font-size: 0.92rem;
  line-height: 1.75;
  color: var(--c-gray);
  flex: 1;
  margin: 0;
}

.page-about .about-system-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-red-deep);
  border-top: 1px solid var(--c-gray-light);
  padding-top: var(--space-4);
}

.page-about .about-system-visual {
  display: grid;
  gap: var(--space-8);
  margin-top: var(--space-16);
  align-items: center;
}

.page-about .about-system-visual-copy {
  font-size: 1rem;
  line-height: 1.85;
  color: rgba(255, 255, 255, 0.84);
  border-left: 6px solid var(--c-yellow);
  padding-left: var(--space-6);
}

.page-about .about-system-visual-copy p {
  margin: 0;
}

.page-about .about-system-visual-media {
  max-width: 360px;
  border: 4px solid var(--c-yellow);
  box-shadow: 10px 10px 0 var(--c-red);
  background: var(--c-gray);
}

.page-about .about-system-visual-media img {
  display: block;
  width: 100%;
  height: auto;
}

/* ===== 服务能力 ===== */
.page-about .about-services {
  padding: var(--space-16) 0;
  background-color: var(--c-cream);
}

.page-about .about-services-inner {
  display: grid;
  gap: var(--space-16);
  align-items: center;
}

.page-about .about-service-desc {
  max-width: 60ch;
  line-height: 1.85;
  color: var(--c-gray);
  margin: 0 0 var(--space-8);
}

.page-about .about-service-list {
  list-style: none;
  display: grid;
  gap: 0;
  border-top: 4px solid var(--c-blue);
  padding: 0;
  margin: 0 0 var(--space-12);
}

.page-about .about-service-list li {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.25rem;
  padding: var(--space-6);
  background: var(--c-white);
  border-bottom: 2px solid var(--c-gray-light);
  border-left: 4px solid var(--c-yellow);
}

.page-about .about-service-list li strong {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--c-blue);
}

.page-about .about-service-list li span {
  color: var(--c-gray);
  font-size: 0.95rem;
  line-height: 1.7;
}

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

.page-about .about-service-visual {
  position: relative;
}

.page-about .about-service-media {
  position: relative;
  border: 5px solid var(--c-blue);
  box-shadow: 12px 12px 0 var(--c-red);
  transform: rotate(1.2deg);
  background: var(--c-gray-light);
}

.page-about .about-service-media img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-service-media::after {
  content: "HISTORY SYNC";
  position: absolute;
  top: 16px;
  right: 16px;
  background: var(--c-red);
  color: var(--c-white);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: 0.22em;
  padding: 0.4rem 0.9rem;
  border: 2px solid var(--c-blue);
}

/* ===== 平板适配 ===== */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .about-fact + .about-fact {
    border-top: 0;
    border-left: 3px solid rgba(255, 255, 255, 0.3);
  }

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

  .page-about .about-system-visual {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .page-about .about-service-list li {
    grid-template-columns: 140px 1fr;
    gap: var(--space-6);
  }
}

/* ===== 桌面适配 ===== */
@media (min-width: 1024px) {
  .page-about .about-hero {
    padding-top: var(--space-16);
    padding-bottom: var(--space-24);
  }

  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: var(--space-16);
  }

  .page-about .about-hero-visual {
    margin-top: 0;
  }

  .page-about .about-hero-sticker {
    left: -18px;
  }

  .page-about .about-hero-title {
    max-width: none;
  }

  .page-about .about-milestone-layout {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    gap: var(--space-16);
  }

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

  .page-about .system-nav,
  .page-about .system-column {
    transform: rotate(0.6deg);
  }

  .page-about .system-video,
  .page-about .system-analysis {
    transform: rotate(-0.4deg);
  }

  .page-about .about-system-visual {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

  .page-about .about-system-visual-media {
    max-width: 420px;
    justify-self: end;
  }

  .page-about .about-services-inner {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    gap: var(--space-16);
  }
}