.page-about {
  background: var(--deep-black);
  color: var(--ink-white);
  position: relative;
  overflow: hidden;
}

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

.page-about .about-breadcrumb {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: var(--space-md) var(--container-pad) 0;
}

.page-about .about-welcome {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--container-pad) var(--space-lg);
}

.page-about .section-index {
  font-size: var(--caption-size);
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--champagne-gold);
  text-transform: uppercase;
  margin: 0 0 var(--space-sm);
}

.page-about .about-welcome h1 {
  font-size: var(--heading-size-xl);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: 0.01em;
  margin: 0 0 var(--space-md);
  max-width: 18em;
}

.page-about .about-manifesto {
  font-size: clamp(1.125rem, 2.4vw, 1.75rem);
  font-weight: 300;
  line-height: 1.8;
  color: rgba(245, 243, 239, 0.92);
  max-width: 42rem;
  margin: 0 0 var(--space-md);
}

.page-about .about-manifesto-note {
  font-size: var(--caption-size);
  color: var(--dim-gray);
  line-height: 1.7;
  max-width: 34rem;
  margin: 0;
  border-left: 2px solid var(--border-red);
  padding-left: var(--space-sm);
}

.page-about .about-principle {
  max-width: var(--container-width);
  margin: 0 auto;
  display: grid;
  gap: var(--space-lg);
  padding: var(--space-lg) var(--container-pad) var(--space-xl);
  border-top: 1px solid rgba(200, 16, 46, 0.4);
}

.page-about .principle-word {
  margin: 0;
  font-size: clamp(2rem, 5.5vw, 4.25rem);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink-white);
  position: relative;
  padding-bottom: var(--space-md);
}

.page-about .principle-word::after {
  content: "";
  display: block;
  width: 6.5rem;
  height: 4px;
  background: linear-gradient(90deg, var(--lafei-red), var(--champagne-gold));
  margin-top: var(--space-sm);
}

.page-about .word-accent {
  color: var(--champagne-gold);
}

.page-about .principle-copy h2 {
  font-size: var(--heading-size-lg);
  font-weight: 900;
  margin: 0 0 var(--space-sm);
}

.page-about .principle-copy p {
  color: rgba(245, 243, 239, 0.75);
  line-height: 1.7;
  margin: 0 0 var(--space-sm);
}

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

.page-about .about-timeline {
  background: var(--soft-black);
  padding: var(--space-xl) var(--container-pad);
}

.page-about .timeline-head,
.page-about .timeline-layout {
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
}

.page-about .timeline-head {
  margin-bottom: var(--space-lg);
}

.page-about .timeline-head h2,
.page-about .about-commitment h2,
.page-about .about-evolution h2 {
  font-size: var(--heading-size-lg);
  font-weight: 900;
  margin: 0;
}

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

.page-about .timeline-visual {
  margin: 0;
}

.page-about .timeline-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  clip-path: polygon(0 0, calc(100% - 28px) 0, 100% 28px, 100% 100%, 0 100%);
}

.page-about .timeline-list {
  position: relative;
  padding-left: 56px;
}

.page-about .timeline-list::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 6px;
  bottom: 6px;
  width: 3px;
  background: linear-gradient(180deg, var(--lafei-red) 0%, var(--lafei-red) 78%, var(--champagne-gold) 100%);
  border-radius: 2px;
}

.page-about .timeline-item {
  position: relative;
  padding-bottom: var(--space-md);
}

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

.page-about .era-tag {
  position: absolute;
  left: -56px;
  top: 6px;
  width: 50px;
  text-align: right;
  font-size: var(--caption-size);
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--champagne-gold);
  white-space: nowrap;
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 10px;
  width: 10px;
  height: 10px;
  background: var(--lafei-red);
  border: 2px solid var(--champagne-gold);
  border-radius: 50%;
  z-index: 2;
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
}

.page-about .timeline-item:hover::before {
  transform: scale(1.35);
  box-shadow: 0 0 0 6px rgba(212, 175, 55, 0.15);
}

.page-about .era-card {
  background: var(--deep-black);
  padding: var(--space-md);
  position: relative;
  border-left: 2px solid var(--border-red);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
  transition: border-color 0.3s var(--ease-out);
}

.page-about .era-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--lafei-red), var(--champagne-gold));
}

.page-about .era-card h3 {
  font-size: var(--heading-size-sm);
  font-weight: 900;
  margin: 0 0 var(--space-xs);
}

.page-about .era-card p {
  font-size: var(--body-size);
  line-height: 1.7;
  color: rgba(245, 243, 239, 0.72);
  margin: 0;
}

.page-about .about-commitment {
  max-width: var(--container-width);
  margin: 0 auto;
  display: grid;
  gap: var(--space-lg);
  padding: var(--space-xl) var(--container-pad);
}

.page-about .commitment-copy h2 {
  margin-bottom: var(--space-lg);
}

.page-about .commitment-item {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: var(--space-sm);
  padding: var(--space-sm) 0;
  border-top: 1px solid rgba(245, 243, 239, 0.08);
}

.page-about .commitment-num {
  font-size: 1rem;
  font-weight: 900;
  color: var(--lafei-red);
  line-height: 1.5;
}

.page-about .commitment-item h3 {
  font-size: 1rem;
  font-weight: 700;
  margin: 0 0 6px;
}

.page-about .commitment-item p {
  font-size: var(--body-size);
  line-height: 1.7;
  color: rgba(245, 243, 239, 0.75);
  margin: 0;
}

.page-about .commitment-visual {
  margin: 0;
}

.page-about .commitment-img {
  width: 100%;
  object-fit: cover;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 24px), calc(100% - 24px) 100%, 0 100%);
}

.page-about .about-evolution {
  background: var(--soft-black);
  padding: var(--space-xl) var(--container-pad);
}

.page-about .about-evolution > .section-index,
.page-about .about-evolution > h2,
.page-about .evolution-visual,
.page-about .about-version-list {
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
}

.page-about .about-evolution > h2 {
  margin-bottom: var(--space-lg);
}

.page-about .evolution-visual {
  margin-bottom: var(--space-lg);
}

.page-about .evolution-img {
  width: 100%;
  max-height: 320px;
  object-fit: cover;
}

.page-about .about-version-list {
  display: grid;
  gap: var(--space-sm);
}

.page-about .version-entry {
  border: 1px solid rgba(245, 243, 239, 0.1);
  background: var(--deep-black);
  transition: border-color 0.3s var(--ease-out);
}

.page-about .version-entry:hover {
  border-color: rgba(212, 175, 55, 0.5);
}

.page-about .version-toggle {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
  width: 100%;
  padding: var(--space-md);
  background: none;
  border: none;
  color: var(--ink-white);
  font-family: var(--body-font);
  cursor: pointer;
  text-align: left;
}

.page-about .version-toggle:focus-visible {
  outline: 2px solid var(--champagne-gold);
  outline-offset: -2px;
}

.page-about .version-code {
  min-width: 64px;
  font-weight: 900;
  color: var(--champagne-gold);
  font-size: 1rem;
  letter-spacing: 0.04em;
}

.page-about .version-code.is-current::after {
  content: "当前";
  display: inline-block;
  margin-left: 8px;
  padding: 2px 8px;
  background: var(--lafei-red);
  color: #ffffff;
  font-size: 0.625rem;
  font-weight: 700;
  border-radius: 2px;
  vertical-align: middle;
}

.page-about .version-name {
  flex: 1 1 240px;
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--ink-white);
}

.page-about .version-state {
  margin-left: auto;
  font-size: var(--caption-size);
  color: var(--dim-gray);
}

.page-about .version-panel {
  padding: 0 var(--space-md) var(--space-md);
}

.page-about .version-panel ul {
  margin: 0;
  padding: var(--space-sm) 0 0 var(--space-sm);
  list-style: none;
}

.page-about .version-panel li {
  position: relative;
  padding-left: var(--space-sm);
  font-size: var(--body-size);
  line-height: 1.7;
  color: rgba(245, 243, 239, 0.75);
}

.page-about .version-panel li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.75em;
  width: 6px;
  height: 6px;
  background: var(--lafei-red);
  transform: rotate(45deg);
}

.page-about .about-facts {
  padding: var(--space-xl) var(--container-pad);
  background: linear-gradient(135deg, rgba(200, 16, 46, 0.3), rgba(11, 11, 15, 0.9) 55%), var(--deep-black);
}

.page-about .facts-grid {
  max-width: var(--container-width);
  margin: 0 auto var(--space-lg);
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
}

.page-about .fact-item {
  padding: var(--space-md);
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(11, 11, 15, 0.55);
  backdrop-filter: blur(4px);
  clip-path: polygon(0 0, calc(100% - var(--cut-size)) 0, 100% var(--cut-size), 100% 100%, 0 100%);
}

.page-about .fact-num {
  display: block;
  font-size: clamp(1.75rem, 4vw, 3rem);
  font-weight: 900;
  color: var(--champagne-gold);
  line-height: 1.1;
  font-feature-settings: "tnum";
}

.page-about .fact-label {
  display: block;
  margin-top: var(--space-xs);
  font-size: var(--caption-size);
  color: rgba(245, 243, 239, 0.8);
  letter-spacing: 0.04em;
}

.page-about .facts-links {
  max-width: var(--container-width);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

@media (min-width: 900px) {
  .page-about .about-principle {
    grid-template-columns: 1.15fr 1fr;
    align-items: center;
    gap: var(--space-xl);
  }

  .page-about .timeline-layout {
    grid-template-columns: 300px 1fr;
    align-items: start;
    gap: var(--space-xl);
  }

  .page-about .timeline-visual {
    position: sticky;
    top: 150px;
  }

  .page-about .timeline-list {
    padding-left: 96px;
  }

  .page-about .timeline-list::before {
    left: 24px;
  }

  .page-about .timeline-item::before {
    left: 20px;
  }

  .page-about .era-tag {
    left: -96px;
    width: 72px;
  }

  .page-about .about-commitment {
    grid-template-columns: 1.2fr 0.75fr;
    align-items: center;
    gap: var(--space-xl);
  }

  .page-about .commitment-visual {
    order: 2;
  }

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