.page-about {
  --about-grid-size: 32px;
  --about-sand: #F5F0E6;
  --about-shadow-card: 0 12px 32px rgba(0, 0, 0, 0.12);
  --about-shadow-float: 0 12px 32px rgba(0, 0, 0, 0.45);
  --about-transition-fast: 0.2s ease;
  --about-transition-slow: 0.4s ease;
  background: var(--color-cream);
  color: var(--color-graphite);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .container {
  max-width: var(--container-width, 1280px);
  margin-inline: auto;
  padding-inline: 24px;
}

/* ===== 页头 ===== */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(135deg, transparent 0 42%, rgba(230, 57, 70, 0.12) 42% 42.5%, transparent 42.5% 100%),
    var(--color-graphite);
  color: var(--color-cream);
  border-bottom: 4px solid var(--color-flame);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -70px;
  bottom: 24px;
  width: 460px;
  height: 6px;
  transform: rotate(-8deg);
  background: linear-gradient(90deg, var(--color-flame), transparent 82%);
  opacity: 0.65;
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  padding-top: 48px;
  padding-bottom: 64px;
}

.page-about .about-hero .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 28px;
  font-size: var(--fs-small, 0.875rem);
  color: var(--color-rock);
}

.page-about .about-hero .breadcrumb a {
  color: var(--color-gold);
  text-decoration: none;
}

.page-about .about-hero .breadcrumb a:hover {
  color: var(--color-flame);
}

.page-about .about-hero .page-title {
  margin: 0 0 4px;
  font-family: var(--font-heading);
  font-size: var(--fs-hero, 3rem);
  line-height: 1.06;
  letter-spacing: 0.02em;
}

.page-about .about-hero .page-subtitle {
  margin: 0 0 18px;
  font-family: var(--font-heading);
  font-size: 1.25rem;
  color: var(--color-gold);
}

.page-about .about-hero__desc {
  max-width: 640px;
  margin: 0;
  line-height: 1.8;
  color: var(--color-cream);
  font-size: 1rem;
}

.page-about .about-hero__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 28px;
}

.page-about .about-hero__tags span {
  border: 1px solid var(--color-gold);
  color: var(--color-gold);
  font-size: 0.8125rem;
  padding: 5px 12px 5px 16px;
  line-height: 1.4;
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 100%, 10px 100%);
}

.page-about .about-hero__aside {
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 24px;
  background: var(--color-charcoal);
  border: 1px solid rgba(212, 175, 55, 0.5);
  box-shadow: 10px 10px 0 rgba(230, 57, 70, 0.2);
  align-self: start;
}

.page-about .about-hero__version {
  font-family: var(--font-heading);
  font-size: 1rem;
  color: var(--color-flame);
  letter-spacing: 0.06em;
}

.page-about .about-hero__facts {
  margin: 0;
}

.page-about .about-hero__facts > div {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding-block: 10px;
  border-bottom: 1px solid rgba(224, 224, 224, 0.14);
}

.page-about .about-hero__facts dt {
  color: var(--color-gold);
  font-size: var(--fs-small, 0.875rem);
}

.page-about .about-hero__facts dd {
  margin: 0;
  font-size: var(--fs-card, 1.25rem);
  font-weight: 700;
  color: var(--color-cream);
}

.page-about .about-hero__facts .stat-highlight {
  color: var(--color-flame);
}

/* ===== 章节通用 ===== */
.page-about .about-kicker {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin: 0 0 10px;
  font-family: var(--font-heading);
  font-size: 1rem;
  letter-spacing: 0.14em;
  color: var(--color-flame);
}

.page-about .about-kicker span {
  color: var(--color-rock);
  font-size: 0.875rem;
  letter-spacing: 0.08em;
}

.page-about .about-kicker--light span {
  color: rgba(245, 240, 230, 0.55);
}

.page-about .section-title {
  margin: 0 0 12px;
  font-family: var(--font-heading);
  font-size: var(--fs-section, 2rem);
  line-height: 1.15;
}

.page-about .about-section-head {
  margin-bottom: 16px;
}

.page-about .about-section-desc {
  margin: 0 0 24px;
  max-width: 680px;
  line-height: 1.75;
  color: var(--color-rock);
}

.page-about .about-aside-label {
  display: block;
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid currentColor;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-flame);
}

/* ===== 品牌由来 ===== */
.page-about .about-origin {
  padding-top: 72px;
  padding-bottom: 80px;
  background:
    linear-gradient(rgba(26, 26, 26, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(26, 26, 26, 0.035) 1px, transparent 1px),
    var(--color-cream);
  background-size: var(--about-grid-size) var(--about-grid-size), var(--about-grid-size) var(--about-grid-size), auto;
}

.page-about .about-origin__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 48px;
}

.page-about .about-origin__main {
  max-width: 780px;
}

.page-about .about-origin__lead {
  margin: 0 0 20px;
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1.8;
  color: var(--color-graphite);
}

.page-about .about-origin__main p:not(.about-origin__lead) {
  line-height: 1.85;
  color: var(--color-graphite);
}

.page-about .about-origin__figure {
  margin: 32px 0 0;
}

.page-about .about-origin__figure figcaption {
  margin-top: 12px;
  border-left: 2px solid var(--color-flame);
  padding-left: 12px;
  font-size: var(--fs-small, 0.875rem);
  color: var(--color-rock);
}

.page-about .about-origin__aside {
  align-self: start;
  padding: 28px;
  background: var(--color-terra);
  color: var(--color-graphite);
  border-left: 6px solid var(--color-flame);
  line-height: 1.75;
}

.page-about .about-origin__aside p {
  font-size: 0.9375rem;
}

.page-about .about-aside-tags {
  list-style: none;
  margin: 20px 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-aside-tags li {
  background: rgba(255, 255, 255, 0.45);
  border: 1px solid rgba(26, 26, 26, 0.2);
  font-size: 0.8125rem;
  padding: 4px 10px;
}

.page-about .about-aside-link {
  margin: 0;
}

.page-about .about-aside-link a {
  color: var(--color-graphite);
  text-decoration: none;
  border-bottom: 2px solid var(--color-graphite);
  font-weight: 700;
}

.page-about .about-aside-link a:hover {
  color: var(--color-flame);
  border-color: var(--color-flame);
}

/* ===== 发展里程碑 ===== */
.page-about .about-milestones {
  position: relative;
  overflow: hidden;
  padding-top: 80px;
  padding-bottom: 80px;
  background:
    linear-gradient(160deg, rgba(230, 57, 70, 0.08) 0%, transparent 36%),
    var(--color-graphite);
  color: var(--color-cream);
}

.page-about .about-milestones::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--color-flame), var(--color-gold), transparent);
}

.page-about .about-milestones .section-title {
  color: var(--color-cream);
}

.page-about .about-milestones .about-section-desc {
  color: rgba(245, 240, 230, 0.68);
}

.page-about .about-timeline {
  position: relative;
  margin-top: 56px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 24px;
  width: 2px;
  background: linear-gradient(180deg, var(--color-flame), var(--color-gold) 70%, transparent);
}

.page-about .timeline__item {
  position: relative;
  padding-left: 64px;
  margin-bottom: 40px;
}

.page-about .timeline__badge {
  position: absolute;
  left: 0;
  top: 24px;
  width: 18px;
  height: 18px;
  border: 3px solid var(--color-flame);
  border-radius: 50%;
  background: var(--color-graphite);
}

.page-about .timeline__card {
  background: var(--color-charcoal);
  border: 1px solid rgba(224, 224, 224, 0.12);
  border-top: 3px solid var(--color-flame);
  padding: 24px;
  transition: transform var(--about-transition-fast), box-shadow var(--about-transition-fast), border-color var(--about-transition-fast);
}

.page-about .timeline__card:hover {
  transform: translateY(-4px);
  box-shadow: var(--about-shadow-float);
  border-color: rgba(212, 175, 55, 0.6);
}

.page-about .timeline__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 10px;
}

.page-about .timeline__version {
  font-family: var(--font-heading);
  font-size: 1.375rem;
  color: var(--color-gold);
}

.page-about .timeline__tag {
  font-size: 0.8125rem;
  color: var(--color-terra);
  letter-spacing: 0.05em;
}

.page-about .timeline__card h3 {
  margin: 0 0 10px;
  font-family: var(--font-heading);
  font-size: var(--fs-card, 1.25rem);
  color: var(--color-cream);
}

.page-about .timeline__card p {
  margin: 0;
  line-height: 1.8;
  color: rgba(245, 240, 230, 0.78);
  font-size: 0.9375rem;
}

.page-about .timeline__item .collapsible-trigger {
  margin-top: 16px;
  background: none;
  border: none;
  padding: 4px 0;
  border-bottom: 1px dashed var(--color-gold);
  color: var(--color-gold);
  font-family: var(--font-body);
  font-size: 0.875rem;
  cursor: pointer;
}

.page-about .timeline__item .collapsible-trigger:hover {
  color: var(--color-flame);
  border-bottom-style: solid;
}

.page-about .timeline__item .collapsible-panel {
  margin-top: 16px;
  padding: 16px 20px;
  background: rgba(212, 175, 55, 0.07);
  border-left: 2px solid var(--color-gold);
}

.page-about .timeline__item .collapsible-panel ul {
  margin: 0;
  padding-left: 18px;
  color: rgba(245, 240, 230, 0.82);
  font-size: 0.875rem;
  line-height: 1.9;
}

.page-about .about-milestones__visual {
  max-width: 360px;
  margin: 72px auto 0;
}

.page-about .about-milestones__visual figcaption {
  margin-top: 12px;
  border-left: 2px solid var(--color-gold);
  padding-left: 12px;
  color: rgba(245, 240, 230, 0.6);
  font-size: var(--fs-small, 0.875rem);
}

/* ===== 内容体系 ===== */
.page-about .about-system {
  padding-top: 80px;
  padding-bottom: 80px;
  background:
    linear-gradient(rgba(26, 26, 26, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(26, 26, 26, 0.03) 1px, transparent 1px),
    var(--color-cream);
  background-size: calc(var(--about-grid-size) * 2) calc(var(--about-grid-size) * 2), calc(var(--about-grid-size) * 2) calc(var(--about-grid-size) * 2), auto;
}

.page-about .about-system .filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 32px 0 28px;
}

.page-about .about-system .filter-btn {
  background: transparent;
  border: 1px solid var(--color-rock);
  color: var(--color-graphite);
  padding: 8px 16px;
  font-family: var(--font-body);
  font-size: 0.875rem;
  cursor: pointer;
  transition: background var(--about-transition-fast), color var(--about-transition-fast), border-color var(--about-transition-fast);
}

.page-about .about-system .filter-btn:hover {
  border-color: var(--color-flame);
  color: var(--color-flame);
}

.page-about .about-system .filter-btn.is-active {
  background: var(--color-flame);
  border-color: var(--color-flame);
  color: var(--color-cream);
}

.page-about .about-system__cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.page-about .about-system-card {
  position: relative;
  background: var(--color-cream);
  border: 1px solid var(--color-silver);
  border-left: 4px solid var(--color-flame);
  padding: 24px;
  transition: transform var(--about-transition-fast), box-shadow var(--about-transition-fast), border-color var(--about-transition-fast);
}

.page-about .about-system-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--about-shadow-card);
  border-color: var(--color-gold);
}

.page-about .about-system-card__code {
  position: absolute;
  top: 18px;
  right: 20px;
  font-family: var(--font-heading);
  font-size: 1.625rem;
  color: var(--color-silver);
  line-height: 1;
  transition: color var(--about-transition-fast);
}

.page-about .about-system-card:hover .about-system-card__code {
  color: var(--color-flame);
}

.page-about .about-system-card__tag {
  display: inline-block;
  margin-bottom: 8px;
  background: var(--color-terra);
  color: var(--color-graphite);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 3px 10px;
}

.page-about .about-system-card h3 {
  margin: 0 0 8px;
  padding-right: 44px;
  font-family: var(--font-heading);
  font-size: var(--fs-card, 1.25rem);
  color: var(--color-graphite);
}

.page-about .about-system-card p {
  margin: 0;
  line-height: 1.75;
  color: var(--color-rock);
  font-size: 0.9375rem;
}

.page-about .about-system__notes {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  margin-top: 48px;
  padding: 28px;
  background: var(--color-terra);
  border-left: 4px solid var(--color-graphite);
}

.page-about .about-system__notes p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
}

.page-about .about-system__list {
  margin: 0;
  padding-left: 20px;
  line-height: 2;
  font-size: 0.9375rem;
}

.page-about .about-system__list strong {
  color: var(--color-graphite);
}

/* ===== 技术架构 ===== */
.page-about .about-arch {
  padding-top: 80px;
  padding-bottom: 80px;
  background: var(--color-charcoal);
  color: var(--color-cream);
}

.page-about .about-arch .section-title {
  color: var(--color-cream);
}

.page-about .about-arch .about-section-desc {
  color: rgba(245, 240, 230, 0.66);
}

.page-about .about-arch__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 36px;
}

.page-about .about-arch-card {
  padding: 24px;
  background: var(--color-graphite);
  border-top: 3px solid var(--color-flame);
  border-right: 1px solid rgba(212, 175, 55, 0.35);
  border-bottom: 1px solid rgba(212, 175, 55, 0.35);
  border-left: 1px solid transparent;
  transition: transform var(--about-transition-fast), box-shadow var(--about-transition-fast);
}

.page-about .about-arch-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--about-shadow-float);
}

.page-about .about-arch-card__key {
  display: block;
  margin-bottom: 10px;
  color: var(--color-gold);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.page-about .about-arch-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-heading);
  font-size: 1.125rem;
  color: var(--color-cream);
}

.page-about .about-arch-card p {
  margin: 0;
  color: rgba(245, 240, 230, 0.74);
  font-size: 0.9375rem;
  line-height: 1.8;
}

.page-about .about-arch__note {
  margin-top: 40px;
  padding: 28px;
  background: linear-gradient(135deg, rgba(230, 57, 70, 0.16) 0%, transparent 70%);
  border: 1px solid rgba(212, 175, 55, 0.4);
}

.page-about .about-arch__note p {
  margin: 0;
  color: rgba(245, 240, 230, 0.86);
  line-height: 1.85;
  font-size: 0.9375rem;
}

/* ===== 团队理念 ===== */
.page-about .about-team {
  padding-top: 80px;
  padding-bottom: 80px;
  background: var(--color-cream);
}

.page-about .about-team__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 48px;
}

.page-about .about-team__lead {
  margin: 0 0 24px;
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1.8;
}

.page-about .about-team__values {
  list-style: none;
  margin: 0 0 28px;
  padding: 0;
  border-top: 1px solid var(--color-silver);
}

.page-about .about-team__values li {
  display: grid;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--color-silver);
}

.page-about .about-team__values strong {
  color: var(--color-flame);
  font-size: 1rem;
  letter-spacing: 0.04em;
}

.page-about .about-team__values span {
  color: var(--color-rock);
  font-size: 0.9375rem;
  line-height: 1.75;
}

.page-about .about-team__main p:last-child {
  line-height: 1.85;
  color: var(--color-rock);
}

.page-about .about-team__figure {
  margin: 0;
  align-self: center;
}

.page-about .about-team__figure figcaption {
  margin-top: 12px;
  border-left: 2px solid var(--color-flame);
  padding-left: 12px;
  font-size: var(--fs-small, 0.875rem);
  color: var(--color-rock);
}

/* ===== 图片 ===== */
.page-about .image-container img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
}

/* ===== 延伸入口 ===== */
.page-about .about-links {
  padding-top: 48px;
  padding-bottom: 48px;
  background: var(--color-graphite);
}

.page-about .about-links__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .about-links__item {
  display: block;
  padding: 24px;
  background: var(--color-charcoal);
  border: 1px solid rgba(224, 224, 224, 0.15);
  text-decoration: none;
  color: var(--color-cream);
  transition: border-color var(--about-transition-fast), transform var(--about-transition-fast), box-shadow var(--about-transition-fast);
}

.page-about .about-links__item:hover {
  border-color: var(--color-gold);
  transform: translateY(-4px);
  box-shadow: var(--about-shadow-card);
}

.page-about .about-links__item span {
  display: block;
  color: var(--color-terra);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.page-about .about-links__item strong {
  display: block;
  margin: 8px 0 4px;
  font-family: var(--font-heading);
  font-size: 1.125rem;
  color: var(--color-cream);
}

.page-about .about-links__item small {
  color: rgba(245, 240, 230, 0.58);
  font-size: 0.875rem;
}

/* ===== 响应式 ===== */
@media (min-width: 720px) {
  .page-about .about-system__cards {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-about .about-system__notes {
    grid-template-columns: 260px 1fr;
    align-items: start;
  }

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

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

@media (min-width: 920px) {
  .page-about .about-hero__grid {
    grid-template-columns: 1fr 340px;
    align-items: start;
    padding-top: 72px;
    padding-bottom: 80px;
  }

  .page-about .about-origin__layout {
    grid-template-columns: 1fr 320px;
    gap: 64px;
  }

  .page-about .about-origin__aside {
    position: sticky;
    top: 24px;
  }

  .page-about .about-timeline::before {
    left: 50%;
    margin-left: -1px;
  }

  .page-about .timeline__item {
    width: 50%;
    padding-left: 0;
  }

  .page-about .timeline__item:nth-child(odd) {
    margin-left: 0;
    padding-right: 64px;
    text-align: right;
  }

  .page-about .timeline__item:nth-child(odd) .timeline__meta,
  .page-about .timeline__item:nth-child(odd) .collapsible-trigger,
  .page-about .timeline__item:nth-child(odd) .collapsible-panel {
    text-align: right;
  }

  .page-about .timeline__item:nth-child(even) {
    margin-left: 50%;
    padding-left: 64px;
  }

  .page-about .timeline__badge {
    left: auto;
    right: -11px;
  }

  .page-about .timeline__item:nth-child(even) .timeline__badge {
    right: auto;
    left: -11px;
  }

  .page-about .about-team__grid {
    grid-template-columns: 1.1fr 0.9fr;
    gap: 64px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-system__cards {
    grid-template-columns: repeat(3, 1fr);
  }

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

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