.page-about {
  background: var(--ink);
  color: var(--bone);
  overflow-x: hidden;
}

.page-about p {
  line-height: 1.75;
}

/* ---------- 首屏 ---------- */
.page-about .about-intro {
  position: relative;
  padding: var(--step-5) 0 var(--step-6);
  border-bottom: 1px solid var(--line);
}

.page-about .about-intro::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(var(--line-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: linear-gradient(180deg, #000 0%, transparent 88%);
  mask-image: linear-gradient(180deg, #000 0%, transparent 88%);
}

.page-about .about-intro > .container {
  position: relative;
  z-index: 1;
}

.page-about .intro-grid {
  align-items: start;
  row-gap: var(--step-5);
}

.page-about .about-intro h1 {
  margin: var(--step-3) 0;
  max-width: 16ch;
  letter-spacing: -0.02em;
}

.page-about .about-intro .lede {
  max-width: 46ch;
  color: var(--bone);
  opacity: 0.86;
  font-size: 16px;
}

.page-about .about-vert {
  position: absolute;
  top: 130px;
  right: 24px;
  z-index: 1;
  display: none;
  writing-mode: vertical-rl;
  letter-spacing: 0.32em;
  font-size: 12px;
  color: var(--mist);
}

.page-about .about-index {
  padding: var(--step-4);
  border-top: 2px solid var(--red);
}

.page-about .about-index__list {
  list-style: none;
  margin: var(--step-3) 0 0;
  padding: 0;
}

.page-about .about-index__list li + li {
  border-top: 1px solid var(--line);
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 0;
  color: var(--bone);
  text-decoration: none;
  font-size: 16px;
  transition: color 180ms ease, transform 180ms ease;
}

.page-about .about-index__list a .mono {
  font-size: 12px;
  color: var(--mist);
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--cyan);
  transform: translateX(4px);
}

.page-about .about-index__list a:hover .mono,
.page-about .about-index__list a:focus-visible .mono {
  color: var(--cyan);
}

/* ---------- 区块通用 ---------- */
.page-about .zone {
  padding: var(--step-6) 0;
  border-top: 1px solid var(--line);
}

.page-about .sec-head {
  max-width: 760px;
  margin-bottom: var(--step-5);
}

.page-about .sec-head h2 {
  margin: var(--step-2) 0 var(--step-3);
  letter-spacing: -0.02em;
}

.page-about .sec-head p {
  color: var(--mist);
  max-width: 58ch;
}

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

.page-about .side-note {
  padding: var(--step-3);
  font-size: 13px;
  line-height: 1.75;
  color: var(--mist);
  border-left: 2px solid var(--cyan);
}

/* ---------- 起点与定位 ---------- */
.page-about .origin-grid {
  align-items: start;
  row-gap: var(--step-5);
}

.page-about .origin-text h2 {
  margin: var(--step-2) 0 var(--step-3);
  letter-spacing: -0.02em;
}

.page-about .origin-text p + p {
  margin-top: var(--step-3);
}

.page-about .origin-text p {
  color: rgba(242, 239, 245, 0.84);
  max-width: 54ch;
}

.page-about .origin-side .media-frame {
  margin-bottom: var(--step-3);
}

/* ---------- 年表 ---------- */
.page-about .timeline-banner {
  margin-bottom: var(--step-5);
}

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .tl-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--step-2);
}

.page-about .tl-year {
  font-family: var(--font-mono);
  font-size: 28px;
  line-height: 1.1;
  color: var(--cyan);
  letter-spacing: -0.01em;
}

.page-about .tl-mark {
  display: none;
}

.page-about .tl-body h3 {
  font-size: 20px;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}

.page-about .tl-body p {
  color: var(--mist);
  max-width: 62ch;
}

.page-about .tl-body {
  padding-bottom: var(--step-5);
}

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

.page-about .tl-break {
  list-style: none;
  margin: 0 0 var(--step-5);
}

.page-about .break-panel {
  display: flex;
  flex-direction: column;
  gap: var(--step-2);
  padding: var(--step-4);
  border-left: 2px solid var(--amber);
}

.page-about .break-num {
  font-size: 40px;
  line-height: 1;
  color: var(--amber);
}

.page-about .break-panel p:last-child {
  color: rgba(242, 239, 245, 0.84);
  max-width: 60ch;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  align-items: start;
  row-gap: var(--step-5);
}

.page-about .role-grid {
  display: grid;
  gap: var(--step-2);
}

.page-about .role-card {
  padding: var(--step-3);
  border-top: 2px solid var(--red);
}

.page-about .role-num {
  font-size: 28px;
  line-height: 1;
  color: var(--cyan);
}

.page-about .role-card h3 {
  font-size: 15px;
  margin: 10px 0 8px;
}

.page-about .role-card p {
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .team-side .media-frame {
  margin-bottom: var(--step-3);
}

.page-about .flow {
  list-style: none;
  margin: var(--step-5) 0 0;
  padding: 0;
  display: grid;
  gap: var(--step-4);
}

.page-about .flow li {
  border-top: 1px solid var(--line);
  padding-top: var(--step-3);
}

.page-about .flow-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .flow h3 {
  font-size: 18px;
  margin: 10px 0 8px;
}

.page-about .flow p {
  font-size: 13px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 合作与服务范围 ---------- */
.page-about .partner-grid {
  align-items: start;
  row-gap: var(--step-5);
}

.page-about .partner-grid .col-7 p + p {
  margin-top: var(--step-3);
}

.page-about .partner-grid .col-7 p {
  color: rgba(242, 239, 245, 0.84);
  max-width: 54ch;
}

.page-about .coverage {
  padding: var(--step-4);
  border-left: 2px solid var(--cyan);
}

.page-about .coverage .stat-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 56px;
  line-height: 1;
  color: var(--cyan);
}

.page-about .coverage .stat-label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  color: var(--mist);
}

.page-about .coverage p {
  margin-top: var(--step-3);
  font-size: 13px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 里程碑 ---------- */
.page-about .ms-grid {
  display: grid;
  gap: var(--step-2);
}

.page-about .ms-card {
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--step-3);
  transition: border-color 180ms ease;
}

.page-about .ms-card:hover,
.page-about .ms-card[open] {
  border-color: var(--line-strong);
}

.page-about .ms-card summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 600;
  color: var(--bone);
}

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

.page-about .ms-card summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--cyan);
}

.page-about .ms-card[open] summary::after {
  content: "–";
}

.page-about .ms-card p {
  margin-top: var(--step-2);
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 数字索引 ---------- */
.page-about .num-head {
  margin-bottom: var(--step-4);
  letter-spacing: -0.02em;
}

.page-about .num-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .num-item {
  position: relative;
  background: var(--teal);
  padding: var(--step-3) var(--step-3) var(--step-5);
}

.page-about .num-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 30px;
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .num-label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .num-item::after {
  content: attr(data-source);
  position: absolute;
  left: var(--step-3);
  bottom: var(--step-2);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--amber);
  opacity: 0;
  transform: translateY(4px);
  transition: opacity 180ms ease, transform 180ms ease;
  pointer-events: none;
}

.page-about .num-item:hover::after,
.page-about .num-item:focus-visible::after {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 延伸入口 ---------- */
.page-about .next-grid {
  align-items: center;
  row-gap: var(--step-4);
}

.page-about .next-grid h2 {
  margin-bottom: var(--step-3);
  letter-spacing: -0.02em;
}

.page-about .next-grid p {
  color: var(--mist);
  max-width: 52ch;
}

.page-about .next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .role-grid {
    grid-template-columns: repeat(3, 1fr);
  }

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

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

@media (min-width: 780px) {
  .page-about .tl-item {
    grid-template-columns: 150px 28px 1fr;
    gap: 0;
  }

  .page-about .tl-year {
    font-size: 40px;
    text-align: right;
    padding-right: 20px;
  }

  .page-about .tl-mark {
    display: block;
    position: relative;
  }

  .page-about .tl-mark::before {
    content: "";
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 1px;
    background: var(--line);
    transform: translateX(-50%);
  }

  .page-about .tl-item:last-child .tl-mark::before {
    background: linear-gradient(180deg, var(--line), transparent);
  }

  .page-about .tl-mark::after {
    content: "";
    position: absolute;
    left: 50%;
    top: 8px;
    width: 9px;
    height: 9px;
    background: var(--cyan);
    transform: translateX(-50%) rotate(45deg);
    box-shadow: 0 0 0 4px rgba(75, 240, 214, 0.12);
  }

  .page-about .tl-break {
    padding-left: 178px;
  }

  .page-about .break-panel {
    flex-direction: row;
    align-items: center;
    gap: var(--step-5);
  }

  .page-about .break-num {
    min-width: 190px;
    font-size: 48px;
  }
}

@media (min-width: 900px) {
  .page-about .flow {
    grid-template-columns: repeat(4, 1fr);
    gap: var(--step-3);
  }

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

@media (min-width: 1100px) {
  .page-about .ms-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .num-value {
    font-size: 34px;
  }
}

@media (min-width: 1240px) {
  .page-about .about-vert {
    display: block;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__list a,
  .page-about .ms-card,
  .page-about .num-item::after {
    transition: none;
  }

  .page-about .about-index__list a:hover,
  .page-about .about-index__list a:focus-visible {
    transform: none;
  }
}