.page-about {
  --about-line: 1px solid var(--rule);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  overflow-x: hidden;
  padding-bottom: clamp(40px, 7vw, 88px);
}

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

.page-about figure {
  margin: 0;
}

.page-about .about-crumb {
  padding-top: clamp(14px, 3vw, 26px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(20px, 4vw, 40px) 0 clamp(32px, 6vw, 64px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -16%;
  right: -14%;
  width: 62%;
  height: 132%;
  background: var(--pitch);
  opacity: 0.55;
  clip-path: polygon(38% 0, 100% 0, 100% 100%, 0 100%);
  z-index: 0;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(22px, 4vw, 44px);
}

.page-about .about-hero__figure {
  border: var(--about-line);
  background: var(--stand);
  padding: 8px;
  box-shadow: 10px 10px 0 0 rgba(44, 90, 78, 0.28);
}

.page-about .about-hero__figure img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
}

.page-about .about-hero h1 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 6vw, 54px);
  line-height: 1.14;
  letter-spacing: -0.012em;
}

.page-about .about-hero__lead {
  margin: clamp(14px, 2.4vw, 20px) 0 0;
  max-width: 34em;
  font-size: clamp(15px, 2.2vw, 17px);
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-stats {
  list-style: none;
  margin: clamp(22px, 4vw, 32px) 0 0;
  padding: clamp(16px, 3vw, 22px) 0 0;
  border-top: var(--about-line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 14px;
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .about-stats__num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(20px, 3.2vw, 27px);
  line-height: 1.1;
  color: var(--amber);
  letter-spacing: 0.02em;
}

.page-about .about-stats__key {
  font-size: 12.5px;
  color: var(--mist);
  letter-spacing: 0.04em;
}

/* ---------- 年份导航 ---------- */
.page-about .year-nav {
  display: grid;
  gap: 10px;
  padding: clamp(14px, 2.5vw, 20px) 0;
  border-top: var(--about-line);
  border-bottom: var(--about-line);
}

.page-about .year-nav .annotation {
  color: var(--mist);
}

.page-about .year-nav ol {
  list-style: none;
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  overflow-x: auto;
}

.page-about .year-nav a {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 128px;
  padding: 10px 14px;
  border: var(--about-line);
  color: var(--paper);
  text-decoration: none;
  transition: border-color 180ms ease, background 180ms ease, color 180ms ease;
}

.page-about .year-nav a:hover,
.page-about .year-nav a:focus-visible {
  border-color: var(--cyan);
  background: rgba(47, 243, 208, 0.08);
  color: var(--cyan);
}

.page-about .year-nav__num {
  font-family: var(--font-mono);
  font-size: 17px;
  letter-spacing: 0.02em;
}

.page-about .year-nav__key {
  font-size: 12px;
  color: var(--mist);
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding: clamp(36px, 6.5vw, 76px) 0 0;
}

.page-about .about-section__head {
  display: grid;
  gap: 10px;
  margin-bottom: clamp(24px, 4vw, 40px);
  max-width: 46em;
}

.page-about .section-index {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(30px, 6vw, 54px);
  line-height: 1;
  letter-spacing: 0.02em;
  color: transparent;
  -webkit-text-stroke: 1px var(--rule);
}

.page-about .about-section__head h2 {
  margin: 0;
  font-size: clamp(23px, 4vw, 36px);
  line-height: 1.24;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .about-section__intro {
  margin: 0;
  max-width: 34em;
  color: var(--mist);
  font-size: 15.5px;
  line-height: 1.78;
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  --tl-pad: 26px;
  list-style: none;
  margin: 0;
  padding: 0 0 0 var(--tl-pad);
  border-left: 1px solid var(--rule);
  display: grid;
  gap: clamp(24px, 4vw, 38px);
}

.page-about .timeline__item {
  position: relative;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  top: 12px;
  left: calc(-1 * var(--tl-pad) - 4px);
  width: 8px;
  height: 8px;
  background: var(--cyan);
}

.page-about .timeline__year {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .timeline__year-num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(34px, 7vw, 56px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--paper);
}

.page-about .timeline__year-tag {
  color: var(--mist);
  letter-spacing: 0.18em;
}

.page-about .timeline__card {
  background: var(--stand);
  border: var(--about-line);
  padding: clamp(18px, 3vw, 28px);
  box-shadow: 7px 7px 0 0 rgba(18, 61, 49, 0.9);
}

.page-about .timeline__card h3 {
  margin: 12px 0 0;
  font-size: clamp(18px, 2.6vw, 22px);
  line-height: 1.32;
  font-weight: 800;
}

.page-about .timeline__card p {
  margin: 10px 0 0;
  max-width: 34em;
  color: var(--mist);
  font-size: 15px;
  line-height: 1.82;
}

.page-about .timeline__list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .timeline__list li {
  position: relative;
  padding-left: 18px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .timeline__list li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--cyan);
}

.page-about .timeline__figure {
  padding-left: 0;
}

/* ---------- 图片框 ---------- */
.page-about .about-figure {
  border: var(--about-line);
  background: var(--stand);
  padding: 8px;
}

.page-about .about-figure img {
  width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .about-figlabel {
  display: block;
  padding: 9px 2px 2px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

/* ---------- 团队角色切换 ---------- */
.page-about .roles {
  position: relative;
}

.page-about .roles__radio {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.page-about .roles__tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-bottom: 16px;
  border-bottom: var(--about-line);
}

.page-about .roles__tab {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  padding: 9px 15px;
  border: var(--about-line);
  color: var(--mist);
  cursor: pointer;
  transition: color 180ms ease, border-color 180ms ease, background 180ms ease;
}

.page-about .roles__tab:hover {
  border-color: var(--cyan-soft);
  color: var(--paper);
}

.page-about .roles__radio:nth-of-type(1):checked ~ .roles__tablist .roles__tab:nth-child(1),
.page-about .roles__radio:nth-of-type(2):checked ~ .roles__tablist .roles__tab:nth-child(2),
.page-about .roles__radio:nth-of-type(3):checked ~ .roles__tablist .roles__tab:nth-child(3),
.page-about .roles__radio:nth-of-type(4):checked ~ .roles__tablist .roles__tab:nth-child(4),
.page-about .roles__radio:nth-of-type(5):checked ~ .roles__tablist .roles__tab:nth-child(5) {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
}

.page-about .roles__radio:nth-of-type(1):focus-visible ~ .roles__tablist .roles__tab:nth-child(1),
.page-about .roles__radio:nth-of-type(2):focus-visible ~ .roles__tablist .roles__tab:nth-child(2),
.page-about .roles__radio:nth-of-type(3):focus-visible ~ .roles__tablist .roles__tab:nth-child(3),
.page-about .roles__radio:nth-of-type(4):focus-visible ~ .roles__tablist .roles__tab:nth-child(4),
.page-about .roles__radio:nth-of-type(5):focus-visible ~ .roles__tablist .roles__tab:nth-child(5) {
  outline: 2px solid var(--cyan-soft);
  outline-offset: 3px;
}

.page-about .roles__panels {
  margin-top: clamp(20px, 3vw, 28px);
}

.page-about .roles__panel {
  display: none;
  border-left: 2px solid var(--cyan);
  padding: 4px 0 4px 20px;
}

.page-about .roles__radio:nth-of-type(1):checked ~ .roles__panels .roles__panel:nth-child(1),
.page-about .roles__radio:nth-of-type(2):checked ~ .roles__panels .roles__panel:nth-child(2),
.page-about .roles__radio:nth-of-type(3):checked ~ .roles__panels .roles__panel:nth-child(3),
.page-about .roles__radio:nth-of-type(4):checked ~ .roles__panels .roles__panel:nth-child(4),
.page-about .roles__radio:nth-of-type(5):checked ~ .roles__panels .roles__panel:nth-child(5) {
  display: block;
}

.page-about .roles__panel h3 {
  margin: 0;
  font-size: 18px;
  line-height: 1.4;
}

.page-about .roles__panel p {
  margin: 8px 0 0;
  max-width: 34em;
  color: var(--mist);
  font-size: 15px;
  line-height: 1.82;
}

/* ---------- 更新流程 ---------- */
.page-about .about-split {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
}

.page-about .flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .flow__step {
  border-top: 2px solid var(--pitch);
  padding-top: 14px;
}

.page-about .flow__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .flow__step h3 {
  margin: 6px 0 0;
  font-size: 17.5px;
  line-height: 1.4;
}

.page-about .flow__step p {
  margin: 6px 0 0;
  max-width: 32em;
  color: var(--mist);
  font-size: 14.5px;
  line-height: 1.78;
}

/* ---------- 服务版图 ---------- */
.page-about .reach {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
}

.page-about .about-chart svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .chart-grid {
  stroke: rgba(44, 90, 78, 0.7);
  stroke-width: 1;
}

.page-about .chart-line {
  fill: none;
  stroke: var(--cyan);
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.page-about .chart-dot {
  fill: var(--amber);
}

.page-about .chart-label {
  fill: var(--mist);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
}

.page-about .chart-value {
  fill: var(--paper);
  font-family: var(--font-mono);
  font-size: 14px;
}

.page-about .reach__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 14px;
}

.page-about .reach__stats li {
  border-left: 2px solid var(--pitch);
  padding-left: 12px;
}

.page-about .reach__num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(24px, 4vw, 32px);
  line-height: 1.1;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .reach__key {
  font-size: 12.5px;
  color: var(--mist);
  letter-spacing: 0.04em;
}

.page-about .reach__note {
  margin: clamp(18px, 3vw, 26px) 0 0;
  max-width: 34em;
  color: var(--mist);
  font-size: 15px;
  line-height: 1.82;
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  margin-top: clamp(32px, 5vw, 56px);
  padding: clamp(28px, 5vw, 52px) 0 0;
  border-top: var(--about-line);
}

.page-about .about-cta h2 {
  margin: 10px 0 0;
  font-size: clamp(22px, 3.6vw, 32px);
  line-height: 1.26;
  font-weight: 800;
}

.page-about .about-cta p {
  margin: 12px 0 0;
  max-width: 34em;
  color: var(--mist);
  font-size: 15px;
  line-height: 1.8;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(20px, 3vw, 28px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .reach__stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 300px) minmax(0, 1fr);
    align-items: start;
    gap: clamp(30px, 4vw, 52px);
  }

  .page-about .timeline {
    --tl-pad: 34px;
  }

  .page-about .timeline__item {
    display: grid;
    grid-template-columns: 180px minmax(0, 1fr);
    column-gap: clamp(22px, 3vw, 40px);
    align-items: start;
  }

  .page-about .timeline__year {
    flex-direction: column;
    align-items: flex-end;
    gap: 12px;
    margin: 0;
    padding-top: 4px;
    text-align: right;
  }

  .page-about .timeline__year-tag {
    writing-mode: vertical-rl;
    letter-spacing: 0.28em;
  }

  .page-about .timeline__figure {
    margin-left: calc(-1 * var(--tl-pad) - 180px - clamp(22px, 3vw, 40px));
    padding-left: calc(var(--tl-pad) + 180px + clamp(22px, 3vw, 40px));
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.92fr);
    align-items: start;
  }

  .page-about .reach {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: start;
  }
}

@media (min-width: 1120px) {
  .page-about .year-nav {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: center;
  }

  .page-about .year-nav ol {
    justify-content: space-between;
    overflow-x: visible;
  }

  .page-about .year-nav li {
    flex: 1 1 0;
  }

  .page-about .year-nav a {
    min-width: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .year-nav a,
  .page-about .roles__tab {
    transition-duration: 0.01ms;
  }
}