.page-about {
  --about-rail-w: 208px;
  --about-gap: clamp(24px, 4vw, 48px);
  background: var(--void);
  color: var(--silver);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(36px, 7vw, 88px) 0 clamp(34px, 6vw, 76px);
  background: linear-gradient(180deg, var(--void) 0%, var(--hull) 94%, var(--hull) 100%);
  border-bottom: 1px solid var(--grid);
}

.page-about .about-hero__bg {
  position: absolute;
  inset: 0;
  z-index: -1;
}

.page-about .about-hero__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 34%;
  opacity: 0.22;
  filter: grayscale(0.45) contrast(1.08);
}

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

/* 面包屑 */
.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(22px, 3vw, 32px);
}

.page-about .about-hero .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-hero .breadcrumb li {
  font-family: var(--font-mono);
  font-size: var(--step-1);
  letter-spacing: 0.08em;
  color: var(--steel);
}

.page-about .about-hero .breadcrumb li + li::before {
  content: "／";
  margin: 0 8px;
  color: var(--grid);
}

.page-about .about-hero .breadcrumb a {
  color: var(--steel);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}

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

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.8rem, 5.4vw, 3.4rem);
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--paper);
  margin: 14px 0 0;
  max-width: 17em;
}

.page-about .about-hero__lede {
  max-width: 34em;
  margin: clamp(18px, 2.5vw, 24px) 0 0;
  font-size: var(--step-3);
  line-height: 1.85;
  color: var(--steel);
}

/* 坐标读数 */
.page-about .about-coords {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  margin: clamp(28px, 5vw, 52px) 0 0;
}

.page-about .about-coords__item {
  background: var(--void);
  padding: 16px 18px;
}

.page-about .about-coords dt {
  font-family: var(--font-mono);
  font-size: var(--step-1);
  letter-spacing: 0.1em;
  color: var(--steel);
}

.page-about .about-coords dd {
  margin: 10px 0 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .about-coords__num {
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--amber);
  font-variant-numeric: tabular-nums;
}

.page-about .about-coords__unit {
  font-size: var(--step-2);
  color: var(--steel);
}

/* ---------- 01 站点坐标 ---------- */
.page-about .about-scope__grid {
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-scope__card {
  background: var(--hull);
  padding: clamp(20px, 3vw, 32px);
}

.page-about .about-scope__card--muted {
  background: var(--void);
}

.page-about .about-scope__list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-scope__list li {
  position: relative;
  padding-left: 24px;
  font-size: var(--step-3);
  line-height: 1.8;
  color: var(--silver);
}

.page-about .about-scope__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 13px;
  height: 1px;
  background: var(--amber);
}

.page-about .about-scope__card--muted .about-scope__list li::before {
  background: var(--grid);
}

/* ---------- 02 沿革轴线 ---------- */
.page-about .about-axis__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-rail {
  border-top: 1px solid var(--grid);
  padding-top: 16px;
}

.page-about .about-rail__label {
  margin: 0 0 12px;
  font-size: var(--step-1);
  letter-spacing: 0.14em;
  color: var(--steel);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__item a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 20px 10px 0;
  white-space: nowrap;
  text-decoration: none;
  color: var(--steel);
  transition: color 0.25s var(--ease);
}

.page-about .about-rail__dot {
  flex: none;
  width: 10px;
  height: 10px;
  border: 1px solid var(--grid);
  background: var(--void);
  transition: background-color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-rail__item a:hover,
.page-about .about-rail__item a:focus-visible {
  color: var(--amber-soft);
}

.page-about .about-rail__item a:hover .about-rail__dot,
.page-about .about-rail__item a:focus-visible .about-rail__dot {
  background: var(--amber);
  border-color: var(--amber);
}

.page-about .about-rail__year {
  font-size: var(--step-2);
  letter-spacing: 0.06em;
}

.page-about .about-rail__scale {
  margin-top: 16px;
  height: 9px;
  border-bottom: 1px solid var(--amber);
  background-image: repeating-linear-gradient(
    90deg,
    var(--grid) 0,
    var(--grid) 1px,
    transparent 1px,
    transparent calc(100% / 28)
  );
}

.page-about .about-rail__foot {
  margin: 10px 0 0;
  font-size: var(--step-1);
  letter-spacing: 0.12em;
  color: var(--steel);
}

/* 阶段面板 */
.page-about .about-stage {
  position: relative;
  border: 1px solid var(--grid);
  background: var(--hull);
  padding: clamp(22px, 3.2vw, 38px);
  transition: border-color 0.4s var(--ease);
}

.page-about .about-stage + .about-stage {
  margin-top: 18px;
}

.page-about .about-stage:target {
  border-color: var(--amber);
}

.page-about .about-stage__mark {
  position: absolute;
  top: -1px;
  left: -1px;
  width: 20px;
  height: 20px;
  border-top: 2px solid var(--amber);
  border-left: 2px solid var(--amber);
  pointer-events: none;
}

.page-about .about-stage__year {
  margin: 0;
  font-size: var(--step-2);
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .about-stage__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 3vw, 1.7rem);
  line-height: 1.42;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-stage__body {
  margin: 16px 0 0;
  max-width: 34em;
  font-size: var(--step-3);
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-stage__note {
  margin: 22px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--grid);
  font-size: var(--step-1);
  letter-spacing: 0.08em;
  color: var(--steel);
}

/* 图容器 */
.page-about .about-figure {
  margin: 24px 0 0;
}

.page-about .about-figure__frame {
  position: relative;
  aspect-ratio: 3 / 2;
  border: 1px solid var(--grid);
  background: var(--void);
  overflow: hidden;
}

.page-about .about-figure--square .about-figure__frame {
  aspect-ratio: 1 / 1;
}

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

.page-about .about-figure__corner {
  position: absolute;
  width: 16px;
  height: 16px;
  pointer-events: none;
}

.page-about .about-figure__corner--tl {
  top: 6px;
  left: 6px;
  border-top: 1px solid var(--amber);
  border-left: 1px solid var(--amber);
}

.page-about .about-figure__corner--br {
  right: 6px;
  bottom: 6px;
  border-right: 1px solid var(--amber);
  border-bottom: 1px solid var(--amber);
}

.page-about .about-figure__caption {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: var(--step-1);
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--steel);
}

/* ---------- 呼吸区 ---------- */
.page-about .about-breath {
  padding: clamp(72px, 15vw, 168px) 0;
  border-top: 1px solid var(--grid);
  border-bottom: 1px solid var(--grid);
  background: var(--void);
}

.page-about .about-breath__line {
  margin: 0;
  padding-left: 22px;
  border-left: 2px solid var(--amber);
  max-width: 24em;
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 3.4vw, 2.1rem);
  line-height: 1.62;
  letter-spacing: -0.01em;
  color: var(--silver);
}

.page-about .about-breath__meta {
  margin: 24px 0 0 24px;
  font-size: var(--step-1);
  letter-spacing: 0.12em;
  color: var(--steel);
}

/* ---------- 03 规模构成 ---------- */
.page-about .about-scale__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  align-items: center;
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-rings {
  max-width: 280px;
  margin: 0 auto;
}

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

.page-about .about-rings__svg circle {
  fill: none;
  stroke: var(--grid);
  stroke-width: 1;
}

.page-about .about-rings__c1 {
  stroke: var(--deck);
  stroke-width: 2;
}

.page-about .about-rings__c2 {
  stroke: var(--grid);
}

.page-about .about-rings__c3 {
  stroke: var(--amber);
  stroke-dasharray: 4 5;
}

.page-about .about-rings__tick {
  stroke: var(--grid);
  stroke-width: 1;
}

.page-about .about-scale__notes p {
  margin: 0;
  max-width: 34em;
  font-size: var(--step-3);
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-scale__facts {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-scale__facts li {
  background: var(--hull);
  padding: 14px 16px;
  font-size: var(--step-2);
  line-height: 1.65;
  color: var(--steel);
}

.page-about .about-scale__facts .mono {
  display: block;
  margin-bottom: 6px;
  font-size: var(--step-4);
  font-weight: 700;
  color: var(--amber);
  letter-spacing: 0.04em;
}

.page-about .about-scale__table {
  margin-top: clamp(28px, 4vw, 44px);
  width: 100%;
  min-width: 540px;
}

.page-about .about-scale__caption {
  caption-side: top;
  text-align: left;
  padding: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--step-1);
  letter-spacing: 0.08em;
  color: var(--steel);
}

.page-about .about-scale__foot {
  margin: 22px 0 0;
  max-width: 34em;
  font-size: var(--step-2);
  line-height: 1.85;
  color: var(--steel);
}

/* ---------- 04 团队 ---------- */
.page-about .about-team__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-team__groups {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-group {
  background: var(--hull);
  padding: 22px;
}

.page-about .about-group__name {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--step-2);
  letter-spacing: 0.12em;
  color: var(--silver);
}

.page-about .about-group__num {
  margin: 10px 0 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .about-group__num .mono {
  font-size: clamp(1.6rem, 4vw, 2rem);
  font-weight: 700;
  color: var(--amber);
  font-variant-numeric: tabular-nums;
}

.page-about .about-group__unit {
  font-size: var(--step-1);
  color: var(--steel);
}

.page-about .about-group__bar {
  height: 2px;
  margin: 14px 0 0;
  background: var(--grid);
}

.page-about .about-group__bar span {
  display: block;
  height: 100%;
  background: var(--amber);
}

.page-about .about-group:nth-child(1) .about-group__bar span { width: 32.4%; }
.page-about .about-group:nth-child(2) .about-group__bar span { width: 20.6%; }
.page-about .about-group:nth-child(3) .about-group__bar span { width: 29.4%; }
.page-about .about-group:nth-child(4) .about-group__bar span { width: 17.6%; }

.page-about .about-group__desc {
  margin: 14px 0 0;
  font-size: var(--step-2);
  line-height: 1.78;
  color: var(--steel);
}

/* ---------- 05 季度复核 ---------- */
.page-about .about-review__list {
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-review__list > li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 18px;
  background: var(--hull);
  padding: clamp(20px, 3vw, 30px);
}

.page-about .about-review__no {
  padding-top: 5px;
  font-size: var(--step-2);
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .about-review__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--step-4);
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-review__list p {
  margin: 10px 0 0;
  max-width: 34em;
  font-size: var(--step-3);
  line-height: 1.85;
  color: var(--silver);
}

/* ---------- 06 覆盖 ---------- */
.page-about .about-reach__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-reach__cell {
  background: var(--void);
  padding: clamp(20px, 3vw, 30px);
}

.page-about .about-reach__label {
  margin: 0;
  font-size: var(--step-1);
  letter-spacing: 0.14em;
  color: var(--steel);
}

.page-about .about-reach__value {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 4.4vw, 2.4rem);
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--silver);
}

.page-about .about-reach__value--num {
  font-family: var(--font-mono);
  color: var(--amber);
  font-variant-numeric: tabular-nums;
}

.page-about .about-reach__desc {
  margin: 14px 0 0;
  font-size: var(--step-2);
  line-height: 1.8;
  color: var(--steel);
}

/* ---------- 07 继续查阅 ---------- */
.page-about .about-next__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-next__link {
  display: block;
  background: var(--hull);
  padding: 24px;
  text-decoration: none;
  transition: background-color 0.3s var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  background: var(--deck);
}

.page-about .about-next__no {
  display: block;
  font-size: var(--step-1);
  letter-spacing: 0.14em;
  color: var(--amber);
}

.page-about .about-next__label {
  display: block;
  margin-top: 10px;
  font-family: var(--font-display);
  font-size: var(--step-4);
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-next__desc {
  display: block;
  margin-top: 8px;
  font-size: var(--step-2);
  line-height: 1.75;
  color: var(--steel);
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .about-scale__facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 760px) {
  .page-about .about-coords {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 820px) {
  .page-about .about-scope__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-scale__layout {
    grid-template-columns: minmax(180px, 260px) minmax(0, 1fr);
  }

  .page-about .about-reach__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-team__layout {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 960px) {
  .page-about .about-axis__layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-axis__rail {
    position: sticky;
    top: 96px;
  }

  .page-about .about-rail {
    border-top: 0;
    padding-top: 0;
    border-left: 1px solid var(--grid);
    padding-left: 18px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    overflow: visible;
  }

  .page-about .about-rail__item a {
    padding: 11px 0;
  }
}

@media (min-width: 1080px) {
  .page-about .about-next__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__dot,
  .page-about .about-stage,
  .page-about .about-next__link {
    transition: none;
  }
}