.page-about {
  --about-tick: 46px;
  padding-bottom: 76px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 22px 0 38px;
  border-bottom: 2px solid var(--edge-strong);
}

.page-about .about-hero__title {
  margin: 14px 0 18px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(30px, 8vw, 58px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--text);
  max-width: 17em;
}

.page-about .about-hero__lede {
  margin: 0 0 30px;
  max-width: 34em;
  font-size: 16px;
  line-height: 1.78;
  color: var(--dim);
}

.page-about .about-hero__metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--edge);
  border: 2px solid var(--edge-strong);
}

.page-about .about-metric {
  background: var(--panel);
  padding: 16px 14px 15px;
  min-width: 0;
}

.page-about .about-metric__v {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 7vw, 40px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-metric__k {
  display: block;
  margin-top: 9px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--dim);
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding-top: 52px;
}

.page-about .about-section__head {
  margin-bottom: 28px;
}

.page-about .about-section__title {
  margin: 10px 0 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(23px, 5.4vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--text);
  max-width: 20em;
}

.page-about .about-section__intro {
  margin: 14px 0 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.78;
  color: var(--dim);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-node {
  position: relative;
  display: grid;
  grid-template-columns: var(--about-tick) minmax(0, 1fr);
  gap: 0 16px;
  padding-bottom: 30px;
}

.page-about .about-node:not(:last-child)::after {
  content: "";
  position: absolute;
  left: calc(var(--about-tick) / 2 - 1px);
  top: calc(var(--about-tick) + 10px);
  bottom: 4px;
  width: 2px;
  background: linear-gradient(var(--edge-strong), var(--edge));
}

.page-about .about-node__idx {
  display: grid;
  place-items: center;
  width: var(--about-tick);
  height: var(--about-tick);
  border: 2px solid var(--edge-strong);
  background: var(--panel);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-node:hover .about-node__idx {
  border-color: var(--cyan);
}

.page-about .about-node__body {
  min-width: 0;
  padding-top: 2px;
}

.page-about .about-node__phase {
  color: var(--dim);
}

.page-about .about-node__title {
  margin: 8px 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(18px, 4.6vw, 22px);
  line-height: 1.34;
  color: var(--text);
}

.page-about .about-node__text {
  margin: 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.78;
  color: var(--dim);
}

/* 事实带 */
.page-about .about-node--band {
  grid-template-columns: minmax(0, 1fr);
  padding-bottom: 30px;
}

.page-about .about-node--band::after {
  display: none;
}

.page-about .about-factband {
  border-top: 2px solid var(--edge-strong);
  border-bottom: 2px solid var(--edge-strong);
  background: linear-gradient(180deg, var(--panel), var(--steel));
  padding: 18px 16px 20px;
}

.page-about .about-factband__label {
  color: var(--orange);
}

.page-about .about-factband__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-factband__v {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 7vw, 36px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-factband__k {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.55;
  color: var(--dim);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 30px;
}

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

.page-about .about-figure__cap {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--dim);
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
}

.page-about .about-figure--mid {
  margin-top: 30px;
}

/* ---------- 团队构成 ---------- */
.page-about .about-crew__bar {
  display: flex;
  height: 60px;
  border: 2px solid var(--edge-strong);
  background: var(--steel);
  overflow: hidden;
}

.page-about .about-crew__seg {
  display: grid;
  place-items: center;
  min-width: 0;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: filter var(--dur) var(--ease);
}

.page-about .about-crew__seg--a {
  flex: 22 1 0;
  background: var(--cyan);
  color: var(--void);
}

.page-about .about-crew__seg--b {
  flex: 9 1 0;
  background: var(--orange);
  color: var(--void);
  border-left: 2px solid var(--void);
}

.page-about .about-crew__seg--c {
  flex: 15 1 0;
  background: var(--void);
  color: var(--cyan);
  border-left: 2px solid var(--edge-strong);
  box-shadow: inset 0 0 0 2px var(--edge-strong);
}

.page-about .about-crew__seg:hover {
  filter: brightness(1.12);
}

.page-about .about-crew__list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin: 2px 0 0;
  padding: 0;
  list-style: none;
  background: var(--edge);
}

.page-about .about-crew__item {
  position: relative;
  background: var(--panel);
  padding: 18px 16px 18px 30px;
}

.page-about .about-crew__dot {
  position: absolute;
  left: 14px;
  top: 24px;
  width: 8px;
  height: 8px;
}

.page-about .about-crew__dot--a {
  background: var(--cyan);
}

.page-about .about-crew__dot--b {
  background: var(--orange);
}

.page-about .about-crew__dot--c {
  background: var(--void);
  box-shadow: inset 0 0 0 2px var(--cyan);
}

.page-about .about-crew__name {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text);
}

.page-about .about-crew__desc {
  margin: 0;
  max-width: 34em;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--dim);
}

/* ---------- 记录流程 ---------- */
.page-about .about-flow {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--edge);
  border: 2px solid var(--edge-strong);
}

.page-about .about-flow__step {
  background: var(--panel);
  padding: 18px 16px;
  min-width: 0;
}

.page-about .about-flow__step:nth-child(3) {
  background: var(--steel);
}

.page-about .about-flow__n {
  display: block;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-flow__t {
  margin: 8px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.3;
  color: var(--text);
}

.page-about .about-flow__d {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--dim);
}

.page-about .about-timing {
  margin-top: 28px;
  border: 2px solid var(--edge-strong);
  border-left: 6px solid var(--orange);
  background: var(--panel);
  padding: 18px 16px 20px;
}

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

.page-about .about-timing__list li {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 12px;
  align-items: baseline;
  background: var(--steel);
  padding: 12px 14px;
}

.page-about .about-timing__list b {
  font-family: var(--font-mono);
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text);
  min-width: 5.5em;
}

.page-about .about-timing__list span {
  font-size: 14px;
  line-height: 1.6;
  color: var(--dim);
}

/* ---------- 覆盖版图 ---------- */
.page-about .about-tiers {
  border-top: 2px solid var(--edge-strong);
}

.page-about .about-tier {
  border-bottom: 2px solid var(--edge);
  background: var(--void);
  transition: background var(--dur) var(--ease);
}

.page-about .about-tier[open] {
  background: var(--panel);
  border-bottom-color: var(--edge-strong);
}

.page-about .about-tier__sum {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr) 22px;
  align-items: center;
  gap: 12px;
  padding: 15px 12px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-tier__sum::-webkit-details-marker {
  display: none;
}

.page-about .about-tier__sum::marker {
  content: "";
}

.page-about .about-tier__n {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-tier__name {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.35;
  color: var(--text);
}

.page-about .about-tier__mark {
  position: relative;
  width: 16px;
  height: 16px;
  justify-self: end;
}

.page-about .about-tier__mark::before,
.page-about .about-tier__mark::after {
  content: "";
  position: absolute;
  background: var(--cyan);
}

.page-about .about-tier__mark::before {
  left: 0;
  top: 7px;
  width: 16px;
  height: 2px;
}

.page-about .about-tier__mark::after {
  left: 7px;
  top: 0;
  width: 2px;
  height: 16px;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.page-about .about-tier[open] .about-tier__mark::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .about-tier__body {
  margin: 0;
  padding: 0 12px 18px 62px;
  max-width: 40em;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--dim);
}

.page-about .about-regions {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 2px;
  margin-top: 28px;
  padding: 2px;
  background: var(--edge);
  border: 2px solid var(--edge-strong);
}

.page-about .about-region {
  background: var(--panel);
  padding: 14px 14px 16px;
  min-width: 0;
  transition: background var(--dur) var(--ease);
}

.page-about .about-region:hover {
  background: var(--steel);
}

.page-about .about-region__n {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 15.5px;
  line-height: 1.35;
  color: var(--text);
}

.page-about .about-region__d {
  margin: 0;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--dim);
}

/* ---------- 服务对象 ---------- */
.page-about .about-audience {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--edge);
  border: 2px solid var(--edge-strong);
}

.page-about .about-audience__item {
  position: relative;
  background: var(--panel);
  padding: 20px 16px 20px;
  min-width: 0;
}

.page-about .about-audience__item:nth-child(2),
.page-about .about-audience__item:nth-child(3) {
  background: var(--steel);
}

.page-about .about-audience__n {
  display: block;
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-audience__t {
  margin: 10px 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.36;
  color: var(--text);
}

.page-about .about-audience__d {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--dim);
}

/* ---------- 年度观察 ---------- */
.page-about .about-report__lede {
  margin: 0 0 24px;
  max-width: 34em;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--dim);
}

.page-about .about-report__list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--edge-strong);
}

.page-about .about-report__list li {
  border-bottom: 2px solid var(--edge);
  padding: 16px 0 18px;
}

.page-about .about-report__t {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 16.5px;
  line-height: 1.35;
  color: var(--text);
}

.page-about .about-report__list li .about-report__t::before {
  content: "—";
  color: var(--cyan);
  margin-right: 8px;
  font-family: var(--font-mono);
}

.page-about .about-report__d {
  margin: 0 0 0 22px;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--dim);
}

.page-about .about-report__figure {
  margin-top: 26px;
}

/* ---------- 延伸阅读 ---------- */
.page-about .about-next__title {
  margin-bottom: 22px;
}

.page-about .about-next__list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--edge);
  border: 2px solid var(--edge-strong);
}

.page-about .about-next__item {
  background: var(--panel);
  padding: 16px 16px 18px;
  min-width: 0;
}

.page-about .about-next__link {
  display: inline-block;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.35;
  color: var(--text);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .about-next__d {
  display: block;
  margin-top: 8px;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--dim);
}

/* ---------- 中屏 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

  .page-about .about-flow__step:nth-child(5) {
    grid-column: 1 / -1;
  }

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

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

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

/* ---------- 桌面 ---------- */
@media (min-width: 960px) {
  .page-about {
    --about-tick: 54px;
  }

  .page-about .about-hero {
    padding: 34px 0 48px;
  }

  .page-about .about-section {
    padding-top: 72px;
  }

  .page-about .about-section__head {
    margin-bottom: 34px;
  }

  .page-about .about-node {
    gap: 0 26px;
    padding-bottom: 38px;
  }

  .page-about .about-node__body {
    padding-top: 4px;
  }

  .page-about .about-node--band {
    padding-bottom: 38px;
  }

  .page-about .about-factband {
    padding: 22px 26px 24px;
  }

  .page-about .about-crew__bar {
    height: 70px;
  }

  .page-about .about-crew__item {
    padding: 22px 20px 22px 34px;
  }

  .page-about .about-crew__dot {
    left: 18px;
  }

  .page-about .about-flow {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

  .page-about .about-flow__step:nth-child(5) {
    grid-column: auto;
  }

  .page-about .about-flow__step {
    padding: 22px 18px 24px;
  }

  .page-about .about-report {
    display: grid;
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.85fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .about-report__figure {
    margin-top: 0;
    position: sticky;
    top: calc(var(--bar-h) + 20px);
  }

  .page-about .about-next__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__title {
    max-width: 15em;
  }

  .page-about .about-factband__grid {
    gap: 28px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
  }
}