.page-about {
  --about-tick: 108px;
  --about-axis: 1px;
}

.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

.page-about .scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: transparent;
  z-index: 60;
  pointer-events: none;
}

.page-about .scroll-progress__bar {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--cyan), var(--cyan-soft));
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(22px, 4vw, 40px) clamp(36px, 6vw, 76px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -6% -28% 44% 30%;
  background:
    radial-gradient(120% 140% at 78% 4%, rgba(59, 240, 196, 0.20), transparent 60%),
    linear-gradient(158deg, rgba(18, 51, 38, 0.95) 0%, rgba(6, 23, 15, 0) 74%);
  clip-path: polygon(22% 0%, 100% 0%, 100% 100%, 0% 58%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero > .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__inner {
  max-width: 74ch;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--gap);
  margin: clamp(24px, 4vw, 42px) 0 0;
}

.page-about .about-fact {
  border-top: var(--about-axis) solid var(--line);
  padding-top: 12px;
  min-width: 0;
}

.page-about .about-fact__label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--text-mute);
}

.page-about .about-fact__value {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(30px, 7vw, 46px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .about-hero__media {
  margin: clamp(30px, 5vw, 60px) 0 0;
}

/* ---------- 时间轴骨架 ---------- */

.page-about .about-track {
  list-style: none;
  margin: clamp(28px, 5vw, 56px) 0 0;
  padding: 0;
  display: grid;
  gap: clamp(34px, 6vw, 88px);
}

.page-about .about-stop {
  display: grid;
  gap: clamp(14px, 2vw, 20px);
}

.page-about .about-stop__tick {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 10px;
  border-bottom: var(--about-axis) solid var(--line);
}

.page-about .about-stop__num {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .about-stop__stage {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--text-mute);
}

.page-about .about-stop__body {
  min-width: 0;
}

.page-about .about-stop__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: clamp(22px, 2.8vw, 33px);
  font-weight: 600;
  line-height: 1.36;
  letter-spacing: -0.01em;
  color: var(--warm);
}

.page-about .about-stop__lede {
  margin: 0;
  max-width: 64ch;
  font-size: 17px;
  line-height: 1.88;
  color: var(--text-dim);
}

.page-about .about-points {
  list-style: none;
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
  max-width: 68ch;
}

.page-about .about-points li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.82;
  color: var(--text-dim);
}

.page-about .about-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.76em;
  width: 10px;
  height: 1px;
  background: var(--cyan);
}

/* ---------- 小组卡片 ---------- */

.page-about .about-crew__media,
.page-about .about-stop__media {
  margin: clamp(20px, 3vw, 34px) 0 0;
}

.page-about .about-crew {
  margin-top: clamp(20px, 3vw, 32px);
  display: grid;
  gap: var(--about-axis);
  background: var(--line);
  border: var(--about-axis) solid var(--line);
}

.page-about .about-crew__card {
  background: var(--pitch-800);
  padding: clamp(18px, 2.4vw, 26px);
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-crew__card:hover {
  background: var(--pitch-700);
  box-shadow: inset 0 0 0 1px var(--cyan);
}

.page-about .about-crew__code {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.page-about .about-crew__card--flag .about-crew__code {
  color: var(--amber);
}

.page-about .about-crew__card--flag:hover {
  box-shadow: inset 0 0 0 1px var(--amber);
}

.page-about .about-crew__name {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 600;
  color: var(--warm);
}

.page-about .about-crew__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-dim);
}

.page-about .about-crew__meta {
  margin: auto 0 0;
  padding-top: 12px;
  border-top: var(--about-axis) solid var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--text-mute);
}

/* ---------- 字段对照 ---------- */

.page-about .disclosure {
  margin-top: clamp(20px, 3vw, 30px);
  border-top: var(--about-axis) solid var(--line);
}

.page-about .about-fields {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--about-axis);
  background: var(--line);
}

.page-about .about-fields li {
  background: var(--pitch-800);
  padding: 13px 16px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-dim);
}

.page-about .about-fields b {
  display: inline-block;
  min-width: 5.5em;
  margin-right: 10px;
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--cyan-soft);
}

/* ---------- 使用场景 ---------- */

.page-about .about-uses {
  margin-top: clamp(22px, 3vw, 34px);
  display: grid;
  gap: var(--gap);
}

.page-about .about-use {
  border: var(--about-axis) solid var(--line);
  border-top: 3px solid var(--cyan);
  background: var(--pitch-800);
  padding: clamp(18px, 2.4vw, 28px);
  transition: box-shadow var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-use:nth-child(2) {
  border-top-color: var(--cyan-soft);
}

.page-about .about-use:nth-child(3) {
  border-top-color: var(--amber);
}

.page-about .about-use:hover {
  background: var(--pitch-700);
  box-shadow: inset 0 0 0 1px var(--cyan);
}

.page-about .about-use__title {
  margin: 0 0 10px;
  font-family: var(--font-sans);
  font-size: 18px;
  font-weight: 600;
  color: var(--warm);
}

.page-about .about-use__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-dim);
}

/* ---------- 地区 ---------- */

.page-about .about-region {
  margin-top: clamp(22px, 3vw, 34px);
  display: grid;
  gap: clamp(20px, 2.6vw, 32px);
}

.page-about .about-region__item {
  border-left: 2px solid var(--cyan);
  padding: 2px 0 2px clamp(16px, 2vw, 24px);
}

.page-about .about-region__item:nth-child(2) {
  border-left-color: var(--amber);
}

.page-about .about-region__name {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.12em;
  color: var(--cyan-soft);
}

.page-about .about-region__item:nth-child(2) .about-region__name {
  color: var(--amber);
}

.page-about .about-region__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-dim);
}

/* ---------- 后续入口 ---------- */

.page-about .about-next__list {
  list-style: none;
  margin: clamp(20px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  gap: var(--about-axis);
  background: var(--line);
  border-top: var(--about-axis) solid var(--line);
}

.page-about .about-next__list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px clamp(16px, 2vw, 24px);
  background: var(--pitch-900);
  color: var(--warm);
  font-size: 16px;
  text-decoration: none;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-next__list a::after {
  content: "\2192";
  font-family: var(--font-mono);
  color: var(--cyan);
}

.page-about .about-next__list a:hover {
  background: var(--pitch-700);
  color: var(--cyan-soft);
  box-shadow: inset 0 0 0 1px var(--cyan);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-crew,
  .page-about .about-fields {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 760px) {
  .page-about .about-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-stop {
    grid-template-columns: var(--about-tick) minmax(0, 1fr);
    gap: 0;
  }

  .page-about .about-stop__tick {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding: 0 30px 0 0;
    border-bottom: 0;
    border-right: var(--about-axis) solid var(--line);
  }

  .page-about .about-stop__tick::after {
    content: "";
    position: absolute;
    top: 9px;
    right: -4.5px;
    width: 8px;
    height: 8px;
    background: var(--cyan);
  }

  .page-about .about-stop__body {
    padding-left: clamp(28px, 4vw, 56px);
  }

  .page-about .about-uses {
    grid-template-columns: 1.3fr 1fr 1fr;
  }
}

@media (min-width: 1120px) {
  .page-about .about-crew {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}