.page-about {
  --line-x: 15px;
  --rail-w: 30px;
  background: var(--paper);
  color: var(--ink);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-top: clamp(1.25rem, 3vw, 2rem);
  padding-bottom: clamp(5.5rem, 13vw, 9rem);
}

.page-about .about-hero__slice {
  position: absolute;
  right: 0;
  bottom: 0;
  width: min(58%, 620px);
  height: clamp(110px, 16vw, 190px);
  background: linear-gradient(150deg, var(--green) 0%, var(--ink) 78%);
  clip-path: polygon(16% 0, 100% 0, 100% 100%, 0 100%);
  z-index: 0;
}

.page-about .about-hero__slice::after {
  content: "";
  position: absolute;
  right: 10%;
  bottom: 0;
  width: 30%;
  height: 42%;
  background: var(--orange);
  clip-path: polygon(0 100%, 100% 0, 100% 100%);
  opacity: 0.92;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
  margin-top: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-hero__title .eyebrow {
  margin-bottom: 0.9rem;
}

.page-about .about-hero__title h1 {
  margin: 0;
  line-height: 1.02;
}

.page-about .about-hero__thin {
  color: var(--green-2);
  display: inline-block;
}

.page-about .about-hero__aside .lede {
  margin: 0;
  max-width: 46ch;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.9rem;
  margin: clamp(1.5rem, 4vw, 2.25rem) 0 0;
  padding-top: 1.1rem;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-hero__facts > div {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 0;
}

.page-about .about-hero__facts dt {
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--index);
  line-height: 1.4;
}

.page-about .about-hero__facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1rem, 2.2vw, 1.35rem);
  color: var(--ink);
  letter-spacing: 0.01em;
  line-height: 1.3;
}

@media (min-width: 880px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    align-items: end;
    gap: clamp(2.5rem, 6vw, 6rem);
  }
}

/* ---------- 章节索引 ---------- */
.page-about .about-index {
  background: var(--ink);
  padding: clamp(1.35rem, 3.5vw, 2rem) 0;
}

.page-about .about-index__inner {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.page-about .about-index .index-label {
  margin: 0;
  color: var(--cyan);
}

.page-about .about-index .chapter-index {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 1.35rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-index .chapter-index__link {
  color: var(--paper);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-decoration: none;
  opacity: 0.7;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: opacity 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-index .chapter-index__link:hover,
.page-about .about-index .chapter-index__link:focus-visible,
.page-about .about-index .chapter-index__link.is-active {
  opacity: 1;
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

@media (min-width: 880px) {
  .page-about .about-index__inner {
    flex-direction: row;
    align-items: center;
    gap: 2.25rem;
  }

  .page-about .about-index .chapter-index {
    flex: 1;
  }
}

/* ---------- 纵向坐标轴 ---------- */
.page-about .about-axis {
  padding: clamp(2.25rem, 6vw, 4.5rem) 0 clamp(3rem, 8vw, 6rem);
}

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

.page-about .about-axis__line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: calc(var(--gutter) + var(--line-x));
  width: 1px;
  background: linear-gradient(
    to bottom,
    transparent 0,
    var(--line-strong) 4%,
    var(--line-strong) 96%,
    transparent 100%
  );
  z-index: 0;
}

.page-about .about-station {
  position: relative;
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr);
  gap: clamp(0.9rem, 3vw, 2.5rem);
  padding-block: clamp(1.75rem, 5vw, 3.25rem);
  scroll-margin-top: calc(var(--header-h) + 2rem);
}

.page-about .about-station__rail {
  position: relative;
  z-index: 1;
}

.page-about .about-station__dot {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: var(--radius-pill);
  background: var(--paper);
  border: 1px solid var(--line-strong);
  color: var(--ink);
  font-size: 0.62rem;
  letter-spacing: 0.02em;
  font-weight: 700;
}

.page-about .about-station:nth-of-type(3) .about-station__dot,
.page-about .about-station:nth-of-type(5) .about-station__dot {
  border-color: var(--green-2);
  color: var(--green);
}

.page-about .about-station__body {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: clamp(0.85rem, 2vw, 1.15rem);
}

.page-about .about-station__body > h2 {
  margin: 0;
  line-height: 1.15;
}

.page-about .about-station__body .index-label {
  margin: 0;
  color: var(--green-2);
}

.page-about .about-station__body p {
  margin: 0;
}

.page-about .about-figure {
  margin: clamp(0.5rem, 2vw, 1rem) 0 0;
}

.page-about .about-figure--rail .figure-frame__media img {
  max-height: 640px;
  object-fit: cover;
}

.page-about .about-link {
  color: var(--green);
  text-decoration: none;
  border-bottom: 1px solid var(--green-2);
  transition: color 0.18s ease, border-color 0.18s ease;
}

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

@media (min-width: 720px) {
  .page-about .about-station {
    gap: clamp(1.75rem, 4vw, 3.5rem);
  }
}

/* ---------- 数据脉冲板 ---------- */
.page-about .about-pulse {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  border-radius: var(--radius-m);
  overflow: hidden;
  margin: clamp(0.25rem, 1.5vw, 0.75rem) 0;
}

.page-about .about-pulse__cell {
  padding: 1.15rem 1.2rem 1.3rem;
  border-left: 1px solid var(--line-paper);
  min-width: 0;
}

.page-about .about-pulse__cell:first-child {
  border-left: 0;
}

.page-about .about-pulse__k {
  display: block;
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
  line-height: 1.5;
}

.page-about .about-pulse__v {
  display: block;
  margin-top: 0.45rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.35rem, 3.4vw, 1.95rem);
  color: var(--paper);
  line-height: 1.15;
}

@media (max-width: 559px) {
  .page-about .about-pulse__cell {
    border-left: 0;
    border-top: 1px solid var(--line-paper);
  }

  .page-about .about-pulse__cell:first-child {
    border-top: 0;
  }
}

/* ---------- 城市节点点阵 ---------- */
.page-about .about-nodes {
  border-radius: var(--radius-m);
  padding: clamp(1.15rem, 3vw, 1.9rem);
  margin: clamp(0.25rem, 1.5vw, 0.75rem) 0;
}

.page-about .about-nodes__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(70px, 1fr));
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-nodes__item {
  padding: 0.55rem 0.25rem;
  text-align: center;
  font-size: 0.78rem;
  line-height: 1.3;
  color: rgba(244, 239, 230, 0.82);
  background: rgba(46, 211, 226, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 6px;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-nodes__item:hover,
.page-about .about-nodes__item:focus-visible {
  background: rgba(46, 211, 226, 0.18);
  color: var(--paper);
  border-color: var(--cyan);
}

.page-about .about-nodes__item--home {
  color: var(--orange);
  border-color: rgba(255, 107, 44, 0.5);
  background: rgba(255, 107, 44, 0.08);
}

.page-about .about-nodes__note {
  margin: 0.95rem 0 0;
  font-size: 0.78rem;
  line-height: 1.6;
  color: rgba(244, 239, 230, 0.68);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: clamp(0.25rem, 1.5vw, 0.75rem) 0 0;
  padding: 0;
}

.page-about .about-timeline__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.35rem;
  padding: 1.05rem 0.75rem;
  border-top: 1px solid var(--line);
  border-radius: var(--radius-s);
  outline-offset: -2px;
  transition: background 0.18s ease;
}

.page-about .about-timeline__item:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-timeline__item:hover,
.page-about .about-timeline__item:focus-within {
  background: var(--paper-2);
}

.page-about .about-timeline__meta {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  flex-wrap: wrap;
}

.page-about .about-timeline__season {
  font-weight: 700;
  color: var(--ink);
  font-size: 0.9rem;
  letter-spacing: 0.02em;
}

.page-about .about-timeline__ver {
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--index);
}

.page-about .about-timeline__body h3 {
  margin: 0 0 0.3rem;
  font-size: 1.02rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
  transition: color 0.18s ease;
}

.page-about .about-timeline__item:hover .about-timeline__title,
.page-about .about-timeline__item:focus-within .about-timeline__title {
  color: var(--green-2);
}

.page-about .about-timeline__body p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.75;
  color: var(--ink-2);
}

.page-about .about-timeline__item--now {
  background: linear-gradient(90deg, rgba(46, 211, 226, 0.12), transparent 78%);
  border-top-color: var(--cyan);
}

.page-about .about-timeline__item--now .about-timeline__season {
  color: var(--green);
}

@media (min-width: 720px) {
  .page-about .about-timeline__item {
    grid-template-columns: minmax(130px, 170px) minmax(0, 1fr);
    gap: 1.5rem;
    align-items: start;
  }

  .page-about .about-timeline__meta {
    flex-direction: column;
    gap: 0.25rem;
  }
}

/* ---------- 收束卡 ---------- */
.page-about .about-close {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: clamp(1.35rem, 3.5vw, 2.15rem);
  border-radius: var(--radius-l);
  margin-top: clamp(0.5rem, 2vw, 1rem);
}

.page-about .about-close .index-label {
  margin: 0;
  color: var(--green-2);
}

.page-about .about-close__title {
  margin: 0;
  font-size: clamp(1.1rem, 2.6vw, 1.45rem);
  font-weight: 300;
  letter-spacing: 0.04em;
  line-height: 1.35;
}

.page-about .about-close__text {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--ink-2);
  max-width: 44ch;
}

.page-about .about-close__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 0.4rem;
}

.page-about .about-close__actions .btn {
  text-decoration: none;
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}
</main>