.page-about {
  --about-rail-w: 240px;
  padding-inline: 20px;
  padding-block: 0 88px;
}

.page-about > * {
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
}

@media (min-width: 768px) {
  .page-about {
    padding-inline: 40px;
    padding-block: 0 120px;
  }
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  padding-block: 22px 4px;
}

.page-about .breadcrumb__list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  font-size: 13px;
  letter-spacing: .6px;
  color: var(--text-muted);
}

.page-about .breadcrumb__link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .2s var(--ease);
}

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

.page-about .breadcrumb__sep {
  color: var(--line-soft);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  padding-block: 28px 52px;
}

@media (min-width: 980px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.06fr) minmax(0, .94fr);
    gap: 56px;
    align-items: center;
    padding-block: 40px 76px;
  }
}

.page-about .about-hero__kicker {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin: 0 0 18px;
}

.page-about .about-hero__kicker-num {
  font-size: 13px;
  letter-spacing: 1.6px;
  color: var(--flame);
}

.page-about .about-hero__title {
  margin: 0 0 20px;
  font-size: clamp(30px, 5.4vw, 54px);
  line-height: 1.08;
  letter-spacing: -0.5px;
  font-weight: 800;
  color: var(--mint);
}

.page-about .about-hero__lede {
  margin: 0 0 28px;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-on-dark);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 30px;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
}

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

.page-about .about-hero__fact {
  background: var(--ink-night);
  padding: 14px 14px 16px;
}

.page-about .about-hero__fact dt {
  font-size: 12px;
  letter-spacing: .8px;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.page-about .about-hero__fact dd {
  margin: 0;
  font-size: 20px;
  font-weight: 700;
  color: var(--mint);
}

.page-about .about-hero__fact .num {
  font-size: 28px;
  color: var(--cyan);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero__visual {
  padding: 18px;
  background:
    linear-gradient(160deg, rgba(53, 233, 200, .10), rgba(10, 30, 25, 0) 62%),
    var(--ink-slab);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 30px), calc(100% - 30px) 100%, 0 100%);
}

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

.page-about .about-graph__bar {
  fill: var(--ink-slab);
  stroke: var(--cyan);
  stroke-width: 1;
  stroke-opacity: .38;
}

.page-about .about-graph__bar--now {
  fill: var(--flame);
  stroke: var(--flame);
  stroke-opacity: 1;
}

.page-about .about-graph__dash {
  stroke: var(--mist);
  stroke-opacity: .3;
  stroke-width: 1;
  stroke-dasharray: 4 6;
}

.page-about .about-graph__label {
  fill: var(--mist);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 1.2px;
}

/* ---------- 通用章节骨架 ---------- */
.page-about .about-section {
  padding-block: clamp(44px, 6vw, 80px);
  border-top: 1px solid var(--line);
}

.page-about .about-section__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}

@media (min-width: 900px) {
  .page-about .about-section__grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 52px;
  }
}

.page-about .about-section__rail {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

@media (min-width: 900px) {
  .page-about .about-section__rail {
    position: sticky;
    top: calc(var(--topbar-h) + 28px);
    align-self: start;
  }
}

.page-about .about-rail__note {
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid var(--cyan);
  font-size: 13px;
  line-height: 1.75;
  letter-spacing: .6px;
  color: var(--text-muted);
}

.page-about .about-section__body h2 {
  margin: 0 0 18px;
  font-size: clamp(24px, 3.4vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.3px;
  font-weight: 800;
  color: var(--mint);
}

.page-about .about-section__body p {
  margin: 0 0 16px;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-on-dark);
}

.page-about .media-frame {
  margin: 26px 0;
}

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

/* ---------- 三条内容线 ---------- */
.page-about .about-lines {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: 28px 0 8px;
}

@media (min-width: 720px) {
  .page-about .about-lines {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-line {
  position: relative;
  padding: 22px 18px 24px;
  background:
    linear-gradient(180deg, rgba(53, 233, 200, .07), rgba(18, 51, 42, 0) 58%),
    var(--ink-slab);
  border: 1px solid var(--line);
}

.page-about .about-line::before {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  width: 58px;
  height: 3px;
  background: var(--cyan);
}

.page-about .about-line__num {
  display: block;
  margin-bottom: 10px;
  font-size: 13px;
  letter-spacing: 1.6px;
  color: var(--flame);
}

.page-about .about-line h3 {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 700;
  color: var(--mint);
  letter-spacing: .3px;
}

.page-about .about-line p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-muted);
}

/* ---------- 版本时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 34px 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 27px;
  top: 12px;
  bottom: 12px;
  width: 1px;
  background: var(--line-soft);
}

.page-about .about-ver {
  position: relative;
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 16px;
  padding-block: 20px;
}

.page-about .about-ver + .about-ver {
  border-top: 1px dashed var(--line);
}

.page-about .about-ver__num {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  margin-left: 8px;
  font-size: 15px;
  letter-spacing: 1px;
  color: var(--cyan);
  background: var(--ink-night);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% 72%, 72% 100%, 0 100%);
}

.page-about .about-ver--now .about-ver__num {
  color: var(--ink-deep);
  background: var(--flame);
  border-color: var(--flame);
}

.page-about .about-ver__body h3 {
  margin: 6px 0 8px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--mint);
}

.page-about .about-ver__body p {
  margin: 0;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-muted);
}

/* ---------- 栏节目录 ---------- */
.page-about .about-dir {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-dir__row {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 4px 12px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  transition: background-color .2s var(--ease);
}

.page-about .about-dir__row:hover {
  background: rgba(53, 233, 200, .05);
}

.page-about .about-dir__no {
  grid-column: 1;
  grid-row: 1;
  font-size: 14px;
  letter-spacing: 1.2px;
  color: var(--cyan);
}

.page-about .about-dir__name {
  grid-column: 2;
  grid-row: 1;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: .4px;
  color: var(--mint);
}

.page-about .about-dir__meta {
  grid-column: 2;
  grid-row: 2;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-muted);
}

@media (min-width: 720px) {
  .page-about .about-dir__row {
    grid-template-columns: 56px 200px minmax(0, 1fr);
    align-items: baseline;
    gap: 0 20px;
  }

  .page-about .about-dir__name {
    grid-column: 2;
  }

  .page-about .about-dir__meta {
    grid-column: 3;
    grid-row: 1;
  }
}

/* ---------- 版权页式备案块 ---------- */
.page-about .about-legal {
  padding-block: clamp(40px, 5.5vw, 72px) 0;
  border-top: none;
}

.page-about .about-paper {
  position: relative;
  padding: clamp(26px, 4vw, 52px);
  background: var(--paper);
  color: var(--ink-deep);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), calc(100% - 28px) 100%, 0 100%);
}

.page-about .about-paper::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: repeating-linear-gradient(90deg, var(--flame) 0 24px, rgba(27, 22, 19, 0) 24px 42px);
}

.page-about .about-paper__kicker {
  margin: 6px 0 14px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 1.6px;
  color: var(--flame);
}

.page-about .about-paper h2 {
  margin: 0 0 16px;
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.22;
  font-weight: 800;
  letter-spacing: -0.2px;
  color: var(--ink-deep);
}

.page-about .about-paper p {
  margin: 0 0 14px;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--paper-muted);
}

.page-about .about-paper__meta {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 26px 0 20px;
  padding: 0;
  background: var(--paper-line);
  border: 1px solid var(--paper-line);
}

@media (min-width: 640px) {
  .page-about .about-paper__meta {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-paper__meta > div {
  background: var(--paper);
  padding: 14px 16px;
}

.page-about .about-paper__meta dt {
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: .9px;
  color: var(--paper-muted);
}

.page-about .about-paper__meta dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink-deep);
}

.page-about .about-paper__cta {
  margin: 0;
}

.page-about .about-paper a {
  color: var(--ink-deep);
  font-weight: 600;
  text-decoration: underline;
  text-decoration-color: var(--flame);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

.page-about .about-paper a:hover,
.page-about .about-paper a:focus-visible {
  text-decoration-color: var(--ink-deep);
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-dir__row,
  .page-about .breadcrumb__link {
    transition: none;
  }
}