.page-about {
  --about-rule: rgba(140, 153, 173, .26);
  --about-rule-2: rgba(140, 153, 173, .5);
  --about-shell: #0E2038;
  padding-bottom: 88px;
  overflow-x: clip;
}

.page-about .breadcrumb {
  margin: 24px 0 26px;
  font-size: 13px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  border: 2px solid var(--rock);
  background:
    repeating-linear-gradient(0deg, var(--about-rule) 0 1px, transparent 1px 24px),
    repeating-linear-gradient(90deg, var(--about-rule) 0 1px, transparent 1px 24px),
    linear-gradient(158deg, rgba(255, 106, 43, .15), transparent 54%),
    var(--ink-2);
  box-shadow: var(--shadow);
  padding: 26px 20px 28px;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 104px;
  height: 4px;
  background: linear-gradient(90deg, var(--orange), var(--cyan));
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-size: clamp(1.85rem, 6vw, 3.2rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.16;
  color: var(--paper);
  max-width: 22em;
}

.page-about .about-hero .lede {
  margin: 16px 0 0;
  max-width: 36em;
  color: var(--body-soft);
}

.page-about .about-stats {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
}

.page-about .about-stat {
  background: var(--ink);
  padding: 14px 15px;
  min-width: 0;
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--mono);
  font-size: 24px;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--gold);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.page-about .about-hero__paths {
  margin: 20px 0 0;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.page-about .about-hero__paths a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, .45);
  padding-bottom: 2px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

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

.page-about .about-hero__paths span {
  margin: 0 8px;
  color: var(--about-rule-2);
}

/* ---------- 层叠目录布局 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  margin-top: 52px;
}

.page-about .about-toc {
  border: 2px solid var(--rock);
  background: var(--about-shell);
  box-shadow: var(--shadow);
  padding: 18px 16px 14px;
}

.page-about .about-toc__title {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--mist);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
  counter-reset: none;
}

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 8px 8px 6px;
  border-left: 2px solid transparent;
  color: var(--body-soft);
  font-size: 14px;
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  border-left-color: var(--orange);
  color: var(--paper);
  transform: translateX(2px);
}

.page-about .about-toc__num {
  flex: none;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .about-body {
  display: grid;
  gap: 56px;
  min-width: 0;
}

/* ---------- 段落 ---------- */
.page-about .about-sec {
  scroll-margin-top: 88px;
  min-width: 0;
}

.page-about .about-sec__head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  border-bottom: 2px solid var(--rock);
  padding-bottom: 12px;
  margin-bottom: 20px;
}

.page-about .about-sec__num {
  flex: none;
  padding-top: 6px;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--orange);
}

.page-about .about-sec__title {
  margin: 0;
  font-size: clamp(1.2rem, 3.6vw, 1.7rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.28;
  color: var(--paper);
}

.page-about .about-sec__body > p {
  margin: 0;
  max-width: 36em;
  color: var(--body-soft);
}

.page-about .about-sec__body > p + p {
  margin-top: 14px;
}

/* ---------- 四步清单 ---------- */
.page-about .about-list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
}

.page-about .about-list li {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 12px;
  background: var(--ink-2);
  padding: 13px 14px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--body-soft);
}

.page-about .about-list b {
  color: var(--paper);
  font-weight: 700;
}

.page-about .about-list__k {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  padding-top: 4px;
}

/* ---------- 图 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
  border: 2px solid var(--rock);
  background: var(--about-shell);
  box-shadow: var(--shadow);
  overflow: hidden;
}

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

.page-about .about-figure__cap {
  display: block;
  padding: 10px 14px;
  border-top: 1px solid var(--about-rule);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

/* ---------- 分工 ---------- */
.page-about .about-roles {
  margin-top: 24px;
  display: grid;
  gap: 14px;
}

.page-about .about-role {
  border: 2px solid var(--rock);
  border-left: 4px solid var(--cyan);
  background: var(--about-shell);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, .4);
  padding: 16px 16px 18px;
}

.page-about .about-role__name {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.page-about .about-role__mark {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--orange);
  flex: none;
}

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

.page-about .about-role:nth-child(2) .about-role__mark {
  background: var(--gold);
}

.page-about .about-role:nth-child(3) {
  border-left-color: var(--moss);
}

.page-about .about-role:nth-child(3) .about-role__mark {
  background: var(--moss);
}

.page-about .about-role__desc {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 版本分段 ---------- */
.page-about .about-tl {
  margin-top: 26px;
}

.page-about .about-tl__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.page-about .about-tl__btn {
  appearance: none;
  border: 2px solid var(--rock);
  background: var(--ink);
  color: var(--mist);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  padding: 9px 14px;
  cursor: pointer;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-tl__btn::before {
  content: "";
  display: inline-block;
  width: 7px;
  height: 7px;
  margin-right: 8px;
  border-radius: 50%;
  background: currentColor;
  vertical-align: middle;
}

.page-about .about-tl__btn:hover {
  color: var(--paper);
  border-color: var(--mist);
}

.page-about .about-tl__btn[aria-selected="true"] {
  background: var(--orange);
  border-color: var(--orange);
  color: #14171d;
  font-weight: 700;
}

.page-about .about-tl__panel {
  border: 2px solid var(--rock);
  border-left: 4px solid var(--cyan);
  background: var(--ink-2);
  box-shadow: var(--shadow);
  padding: 18px 16px;
  max-width: 40em;
}

.page-about .about-tl__panel[hidden] {
  display: none;
}

.page-about .about-tl__panel-title {
  margin: 0 0 8px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gold);
}

.page-about .about-tl__panel p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--body-soft);
}

/* ---------- 设备与场景 ---------- */
.page-about .about-clients {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.page-about .about-client {
  border: 1px solid var(--about-rule-2);
  background: var(--ink-2);
  padding: 10px 12px;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--paper);
  text-align: center;
}

.page-about .about-scenes {
  margin-top: 20px;
  display: grid;
  gap: 14px;
}

.page-about .about-scene {
  border-top: 2px solid var(--rock);
  padding-top: 12px;
}

.page-about .about-scene__title {
  margin: 0;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--cyan);
}

.page-about .about-scene__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 折叠说明 ---------- */
.page-about .about-details {
  margin-top: 22px;
  border: 2px solid var(--rock);
  background: var(--ink-2);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, .4);
}

.page-about .about-details + .about-details {
  margin-top: 12px;
}

.page-about .about-details summary {
  cursor: pointer;
  padding: 14px 16px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--paper);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
}

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

.page-about .about-details summary::before {
  content: "+";
  flex: none;
  font-family: var(--mono);
  font-size: 15px;
  color: var(--orange);
}

.page-about .about-details[open] summary::before {
  content: "–";
  color: var(--cyan);
}

.page-about .about-details summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -4px;
}

.page-about .about-details p {
  margin: 0;
  padding: 0 16px 16px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
  max-width: 38em;
}

/* ---------- 起步两条路 ---------- */
.page-about .about-start {
  margin-top: 22px;
  display: grid;
  gap: 16px;
}

.page-about .about-start__card {
  border: 2px solid var(--rock);
  background: var(--about-shell);
  box-shadow: var(--shadow);
  padding: 20px 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.page-about .about-start__tag {
  margin: 0;
  align-self: flex-start;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink);
  background: var(--gold);
  padding: 3px 8px;
}

.page-about .about-start__card:last-child .about-start__tag {
  background: var(--cyan);
}

.page-about .about-start__title {
  margin: 0;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-start__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-link {
  margin-top: auto;
  align-self: flex-start;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--orange);
  text-decoration: none;
  border-bottom: 2px solid rgba(255, 106, 43, .5);
  padding-bottom: 2px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
  transform: translateX(2px);
}

.page-about .about-foot-links {
  margin: 22px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
  max-width: 38em;
}

.page-about .about-foot-links a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, .45);
  padding-bottom: 1px;
}

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

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 36px 34px 38px;
  }

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

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

  .page-about .about-role:nth-child(2) {
    transform: translateY(14px);
  }

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

  .page-about .about-scenes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px 22px;
  }

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

  .page-about .about-start__card:last-child {
    transform: translateY(14px);
  }
}

@media (min-width: 960px) {
  .page-about .about-layout {
    grid-template-columns: 244px minmax(0, 1fr);
    gap: 60px;
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 24px;
  }

  .page-about .about-body {
    gap: 72px;
  }

  .page-about .about-sec__head {
    align-items: baseline;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__link,
  .page-about .about-tl__btn,
  .page-about .about-link,
  .page-about .about-hero__paths a,
  .page-about .about-role:nth-child(2),
  .page-about .about-start__card:last-child {
    transition: none;
    transform: none;
  }
}