.page-about {
  --about-chap-gap: clamp(44px, 7vw, 88px);
  --about-note-gap: clamp(18px, 3vw, 40px);
  position: relative;
  background: var(--ink);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: calc(var(--hdr-h) + clamp(36px, 8vw, 84px)) 0 clamp(40px, 6vw, 72px);
  background:
    radial-gradient(120% 90% at 10% -10%, rgba(79, 240, 208, .08), transparent 60%),
    linear-gradient(180deg, var(--ink) 0%, var(--pitch) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -22%;
  top: 6%;
  width: 58vw;
  height: 58vw;
  max-width: 720px;
  max-height: 720px;
  border: 1px solid var(--hair);
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
}

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

.page-about .breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--warm);
}

.page-about .breadcrumbs li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--teal);
}

.page-about .breadcrumbs a {
  color: var(--warm);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.page-about .breadcrumbs a:hover,
.page-about .breadcrumbs a:focus-visible {
  color: var(--cyan);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(28px, 5vw, 60px);
  margin-top: clamp(26px, 4vw, 44px);
}

@media (min-width: 920px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
    align-items: start;
  }
}

.page-about .about-hero h1 {
  margin: 16px 0 0;
  max-width: 15em;
  font-size: clamp(32px, 4.8vw, 58px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--white);
}

.page-about .about-lede {
  margin: clamp(18px, 3vw, 26px) 0 0;
  max-width: 42ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-facts {
  margin: 0;
  border-top: 1px solid var(--hair-strong);
}

.page-about .about-fact {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  gap: 18px;
  align-items: baseline;
  padding: 14px 0;
  border-bottom: 1px solid var(--hair);
  transition: border-color var(--dur) var(--ease);
}

.page-about .about-fact:hover {
  border-bottom-color: var(--cyan);
}

.page-about .about-fact-num {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .about-fact-num--amber {
  color: var(--amber);
}

.page-about .about-fact-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--text);
}

/* ---------- 图片通用 ---------- */
.page-about .about-figure {
  margin: 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--hair-strong);
  border-radius: 2px;
  background: var(--panel);
  object-fit: cover;
  filter: saturate(.84) brightness(.94);
  transition: border-color var(--dur) var(--ease), filter var(--dur) var(--ease);
}

.page-about .about-figure:hover img {
  border-color: var(--cyan);
  filter: saturate(1) brightness(1);
}

.page-about .about-figure--hero {
  margin-top: clamp(36px, 6vw, 76px);
}

/* ---------- 章节导航 ---------- */
.page-about .about-toc {
  position: sticky;
  top: var(--hdr-h);
  z-index: 20;
  padding: 10px 0;
  background: var(--pitch);
  border-top: 1px solid var(--hair);
  border-bottom: 1px solid var(--hair);
}

.page-about .about-toc ol {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 2px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-toc ol::-webkit-scrollbar {
  display: none;
}

.page-about .about-toc a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 13px;
  border: 1px solid var(--hair);
  border-radius: 2px;
  white-space: nowrap;
  font-size: 13px;
  color: var(--text);
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  border-color: var(--cyan);
  color: var(--white);
  background: rgba(46, 110, 94, .2);
}

.page-about .about-toc a.is-active {
  border-color: var(--cyan);
  color: var(--white);
}

.page-about .about-toc .toc-num {
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--warm);
}

.page-about .about-toc a.is-active .toc-num {
  color: var(--cyan);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapters {
  padding-bottom: clamp(48px, 7vw, 84px);
}

.page-about .about-chapter {
  padding: var(--about-chap-gap) 0;
  border-top: 1px solid var(--hair);
  scroll-margin-top: calc(var(--hdr-h) + 72px);
}

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

.page-about .chapter-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
}

.page-about .chapter-head::after {
  content: "";
  flex: 1 1 auto;
  min-width: 20px;
  height: 1px;
  background: var(--hair-strong);
  transform: translateY(-5px);
}

.page-about .chapter-num {
  flex: none;
  font-size: 13px;
  letter-spacing: .18em;
  color: var(--cyan);
}

.page-about .chapter-head h2 {
  flex: 0 1 auto;
  margin: 0;
  font-size: clamp(23px, 3vw, 33px);
  font-weight: 800;
  letter-spacing: -.015em;
  line-height: 1.2;
  color: var(--white);
}

.page-about .chapter-body {
  display: grid;
  gap: var(--about-note-gap);
  margin-top: clamp(20px, 3vw, 34px);
}

@media (min-width: 1020px) {
  .page-about .chapter-body {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: start;
  }
}

.page-about .chapter-main p {
  margin: 0 0 15px;
  max-width: 62ch;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--text);
}

.page-about .chapter-main p:last-child {
  margin-bottom: 0;
}

.page-about .chapter-main strong {
  color: var(--white);
  font-weight: 700;
}

.page-about .lead-tag {
  display: inline-block;
  margin-right: 8px;
  padding: 2px 8px;
  border-radius: 2px;
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  vertical-align: 2px;
}

.page-about .chapter-aside {
  display: none;
}

@media (min-width: 1020px) {
  .page-about .chapter-aside {
    display: block;
    justify-self: end;
    padding-top: 8px;
  }

  .page-about .chapter-note {
    margin: 0;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 12px;
    letter-spacing: .16em;
    color: var(--warm);
    white-space: nowrap;
    transition: color var(--dur) var(--ease);
  }

  .page-about .about-chapter:hover .chapter-note {
    color: var(--cyan);
  }
}

/* ---------- 工作流 ---------- */
.page-about .flow-block {
  margin-top: clamp(28px, 5vw, 52px);
}

.page-about .about-flow {
  display: block;
  width: 100%;
  height: auto;
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .about-flow .flow-lane {
  stroke: var(--hair);
  stroke-width: 1;
}

.page-about .about-flow .flow-handoff {
  stroke: var(--hair-strong);
  stroke-width: 1;
  stroke-dasharray: 3 5;
}

.page-about .about-flow .flow-lane-name {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  fill: var(--warm);
}

.page-about .about-flow .flow-node-label {
  font-size: 13px;
  fill: var(--text);
  transition: fill var(--dur) var(--ease);
}

.page-about .about-flow .flow-dot {
  fill: var(--ink);
  stroke: var(--line);
  stroke-width: 1.5;
  transition: fill var(--dur) var(--ease), stroke var(--dur) var(--ease), r var(--dur) var(--ease);
}

.page-about .about-flow .flow-node {
  cursor: help;
  outline: none;
}

.page-about .about-flow .flow-node:hover .flow-dot,
.page-about .about-flow .flow-node:focus-visible .flow-dot {
  fill: var(--cyan);
  stroke: var(--cyan);
}

.page-about .about-flow .flow-node:hover .flow-node-label,
.page-about .about-flow .flow-node:focus-visible .flow-node-label {
  fill: var(--white);
}

/* ---------- 原则与边界 ---------- */
.page-about .boundary-grid {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  margin-top: clamp(20px, 3vw, 30px);
}

@media (min-width: 780px) {
  .page-about .boundary-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.page-about .boundary-col h3 {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--white);
}

.page-about .boundary-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .boundary-list li {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  gap: 10px;
  padding: 12px 0;
  border-bottom: 1px solid var(--hair);
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text);
}

.page-about .boundary-mark {
  padding-top: 3px;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--cyan);
}

.page-about .boundary-mark--coral {
  color: var(--coral);
}

/* ---------- 发布节奏 ---------- */
.page-about .about-cadence {
  position: relative;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-cadence::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--hair-strong);
}

.page-about .cadence-item {
  position: relative;
  padding: 0 0 28px 32px;
}

.page-about .cadence-item:last-child {
  padding-bottom: 0;
}

.page-about .cadence-item::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink);
  border: 1.5px solid var(--line);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .cadence-item:hover::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .cadence-time {
  display: block;
  margin-bottom: 5px;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--cyan);
}

.page-about .cadence-item h3 {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  color: var(--white);
}

.page-about .cadence-item p {
  margin: 0;
  max-width: 48ch;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--text);
}

/* ---------- 赛季刻度 ---------- */
.page-about .about-figure--season {
  margin-top: clamp(30px, 5vw, 52px);
}

.page-about .about-seasons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--hair-strong);
}

.page-about .about-season {
  position: relative;
  padding: 22px 16px 20px 0;
  border-bottom: 1px solid var(--hair);
  outline: none;
  transition: background var(--dur) var(--ease);
}

.page-about .about-season::before {
  content: "";
  position: absolute;
  top: -4px;
  left: 0;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--line);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-season:hover::before,
.page-about .about-season:focus-visible::before,
.page-about .about-season--current::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

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

.page-about .season-num {
  display: block;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--white);
}

.page-about .about-season--current .season-num {
  color: var(--cyan);
}

.page-about .season-note {
  display: block;
  margin-top: 8px;
  max-width: 22ch;
  font-size: 13px;
  line-height: 1.62;
  color: var(--warm);
  transition: color var(--dur) var(--ease);
}

.page-about .about-season:hover .season-note,
.page-about .about-season:focus-visible .season-note {
  color: var(--text);
}

/* ---------- 反馈区 ---------- */
.page-about .about-contact {
  margin-top: clamp(32px, 5vw, 56px);
  padding-top: clamp(28px, 4vw, 44px);
  border-top: 1px solid var(--hair-strong);
}

.page-about .about-contact__inner {
  display: grid;
  gap: clamp(22px, 3vw, 36px);
  padding-left: clamp(18px, 3vw, 32px);
  border-left: 2px solid var(--cyan);
}

@media (min-width: 900px) {
  .page-about .about-contact__inner {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: start;
  }
}

.page-about .about-contact__inner h3 {
  margin: 12px 0 0;
  font-size: clamp(20px, 2.6vw, 27px);
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--white);
}

.page-about .about-contact__text {
  margin: 14px 0 0;
  max-width: 46ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-contact__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-content: start;
}

.page-about .about-contact__meta {
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding-left: clamp(18px, 3vw, 32px);
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--warm);
}

.page-about .about-contact__meta a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(79, 240, 208, .35);
  transition: border-color var(--dur) var(--ease);
}

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-figure img,
  .page-about .about-fact,
  .page-about .about-toc a,
  .page-about .about-flow .flow-dot,
  .page-about .season-note,
  .page-about .chapter-note {
    transition-duration: 1ms;
  }
}
</main>