.page-about {
  --ab-edge: clamp(18px, 4vw, 40px);
  --ab-shell: 1320px;
  background: var(--ink);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  overflow-x: clip;
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .about-shell {
  width: 100%;
  max-width: var(--ab-shell);
  margin: 0 auto;
  padding: 0 var(--ab-edge);
}

.page-about .breadcrumb {
  padding-top: clamp(18px, 3vw, 28px);
}

/* ===== 首屏：竖排年份刻度 + 团队说明 ===== */
.page-about .about-hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 5vw, 44px);
  padding: clamp(28px, 5vw, 56px) 0 clamp(40px, 7vw, 80px);
  border-bottom: 1px solid var(--line);
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(150px, 210px) 1fr;
    gap: clamp(48px, 7vw, 96px);
    align-items: start;
  }
}

.page-about .year-rail {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  position: relative;
  display: grid;
  gap: 20px;
  align-content: start;
}

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

.page-about .year-node {
  position: relative;
  display: grid;
  gap: 2px;
}

.page-about .year-node::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 6px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--line);
  background: var(--ink);
  transform: rotate(45deg);
}

.page-about .year-node--start::before,
.page-about .year-node--now::before {
  border-color: var(--cyan);
}

.page-about .year-node--now::before {
  background: var(--cyan);
}

.page-about .year-num {
  font-family: var(--mono);
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .year-node--start .year-num,
.page-about .year-node--now .year-num {
  color: var(--cyan);
}

.page-about .year-note {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .hero-kicker {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--amber);
  margin: 0 0 16px;
}

.page-about .about-hero h1 {
  font-family: var(--mono);
  font-size: clamp(2rem, 5vw, 3.6rem);
  line-height: 1.08;
  letter-spacing: -0.01em;
  font-weight: 600;
  margin: 0 0 22px;
}

.page-about .hero-lede {
  max-width: 62ch;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--muted);
  margin: 0 0 30px;
}

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

@media (min-width: 720px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .hero-stat {
  background: var(--panel-deep);
  padding: 16px 18px 18px;
}

.page-about .hero-stat-value {
  display: block;
  font-family: var(--mono);
  font-size: 24px;
  line-height: 1.15;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

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

/* ===== 通用章节 ===== */
.page-about .about-section {
  padding: clamp(40px, 7vw, 84px) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-section--last {
  border-bottom: 0;
  padding-bottom: clamp(24px, 4vw, 40px);
}

.page-about .about-head {
  display: grid;
  gap: 12px;
  margin-bottom: clamp(26px, 4vw, 46px);
}

.page-about .about-code {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan);
  margin: 0;
}

.page-about .about-title {
  font-family: var(--mono);
  font-size: clamp(1.35rem, 2.6vw, 2rem);
  line-height: 1.22;
  font-weight: 600;
  margin: 0;
}

.page-about .about-sub {
  max-width: 68ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .mini-title {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text);
  margin: 0 0 16px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--line);
}

.page-about .mini-title--gap {
  margin-top: 34px;
}

/* ===== 历程 ===== */
.page-about .milestones {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .milestone {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}

@media (min-width: 760px) {
  .page-about .milestone {
    grid-template-columns: minmax(96px, 132px) 1fr;
    gap: 4px 32px;
    align-items: start;
  }
}

.page-about .milestone-mark {
  font-family: var(--mono);
  font-size: 15px;
  letter-spacing: 0.1em;
  color: var(--amber);
  line-height: 1.6;
}

.page-about .milestone-body h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  line-height: 1.45;
}

.page-about .milestone-body p {
  margin: 0;
  max-width: 78ch;
  font-size: 15.5px;
  color: var(--muted);
}

/* ===== 团队分工 ===== */
.page-about .team-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

@media (min-width: 860px) {
  .page-about .team-split {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .team-cell {
  --cell-accent: var(--cyan);
  position: relative;
  background: var(--panel);
  padding: 28px 22px 30px;
  transition: background var(--dur) var(--ease);
}

.page-about .team-cell::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: var(--cell-accent);
}

.page-about .team-cell[data-accent="violet"] { --cell-accent: var(--violet); }
.page-about .team-cell[data-accent="amber"] { --cell-accent: var(--amber); }

.page-about .team-cell:hover {
  background: var(--panel-deep);
}

.page-about .team-cell:focus-within {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .team-role {
  margin: 0 0 14px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cell-accent);
}

.page-about .team-count {
  margin: 0 0 14px;
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.04em;
}

.page-about .team-num {
  font-family: var(--mono);
  font-size: 30px;
  line-height: 1;
  color: var(--text);
  letter-spacing: 0.02em;
}

.page-about .team-text {
  margin: 0 0 18px;
  font-size: 15px;
  line-height: 1.72;
  color: var(--muted);
}

.page-about .team-rhythm {
  margin: 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.03em;
  color: var(--text);
}

/* ===== 四步流程 ===== */
.page-about .flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

@media (min-width: 700px) {
  .page-about .flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1080px) {
  .page-about .flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .flow-step {
  background: var(--panel-deep);
  padding: 24px 20px 26px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: background var(--dur) var(--ease);
}

.page-about .flow-step:hover {
  background: var(--panel);
}

.page-about .flow-step:focus-within {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

.page-about .flow-index {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .flow-name {
  margin: 0;
  font-size: 16.5px;
  font-weight: 600;
  line-height: 1.4;
}

.page-about .flow-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--muted);
  flex: 1 1 auto;
}

.page-about .flow-output {
  margin: 0;
  padding-top: 12px;
  border-top: 1px dashed var(--line);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.03em;
  color: var(--amber);
}

/* ===== 媒体 ===== */
.page-about .about-media {
  margin: clamp(26px, 4vw, 40px) 0 0;
  padding: 0;
}

.page-about .about-media--aside {
  margin-top: 0;
}

.page-about .about-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  background: var(--panel-deep);
  object-fit: cover;
}

.page-about .about-media figcaption {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.03em;
  line-height: 1.6;
  color: var(--muted);
}

/* ===== 校验与纠错 ===== */
.page-about .check-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 44px);
}

@media (min-width: 920px) {
  .page-about .check-layout {
    grid-template-columns: 1fr minmax(300px, 460px);
    align-items: start;
  }
}

.page-about .check-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .check-item {
  position: relative;
  padding-left: 24px;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .check-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--cyan);
  background: rgba(53, 224, 214, 0.16);
}

.page-about .path-list {
  list-style: none;
  counter-reset: p;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 13px;
}

.page-about .path-list li {
  counter-increment: p;
  position: relative;
  padding-left: 36px;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .path-list li::before {
  content: counter(p, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 2px;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--amber);
}

/* ===== 新用户入门 ===== */
.page-about .boot-steps {
  list-style: none;
  margin: 0 0 clamp(24px, 4vw, 36px);
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

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

@media (min-width: 1000px) {
  .page-about .boot-steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .boot-step {
  background: var(--panel);
  padding: 18px 18px 20px;
  border-top: 2px solid transparent;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .boot-step:hover {
  background: var(--panel-deep);
  border-top-color: var(--cyan);
}

.page-about .boot-step-index {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .boot-step-name {
  margin: 9px 0 0;
  font-size: 15.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.page-about .boot-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 44px);
}

@media (min-width: 920px) {
  .page-about .boot-layout {
    grid-template-columns: 1fr minmax(300px, 480px);
    align-items: start;
  }
}

.page-about .boot-text p {
  margin: 0 0 16px;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--muted);
  max-width: 72ch;
}

.page-about .boot-text p:last-child {
  margin-bottom: 0;
}

.page-about .boot-text a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 214, 0.4);
}

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

.page-about .boot-foot {
  margin: clamp(26px, 4vw, 38px) 0 0;
  padding: 18px 20px;
  border-left: 2px solid var(--violet);
  background: var(--panel-deep);
  font-size: 15px;
  line-height: 1.72;
  color: var(--muted);
}

/* ===== 联络 ===== */
.page-about .reach-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

@media (min-width: 800px) {
  .page-about .reach-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .reach-cell {
  background: var(--panel-deep);
  padding: 22px 20px 24px;
}

.page-about .reach-label {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .reach-value {
  margin: 0;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  word-break: break-word;
}

.page-about .reach-note {
  margin: 22px 0 0;
  max-width: 80ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .reach-note a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 214, 0.4);
}

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

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

@media (prefers-reduced-motion: reduce) {
  .page-about .team-cell,
  .page-about .flow-step,
  .page-about .boot-step {
    transition: none;
  }
}