.page-about {
  --about-rail-w: 7.5rem;
  --about-hair: rgba(30, 74, 50, 0.6);
  --about-ink-soft: #453a2e;
  background: var(--field-900);
  color: var(--paper);
  overflow-x: clip;
}

.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  padding-block: 1.5rem 0.75rem;
}
.page-about .breadcrumb__link {
  color: var(--moss);
  text-decoration: none;
  transition: color 0.2s var(--ease);
}
.page-about .breadcrumb__link:hover {
  color: var(--lemon);
}
.page-about .breadcrumb__sep {
  color: var(--line-700);
}
.page-about .breadcrumb__current {
  color: var(--ash);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(1.5rem, 5vw, 3rem) clamp(2.25rem, 6vw, 4rem);
  border-bottom: 1px solid var(--line-700);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 3.5rem);
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    align-items: end;
    gap: clamp(2.5rem, 6vw, 6rem);
  }
}

.page-about .about-hero__kicker {
  margin: 0 0 1rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--lemon);
}

.page-about .about-hero__title {
  margin: 0 0 1.25rem;
  font-family: var(--display);
  font-weight: 900;
  font-size: clamp(2.1rem, 7.4vw, 3.7rem);
  line-height: 1.06;
  letter-spacing: -0.022em;
  color: var(--paper);
  max-width: 16ch;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 46ch;
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--ash);
}

.page-about .about-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 2.25rem;
  margin: 2rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line-700);
}

.page-about .about-hero__fact {
  margin: 0;
}
.page-about .about-hero__fact dt {
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--moss);
  margin-bottom: 0.35rem;
}
.page-about .about-hero__fact dd {
  margin: 0;
  font-size: 0.9375rem;
  letter-spacing: 0.05em;
  color: var(--lemon);
}

/* 首屏刻度视觉 */
.page-about .about-hero__visual {
  padding: clamp(1.25rem, 4vw, 2rem) 0 0 clamp(1rem, 4vw, 1.75rem);
  border-left: 1px solid var(--line-700);
}

.page-about .about-hero__visual-cap {
  margin: 0 0 1.25rem;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--moss);
}

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

.page-about .about-meter__row {
  display: grid;
  grid-template-columns: 2.25rem minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.75rem;
  padding-block: 0.85rem;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-meter__num {
  font-size: 0.875rem;
  letter-spacing: 0.1em;
  color: var(--moss);
}

.page-about .about-meter__bar {
  position: relative;
  display: block;
  height: 6px;
  background: var(--field-800);
  border: 1px solid var(--line-700);
}

.page-about .about-meter__bar::after {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 40%;
  background: var(--moss);
}

.page-about .about-meter__row--now .about-meter__bar::after {
  width: 100%;
  background: var(--lemon);
}

.page-about .about-meter__row--now .about-meter__num {
  color: var(--lemon);
}

.page-about .about-meter__cap {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--ash);
  white-space: nowrap;
}

.page-about .about-hero__visual-note {
  margin: 1.25rem 0 0;
  font-size: 0.8125rem;
  line-height: 1.75;
  color: var(--moss);
}

/* ---------- 编年体主体 ---------- */
.page-about .about-timeline {
  padding-block: clamp(2.5rem, 7vw, 5rem) clamp(2rem, 6vw, 4rem);
}

.page-about .about-timeline__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.75rem;
}

@media (min-width: 900px) {
  .page-about .about-timeline__grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(2.5rem, 6vw, 5.5rem);
    align-items: start;
  }
}

/* 左侧年份索引 */
.page-about .about-rail {
  overflow-x: auto;
  scrollbar-width: none;
  border-bottom: 1px solid var(--line-700);
  padding-bottom: 0.75rem;
}
.page-about .about-rail::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__list {
  display: flex;
  gap: 0.25rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-rail__item {
  margin: 0;
  flex: 0 0 auto;
}

.page-about .about-rail__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 0.45rem;
  padding: 0.5rem 0.7rem;
  color: var(--moss);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease);
}

.page-about .about-rail__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.45rem;
  bottom: 0.45rem;
  width: 2px;
  background: var(--lemon);
  opacity: 0;
  transition: opacity 0.2s var(--ease);
}

.page-about .about-rail__link:hover {
  color: var(--ash);
}

.page-about .about-rail__link.is-active,
.page-about .about-rail__link[aria-current] {
  color: var(--lemon);
}

.page-about .about-rail__link.is-active::before,
.page-about .about-rail__link[aria-current]::before {
  opacity: 1;
}

.page-about .about-rail__num {
  font-size: 0.75rem;
  letter-spacing: 0.12em;
}

.page-about .about-rail__name {
  font-size: 0.8125rem;
  letter-spacing: 0.05em;
}

@media (min-width: 900px) {
  .page-about .about-rail {
    position: sticky;
    top: 6rem;
    overflow: visible;
    border-bottom: 0;
    border-left: 1px solid var(--line-700);
    padding: 0 0 0 0.85rem;
  }
  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0.125rem;
  }
  .page-about .about-rail__item {
    flex: 0 0 auto;
  }
}

/* 章节 */
.page-about .about-stage {
  position: relative;
  padding-block: clamp(1.75rem, 5vw, 3rem);
  border-top: 1px solid var(--line-700);
}

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

.page-about .about-stage__head {
  display: grid;
  gap: 0.6rem;
  margin-bottom: 1.25rem;
}

.page-about .about-stage__index {
  font-size: 0.75rem;
  letter-spacing: 0.22em;
  color: var(--flag);
}

.page-about .about-stage__title {
  margin: 0;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(1.35rem, 4vw, 1.875rem);
  line-height: 1.35;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .about-stage__body {
  max-width: 62ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--ash);
}

.page-about .about-stage__body p {
  margin: 0 0 1.05em;
}
.page-about .about-stage__body p:last-child {
  margin-bottom: 0;
}

/* 纸面章节 */
.page-about .about-stage--paper {
  background: var(--paper);
  color: var(--ink-900);
  border-top: 0;
  border-left: 4px solid var(--flag);
  padding: clamp(1.5rem, 4vw, 2.5rem);
  margin-block: clamp(1.25rem, 4vw, 2rem);
}

.page-about .about-stage--paper .about-stage__title {
  color: var(--ink-900);
}

.page-about .about-stage--paper .about-stage__body {
  color: var(--about-ink-soft);
}

/* 字段清单 */
.page-about .about-fields {
  list-style: none;
  margin: 1.75rem 0 1.75rem;
  padding: 0;
  border-top: 1px solid var(--about-hair);
}

.page-about .about-fields__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.3rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--about-hair);
}

@media (min-width: 640px) {
  .page-about .about-fields__item {
    grid-template-columns: 9.5rem minmax(0, 1fr);
    gap: 1.25rem;
    align-items: baseline;
  }
}

.page-about .about-fields__key {
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--lemon);
}

.page-about .about-fields__val {
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--ash);
}

/* 图片 */
.page-about .about-stage__figure {
  margin: 1.75rem 0;
}

/* 覆盖刻度 */
.page-about .about-scale {
  margin-top: 1.75rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--about-hair);
}

.page-about .about-scale__track {
  position: relative;
  height: 18px;
  background-color: var(--field-800);
  border: 1px solid var(--line-700);
  background-image: repeating-linear-gradient(
    90deg,
    var(--line-700) 0,
    var(--line-700) 1px,
    transparent 1px,
    transparent calc(100% / 12)
  );
}

.page-about .about-scale__fill {
  position: absolute;
  inset: 0 auto 0 0;
  width: calc(100% * 5 / 12);
  background: var(--moss);
  opacity: 0.85;
}

.page-about .about-scale__mark {
  position: absolute;
  top: -5px;
  bottom: -5px;
  left: calc(100% * 5 / 12);
  width: 1px;
  background: var(--lemon);
}

.page-about .about-scale__legend {
  margin: 1rem 0 0;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: var(--moss);
}

.page-about .about-scale__legend .u-mono {
  color: var(--lemon);
}

.page-about .about-scale__tip {
  margin: 0.6rem 0 0;
  font-size: 0.8125rem;
  line-height: 1.75;
  color: var(--moss);
  transition: color 0.25s var(--ease);
}

.page-about .about-scale:hover .about-scale__tip,
.page-about .about-scale:focus-within .about-scale__tip {
  color: var(--ash);
}

/* 版本标签页 */
.page-about .about-versions {
  margin-top: 1.75rem;
}

.page-about .about-versions__list {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.375rem;
  margin: 0 0 1.25rem;
  padding-bottom: 0.5rem;
  overflow-x: auto;
  scrollbar-width: none;
  border-bottom: 1px solid var(--line-700);
}
.page-about .about-versions__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-versions__btn {
  flex: 0 0 auto;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--line-700);
  background: transparent;
  color: var(--moss);
  cursor: pointer;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease),
    background-color 0.2s var(--ease);
}

.page-about .about-versions__btn:hover {
  color: var(--ash);
  border-color: var(--moss);
}

.page-about .about-versions__btn[aria-selected="true"] {
  background: var(--flag);
  border-color: var(--flag);
  color: var(--paper);
}

.page-about .about-versions__panel {
  padding: 1.25rem;
  background: var(--field-800);
  border-left: 2px solid var(--flag);
}

.page-about .about-versions__lead {
  margin: 0 0 0.9rem;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--paper);
}

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

.page-about .about-versions__list-items li {
  position: relative;
  padding-left: 1rem;
  margin-bottom: 0.55rem;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--ash);
}

.page-about .about-versions__list-items li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 0.4rem;
  height: 1px;
  background: var(--lemon);
}

.page-about .about-versions__list-items li:last-child {
  margin-bottom: 0;
}

/* 岗位 */
.page-about .about-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.5rem;
  margin: 1.75rem 0;
}

@media (min-width: 720px) {
  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2.5rem;
  }
}

.page-about .about-roles__item {
  border-top: 2px solid var(--flag);
  padding-top: 0.9rem;
}

.page-about .about-roles__name {
  margin: 0 0 0.5rem;
  font-family: var(--display);
  font-weight: 800;
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.page-about .about-roles__desc {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--ash);
}

/* 交叉入口 */
.page-about .about-cross {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0;
  border-top: 1px solid var(--ash);
}

.page-about .about-cross__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.3rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--ash);
}

@media (min-width: 640px) {
  .page-about .about-cross__item {
    grid-template-columns: 15rem minmax(0, 1fr);
    gap: 1.25rem;
    align-items: baseline;
  }
}

.page-about .about-cross__link {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1rem;
  color: var(--ink-900);
  text-decoration: none;
  border-bottom: 1px solid var(--flag);
  padding-bottom: 1px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-cross__link:hover {
  color: var(--flag);
  border-color: var(--ink-900);
}

.page-about .about-cross__note {
  font-size: 0.8125rem;
  line-height: 1.75;
  color: var(--about-ink-soft);
}

/* 页尾横图 */
.page-about .about-outro {
  padding-block: clamp(1.5rem, 5vw, 3rem) clamp(2.5rem, 7vw, 5rem);
}

/* 窄屏防溢出 */
@media (max-width: 639px) {
  .page-about .about-hero__title,
  .page-about .about-stage__title,
  .page-about .about-hero__lede,
  .page-about .about-stage__body {
    overflow-wrap: break-word;
    word-break: break-word;
  }
  .page-about .about-meter__row {
    grid-template-columns: 2rem minmax(0, 1fr);
  }
  .page-about .about-meter__cap {
    grid-column: 2;
    white-space: normal;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
  }
}
<<<END>>>