.page-about {
  --ab-rail-w: 224px;
  --ab-edge: 2px;
  color: var(--sand);
  padding-block: clamp(18px, 3vw, 34px) clamp(30px, 5vw, 56px);
}

/* ---------- 面包屑 ---------- */
.page-about .crumb {
  margin-bottom: clamp(20px, 3vw, 32px);
}

.page-about .crumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .crumb__item + .crumb__item::before {
  content: "/";
  margin-right: 6px;
  color: var(--sandbrown);
}

.page-about .crumb__item a {
  color: var(--jade-light);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.page-about .crumb__item a:hover {
  border-bottom-color: var(--jade-light);
}

.page-about .crumb__item a:focus-visible {
  outline: 2px solid var(--jade-light);
  outline-offset: 2px;
}

/* ---------- 首屏自述 ---------- */
.page-about .about-intro {
  border-top: var(--ab-edge) solid var(--gold);
  padding-top: clamp(20px, 3vw, 30px);
  margin-bottom: clamp(34px, 6vw, 66px);
}

.page-about .about-intro__coord {
  margin: 0 0 16px;
  font-size: 12px;
  letter-spacing: 0.26em;
  color: var(--gold);
}

.page-about .about-intro__title {
  margin: 0 0 20px;
  font-family: var(--font-title);
  font-size: clamp(30px, 5.6vw, 58px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: 0.01em;
  color: var(--sand);
  max-width: 20ch;
}

.page-about .about-intro__lede {
  margin: 0 0 clamp(24px, 4vw, 36px);
  max-width: 62ch;
  font-size: clamp(16px, 1.5vw, 18px);
  line-height: 1.8;
  color: var(--stone);
}

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

.page-about .about-fact {
  background: var(--ink-2);
  padding: 16px 16px 18px;
  min-width: 0;
}

.page-about .about-fact__value {
  display: block;
  font-size: clamp(24px, 3vw, 30px);
  line-height: 1.15;
  color: var(--gold-soft);
}

.page-about .about-fact__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--muted);
}

/* ---------- 双栏框架 ---------- */
.page-about .about-frame {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  align-items: start;
}

.page-about .about-canvas {
  min-width: 0;
}

/* ---------- 左侧年份刻度轴 ---------- */
.page-about .about-rail {
  border-top: var(--ab-edge) solid var(--gold);
  padding-top: 14px;
}

.page-about .about-rail__title {
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: 0.26em;
  color: var(--gold);
}

.page-about .about-rail__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 5px 10px;
  border: 1px solid var(--sandbrown);
  text-decoration: none;
  color: var(--stone);
  transition: border-color 120ms ease-out, background-color 120ms ease-out, color 120ms ease-out;
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  border-color: var(--gold);
  background: rgba(201, 162, 39, 0.16);
  color: var(--sand);
}

.page-about .about-rail__link:focus-visible {
  outline: 2px solid var(--jade-light);
  outline-offset: 2px;
}

.page-about .about-rail__year {
  font-size: 14px;
  color: var(--gold-soft);
}

.page-about .about-rail__note {
  font-size: 12px;
  color: var(--muted);
}

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  border-top: var(--ab-edge) solid var(--paper-line);
  padding: clamp(28px, 4vw, 40px) 0 clamp(34px, 5vw, 52px);
}

.page-about .about-chapter:first-child {
  border-top-color: var(--gold);
}

.page-about .about-chapter__num {
  display: inline-block;
  margin: 0 0 12px;
  padding: 2px 8px;
  border: 1px solid var(--sandbrown);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.2em;
  color: var(--gold);
  line-height: 1.4;
}

.page-about .about-chapter__body {
  min-width: 0;
}

.page-about .about-chapter h2 {
  margin: 0 0 18px;
  font-family: var(--font-title);
  font-size: clamp(23px, 3.2vw, 34px);
  font-weight: 800;
  line-height: 1.24;
  color: var(--sand);
}

.page-about .about-chapter h3 {
  margin: 0 0 8px;
  font-family: var(--font-title);
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--gold-soft);
}

.page-about .about-chapter p {
  margin: 0 0 1.1em;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--stone);
}

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

.page-about .about-chapter a {
  color: var(--jade-light);
  text-decoration: none;
  border-bottom: 1px solid rgba(79, 179, 162, 0.45);
}

.page-about .about-chapter a:hover {
  border-bottom-color: var(--jade-light);
}

.page-about .about-chapter a:focus-visible {
  outline: 2px solid var(--jade-light);
  outline-offset: 2px;
}

.page-about .about-chapter__note {
  margin: -8px 0 22px !important;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--sandbrown);
}

/* ---------- 业务范围列表 ---------- */
.page-about .about-scope {
  margin: 24px 0 0;
  border-top: 1px solid var(--paper-line);
}

.page-about .about-scope__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--paper-line);
}

.page-about .about-scope dt {
  font-size: 16px;
  font-weight: 700;
  color: var(--sand);
  line-height: 1.5;
}

.page-about .about-scope dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--stone);
}

/* ---------- 图片 ---------- */
.page-about .about-media {
  margin: 0 0 26px;
}

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

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  margin: 26px 0 0;
  padding: 0 0 0 24px;
  list-style: none;
  border-left: var(--ab-edge) solid var(--paper-line);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: 28px;
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 6px;
  width: 10px;
  height: 10px;
  background: var(--ink);
  border: var(--ab-edge) solid var(--gold);
}

.page-about .about-timeline__year {
  margin: 0 0 4px;
  font-size: 19px;
  letter-spacing: 0.06em;
  color: var(--gold);
}

.page-about .about-timeline__body p {
  margin-bottom: 10px;
}

/* ---------- 折叠详情 ---------- */
.page-about .about-details {
  border-top: 1px dashed var(--paper-line);
  padding-top: 10px;
}

.page-about .about-details > summary {
  display: flex;
  align-items: baseline;
  gap: 8px;
  cursor: pointer;
  list-style: none;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--jade-light);
}

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

.page-about .about-details > summary::before {
  content: "+";
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--gold);
}

.page-about .about-details[open] > summary::before {
  content: "−";
}

.page-about .about-details > summary:focus-visible {
  outline: 2px solid var(--jade-light);
  outline-offset: 3px;
}

.page-about .about-details__panel {
  padding-top: 10px;
}

.page-about .about-details__panel p {
  font-size: 15px;
  color: var(--stone);
}

/* ---------- 团队图表 ---------- */
.page-about .about-chart {
  margin: 26px 0 24px;
  padding: 20px 18px 16px;
  border: var(--ab-edge) solid var(--paper-line);
  background: var(--ink-2);
  box-shadow: var(--shadow-hard);
}

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

.page-about .about-chart__label {
  fill: var(--stone);
  font-family: var(--font-body);
  font-size: 14px;
}

.page-about .about-chart__num {
  fill: var(--gold-soft);
  font-family: var(--font-mono);
  font-size: 15px;
}

.page-about .about-chart__bar {
  transition: opacity 120ms ease-out;
}

.page-about .about-chart__bar--test {
  fill: var(--gold);
}

.page-about .about-chart__bar--doc {
  fill: var(--jade);
}

.page-about .about-chart__bar--cs {
  fill: var(--sandbrown);
}

.page-about .about-chart__cap {
  margin: 16px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 角色说明 ---------- */
.page-about .about-role {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--paper-line);
  border: var(--ab-edge) solid var(--paper-line);
}

.page-about .about-role__item {
  background: var(--ink);
  padding: 18px 16px;
  min-width: 0;
}

.page-about .about-role__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--stone);
}

/* ---------- 节奏对照 ---------- */
.page-about .about-ledger {
  margin: 22px 0 26px;
}

.page-about .about-ledger__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--paper-line);
  background: var(--ink-2);
}

.page-about .about-ledger__row:last-child {
  border-bottom: 0;
}

.page-about .about-ledger__row .ledger__key {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--gold-soft);
}

.page-about .about-ledger__row .ledger__val {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--stone);
}

/* ---------- 服务地区 ---------- */
.page-about .about-region {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 22px 0 26px;
  padding: 0;
  list-style: none;
}

.page-about .about-region__item {
  position: relative;
  border: var(--ab-edge) solid var(--paper-line);
  background: var(--ink-2);
  padding: 13px 14px;
  font-size: 15px;
  line-height: 1.5;
  color: var(--stone);
  min-width: 0;
}

.page-about .about-region__item--core {
  border-color: var(--gold);
  background: linear-gradient(155deg, rgba(201, 162, 39, 0.26), rgba(15, 27, 42, 0) 72%);
  color: var(--sand);
}

.page-about .about-region__tag {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--gold-soft);
}

/* ---------- 能力积累 ---------- */
.page-about .about-capability {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin: 22px 0 24px;
  padding: 0;
  list-style: none;
}

.page-about .about-capability__item {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding-left: 16px;
  border-left: var(--ab-edge) solid var(--sandbrown);
  min-width: 0;
}

.page-about .about-capability__value {
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.1;
  color: var(--gold-soft);
}

.page-about .about-capability__text {
  font-size: 15px;
  line-height: 1.7;
  color: var(--stone);
}

/* ---------- 底部档案条 ---------- */
.page-about .about-outro {
  margin-top: clamp(30px, 5vw, 52px);
  border-top: var(--ab-edge) solid var(--gold);
  padding-top: clamp(20px, 3vw, 30px);
}

.page-about .about-outro__title {
  margin: 0 0 4px;
  font-family: var(--font-title);
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 800;
  color: var(--sand);
}

.page-about .about-outro__links {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-outro__link {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 18px;
  border: var(--ab-edge) solid var(--paper-line);
  background: var(--ink-2);
  color: var(--stone);
  text-decoration: none;
  font-size: 15px;
  line-height: 1.5;
  box-shadow: var(--shadow-hard);
  transition: transform 120ms ease-out, box-shadow 120ms ease-out, border-color 120ms ease-out, color 120ms ease-out;
}

.page-about .about-outro__link:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hard-hi);
  border-color: var(--gold);
  color: var(--sand);
}

.page-about .about-outro__link:focus-visible {
  outline: 2px solid var(--jade-light);
  outline-offset: 3px;
}

.page-about .about-outro__lead {
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--gold);
}

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

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

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

  .page-about .about-scope__row {
    grid-template-columns: minmax(180px, 240px) minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }

  .page-about .about-ledger__row {
    grid-template-columns: minmax(140px, 200px) minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }

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

@media (min-width: 900px) {
  .page-about .about-frame {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: clamp(36px, 5vw, 64px);
  }

  .page-about .about-rail {
    position: sticky;
    top: 88px;
    border-top: 0;
    border-left: var(--ab-edge) solid var(--gold);
    padding: 0 0 0 18px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0;
  }

  .page-about .about-rail__link {
    display: grid;
    grid-template-columns: 54px minmax(0, 1fr);
    gap: 10px;
    width: 100%;
    padding: 10px 0;
    border: 0;
    background: transparent;
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    background: rgba(201, 162, 39, 0.14);
    padding-left: 8px;
  }

  .page-about .about-rail__item + .about-rail__item {
    border-top: 1px solid var(--paper-line);
  }

  .page-about .about-rail__note {
    font-size: 12px;
    line-height: 1.5;
  }
}

@media (min-width: 1080px) {
  .page-about .about-chapter {
    display: grid;
    grid-template-columns: 88px minmax(0, 1fr);
    column-gap: 28px;
    align-items: start;
  }

  .page-about .about-chapter__num {
    border: 0;
    padding: 0;
    margin: 6px 0 0;
    font-size: 42px;
    line-height: 1;
    letter-spacing: 0.02em;
    color: var(--sandbrown);
  }

  .page-about .about-capability__item {
    grid-template-columns: 104px minmax(0, 1fr);
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-outro__link,
  .page-about .about-rail__link,
  .page-about .about-chart__bar {
    transition: none;
  }

  .page-about .about-outro__link:hover {
    transform: none;
  }
}