.page-about {
  --about-pad: 18px;
  --about-gap: 18px;
  --about-rule: 1px solid rgba(120, 146, 171, 0.34);
  --about-hairline: 1px dashed rgba(120, 146, 171, 0.42);
  --about-deep-line: 2px solid rgba(55, 230, 217, 0.45);
  --about-ink-line: 2px solid var(--ink);
  --about-soft: rgba(220, 232, 242, 0.55);
  --about-muted: #4A6A87;
  color: var(--paper);
  font-family: var(--font-body);
}

.page-about .about-wrap {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: calc(var(--frame-top-h) + 22px) var(--about-pad) 56px;
}

.page-about .breadcrumb {
  margin-bottom: 20px;
}

/* ============ 首屏 ============ */
.page-about .about-hero__grid {
  display: grid;
  gap: 22px;
}

.page-about .about-hero__main .eyebrow {
  display: block;
  margin: 0 0 12px;
  color: var(--cyan);
  letter-spacing: 0.2em;
  font-size: 0.76rem;
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.05rem, 8.4vw, 4.6rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
  color: var(--paper);
}

.page-about .about-hero__lede {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--mist);
  margin: 0 0 22px;
  max-width: 620px;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero__aside {
  position: relative;
  padding: 16px;
  border: var(--about-deep-line);
  border-radius: var(--radius);
  background: linear-gradient(158deg, rgba(12, 43, 73, 0.96) 0%, rgba(6, 26, 46, 0.96) 100%);
  box-shadow: var(--shadow-deep);
}

.page-about .about-hero__aside-label {
  margin: 0 0 10px;
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  color: var(--steel);
}

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

.page-about .about-toc__item + .about-toc__item {
  border-top: var(--about-hairline);
}

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 0;
  font-size: 0.84rem;
  line-height: 1.5;
  color: var(--mist);
  text-decoration: none;
  transition: color 0.2s var(--ease);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible,
.page-about .about-toc__link.is-current {
  color: var(--cyan);
}

.page-about .about-toc__num {
  font-family: var(--font-num);
  font-size: 0.78rem;
  color: var(--cyan);
  letter-spacing: 0.06em;
}

.page-about .about-hero__aside-note {
  margin: 14px 0 0;
  padding-top: 10px;
  border-top: var(--about-hairline);
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  color: var(--steel);
}

/* ============ 章节骨架 ============ */
.page-about .about-chapter {
  display: grid;
  gap: 14px;
  padding: 30px 0 8px;
  border-top: var(--about-rule);
  scroll-margin-top: calc(var(--frame-top-h) + 26px);
}

.page-about .about-chapter__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-chapter__num {
  font-family: var(--font-num);
  font-size: 1.9rem;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-chapter__label {
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  color: var(--steel);
}

.page-about .about-chapter__body {
  padding: 20px 18px;
  border: var(--about-ink-line);
  border-radius: var(--radius);
  background: var(--paper);
  color: var(--ink);
  box-shadow: var(--shadow-hard);
}

.page-about .about-chapter--deep .about-chapter__body {
  border-color: rgba(55, 230, 217, 0.42);
  background: linear-gradient(155deg, #0C2B49 0%, #061A2E 62%, #0A2338 100%);
  color: var(--paper);
  box-shadow: var(--shadow-deep);
}

.page-about .about-chapter__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(1.4rem, 4.6vw, 2.2rem);
  line-height: 1.22;
  letter-spacing: -0.01em;
  margin: 0 0 14px;
}

.page-about .about-chapter__body p {
  margin: 0 0 12px;
  font-size: 0.98rem;
  line-height: 1.78;
}

.page-about .about-subtitle {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.04em;
  margin: 20px 0 10px;
}

.page-about .about-note {
  margin: 18px 0 0;
  padding-top: 10px;
  border-top: var(--about-hairline);
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--about-muted);
}

.page-about .about-chapter--deep .about-note {
  border-top-color: rgba(55, 230, 217, 0.3);
  color: var(--mist);
}

/* ============ 图片 ============ */
.page-about .about-figure {
  margin: 18px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border: var(--about-ink-line);
  border-radius: var(--radius);
}

.page-about .about-chapter--deep .about-figure img {
  border-color: rgba(55, 230, 217, 0.4);
}

.page-about .about-figure figcaption {
  margin-top: 8px;
  font-size: 0.78rem;
  line-height: 1.6;
  color: var(--about-muted);
}

.page-about .about-chapter--deep .about-figure figcaption {
  color: var(--steel);
}

/* ============ 阶段轴 ============ */
.page-about .about-track {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-track__item {
  padding: 12px 14px;
  border-left: 3px solid var(--sea-800);
  background: var(--about-soft);
}

.page-about .about-track__stage {
  display: block;
  font-family: var(--font-num);
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  color: var(--sea-800);
  margin-bottom: 4px;
}

.page-about .about-track__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  margin: 0 0 6px;
  color: var(--sea-900);
}

.page-about .about-track__item p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.72;
  color: var(--ink);
}

/* ============ 角色矩阵 ============ */
.page-about .about-roles {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-role {
  --role-color: var(--cyan);
  position: relative;
  padding: 14px;
  border: 2px solid rgba(120, 146, 171, 0.45);
  border-top: 4px solid var(--role-color);
  border-radius: var(--radius);
  background: rgba(6, 26, 46, 0.5);
  outline: none;
  transition: border-color 0.22s var(--ease), transform 0.22s var(--ease), background 0.22s var(--ease);
}

.page-about .about-role--product { --role-color: var(--orange); }
.page-about .about-role--tech { --role-color: var(--mint); }
.page-about .about-role--service { --role-color: var(--amber); }

.page-about .about-role:hover,
.page-about .about-role:focus-within {
  border-color: var(--role-color);
  background: rgba(12, 43, 73, 0.72);
  transform: translateY(-2px);
}

.page-about .about-role:focus-visible {
  border-color: var(--role-color);
  box-shadow: 0 0 0 3px rgba(55, 230, 217, 0.35);
}

.page-about .about-role__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
}

.page-about .about-role__name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.04rem;
  margin: 0;
  color: var(--paper);
}

.page-about .about-role__count {
  font-family: var(--font-num);
  font-size: 1.5rem;
  line-height: 1;
  color: var(--role-color);
}

.page-about .about-role__duty {
  margin: 8px 0 0;
  font-size: 0.88rem;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-role__more {
  margin: 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: 0.8rem;
  line-height: 1.68;
  color: var(--mint);
  transition: max-height 0.24s var(--ease), opacity 0.24s var(--ease), margin-top 0.24s var(--ease);
}

.page-about .about-role:hover .about-role__more,
.page-about .about-role:focus-within .about-role__more {
  max-height: 7em;
  opacity: 1;
  margin-top: 8px;
}

/* ============ 服务方法标签 ============ */
.page-about .about-tabs {
  position: relative;
  margin: 18px 0 0;
}

.page-about .about-tabs__radio {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.page-about .about-tabs__labels {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-tabs__label {
  cursor: pointer;
  padding: 8px 13px;
  border: var(--about-ink-line);
  border-radius: var(--radius);
  background: var(--mist);
  color: var(--sea-900);
  font-size: 0.84rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: background 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-tabs__label:hover {
  border-color: var(--sea-800);
}

.page-about #method-guide:checked ~ .about-tabs__labels [for="method-guide"],
.page-about #method-check:checked ~ .about-tabs__labels [for="method-check"],
.page-about #method-loop:checked ~ .about-tabs__labels [for="method-loop"] {
  background: var(--sea-900);
  border-color: var(--sea-900);
  color: var(--cyan);
}

.page-about #method-guide:focus-visible ~ .about-tabs__labels [for="method-guide"],
.page-about #method-check:focus-visible ~ .about-tabs__labels [for="method-check"],
.page-about #method-loop:focus-visible ~ .about-tabs__labels [for="method-loop"] {
  outline: 3px solid rgba(55, 230, 217, 0.6);
  outline-offset: 2px;
}

.page-about .about-tabs__panels {
  margin-top: 14px;
}

.page-about .about-tabs__panel {
  display: none;
  padding: 16px;
  border: 2px solid rgba(120, 146, 171, 0.42);
  border-left: 4px solid var(--cyan);
  border-radius: var(--radius);
  background: var(--about-soft);
}

.page-about #method-guide:checked ~ .about-tabs__panels .about-tabs__panel--guide,
.page-about #method-check:checked ~ .about-tabs__panels .about-tabs__panel--check,
.page-about #method-loop:checked ~ .about-tabs__panels .about-tabs__panel--loop {
  display: block;
}

.page-about .about-tabs__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  margin: 0 0 10px;
  color: var(--sea-900);
}

.page-about .about-tabs__panel p {
  font-size: 0.92rem;
  line-height: 1.76;
  color: var(--ink);
}

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

/* ============ 规模数字 ============ */
.page-about .about-stats {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-stat {
  padding: 10px 12px 10px 14px;
  border-left: 2px solid var(--cyan);
  background: rgba(247, 250, 252, 0.05);
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--font-num);
  font-size: 1.85rem;
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 4px;
  font-size: 0.8rem;
  line-height: 1.6;
  color: var(--mist);
}

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

.page-about .about-chip {
  padding: 6px 11px;
  border: 1px solid rgba(120, 146, 171, 0.55);
  border-radius: var(--radius);
  font-size: 0.8rem;
  color: var(--mist);
}

/* ============ 质量流程 ============ */
.page-about .about-quality {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-quality__item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 12px 14px;
  border-left: 3px solid var(--sea-800);
  background: var(--about-soft);
}

.page-about .about-quality__tag {
  font-family: var(--font-num);
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  color: var(--sea-800);
}

.page-about .about-quality__item p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.72;
  color: var(--ink);
}

/* ============ 北京服务 ============ */
.page-about .about-chapter__body--warm {
  border-color: var(--ink);
  background: var(--paper);
  color: var(--ink);
}

.page-about .about-callout {
  margin: 18px 0 0;
  padding: 14px;
  border: 2px solid var(--orange);
  border-radius: var(--radius);
  background: rgba(255, 156, 74, 0.1);
}

.page-about .about-callout__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  color: #A24E00;
}

.page-about .about-contact {
  margin: 0;
}

.page-about .about-contact__row {
  display: grid;
  gap: 2px;
  padding: 8px 0;
  border-top: var(--about-hairline);
}

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

.page-about .about-contact__key {
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  color: var(--about-muted);
}

.page-about .about-contact__val {
  margin: 0;
  font-family: var(--font-num);
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--sea-900);
  word-break: break-word;
}

.page-about .about-callout__note {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: var(--about-hairline);
  font-size: 0.8rem;
  line-height: 1.7;
  color: var(--about-muted);
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin: 20px 0 0;
}

.page-about .about-cta__link {
  font-size: 0.86rem;
  color: var(--sea-800);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-about .about-cta__link:hover,
.page-about .about-cta__link:focus-visible {
  color: #0B6B72;
}

/* ============ 桌面增强 ============ */
@media (min-width: 760px) {
  .page-about .about-wrap {
    padding-left: 32px;
    padding-right: 32px;
  }

  .page-about .about-track {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

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

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

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

  .page-about .about-contact__row {
    grid-template-columns: 108px minmax(0, 1fr);
    align-items: baseline;
    gap: 12px;
  }
}

@media (min-width: 960px) {
  .page-about .about-wrap {
    padding-left: 40px;
    padding-right: 40px;
    padding-top: calc(var(--frame-top-h) + 36px);
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 40px;
    align-items: start;
  }

  .page-about .about-chapter {
    grid-template-columns: 152px minmax(0, 1fr);
    gap: 30px;
    padding-top: 40px;
  }

  .page-about .about-chapter--wide {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .page-about .about-chapter__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    position: sticky;
    top: calc(var(--frame-top-h) + 28px);
  }

  .page-about .about-chapter--wide .about-chapter__rail {
    flex-direction: row;
    align-items: baseline;
    gap: 14px;
    position: static;
  }

  .page-about .about-chapter__num {
    font-size: 2.4rem;
  }

  .page-about .about-chapter__body {
    padding: 30px 32px;
  }

  .page-about .about-chapter__body p {
    font-size: 1rem;
    max-width: 72ch;
  }

  .page-about .about-hero__lede {
    font-size: 1.06rem;
  }
}

@media (hover: none) {
  .page-about .about-role__more {
    max-height: none;
    opacity: 1;
    margin-top: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-role,
  .page-about .about-role__more,
  .page-about .about-tabs__label,
  .page-about .about-toc__link {
    transition: none;
  }

  .page-about .about-role:hover,
  .page-about .about-role:focus-within {
    transform: none;
  }
}