.page-about {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  overflow-x: hidden;
}

.page-about .about-shell {
  width: 100%;
  max-width: var(--measure);
  margin: 0 auto;
  padding: clamp(18px, 4vw, 32px) clamp(16px, 4vw, 40px) clamp(56px, 8vw, 104px);
}

/* 面包屑 */
.page-about .about-crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .about-crumbs a {
  color: var(--green);
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 1px;
}

.page-about .about-crumbs a:hover {
  color: var(--apricot);
  border-bottom-color: var(--apricot);
}

.page-about .about-crumbs a:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
  border-radius: 4px;
}

/* 首屏声明 */
.page-about .about-hero {
  position: relative;
  margin-top: clamp(18px, 3vw, 30px);
  padding: clamp(28px, 5vw, 58px) clamp(20px, 4vw, 56px) clamp(30px, 4vw, 48px);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(circle at 88% 12%, rgba(232, 111, 50, 0.42), transparent 46%),
    radial-gradient(circle at 12% 96%, rgba(45, 108, 223, 0.26), transparent 52%),
    var(--green);
  color: var(--paper);
  box-shadow: var(--shadow-panel);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -60px;
  bottom: -80px;
  width: 220px;
  height: 220px;
  border: 1px solid rgba(247, 243, 232, 0.24);
  border-radius: 50%;
  pointer-events: none;
}

.page-about .about-hero__kicker {
  margin: 0 0 clamp(14px, 2vw, 22px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--apricot-light);
}

.page-about .about-hero h1 {
  margin: 0;
  max-width: 21em;
  font-family: var(--font-sans);
  font-size: clamp(28px, 5.2vw, 48px);
  line-height: 1.22;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: clamp(16px, 2.4vw, 26px) 0 0;
  max-width: 46em;
  font-family: var(--font-serif);
  font-size: clamp(15px, 1.7vw, 18px);
  line-height: 1.92;
  color: rgba(247, 243, 232, 0.86);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 18px;
  margin: clamp(24px, 4vw, 38px) 0 0;
  padding: clamp(16px, 2.4vw, 22px) 0 0;
  list-style: none;
  border-top: 1px solid rgba(247, 243, 232, 0.22);
  font-size: 13px;
  line-height: 1.6;
  color: rgba(247, 243, 232, 0.74);
}

.page-about .about-hero__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.6vw, 26px);
  font-weight: 700;
  color: var(--apricot-light);
  line-height: 1.2;
}

/* 双栏：固定索引 + 正文 */
.page-about .about-layout {
  display: grid;
  gap: clamp(24px, 4vw, 52px);
  margin-top: clamp(28px, 5vw, 60px);
}

.page-about .about-index {
  padding: 18px 20px;
  border-radius: var(--radius-md);
  background: var(--green-deep);
  color: var(--paper);
  box-shadow: var(--shadow-panel);
}

.page-about .about-index__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--apricot-light);
}

.page-about .about-index__list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 6px;
  border-radius: var(--radius-sm);
  font-size: 13.5px;
  line-height: 1.5;
  color: rgba(247, 243, 232, 0.82);
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease;
}

.page-about .about-index__list a span {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--blue);
  filter: brightness(1.55);
}

.page-about .about-index__list a:hover {
  background: var(--glass);
  color: #ffffff;
}

.page-about .about-index__list a:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 1px;
}

/* 章节通用 */
.page-about .about-body {
  display: grid;
  gap: clamp(26px, 4vw, 46px);
  min-width: 0;
}

.page-about .about-section {
  padding: clamp(22px, 3.4vw, 42px);
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  background: #ffffff;
  box-shadow: var(--shadow-panel);
}

.page-about .about-section--narrow {
  max-width: 46em;
}

.page-about .about-section--sand {
  background: var(--sand);
  border-color: rgba(18, 59, 50, 0.14);
}

.page-about .about-section--green {
  background: var(--green);
  border-color: transparent;
  color: var(--paper);
}

.page-about .about-section h2 {
  margin: 0 0 clamp(12px, 2vw, 18px);
  font-family: var(--font-sans);
  font-size: clamp(22px, 3.1vw, 34px);
  line-height: 1.3;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--green);
}

.page-about .about-section--green h2 {
  color: var(--paper);
}

.page-about .about-eyebrow {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--apricot);
}

.page-about .about-eyebrow--light {
  color: var(--apricot-light);
}

.page-about .about-section__head {
  margin-bottom: clamp(18px, 3vw, 28px);
}

.page-about .about-section__intro {
  margin: 0;
  max-width: 42em;
  font-family: var(--font-serif);
  font-size: 15.5px;
  line-height: 1.9;
  color: rgba(247, 243, 232, 0.8);
}

.page-about .about-prose p {
  margin: 0 0 1em;
  font-family: var(--font-serif);
  font-size: 16px;
  line-height: 1.95;
  color: var(--ink);
}

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

.page-about .about-prose--tight p {
  max-width: 40em;
}

/* 图片 */
.page-about .about-figure {
  margin: clamp(18px, 3vw, 28px) 0 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--sand);
  overflow: hidden;
}

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

.page-about .about-figure figcaption {
  padding: 11px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.72);
  border-top: 1px solid var(--line);
}

.page-about .about-figure--inset {
  max-width: 100%;
}

/* 原则卡 */
.page-about .principle-grid {
  display: grid;
  gap: 14px;
}

.page-about .principle {
  padding: 22px 20px;
  border-radius: var(--radius-md);
  background: var(--glass);
  border: 1px solid rgba(247, 243, 232, 0.28);
  color: var(--paper);
  transition: transform 0.22s ease, background 0.22s ease, border-color 0.22s ease;
}

.page-about .principle__num {
  display: inline-block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--apricot-light);
}

.page-about .principle h3 {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-size: 18px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .principle p {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(247, 243, 232, 0.82);
}

.page-about .principle:hover,
.page-about .principle:focus-visible {
  transform: translateY(-3px);
  background: rgba(255, 255, 255, 0.22);
  border-color: var(--apricot-light);
}

.page-about .principle:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
}

/* 维护流程 */
.page-about .steps {
  display: grid;
  gap: 12px;
  margin: clamp(18px, 3vw, 26px) 0 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.page-about .step {
  position: relative;
  padding: 16px 18px 16px 54px;
  border-radius: var(--radius-sm);
  background: #ffffff;
  border: 1px solid rgba(18, 59, 50, 0.14);
}

.page-about .step::before {
  counter-increment: step;
  content: "0" counter(step);
  position: absolute;
  left: 17px;
  top: 17px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--apricot);
}

.page-about .step h3 {
  margin: 0 0 4px;
  font-family: var(--font-sans);
  font-size: 15.5px;
  font-weight: 700;
  color: var(--green);
}

.page-about .step p {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* 时间线 */
.page-about .tl {
  display: grid;
  gap: 16px;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .tl-item {
  position: relative;
  padding-left: 30px;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: -18px;
  width: 2px;
  background: var(--line-strong);
}

.page-about .tl-item:last-child::before {
  display: none;
}

.page-about .tl-item::after {
  content: "";
  position: absolute;
  left: 2px;
  top: 8px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--blue);
}

.page-about .tl-node {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 0;
  border: 0;
  background: none;
  font: inherit;
  text-align: left;
  cursor: default;
}

.page-about .tl-node:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

.page-about .tl-node__ver {
  padding: 3px 10px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--blue);
  background: rgba(45, 108, 223, 0.1);
  border: 1px solid rgba(45, 108, 223, 0.3);
}

.page-about .tl-node__title {
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 700;
  color: var(--green);
  transition: color 0.2s ease;
}

.page-about .tl-item__note {
  margin: 6px 0 0;
  max-width: 40em;
  font-family: var(--font-serif);
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
  transition: color 0.2s ease;
}

.page-about .tl-item:hover .tl-node__title,
.page-about .tl-item:focus-within .tl-node__title {
  color: var(--apricot);
}

.page-about .tl-item:hover .tl-item__note,
.page-about .tl-item:focus-within .tl-item__note {
  color: var(--ink);
}

/* 团队 */
.page-about .about-section--split {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.page-about .fact {
  margin: 0;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  background: var(--paper);
  border: 1px solid var(--line);
}

.page-about .fact dt {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .fact dd {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
}

.page-about .fact-num {
  display: inline-block;
  margin-right: 2px;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--green);
}

/* 适用人群 */
.page-about .who-grid {
  display: grid;
  gap: 12px;
  margin-top: clamp(16px, 2.4vw, 24px);
}

.page-about .who {
  padding: 20px;
  border-radius: var(--radius-md);
  background: var(--paper);
  border-left: 3px solid var(--apricot);
  transition: border-color 0.2s ease, background 0.2s ease;
}

.page-about .who h3 {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-size: 16.5px;
  font-weight: 700;
  color: var(--green);
}

.page-about .who p {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .who:hover {
  background: #ffffff;
  border-left-color: var(--wine);
}

/* 下一步入口 */
.page-about .about-next {
  margin-top: clamp(22px, 3.4vw, 34px);
  padding-top: clamp(18px, 2.4vw, 24px);
  border-top: 1px solid var(--line);
}

.page-about .about-next__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-next__links .btn {
  font-size: 14px;
}

.page-about .about-next__links .btn:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
}

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

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

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

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

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

/* 桌面：固定索引栏 + 非对称正文 */
@media (min-width: 980px) {
  .page-about .about-layout {
    grid-template-columns: 236px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: 24px;
    padding: 22px 20px;
  }

  .page-about .about-section--split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .about-section--narrow {
    margin-right: auto;
  }

  .page-about .about-section--sand .steps {
    margin-right: 0;
  }

  .page-about .tl {
    padding-left: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .principle,
  .page-about .tl-node__title,
  .page-about .tl-item__note,
  .page-about .about-index__list a,
  .page-about .who {
    transition: none;
  }

  .page-about .principle:hover,
  .page-about .principle:focus-visible {
    transform: none;
  }
}