.page-about {
  --about-line: 1px solid rgba(200, 162, 74, 0.45);
  --about-line-soft: 1px solid rgba(200, 162, 74, 0.22);
  --about-shell: 1160px;
  background: var(--cream);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.8;
  overflow-x: hidden;
}

.page-about [id] {
  scroll-margin-top: 28px;
}

.page-about .about-shell {
  width: 100%;
  max-width: var(--about-shell);
  margin: 0 auto;
  padding: 0 20px 64px;
}

/* 面包屑 */
.page-about .about-crumb {
  padding: 20px 0 0;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--sage);
}

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

.page-about .about-crumb li + li::before {
  content: "／";
  margin-right: 8px;
  color: var(--gold);
}

.page-about .about-crumb a {
  color: var(--vermilion-deep);
  text-decoration: none;
  border-bottom: 1px solid rgba(200, 162, 74, 0.5);
}

.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  border-bottom-color: var(--gold-bright);
  color: var(--vermilion);
}

/* 首屏 */
.page-about .about-hero {
  display: grid;
  gap: 28px;
  padding: 24px 0 44px;
  border-bottom: var(--about-line);
}

.page-about .about-eyebrow {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--vermilion);
}

.page-about .about-title {
  margin: 14px 0 20px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(38px, 9vw, 76px);
  line-height: 1.08;
  letter-spacing: -0.01em;
  color: var(--vermilion-shadow);
}

.page-about .about-lede {
  max-width: 38em;
  margin: 0 0 14px;
  font-size: 17px;
}

.page-about .about-lede strong {
  color: var(--vermilion);
  font-weight: 500;
}

.page-about .about-lede--small {
  font-size: 15px;
  color: rgba(42, 35, 32, 0.78);
}

.page-about .about-hero-side {
  border-top: 3px solid var(--vermilion);
  padding-top: 14px;
}

.page-about .about-side-note {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--sage);
}

.page-about .about-toc-title {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--gold);
}

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

.page-about .about-toc a {
  display: block;
  padding: 8px 2px;
  font-size: 14px;
  color: var(--ink);
  text-decoration: none;
  border-bottom: var(--about-line-soft);
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease), padding-left 0.18s var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--vermilion);
  border-bottom-color: var(--gold-bright);
  padding-left: 6px;
}

/* 章节骨架 */
.page-about .about-chapter {
  display: grid;
  gap: 14px;
  padding: 36px 0;
  border-bottom: var(--about-line);
}

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

.page-about .about-num {
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1;
  color: var(--vermilion);
  border-bottom: 2px solid var(--gold);
  padding-bottom: 4px;
}

.page-about .about-rail-note {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--sage);
}

.page-about .about-h2 {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(24px, 4.2vw, 34px);
  line-height: 1.24;
  letter-spacing: 0.01em;
  color: var(--vermilion-deep);
}

.page-about .about-prose p {
  max-width: 34em;
  margin: 0 0 16px;
}

.page-about .about-prose > p:first-of-type::first-letter {
  float: left;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 3.2em;
  line-height: 0.86;
  padding: 6px 10px 0 0;
  color: var(--vermilion);
}

/* 图片 */
.page-about .about-media {
  margin: 24px 0 0;
  padding: 8px;
  background: var(--paper);
  border: var(--about-line);
}

.page-about .about-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  background: var(--cream);
}

.page-about .about-caption {
  margin: 10px 2px 2px;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(42, 35, 32, 0.72);
  border-top: var(--about-line-soft);
  padding-top: 8px;
}

/* 十二栏目标签墙 */
.page-about .about-tagwall {
  display: grid;
  gap: 12px;
  margin: 26px 0 18px;
}

.page-about .about-taggroup {
  background: var(--paper);
  border: var(--about-line);
  padding: 14px 14px 10px;
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 16px 100%, 0 calc(100% - 16px));
}

.page-about .about-taggroup-title {
  margin: 0 0 10px;
  padding-bottom: 8px;
  font-family: var(--font-display);
  font-size: 15px;
  letter-spacing: 0.08em;
  color: var(--vermilion-deep);
  border-bottom: var(--about-line);
}

.page-about .about-tag {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 6px;
  padding: 6px 8px;
  font-size: 14px;
  color: var(--ink);
  background: rgba(246, 238, 221, 0.7);
  border: 1px solid transparent;
  transition: border-color 0.18s var(--ease), background 0.18s var(--ease);
}

.page-about .about-tag:hover,
.page-about .about-tag:focus-within {
  border-color: var(--gold-bright);
  background: var(--cream);
}

.page-about .about-tag-code {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--vermilion);
}

.page-about .about-inline-link {
  margin: 8px 0 0;
  font-size: 15px;
}

.page-about .about-inline-link a {
  color: var(--vermilion-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--gold);
  padding-bottom: 2px;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-inline-link a::after {
  content: " →";
  color: var(--gold);
}

.page-about .about-inline-link a:hover,
.page-about .about-inline-link a:focus-visible {
  color: var(--vermilion);
  border-bottom-color: var(--gold-bright);
}

/* 时间线 */
.page-about .about-timeline {
  list-style: none;
  position: relative;
  margin: 22px 0 0;
  padding: 0 0 0 26px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, var(--gold-bright), var(--gold) 45%, rgba(200, 162, 74, 0.12));
}

.page-about .about-tl-item {
  position: relative;
  padding: 0 0 22px;
}

.page-about .about-tl-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 7px;
  width: 10px;
  height: 10px;
  background: var(--vermilion);
  border: 1px solid var(--gold-bright);
  transform: rotate(45deg);
  transition: background 0.18s var(--ease), transform 0.18s var(--ease);
}

.page-about .about-tl-item:hover::before,
.page-about .about-tl-item:focus-within::before {
  background: var(--gold-bright);
  transform: rotate(45deg) scale(1.25);
}

.page-about .about-tl-title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 19px;
  line-height: 1.4;
  color: var(--vermilion-shadow);
}

.page-about .about-tl-code {
  display: inline-block;
  margin-right: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--vermilion);
  border: 1px solid rgba(200, 162, 74, 0.6);
  padding: 1px 5px;
}

.page-about .about-tl-text {
  max-width: 34em;
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(42, 35, 32, 0.82);
}

/* 维护机制 */
.page-about .about-maintain {
  margin: 22px 0 16px;
  padding: 26px 20px 22px;
  background: var(--pine);
  color: var(--cream);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 22px 100%, 0 calc(100% - 22px));
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 12px;
  padding-bottom: 20px;
  border-bottom: 1px solid rgba(200, 162, 74, 0.35);
}

.page-about .about-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 24px;
  line-height: 1.2;
  color: var(--gold-bright);
}

.page-about .about-stat-label {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: rgba(246, 238, 221, 0.76);
}

.page-about .about-maintain-list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
}

.page-about .about-maintain-list li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 14px;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(246, 238, 221, 0.92);
}

.page-about .about-maintain-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  width: 6px;
  height: 6px;
  background: var(--vermilion);
  border: 1px solid var(--gold);
}

.page-about .about-maintain-list strong {
  color: var(--gold-bright);
  font-weight: 500;
}

/* 服务范围 */
.page-about .about-scope {
  list-style: none;
  display: grid;
  gap: 12px;
  margin: 22px 0 18px;
  padding: 0;
}

.page-about .about-scope-item {
  padding: 16px 16px 14px;
  background: var(--paper);
  border-left: 3px solid var(--vermilion);
  border-top: var(--about-line-soft);
  border-right: var(--about-line-soft);
  border-bottom: var(--about-line-soft);
  transition: border-left-color 0.18s var(--ease), background 0.18s var(--ease);
}

.page-about .about-scope-item:hover {
  border-left-color: var(--gold);
  background: var(--cream);
}

.page-about .about-scope-code {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--vermilion);
}

.page-about .about-scope-title {
  margin: 4px 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  color: var(--vermilion-shadow);
}

.page-about .about-scope-item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(42, 35, 32, 0.84);
}

/* 收束 */
.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

/* 章节尾页脚 */
.page-about .about-signoff {
  margin-top: 36px;
  padding: 26px 20px 22px;
  background: var(--paper);
  border-top: 3px solid var(--vermilion);
  border-bottom: var(--about-line);
}

.page-about .about-signoff-title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 20px;
  letter-spacing: 0.04em;
  color: var(--vermilion-deep);
}

.page-about .about-signoff-text {
  max-width: 34em;
  margin: 0 0 14px;
  font-size: 15px;
  color: rgba(42, 35, 32, 0.82);
}

.page-about .about-signoff-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0;
  padding-top: 12px;
  border-top: var(--about-line);
  font-size: 14px;
}

.page-about .about-signoff-links a {
  color: var(--vermilion-deep);
  text-decoration: none;
  border-bottom: 1px solid rgba(200, 162, 74, 0.6);
}

.page-about .about-signoff-links a:hover,
.page-about .about-signoff-links a:focus-visible {
  color: var(--vermilion);
  border-bottom-color: var(--gold-bright);
}

.page-about .about-signoff-links span {
  color: var(--gold);
}

/* 交互与可访问性 */
.page-about a:focus-visible,
.page-about .about-tag:focus-visible {
  outline: 2px solid var(--gold-bright);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
  }
}

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

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

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

/* 桌面：左侧年份窄栏 + 右侧宽叙事 */
@media (min-width: 960px) {
  .page-about {
    font-size: 18px;
  }

  .page-about .about-shell {
    padding: 0 32px 88px;
  }

  .page-about .about-hero {
    grid-template-columns: minmax(0, 1fr) 240px;
    gap: 56px;
    align-items: start;
    padding: 44px 0 60px;
  }

  .page-about .about-hero-side {
    position: sticky;
    top: 28px;
  }

  .page-about .about-chapter {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 44px;
    padding: 56px 0;
  }

  .page-about .about-chapter-rail {
    position: sticky;
    top: 32px;
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .page-about .about-num {
    font-size: 40px;
  }

  .page-about .about-rail-note {
    writing-mode: vertical-rl;
    letter-spacing: 0.3em;
    font-size: 11px;
    color: var(--sage);
    padding-top: 4px;
  }

  .page-about .about-tagwall {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
  }

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

  .page-about .about-maintain {
    padding: 32px 30px 26px;
  }

  .page-about .about-signoff {
    padding: 32px 30px 26px;
  }

  .page-about .about-media--square {
    max-width: 620px;
  }
}