/* ============ 关于页 page-about ============ */

.page-about {
  background: var(--color-surface);
  color: var(--color-ink);
}

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

/* ---- 面包屑 ---- */
.page-about .about-crumb {
  padding-top: var(--space-4);
  padding-bottom: var(--space-2);
}

/* ---- 首屏引言 ---- */
.page-about .about-intro {
  padding-bottom: var(--space-8);
}

.page-about .about-intro__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
}

.page-about .about-intro__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-2xl);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  margin: var(--space-2) 0 var(--space-3);
}

.page-about .about-intro__sub {
  font-size: var(--text-lg);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
  margin: 0;
  max-width: 46ch;
}

.page-about .about-intro__facts {
  list-style: none;
  margin: 0;
  padding: var(--space-4) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  border-top: 3px solid var(--color-primary);
}

.page-about .about-fact {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .about-fact__num {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  line-height: 1.1;
  font-weight: var(--weight-heading);
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

.page-about .about-fact__label {
  font-size: var(--text-sm);
  line-height: 1.2;
  color: var(--color-ink-muted);
}

/* ---- 分屏主体：窄深色侧栏 + 宽浅色叙事 ---- */
.page-about .about-body__grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
  margin-top: var(--space-4);
}

.page-about .about-main { order: 1; }

.page-about .about-aside {
  order: 2;
  background-color: var(--color-contrast-surface);
  background-image: repeating-linear-gradient(
    90deg,
    transparent 0 78px,
    color-mix(in srgb, var(--color-contrast-accent) 8%, transparent) 78px 79px
  );
  color: var(--color-contrast-ink);
  padding: var(--space-6) var(--space-4);
}

.page-about .about-aside__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
  margin: 0 0 var(--space-3);
}

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

.page-about .about-toc .toc__link {
  display: block;
  padding: 7px 0;
  color: var(--color-contrast-ink);
  text-decoration: none;
  font-size: var(--text-sm);
  line-height: 1.3;
  border-bottom: 1px solid var(--color-contrast-line);
  transition: color 0.15s ease, padding-left 0.15s ease, border-color 0.15s ease;
}

.page-about .about-toc .toc__link:hover,
.page-about .about-toc .toc__link:focus-visible {
  color: var(--color-contrast-accent);
  padding-left: 6px;
}

.page-about .about-toc .toc__link[aria-current="true"] {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}

.page-about .about-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-top: var(--space-4);
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-contrast-line);
}

.page-about .about-keywords .tag {
  background: transparent;
  color: var(--color-contrast-ink);
  border: 1px solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  line-height: 1.2;
  padding: 4px 8px;
}

.page-about .about-keywords .tag--primary {
  background: transparent;
  border-color: var(--color-primary);
  color: var(--color-contrast-accent);
}

.page-about .about-keywords .tag--accent {
  background: transparent;
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-accent);
}

/* ---- 叙事区块 ---- */
.page-about .about-section {
  padding-bottom: var(--space-6);
  margin-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-line);
}

.page-about .about-section:last-child {
  border-bottom: 0;
  margin-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-section--double {
  border-bottom: 0;
  position: relative;
  padding-bottom: var(--space-8);
}

.page-about .about-section--double::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 5px;
  border-top: 1px solid var(--color-line);
  border-bottom: 1px solid var(--color-line);
}

.page-about .about-section__title {
  position: relative;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  margin: 0 0 var(--space-3);
  padding-left: 14px;
}

.page-about .about-section__title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.26em;
  bottom: 0.26em;
  width: 4px;
  background: var(--color-primary);
}

.page-about .about-para {
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
  margin: 0 0 var(--space-3);
  max-width: var(--measure);
}

.page-about .about-para strong {
  color: var(--color-ink);
  font-weight: var(--weight-heading);
}

.page-about .about-para--lead {
  border-left: 3px solid var(--color-primary);
  padding-left: var(--space-3);
  margin-bottom: var(--space-4);
}

.page-about .about-main a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about .about-main a:hover {
  text-decoration-thickness: 2px;
}

.page-about .pullquote {
  margin: var(--space-4) 0;
  padding-left: var(--space-3);
  border-left: 3px solid var(--color-ink);
}

.page-about .pullquote p {
  font-size: var(--text-lg);
  line-height: 1.5;
  color: var(--color-ink);
  margin: 0;
  text-indent: -0.42em;
}

.page-about .pullquote p::before {
  content: "\201C";
  color: var(--color-primary);
  font-weight: var(--weight-heading);
}

/* ---- 配图 ---- */
.page-about .about-figure {
  margin: var(--space-4) 0 var(--space-4);
}

.page-about .about-figure__frame {
  aspect-ratio: 14 / 9;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--color-surface-deep);
}

.page-about .about-figure__frame--wide {
  aspect-ratio: 3 / 2;
}

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

.page-about .about-figure .figure__caption {
  display: block;
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  line-height: 1.4;
  color: var(--color-ink-muted);
}

/* ---- 角色条目 ---- */
.page-about .about-roles {
  list-style: none;
  margin: var(--space-4) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-3);
}

.page-about .about-role {
  background: var(--color-surface-alt);
  border-left: 3px solid var(--color-primary);
  padding: var(--space-3);
}

.page-about .about-role__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  line-height: 1.3;
  color: var(--color-ink);
  margin: 0;
}

.page-about .about-role__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.3;
  color: var(--color-accent);
  margin: var(--space-1) 0 var(--space-2);
}

.page-about .about-role__desc {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  margin: 0;
}

/* ---- 方法条目 ---- */
.page-about .about-methods {
  list-style: none;
  margin: var(--space-4) 0 0;
  padding: 0;
}

.page-about .about-method {
  display: flex;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-line);
}

.page-about .about-method:first-child {
  border-top: 2px solid var(--color-ink);
}

.page-about .about-method__num {
  flex: 0 0 auto;
  width: 2.2em;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.5;
  font-weight: var(--weight-heading);
  color: var(--color-accent);
}

.page-about .about-method__body {
  flex: 1 1 auto;
  min-width: 0;
}

.page-about .about-method__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  line-height: 1.3;
  color: var(--color-ink);
  margin: 0 0 var(--space-1);
}

.page-about .about-method__desc {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  margin: 0;
  max-width: 52ch;
}

/* ---- 现状数字 ---- */
.page-about .about-stats {
  list-style: none;
  margin: var(--space-4) 0;
  padding: var(--space-4) 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  border-top: 3px solid var(--color-primary);
  border-bottom: 1px solid var(--color-line);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .about-stat__num {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  line-height: 1.05;
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  letter-spacing: -0.02em;
}

.page-about .about-stat__label {
  font-size: var(--text-sm);
  line-height: 1.3;
  color: var(--color-ink-muted);
}

/* ---- 年份带 ---- */
.page-about .about-yearband {
  position: relative;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding: var(--space-8) 0 var(--space-6);
  margin-top: var(--space-8);
}

.page-about .about-yearband::before,
.page-about .about-yearband::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 20px;
  background: var(--color-contrast-surface);
}

.page-about .about-yearband::before {
  top: -19px;
  clip-path: polygon(0 100%, 100% 0, 100% 100%);
}

.page-about .about-yearband::after {
  bottom: -19px;
  clip-path: polygon(0 0, 100% 0, 0 100%);
}

.page-about .about-yearband__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: var(--leading-heading);
  color: var(--color-contrast-ink);
  margin: 0 0 var(--space-6);
}

.page-about .about-yearband__track {
  list-style: none;
  margin: var(--space-6) 0 0;
  padding: 0 0 0 var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  border-left: 2px solid var(--color-contrast-line);
}

.page-about .about-node {
  position: relative;
  padding-right: var(--space-2);
}

.page-about .about-node__dot {
  position: absolute;
  left: calc(-1 * var(--space-4) - 5px);
  top: 0.42em;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-contrast-accent);
}

.page-about .about-node__year {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.2;
  font-weight: var(--weight-heading);
  color: var(--color-contrast-accent);
}

.page-about .about-node__label {
  display: block;
  font-size: var(--text-sm);
  line-height: 1.4;
  color: var(--color-contrast-ink);
  margin-top: 4px;
}

.page-about .about-node__tip {
  display: block;
  margin-top: var(--space-1);
  padding-left: var(--space-2);
  border-left: 2px solid var(--color-contrast-line);
  font-size: var(--text-xs);
  line-height: 1.5;
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
}

/* ---- 结尾行动出口 ---- */
.page-about .about-outro {
  padding: var(--space-8) 0 var(--section-y);
}

.page-about .about-outro__lead {
  max-width: 48ch;
}

.page-about .about-paths {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-3);
  margin: var(--space-4) 0 0;
}

.page-about .about-path {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--color-surface-alt);
  border-top: 3px solid var(--color-primary);
  color: var(--color-ink);
  text-decoration: none;
  transition: transform 0.18s ease, background-color 0.18s ease;
}

.page-about .about-path:hover,
.page-about .about-path:focus-visible {
  transform: translateX(6px);
  background: var(--color-primary-soft);
}

.page-about .about-path__idx {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.2;
  color: var(--color-ink-muted);
}

.page-about .about-path__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.25;
  color: var(--color-ink);
}

.page-about .about-path__desc {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: 40ch;
}

.page-about .about-path__go {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  color: var(--color-primary);
}

.page-about .about-outro__contact {
  margin: var(--space-4) 0 0;
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-line);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-muted);
}

/* ============ 响应式 ============ */
@media (min-width: 720px) {
  .page-about .about-intro__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

@media (min-width: 960px) {
  .page-about .about-intro {
    padding-bottom: var(--space-8);
  }

  .page-about .about-intro__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: var(--space-8);
    align-items: end;
  }

  .page-about .about-intro__title {
    font-size: var(--text-3xl);
    max-width: 16ch;
  }

  .page-about .about-body__grid {
    display: grid;
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    gap: 0;
    align-items: stretch;
    margin-top: var(--space-6);
  }

  .page-about .about-aside {
    order: 1;
    padding: var(--space-8) var(--space-6);
  }

  .page-about .about-aside__sticky {
    position: sticky;
    top: var(--space-8);
  }

  .page-about .about-main {
    order: 2;
    padding: var(--space-8) 0 var(--space-8) var(--space-8);
  }

  .page-about .about-yearband {
    padding: var(--space-8) 0 var(--space-8);
    margin-top: calc(var(--space-8) + var(--space-6));
  }

  .page-about .about-yearband__track {
    flex-direction: row;
    align-items: flex-start;
    gap: 0;
    padding: var(--space-4) 0 0;
    border-left: 0;
    border-top: 2px solid var(--color-contrast-line);
    margin-top: var(--space-8);
  }

  .page-about .about-node {
    flex: 0 0 13%;
    padding-right: var(--space-2);
  }

  .page-about .about-node:nth-child(1) { margin-left: 0; }
  .page-about .about-node:nth-child(2) { margin-left: 1.5%; }
  .page-about .about-node:nth-child(3) { margin-left: 3%; }
  .page-about .about-node:nth-child(4) { margin-left: 4.5%; }
  .page-about .about-node:nth-child(5) { margin-left: 6%; }
  .page-about .about-node:nth-child(6) { margin-left: 7%; }

  .page-about .about-node__dot {
    left: 0;
    top: calc(-1 * var(--space-4) - 6px);
    width: 10px;
    height: 10px;
  }

  .page-about .about-node__tip {
    position: absolute;
    left: 0;
    bottom: calc(100% + var(--space-2));
    width: min(232px, 22vw);
    margin-top: 0;
    padding: var(--space-2);
    background: var(--color-surface);
    color: var(--color-ink);
    border-left: 3px solid var(--color-contrast-accent);
    border-radius: var(--radius-sm);
    font-size: var(--text-xs);
    line-height: 1.5;
    opacity: 0;
    visibility: hidden;
    transform: translateY(4px);
    transition: opacity 0.16s ease, transform 0.16s ease, visibility 0.16s;
    z-index: 3;
  }

  .page-about .about-node:hover .about-node__tip,
  .page-about .about-node:focus-visible .about-node__tip,
  .page-about .about-node:focus-within .about-node__tip {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .page-about .about-outro {
    padding-top: var(--section-y-lg);
  }
}

@media (min-width: 1200px) {
  .page-about .about-intro__title {
    max-width: 15ch;
  }

  .page-about .about-node {
    flex: 0 0 12%;
  }

  .page-about .about-node:nth-child(6) { margin-left: 9%; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-path,
  .page-about .about-toc .toc__link,
  .page-about .about-node__tip {
    transition: none;
  }

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

  .page-about .about-node__tip {
    transform: none;
  }
}