.page-about {
  background: var(--paper);
  color: var(--text);
}

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

/* 面包屑 */
.page-about .about-crumb {
  padding-top: clamp(1rem, 3vw, 1.75rem);
}

.page-about .about-crumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
}

.page-about .about-crumb__list li + li::before {
  content: "/";
  margin-right: 0.45rem;
  color: var(--shallow);
}

.page-about .about-crumb__list a {
  color: var(--tide);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.18s var(--ease);
}

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

.page-about .about-crumb__list [aria-current] {
  color: var(--text);
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  margin-top: clamp(0.9rem, 2.5vw, 1.5rem);
  padding: clamp(2rem, 6vw, 4.25rem) 0;
  background: var(--ink);
  color: var(--paper);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -12%;
  bottom: -55%;
  width: 70%;
  height: 130%;
  background: radial-gradient(circle at 50% 50%, rgba(46, 127, 168, 0.55), rgba(46, 127, 168, 0));
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.75rem);
}

.page-about .about-hero .eyebrow {
  color: var(--shallow);
}

.page-about .about-hero__title {
  margin: 0.6rem 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.85rem, 4.4vw, 3rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .about-hero__lede {
  margin: 1rem 0 0;
  max-width: 34em;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: rgba(248, 245, 239, 0.86);
}

.page-about .about-hero__panel {
  padding: clamp(1.1rem, 3vw, 1.6rem);
  background: rgba(248, 245, 239, 0.12);
  border: 1px solid rgba(159, 196, 216, 0.45);
  border-radius: 2px;
  backdrop-filter: blur(6px);
}

.page-about .about-hero__panel-tag {
  margin: 0;
  color: var(--shallow);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 0.75rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-facts__num {
  display: block;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: var(--fs-28);
  line-height: 1;
  color: var(--paper);
}

.page-about .about-facts__label {
  display: block;
  margin-top: 0.3rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--shallow);
}

/* 主体两栏 */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--gap);
  padding-block: clamp(1.75rem, 5vw, 3.5rem);
}

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

.page-about .about-rail__list {
  display: flex;
  gap: 0.5rem;
  margin: 0;
  padding: 0 0 0.6rem;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  white-space: nowrap;
  padding: 0.45rem 0.7rem;
  font-size: var(--fs-14);
  color: var(--text);
  text-decoration: none;
  background: var(--sand);
  border: 1px solid transparent;
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .about-rail__link:hover {
  border-color: var(--tide);
  color: var(--ink);
}

.page-about .about-rail__num {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--tide);
}

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

/* 章节 */
.page-about .about-sec {
  scroll-margin-top: calc(var(--rail-min) + 5.5rem);
  padding-block: clamp(1.75rem, 4.5vw, 2.75rem);
}

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

.page-about .about-sec__head {
  display: grid;
  gap: 0.2rem;
  margin-bottom: 1.1rem;
}

.page-about .about-sec__num {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(2.4rem, 6vw, 3.75rem);
  line-height: 0.85;
  letter-spacing: -0.02em;
  color: var(--shallow);
}

.page-about .about-sec__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.2rem, 2.6vw, 1.6rem);
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-sec__prose p {
  margin: 0 0 1em;
}

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

.page-about .about-sec__lead {
  margin: 0 0 1rem;
  font-size: var(--fs-16);
  line-height: 1.85;
}

.page-about .about-sec__note {
  margin: 1rem 0 0;
  padding-left: 0.9rem;
  border-left: 2px solid var(--tide);
  font-size: var(--fs-14);
  line-height: 1.8;
}

/* 图片容器 */
.page-about .about-media {
  margin: 0 0 1.25rem;
  border: 1px solid var(--line);
  background: var(--sand);
}

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

.page-about .about-media figcaption {
  padding: 0.55rem 0.8rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--tide);
}

.page-about .about-media--wide img {
  aspect-ratio: 1440 / 420;
}

/* 团队卡 */
.page-about .about-team {
  display: grid;
  gap: 0.75rem;
}

.page-about .about-team__card {
  padding: 0.9rem 1rem;
  background: var(--sand);
  border: 1px solid var(--line);
  transition: border-color 0.16s var(--ease), background-color 0.16s var(--ease);
}

.page-about .about-team__card:hover,
.page-about .about-team__card[open] {
  border-color: var(--tide);
  background: var(--paper);
}

.page-about .about-team__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.5rem;
  list-style: none;
  cursor: pointer;
}

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

.page-about .about-team__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-16);
  line-height: 1;
  color: var(--tide);
  transition: transform 0.22s var(--ease);
}

.page-about .about-team__card[open] .about-team__summary::after {
  transform: rotate(45deg);
}

.page-about .about-team__name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-16);
  color: var(--ink);
}

.page-about .about-team__tag {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--tide);
}

.page-about .about-team__body {
  margin-top: 0.7rem;
  padding-top: 0.7rem;
  border-top: 1px solid var(--line);
  font-size: var(--fs-14);
  line-height: 1.8;
}

.page-about .about-team__body p {
  margin: 0;
}

/* 维护流程 */
.page-about .about-maint {
  display: grid;
  gap: clamp(1rem, 3vw, 1.75rem);
}

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

.page-about .about-steps {
  display: grid;
  gap: 0.85rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-steps__item {
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  gap: 0.7rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--line);
}

.page-about .about-steps__num {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--signal);
  padding-top: 0.15rem;
}

.page-about .about-steps__item p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
}

.page-about .about-steps__tail {
  margin: 0.9rem 0 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--ink);
}

/* 四个板块 */
.page-about .about-boards {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-boards__item {
  display: grid;
  grid-template-columns: 2.1rem minmax(0, 1fr);
  gap: 0.85rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
  transition: background-color 0.18s var(--ease);
}

.page-about .about-boards__item:first-child {
  border-top: 1px solid var(--line);
}

.page-about .about-boards__item:hover {
  background: var(--sand);
}

.page-about .about-boards__num {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--signal);
  padding-top: 0.1rem;
}

.page-about .about-boards__name {
  margin: 0 0 0.3rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-16);
  color: var(--ink);
}

.page-about .about-boards__item p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
}

/* 阶段刻度 */
.page-about .about-phases {
  position: relative;
  display: grid;
  gap: 1.25rem;
  margin: 0;
  padding: 0 0 0 1.15rem;
  list-style: none;
  border-left: 1px solid var(--line);
}

.page-about .about-phases__item {
  position: relative;
}

.page-about .about-phases__item::before {
  content: "";
  position: absolute;
  left: calc(-1.15rem - 5px);
  top: 0.4rem;
  width: 8px;
  height: 8px;
  background: var(--paper);
  border: 1px solid var(--tide);
}

.page-about .about-phases__label {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--tide);
}

.page-about .about-phases__title {
  margin: 0.3rem 0 0.35rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-16);
  color: var(--ink);
}

.page-about .about-phases__item p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
}

/* 结尾 */
.page-about .about-cta {
  display: grid;
  gap: 1rem;
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  padding: clamp(1.25rem, 4vw, 2rem);
  background: var(--sand);
  border: 1px solid var(--shallow);
}

.page-about .about-cta__title {
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-20);
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-cta__text p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

/* 桌面端 */
@media (min-width: 700px) {
  .page-about .about-sec__head {
    grid-template-columns: auto minmax(0, 1fr);
    align-items: end;
    column-gap: 1.25rem;
    padding-bottom: 0.85rem;
    border-bottom: 1px solid var(--line);
  }

  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
    gap: 1rem;
  }

  .page-about .about-team__card:nth-child(2) {
    margin-top: 1.5rem;
  }

  .page-about .about-team__card:nth-child(3) {
    margin-top: 0.75rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    align-items: end;
  }

  .page-about .about-maint {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    align-items: start;
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: 180px minmax(0, 1fr);
    gap: clamp(2rem, 5vw, 4rem);
    padding-block: clamp(2.5rem, 5vw, 4rem);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--rail-min) + 5rem);
    align-self: start;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0;
    padding: 0;
    overflow: visible;
    border-left: 1px solid var(--line);
  }

  .page-about .about-rail__link {
    margin-left: -1px;
    padding: 0.55rem 0 0.55rem 0.85rem;
    background: transparent;
    border: 0;
    border-left: 2px solid transparent;
  }

  .page-about .about-rail__link:hover {
    border-left-color: var(--tide);
  }

  .page-about .about-body:has(#origin:target) .about-rail__link[href="#origin"],
  .page-about .about-body:has(#team:target) .about-rail__link[href="#team"],
  .page-about .about-body:has(#maintain:target) .about-rail__link[href="#maintain"],
  .page-about .about-body:has(#boards:target) .about-rail__link[href="#boards"],
  .page-about .about-body:has(#phases:target) .about-rail__link[href="#phases"],
  .page-about .about-body:has(#ethos:target) .about-rail__link[href="#ethos"] {
    background: var(--sand);
    border-left-color: var(--signal);
    color: var(--ink);
    font-weight: 500;
  }
}