.page-about {
  --ab-hair: 1px solid var(--line);
  --ab-maxw: 62ch;
  color: var(--ink);
}

.page-about .breadcrumb {
  font-size: 13px;
  color: var(--ink-soft);
}

/* ============ Hero ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(28px, 5vw, 56px) 0 clamp(36px, 6vw, 68px);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0 0 0 auto;
  width: 46%;
  background: linear-gradient(148deg, rgba(14, 139, 139, 0.09), rgba(18, 100, 192, 0.05) 55%, transparent);
  clip-path: polygon(34% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-hero .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-hero-grid {
  align-items: start;
  row-gap: clamp(28px, 4vw, 48px);
}

.page-about .about-h1 {
  font-size: clamp(1.9rem, 5.2vw, 3.4rem);
  line-height: 1.08;
  letter-spacing: 0.015em;
  font-weight: 900;
  color: var(--ink);
  margin: 14px 0 20px;
  max-width: 17ch;
}

.page-about .about-hero-main .lede {
  font-size: clamp(1rem, 2.1vw, 1.15rem);
  line-height: 1.85;
  color: var(--ink-soft);
  max-width: var(--ab-maxw);
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-fact {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-fact-num {
  flex: none;
  min-width: 3.6rem;
  font-family: var(--font-mono);
  font-size: 1.7rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--sky);
  line-height: 1;
}

.page-about .about-fact-label {
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink-soft);
}

/* ============ Sticky chapter index ============ */
.page-about .about-toc {
  position: sticky;
  top: var(--header-h);
  z-index: 30;
  background: rgba(243, 247, 251, 0.94);
  backdrop-filter: blur(8px);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-toc-nav {
  display: flex;
  gap: 2px;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-toc-nav::-webkit-scrollbar {
  display: none;
}

.page-about .about-toc-link {
  flex: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 14px;
  font-size: 13px;
  line-height: 1;
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .about-toc-link:hover {
  color: var(--sky);
}

.page-about .about-toc-link.is-active,
.page-about .about-toc-link[aria-current="true"] {
  color: var(--sky);
  border-bottom-color: var(--sun);
}

.page-about .about-toc-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--ink-mute);
}

/* ============ Section basics ============ */
.page-about .about-block {
  padding: clamp(48px, 8vw, 96px) 0;
  scroll-margin-top: calc(var(--header-h) + 56px);
}

.page-about .about-head {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  border-top: 1px solid var(--line);
  padding-top: 18px;
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .about-head-text {
  min-width: 0;
}

.page-about .about-num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--lake);
}

.page-about .about-side-title {
  margin: 0 0 14px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.page-about .about-prose .prose + .prose {
  margin-top: 18px;
}

.page-about .about-prose .prose,
.page-about .about-team-copy .prose {
  max-width: var(--ab-maxw);
}

/* ============ 01 paths ============ */
.page-about .about-paths {
  list-style: none;
  margin: 0;
  padding: 0;
}

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

.page-about .about-path:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-path a {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 13px 0;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
  text-decoration: none;
  transition: color 160ms var(--ease);
}

.page-about .about-path a:hover {
  color: var(--sky);
}

.page-about .about-path em {
  flex: none;
  font-style: normal;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-mute);
}

/* ============ 02 team ============ */
.page-about .about-team-grid {
  align-items: start;
  row-gap: clamp(26px, 4vw, 44px);
}

.page-about .about-figure {
  margin: 0;
  min-width: 0;
}

.page-about .about-figure .img-frame {
  border-radius: var(--r);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--paper);
}

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

.page-about .about-roles {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .about-role {
  position: relative;
  padding-left: 22px;
}

.page-about .about-role::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--lake);
  box-shadow: 0 0 0 4px rgba(14, 139, 139, 0.12);
}

.page-about .about-role b {
  display: block;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.page-about .about-role span {
  display: block;
  margin-top: 4px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink-soft);
}

/* ============ 03 guide ============ */
.page-about .about-steps {
  margin: 26px 0 0;
}

.page-about .about-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.page-about .about-legend .legend-item {
  font-size: 13px;
  color: var(--ink-soft);
}

/* ============ 04 revisions (night) ============ */
.page-about .about-revisions {
  position: relative;
  overflow: hidden;
  background: var(--night);
  color: var(--cloud);
}

.page-about .about-revisions::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(60% 50% at 10% 0%, rgba(14, 139, 139, 0.24), transparent 70%),
    radial-gradient(50% 42% at 94% 14%, rgba(18, 100, 192, 0.22), transparent 72%);
  pointer-events: none;
}

.page-about .about-revisions .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-revisions .about-head {
  border-top-color: rgba(215, 226, 236, 0.24);
}

.page-about .about-revisions .about-num {
  color: var(--sun);
}

.page-about .about-revisions .section-title {
  color: var(--cloud);
}

.page-about .about-revisions .section-desc {
  color: rgba(243, 247, 251, 0.66);
}

.page-about .about-revisions-figure {
  margin: 0 0 clamp(24px, 4vw, 40px);
}

.page-about .about-revisions-figure .img-frame {
  border-radius: var(--r);
  overflow: hidden;
  border: 1px solid rgba(215, 226, 236, 0.18);
}

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

.page-about .about-track-wrap {
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: x proximity;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
  padding: 4px 0 16px;
}

.page-about .about-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 18px;
}

.page-about .about-track-item {
  flex: 0 0 clamp(238px, 78vw, 336px);
  scroll-snap-align: start;
  padding: 22px 20px 24px;
  border: 1px solid rgba(215, 226, 236, 0.2);
  border-top: 2px solid var(--sun);
  border-radius: var(--r);
  background: rgba(11, 36, 56, 0.74);
}

.page-about .about-track-when {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--sun);
}

.page-about .about-track-title {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: 0.01em;
  color: var(--cloud);
}

.page-about .about-track-body {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(243, 247, 251, 0.74);
}

/* ============ 05 sync ============ */
.page-about .about-sync-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .about-sync-card {
  height: 100%;
}

.page-about .about-sync-card .data-card-body {
  font-size: 14px;
  line-height: 1.75;
}

/* ============ 06 credentials ============ */
.page-about .about-legal-list {
  margin: 0;
  padding: 0;
}

.page-about .about-legal-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 16px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-legal-row:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-legal-key {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--ink-soft);
}

.page-about .about-legal-val {
  margin: 0;
  font-size: 16px;
  font-weight: 500;
  line-height: 1.6;
  color: var(--ink);
  word-break: break-word;
}

.page-about .about-legal-mono {
  font-family: var(--font-mono);
  letter-spacing: 0.03em;
}

.page-about .about-contact-card {
  border: 1px solid var(--line);
  border-top: 2px solid var(--sun);
  border-radius: var(--r);
  background: var(--paper);
  padding: 22px 20px 24px;
  box-shadow: var(--shadow);
}

.page-about .about-contact-desc {
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-soft);
  margin: 0 0 18px;
}

.page-about .about-contact-mail {
  display: block;
  font-family: var(--font-mono);
  font-size: 13.5px;
  letter-spacing: 0.02em;
  color: var(--sky);
  word-break: break-all;
}

.page-about .about-contact-card .copy-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  padding: 14px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-contact-note {
  margin: 16px 0 12px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--ink-mute);
}

.page-about .about-contact-card .link-more {
  font-size: 14px;
  font-weight: 600;
  color: var(--sun-ink);
  text-decoration: none;
  border-bottom: 1px solid rgba(194, 83, 15, 0.35);
  padding-bottom: 2px;
}

.page-about .about-contact-card .link-more:hover {
  color: var(--sky);
  border-bottom-color: var(--sky);
}

/* ============ Responsive ============ */
@media (min-width: 760px) {
  .page-about .about-sync-wrap {
    padding-bottom: 56px;
  }

  .page-about .about-sync-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .about-sync-card:nth-child(2) {
    transform: translateY(22px);
  }

  .page-about .about-sync-card:nth-child(3) {
    transform: translateY(44px);
  }
}

@media (min-width: 900px) {
  .page-about .about-head {
    grid-template-columns: 44px minmax(0, 1fr);
    column-gap: 20px;
    align-items: start;
  }

  .page-about .about-num {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    letter-spacing: 0.3em;
    padding-top: 6px;
  }

  .page-about .about-legal-row {
    grid-template-columns: 150px minmax(0, 1fr);
    align-items: baseline;
    gap: 18px;
  }

  .page-about .about-track-item {
    flex-basis: 340px;
  }
}

@media (max-width: 640px) {
  .page-about .about-hero::after {
    width: 62%;
    opacity: 0.7;
  }

  .page-about .about-fact-num {
    font-size: 1.45rem;
    min-width: 3rem;
  }

  .page-about .about-track-wrap {
    margin: 0 calc(-1 * var(--gutter));
    padding-left: var(--gutter);
    padding-right: var(--gutter);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc-link,
  .page-about .about-path a,
  .page-about .about-contact-card .link-more {
    transition: none;
  }

  .page-about .about-sync-card:nth-child(2),
  .page-about .about-sync-card:nth-child(3) {
    transform: none;
  }
}