.page-about {
  --about-gap: clamp(1.25rem, 3.2vw, 2.75rem);
  --about-line: rgba(195, 202, 206, 0.16);
  display: block;
}

.page-about .breadcrumb {
  padding-top: 1.25rem;
  padding-bottom: 0.5rem;
  font-size: 0.8125rem;
}

.page-about .breadcrumb__item {
  color: var(--steel-500);
  text-decoration: none;
}

.page-about .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin: 0 0.5rem;
  color: var(--char-600);
}

.page-about .breadcrumb__item[aria-current="page"] {
  color: var(--frost-400);
}

/* ---------- Hero ---------- */

.page-about .page-about__hero {
  position: relative;
  isolation: isolate;
  display: grid;
  gap: var(--about-gap);
  padding-block: clamp(1.25rem, 4vw, 2.25rem) clamp(2rem, 5vw, 3.5rem);
}

.page-about .page-about__hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -1.5rem;
  left: 0;
  width: min(88%, 44rem);
  height: min(76vw, 28rem);
  background:
    linear-gradient(118deg, rgba(228, 88, 30, 0.3) 0%, rgba(228, 88, 30, 0.05) 48%, rgba(228, 88, 30, 0) 74%),
    repeating-linear-gradient(90deg, rgba(195, 202, 206, 0.07) 0 1px, transparent 1px 44px);
  clip-path: polygon(0 0, 100% 7%, 84% 100%, 0 76%);
  pointer-events: none;
}

.page-about .page-about__kicker {
  margin: 0 0 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.16em;
  color: var(--amber-400);
}

.page-about .page-about__hero .h-display {
  margin: 0;
  max-width: 20ch;
  font-size: clamp(1.95rem, 7.4vw, 3.4rem);
  line-height: 1.08;
  letter-spacing: -0.015em;
}

.page-about .page-about__hero .lede {
  margin: 1.25rem 0 0;
  max-width: 34em;
  font-size: 1rem;
  line-height: 1.75;
}

.page-about .page-about__hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.35rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .page-about__hero-tags li {
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--char-600);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.78125rem;
  font-variant-numeric: tabular-nums;
  color: var(--frost-400);
}

.page-about .page-about__hero-media {
  margin: 0;
}

/* ---------- 时间线 + 原则双栏 ---------- */

.page-about .page-about__ledger {
  display: grid;
  gap: var(--about-gap);
  padding-block: clamp(2rem, 5vw, 3.5rem);
  border-top: 1px solid var(--about-line);
}

.page-about .page-about__timeline > h2,
.page-about .page-about__principles > h2 {
  margin: 0;
  font-size: clamp(1.05rem, 2.6vw, 1.3rem);
  line-height: 1.3;
}

.page-about .tl {
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .tl__item {
  position: relative;
  padding-left: 1.75rem;
  margin-bottom: 0.875rem;
}

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

.page-about .tl__item::before {
  content: "";
  position: absolute;
  left: 0.375rem;
  top: 1.7rem;
  bottom: -1rem;
  width: 2px;
  background: var(--char-600);
}

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

.page-about .tl__item::after {
  content: "";
  position: absolute;
  left: 0.375rem;
  top: 1.5rem;
  width: 9px;
  height: 9px;
  margin-left: -3.5px;
  border-radius: 50%;
  background: var(--steel-500);
  box-shadow: 0 0 0 3px var(--void-black);
  transition: background-color 0.26s var(--ease);
}

.page-about .tl__item:has(.tl__node[open])::after {
  background: var(--ember-500);
}

.page-about .tl__node {
  border: 1px solid var(--char-600);
  border-radius: var(--radius-m);
  background: var(--char-800);
  overflow: hidden;
  transition: border-color 0.26s var(--ease), background-color 0.26s var(--ease);
}

.page-about .tl__node[open] {
  border-color: rgba(228, 88, 30, 0.5);
  background: linear-gradient(180deg, rgba(228, 88, 30, 0.09), var(--char-800) 62%);
}

.page-about .tl__summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.5rem 0.75rem;
  padding: 0.8rem 1rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .tl__summary:focus-visible {
  outline: 2px solid var(--ember-500);
  outline-offset: -2px;
}

.page-about .tl__ver {
  padding: 0.15rem 0.5rem;
  border: 1px solid rgba(63, 126, 168, 0.4);
  border-radius: var(--radius-s);
  background: rgba(63, 126, 168, 0.16);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--data-blue);
}

.page-about .tl__node[open] .tl__ver {
  border-color: rgba(247, 183, 51, 0.45);
  background: rgba(247, 183, 51, 0.15);
  color: var(--amber-400);
}

.page-about .tl__label {
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.45;
  color: var(--frost-100);
}

.page-about .tl__toggle {
  position: relative;
  justify-self: end;
  width: 1.1rem;
  height: 1.1rem;
}

.page-about .tl__toggle::before,
.page-about .tl__toggle::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 1.5px;
  background: var(--ember-300);
  transform: translateY(-50%);
}

.page-about .tl__toggle::after {
  transform: translateY(-50%) rotate(90deg);
  transition: transform 0.26s var(--ease);
}

.page-about .tl__node[open] .tl__toggle::after {
  transform: translateY(-50%) rotate(0deg);
}

.page-about .tl__body {
  padding: 0 1rem 1rem;
}

.page-about .tl__body p {
  margin: 0.85rem 0 0;
  max-width: 34em;
  font-size: 0.9375rem;
  line-height: 1.72;
  color: var(--frost-400);
  border-top: 1px solid var(--char-600);
  padding-top: 0.85rem;
}

/* ---------- 原则卡片 ---------- */

.page-about .principles {
  display: grid;
  gap: 0.75rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .principle {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: start;
  gap: 0.75rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--char-600);
  border-left: 3px solid var(--char-600);
  border-radius: var(--radius-m);
  background: var(--char-800);
  color: var(--frost-400);
  text-decoration: none;
  transition: border-color 0.26s var(--ease), background-color 0.26s var(--ease), transform 0.26s var(--ease);
}

.page-about .principle:hover,
.page-about .principle:focus-visible {
  border-color: rgba(228, 88, 30, 0.42);
  border-left-color: var(--ember-500);
  background: linear-gradient(120deg, rgba(228, 88, 30, 0.12), var(--char-800) 58%);
  transform: translateX(4px);
}

.page-about .principle:focus-visible {
  outline: 2px solid var(--ember-500);
  outline-offset: 2px;
}

.page-about .principle__num {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-variant-numeric: tabular-nums;
  color: var(--amber-400);
  padding-top: 0.15rem;
}

.page-about .principle__text {
  font-size: 0.9375rem;
  line-height: 1.65;
}

.page-about .principle__arrow {
  color: var(--ember-300);
  font-family: var(--font-mono);
  transition: transform 0.26s var(--ease);
}

.page-about .principle:hover .principle__arrow,
.page-about .principle:focus-visible .principle__arrow {
  transform: translateX(3px);
}

/* ---------- 章节 ---------- */

.page-about .chapter {
  display: grid;
  gap: 1rem;
  padding-block: clamp(2rem, 5vw, 3.25rem);
  border-top: 1px solid var(--about-line);
}

.page-about .chapter__frame {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.page-about .chapter__index {
  font-family: var(--font-mono);
  font-size: 1.375rem;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.08em;
  line-height: 1;
  color: var(--ember-500);
}

.page-about .chapter__title {
  margin: 0;
  font-size: clamp(1.2rem, 3.2vw, 1.6rem);
  line-height: 1.24;
  letter-spacing: -0.01em;
  color: var(--frost-100);
}

.page-about .chapter__body > p {
  margin: 0 0 1rem;
  max-width: 34em;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--frost-400);
}

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

.page-about .chapter__body a {
  color: var(--ember-300);
  text-decoration-color: rgba(240, 138, 90, 0.45);
  text-underline-offset: 3px;
}

.page-about .chapter__body a:hover,
.page-about .chapter__body a:focus-visible {
  color: var(--amber-400);
}

/* ---------- 三道校验 ---------- */

.page-about .checklist {
  display: grid;
  gap: 0.75rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .check {
  position: relative;
  padding: 1.1rem 1rem 1.15rem;
  border: 1px solid var(--char-600);
  border-top: 3px solid var(--data-blue);
  border-radius: var(--radius-m);
  background: var(--char-800);
  overflow: hidden;
}

.page-about .check::after {
  content: "";
  position: absolute;
  right: -1.75rem;
  bottom: -1.75rem;
  width: 5.5rem;
  height: 5.5rem;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(63, 126, 168, 0.24), rgba(63, 126, 168, 0) 68%);
  pointer-events: none;
}

.page-about .check__index {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.78125rem;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.1em;
  color: var(--data-blue);
}

.page-about .check__title {
  margin: 0.5rem 0 0.4rem;
  font-size: 1rem;
  line-height: 1.3;
  color: var(--frost-100);
}

.page-about .check__text {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.68;
  color: var(--frost-400);
}

.page-about .verify-grid {
  display: grid;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.page-about .verify-grid .media-frame {
  margin: 0;
}

.page-about .caliber-quote {
  margin: 0;
  padding: 1.1rem 1rem 1.1rem 1.25rem;
  border-left: 3px solid var(--ember-500);
  border-radius: 0 var(--radius-m) var(--radius-m) 0;
  background: linear-gradient(90deg, rgba(228, 88, 30, 0.1), rgba(228, 88, 30, 0) 88%);
}

.page-about .caliber-quote p {
  margin: 0;
  max-width: 30em;
  font-size: 0.9375rem;
  line-height: 1.72;
  color: var(--frost-100);
}

.page-about .caliber-quote cite {
  display: block;
  margin-top: 0.75rem;
  font-style: normal;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--steel-500);
}

/* ---------- 团队分工胶片条 ---------- */

.page-about .crew {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 78%;
  gap: 0.75rem;
  margin: 1.5rem 0 0;
  padding: 0 0 0.85rem;
  list-style: none;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scroll-snap-type: x mandatory;
}

.page-about .crew__item {
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  padding: 1rem;
  border: 1px solid var(--char-600);
  border-radius: var(--radius-m);
  background: linear-gradient(180deg, rgba(36, 80, 107, 0.2), var(--char-800) 58%);
}

.page-about .crew__name {
  margin: 0;
  font-size: 1rem;
  font-weight: 700;
  color: var(--frost-100);
}

.page-about .crew__duty {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.68;
  color: var(--frost-400);
}

.page-about .crew__meta {
  margin: auto 0 0;
  padding: 0.75rem 0 0;
  list-style: none;
  border-top: 1px solid var(--char-600);
}

.page-about .crew__meta li {
  position: relative;
  padding-left: 0.9rem;
  font-size: 0.8125rem;
  line-height: 1.62;
  color: var(--steel-500);
}

.page-about .crew__meta li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55rem;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--data-blue);
}

.page-about .page-about__strip {
  margin: 1.5rem 0 0;
}

/* ---------- 边界条目 ---------- */

.page-about .boundary {
  display: grid;
  gap: 0.5rem;
  margin: 1.25rem 0 1.25rem;
  padding: 0;
  list-style: none;
}

.page-about .boundary__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 0.625rem;
  align-items: start;
  padding: 0.75rem 0.875rem;
  border: 1px dashed var(--char-600);
  border-radius: var(--radius-s);
  font-size: 0.9375rem;
  line-height: 1.62;
  color: var(--frost-400);
}

.page-about .boundary__item::before {
  content: "—";
  font-family: var(--font-mono);
  color: var(--ember-500);
}

/* ---------- 尾注 ---------- */

.page-about .page-about__outro {
  margin-block: clamp(2rem, 5vw, 3.5rem);
  padding: clamp(1.25rem, 3.4vw, 2rem);
  border: 1px solid var(--char-600);
  border-left: 4px solid var(--ember-500);
  border-radius: var(--radius-l);
  background: linear-gradient(122deg, rgba(36, 80, 107, 0.24), var(--char-800) 64%);
}

.page-about .page-about__outro h2 {
  margin: 0 0 0.85rem;
  font-size: 1.05rem;
}

.page-about .page-about__outro p {
  margin: 0 0 0.75rem;
  max-width: 34em;
  font-size: 0.9375rem;
  line-height: 1.72;
  color: var(--frost-400);
}

.page-about .page-about__outro .caption {
  margin-bottom: 0;
  font-size: 0.8125rem;
  color: var(--steel-500);
}

.page-about .page-about__outro a {
  color: var(--ember-300);
  text-underline-offset: 3px;
}

.page-about .page-about__outro a:hover,
.page-about .page-about__outro a:focus-visible {
  color: var(--amber-400);
}

/* ---------- 动效 ---------- */

@media (prefers-reduced-motion: no-preference) {
  .page-about .tl__item:has(.tl__node[open])::after {
    animation: about-node-pulse 2.6s var(--ease) infinite;
  }
}

@keyframes about-node-pulse {
  0%,
  100% {
    box-shadow: 0 0 0 3px var(--void-black), 0 0 0 6px rgba(228, 88, 30, 0.24);
  }
  55% {
    box-shadow: 0 0 0 3px var(--void-black), 0 0 0 13px rgba(228, 88, 30, 0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .principle:hover,
  .page-about .principle:focus-visible {
    transform: none;
  }
  .page-about .principle:hover .principle__arrow,
  .page-about .principle:focus-visible .principle__arrow {
    transform: none;
  }
}

/* ---------- 响应式 ---------- */

@media (min-width: 34rem) {
  .page-about .crew {
    grid-auto-columns: 17rem;
  }
}

@media (min-width: 48rem) {
  .page-about .checklist {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .verify-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: center;
    column-gap: clamp(1.5rem, 3vw, 2.5rem);
  }

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

@media (min-width: 60rem) {
  .page-about .chapter {
    grid-template-columns: minmax(0, 14rem) minmax(0, 1fr);
    column-gap: clamp(2rem, 4vw, 3.5rem);
  }

  .page-about .chapter__frame {
    position: sticky;
    top: var(--sticky-top);
    align-self: start;
  }

  .page-about .crew {
    grid-auto-flow: row;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    overflow-x: visible;
    padding-bottom: 0;
  }
}

@media (min-width: 64rem) {
  .page-about .page-about__hero {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
    align-items: center;
    column-gap: clamp(2rem, 5vw, 4rem);
  }

  .page-about .page-about__hero-media {
    margin-top: 2rem;
  }

  .page-about .page-about__ledger {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    column-gap: clamp(2rem, 5vw, 4rem);
  }

  .page-about .page-about__principles {
    position: sticky;
    top: var(--sticky-top);
    align-self: start;
  }
}
<<<END>>>