.page-about {
  --about-body-text: rgba(242, 246, 250, 0.8);
  --about-toc-w: 200px;
  --about-body-w: 660px;
  --about-grid: 48px;
  background: var(--ink-900);
  color: var(--white-000);
  overflow-x: hidden;
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  position: relative;
  padding: calc(var(--header-h) + 72px) 0 64px;
  border-bottom: 1px solid var(--line-600);
  background:
    radial-gradient(120% 90% at 86% 0%, rgba(0, 229, 255, 0.09), transparent 62%),
    linear-gradient(180deg, var(--ink-900) 0%, var(--deep-800) 100%);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
  background-size: var(--about-grid) var(--about-grid);
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
  pointer-events: none;
}

.page-about .about-hero-grid {
  position: relative;
  display: grid;
  gap: 36px;
  align-items: end;
}

.page-about .about-kicker {
  margin: 24px 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cyan-500);
}

.page-about .about-hero h1 {
  margin: 0 0 24px;
  max-width: 620px;
  font-size: clamp(31px, 5.2vw, 52px);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -0.03em;
  color: var(--white-000);
}

.page-about .about-lede {
  margin: 0;
  max-width: 660px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-body-text);
}

.page-about .about-hero-media {
  position: relative;
  margin: 0;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line-600);
  background: var(--deep-800);
  overflow: hidden;
}

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

/* ===== 目录 + 正文骨架 ===== */
.page-about .about-layout {
  display: grid;
  gap: 44px;
  padding: 64px 0 88px;
}

.page-about .about-toc-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--cyan-500);
}

.page-about .about-toc-list {
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .about-toc-item {
  flex: 0 0 auto;
}

.page-about .about-toc-link {
  display: block;
  padding: 9px 14px;
  border-bottom: 2px solid transparent;
  font-size: 13px;
  line-height: 1.4;
  white-space: nowrap;
  color: var(--grey-400);
  text-decoration: none;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .about-toc-link:hover {
  color: var(--cyan-300);
}

.page-about .about-toc-link[aria-current="true"] {
  color: var(--cyan-500);
  border-bottom-color: var(--cyan-500);
}

.page-about .about-toc-link:focus-visible {
  outline: 2px solid var(--cyan-500);
  outline-offset: 2px;
}

/* ===== 正文 ===== */
.page-about .about-body {
  max-width: var(--about-body-w);
  counter-reset: about-sec;
}

.page-about .about-section {
  padding-top: 48px;
  scroll-margin-top: calc(var(--header-h) + 32px);
}

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

.page-about .about-section + .about-section {
  margin-top: 56px;
  border-top: 1px solid var(--line-600);
}

.page-about .about-section > h2 {
  margin: 0 0 22px;
  font-size: clamp(23px, 2.6vw, 32px);
  font-weight: 800;
  line-height: 1.24;
  letter-spacing: -0.02em;
  color: var(--white-000);
}

.page-about .about-section > h2::before {
  counter-increment: about-sec;
  content: counter(about-sec, decimal-leading-zero);
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.24em;
  color: var(--cyan-500);
}

.page-about .about-p {
  margin: 0 0 1.35em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-body-text);
}

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

.page-about .about-body a {
  color: var(--cyan-500);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-decoration-color: rgba(0, 229, 255, 0.4);
  text-underline-offset: 3px;
  transition: color 200ms var(--ease), text-decoration-color 200ms var(--ease);
}

.page-about .about-body a:hover {
  color: var(--cyan-300);
  text-decoration-color: var(--cyan-300);
}

.page-about .about-hl {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.08em;
  font-weight: 700;
  color: var(--orange-500);
}

/* ===== 通用图 ===== */
.page-about .about-figure {
  margin: 32px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-600);
  background: var(--deep-800);
  object-fit: cover;
}

.page-about .about-figure figcaption {
  margin-top: 12px;
  padding-left: 14px;
  border-left: 2px solid var(--cyan-500);
  font-size: 13px;
  line-height: 1.7;
  color: var(--grey-400);
}

.page-about .about-banner {
  margin: 26px 0 4px;
}

/* ===== 时间轴 ===== */
.page-about .about-timeline {
  position: relative;
  margin: 40px 0 0;
  padding: 0 0 0 96px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 64px;
  top: 12px;
  bottom: 20px;
  width: 1px;
  background: linear-gradient(180deg,
    var(--cyan-500) 0%,
    var(--line-600) 10%,
    var(--line-600) 88%,
    transparent 100%);
}

.page-about .about-season {
  position: relative;
  padding: 28px 0;
}

.page-about .about-season::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 36px;
  width: 7px;
  height: 7px;
  background: var(--ink-900);
  border: 1px solid var(--cyan-500);
  transform: rotate(45deg);
}

.page-about .about-season-year {
  position: absolute;
  left: -96px;
  top: 30px;
  width: 56px;
  text-align: right;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 18px;
  letter-spacing: 0.02em;
  color: var(--cyan-300);
}

.page-about .about-season-details > summary {
  position: relative;
  display: block;
  padding-right: 28px;
  list-style: none;
  cursor: pointer;
}

.page-about .about-season-details > summary::-webkit-details-marker {
  display: none;
}

.page-about .about-season-title {
  display: block;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--white-000);
  transition: color 200ms var(--ease);
}

.page-about .about-season-details > summary:hover .about-season-title {
  color: var(--cyan-300);
}

.page-about .about-season-details > summary:focus-visible {
  outline: 2px solid var(--cyan-500);
  outline-offset: 3px;
}

.page-about .about-season-details > summary::after {
  content: "";
  position: absolute;
  right: 8px;
  top: 9px;
  width: 7px;
  height: 7px;
  border-right: 1px solid var(--cyan-500);
  border-bottom: 1px solid var(--cyan-500);
  transform: rotate(45deg);
  transition: transform 240ms var(--ease);
}

.page-about .about-season-details[open] > summary::after {
  transform: rotate(225deg);
}

.page-about .about-season-body {
  margin-top: 12px;
}

.page-about .about-season-body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-body-text);
}

/* ===== 团队分工 ===== */
.page-about .about-roles {
  display: grid;
  gap: 26px;
  margin: 32px 0 34px;
}

.page-about .about-role {
  position: relative;
  padding-top: 20px;
  border-top: 2px solid var(--cyan-500);
}

.page-about .about-role-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(44px, 8vw, 72px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan-500);
}

.page-about .about-role-name {
  margin: 14px 0 8px;
  font-size: 15px;
  font-weight: 700;
  color: var(--white-000);
}

.page-about .about-role-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--grey-400);
}

/* ===== 更新节奏刻度 ===== */
.page-about .about-cadence {
  display: grid;
  gap: 0;
  margin: 30px 0 28px;
  padding: 0;
  list-style: none;
}

.page-about .about-cadence-step {
  position: relative;
  padding: 0 0 28px 24px;
  border-left: 1px solid var(--line-600);
}

.page-about .about-cadence-step:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-cadence-step::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 6px;
  width: 7px;
  height: 7px;
  background: var(--cyan-500);
  transform: rotate(45deg);
}

.page-about .about-cadence-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan-500);
}

.page-about .about-cadence-unit {
  display: block;
  margin-top: 7px;
  font-size: 13px;
  color: var(--grey-400);
}

.page-about .about-cadence-label {
  display: block;
  margin-top: 8px;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--white-000);
}

/* ===== 条目列表 ===== */
.page-about .about-list {
  display: grid;
  gap: 14px;
  margin: 24px 0 26px;
  padding: 0;
  list-style: none;
}

.page-about .about-list li {
  position: relative;
  padding-left: 22px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-body-text);
}

.page-about .about-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 10px;
  height: 1px;
  background: var(--cyan-500);
}

/* ===== 手册折叠 ===== */
.page-about .about-handbook {
  margin: 26px 0;
  border: 1px solid var(--line-600);
  background: var(--surface-700);
}

.page-about .about-handbook > summary {
  position: relative;
  padding: 16px 46px 16px 18px;
  font-size: 14px;
  font-weight: 700;
  color: var(--cyan-300);
  cursor: pointer;
  list-style: none;
}

.page-about .about-handbook > summary::-webkit-details-marker {
  display: none;
}

.page-about .about-handbook > summary:focus-visible {
  outline: 2px solid var(--cyan-500);
  outline-offset: -2px;
}

.page-about .about-handbook > summary::after {
  content: "+";
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--cyan-500);
}

.page-about .about-handbook[open] > summary::after {
  content: "\2212";
}

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

.page-about .about-handbook-list li {
  padding: 12px 0;
  border-top: 1px solid var(--line-600);
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-body-text);
}

.page-about .about-handbook-list .num {
  display: inline-block;
  min-width: 76px;
  font-size: 13px;
  color: var(--cyan-500);
}

/* ===== 横向查阅带 ===== */
.page-about .about-dock {
  border-top: 1px solid var(--line-600);
  border-bottom: 1px solid var(--line-600);
  background: linear-gradient(180deg, var(--deep-800) 0%, var(--ink-900) 100%);
  padding: 60px 0 68px;
}

.page-about .about-dock-title {
  margin: 0 0 26px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--cyan-500);
}

.page-about .about-dock-grid {
  display: grid;
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
}

.page-about .about-dock-item {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px 20px 40px;
  background: var(--deep-800);
  text-decoration: none;
  transition: background 220ms var(--ease);
}

.page-about .about-dock-item:hover {
  background: var(--surface-700);
}

.page-about .about-dock-item:focus-visible {
  outline: 2px solid var(--cyan-500);
  outline-offset: -2px;
}

.page-about .about-dock-item::after {
  content: "";
  position: absolute;
  left: 20px;
  bottom: 20px;
  width: 20px;
  height: 1px;
  background: var(--cyan-500);
  transition: width 240ms var(--ease);
}

.page-about .about-dock-item:hover::after {
  width: 46px;
}

.page-about .about-dock-kicker {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--grey-400);
}

.page-about .about-dock-name {
  font-size: 15px;
  font-weight: 700;
  line-height: 1.55;
  color: var(--white-000);
  transition: color 220ms var(--ease);
}

.page-about .about-dock-item:hover .about-dock-name {
  color: var(--cyan-500);
}

/* ===== 响应式 ===== */
@media (max-width: 639px) {
  .page-about .about-timeline {
    padding-left: 0;
  }

  .page-about .about-timeline::before {
    left: 7px;
    top: 34px;
  }

  .page-about .about-season {
    padding-left: 32px;
  }

  .page-about .about-season::before {
    left: 4px;
    top: 38px;
  }

  .page-about .about-season-year {
    position: static;
    display: block;
    width: auto;
    margin-bottom: 6px;
    text-align: left;
    font-size: 16px;
  }

  .page-about .about-season-details > summary::after {
    top: 6px;
  }
}

@media (min-width: 640px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

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

@media (min-width: 720px) {
  .page-about .about-cadence {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    margin: 38px 0 32px;
  }

  .page-about .about-cadence-step {
    padding: 28px 22px 0 0;
    border-left: 0;
    border-top: 1px solid var(--line-600);
  }

  .page-about .about-cadence-step:last-child {
    border-left: 0;
    border-top: 1px solid var(--line-600);
    padding-bottom: 0;
  }

  .page-about .about-cadence-step::before {
    left: 0;
    top: -4px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: calc(var(--header-h) + 96px) 0 80px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 72px;
  }

  .page-about .about-hero-media {
    aspect-ratio: 9 / 13;
  }
}

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-toc-w) minmax(0, 1fr);
    gap: 64px;
    align-items: start;
    padding: 88px 0 112px;
  }

  .page-about .about-toc {
    position: sticky;
    top: calc(var(--header-h) + 40px);
    max-height: calc(100vh - var(--header-h) - 80px);
    overflow-y: auto;
  }

  .page-about .about-toc-list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-left: 1px solid var(--line-600);
  }

  .page-about .about-toc-item {
    flex: 1 1 auto;
  }

  .page-about .about-toc-link {
    margin-left: -1px;
    padding: 8px 12px;
    border-bottom: 0;
    border-left: 2px solid transparent;
    white-space: normal;
  }

  .page-about .about-toc-link[aria-current="true"] {
    border-bottom-color: transparent;
    border-left-color: var(--cyan-500);
    background: linear-gradient(90deg, rgba(0, 229, 255, 0.1), transparent 85%);
  }
}

@media (min-width: 1080px) {
  .page-about .about-dock-grid {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-season-details > summary::after,
  .page-about .about-dock-item::after,
  .page-about .about-toc-link,
  .page-about .about-dock-item,
  .page-about .about-dock-name,
  .page-about .about-season-title {
    transition: none;
  }
}
<<<END>>>