.page-about {
  --about-pad: clamp(56px, 8vw, 112px);
  --about-body: 42rem;
  --about-body-wide: 60rem;
  background: var(--ink-900);
  color: var(--fog-100);
}

.page-about .about-crumb {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-top: 22px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  color: var(--steel-500);
}

.page-about .about-crumb a {
  color: var(--steel-500);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .25s var(--ease), border-color .25s var(--ease);
}

.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  color: var(--cyan-400);
  border-bottom-color: var(--cyan-400);
}

.page-about .about-crumb [aria-current="page"] {
  color: var(--fog-100);
}

/* 首屏 */
.page-about .about-lede {
  display: grid;
  gap: 36px;
  padding-top: clamp(32px, 5vw, 56px);
  padding-bottom: clamp(48px, 7vw, 88px);
}

.page-about .about-lede h1 {
  margin: 14px 0 0;
  font-size: var(--fs-64);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--fog-100);
}

.page-about .about-lede__lead {
  margin: 22px 0 0;
  max-width: var(--about-body);
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--steel-500);
}

.page-about .about-fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 13px 0;
  border-bottom: 1px solid var(--grid-300);
  font-family: var(--font-mono);
  font-size: var(--fs-14);
}

.page-about .about-fact:first-child {
  border-top: 1px solid var(--grid-300);
}

.page-about .about-fact__k {
  color: var(--steel-500);
  letter-spacing: .04em;
}

.page-about .about-fact__v {
  color: var(--gold-400);
  font-weight: 500;
  white-space: nowrap;
}

/* 章节分隔色带 */
.page-about .about-band {
  height: 3px;
  background: linear-gradient(
    90deg,
    var(--cyan-400) 0 30%,
    var(--gold-400) 30% 58%,
    var(--grid-300) 58% 100%
  );
  opacity: .55;
}

/* 章节骨架 */
.page-about .about-chapter {
  position: relative;
  padding: var(--about-pad) 0;
  overflow: hidden;
}

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

.page-about .about-chapter__mark {
  position: absolute;
  top: -0.14em;
  right: 0;
  font-family: var(--font-mono);
  font-size: clamp(5rem, 15vw, 13rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.04em;
  color: var(--fog-100);
  opacity: .042;
  pointer-events: none;
  user-select: none;
}

.page-about .about-chapter__body {
  position: relative;
  max-width: var(--about-body);
}

.page-about .about-chapter__body--wide {
  max-width: var(--about-body-wide);
}

.page-about .about-h2 {
  margin: 14px 0 0;
  font-size: var(--fs-40);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -.02em;
  color: var(--fog-100);
}

.page-about .about-chapter .prose {
  margin-top: 22px;
}

.page-about .about-chapter .prose p {
  margin: 0 0 16px;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--steel-500);
}

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

/* 引用块 */
.page-about .about-quote {
  margin: 32px 0 0;
  padding: 2px 0 2px 24px;
  border-left: 2px solid var(--cyan-400);
  font-size: var(--fs-20);
  line-height: 1.7;
  color: var(--fog-100);
}

/* 三条准则 */
.page-about .about-rules {
  display: grid;
  gap: 16px;
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-rule {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 30px 22px 28px;
  background: var(--ink-700);
  border: 1px solid var(--grid-300);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color .3s var(--ease);
}

.page-about .about-rule::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: var(--steel-500);
  transition: height .28s var(--ease);
}

.page-about .about-rule--open::before {
  background: var(--cyan-400);
}

.page-about .about-rule--login::before {
  background: var(--gold-400);
}

.page-about .about-rule--plain::before {
  background: var(--steel-500);
}

.page-about .about-rule:hover {
  border-color: var(--cyan-600);
}

.page-about .about-rule:hover::before {
  height: 5px;
}

.page-about .about-rule__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .08em;
  color: var(--cyan-400);
}

.page-about .about-rule--login .about-rule__idx {
  color: var(--gold-400);
}

.page-about .about-rule--plain .about-rule__idx {
  color: var(--steel-500);
}

.page-about .about-rule h3 {
  margin: 0;
  font-size: var(--fs-20);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--fog-100);
}

.page-about .about-rule p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--steel-500);
}

/* 图片 */
.page-about .about-figure {
  position: relative;
  margin: 32px 0 0;
  border: 1px solid var(--grid-300);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--ink-800);
}

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

.page-about .about-figure__tag {
  position: absolute;
  left: 0;
  bottom: 0;
  padding: 8px 14px;
  background: var(--ink-900);
  border-top: 1px solid var(--grid-300);
  border-right: 1px solid var(--grid-300);
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .04em;
  color: var(--cyan-400);
}

/* 横向历程刻度尺 */
.page-about .about-ruler {
  position: relative;
  margin-top: 28px;
  overflow-x: auto;
  overflow-y: hidden;
  border-top: 1px solid var(--grid-300);
  border-bottom: 1px solid var(--grid-300);
  background: linear-gradient(180deg, rgba(47, 224, 214, .055), transparent 62%);
  scrollbar-color: var(--grid-300) transparent;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-ruler__track {
  position: relative;
  display: flex;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-ruler__track::before {
  content: "";
  position: absolute;
  top: 22px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--grid-300);
}

.page-about .about-ruler__item {
  position: relative;
  flex: 0 0 260px;
  padding: 46px 26px 30px 0;
  border-right: 1px solid var(--grid-300);
}

.page-about .about-ruler__item:last-child {
  border-right: 0;
  padding-right: 8px;
}

.page-about .about-ruler__dot {
  position: absolute;
  top: 17px;
  left: 0;
  width: 10px;
  height: 10px;
  transform: rotate(45deg);
  background: var(--cyan-400);
}

.page-about .about-ruler__item--next .about-ruler__dot {
  background: var(--ink-900);
  border: 1px solid var(--gold-400);
}

.page-about .about-ruler__year {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  font-weight: 500;
  letter-spacing: .06em;
  color: var(--gold-400);
}

.page-about .about-ruler__item h3 {
  margin: 10px 0 0;
  font-size: var(--fs-17);
  font-weight: 700;
  line-height: 1.45;
  color: var(--fog-100);
}

.page-about .about-ruler__item p {
  margin: 8px 0 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--steel-500);
}

.page-about .about-ruler__hint {
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  color: var(--steel-500);
}

.page-about .about-ruler__hint::before {
  content: "← →";
  margin-right: 10px;
  color: var(--gold-400);
}

/* 团队双栏 */
.page-about .about-split {
  display: grid;
  gap: 24px;
  margin-top: 30px;
}

.page-about .about-split__text {
  max-width: none;
}

.page-about .about-figure--side {
  margin: 0;
}

/* 数据条 */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 34px;
  background: var(--grid-300);
  border: 1px solid var(--grid-300);
}

.page-about .about-stat {
  padding: 22px 18px;
  background: var(--ink-800);
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--gold-400);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 8px;
  font-size: var(--fs-14);
  line-height: 1.6;
  color: var(--steel-500);
}

/* 兼容自查步骤 */
.page-about .about-steps {
  display: grid;
  gap: 0;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--grid-300);
}

.page-about .about-steps__item {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 12px;
  padding: 20px 0;
  border-bottom: 1px solid var(--grid-300);
}

.page-about .about-steps__num {
  font-family: var(--font-mono);
  font-size: var(--fs-20);
  font-weight: 500;
  line-height: 1.4;
  color: var(--cyan-400);
}

.page-about .about-steps__item h3 {
  margin: 0;
  font-size: var(--fs-17);
  font-weight: 700;
  color: var(--fog-100);
}

.page-about .about-steps__item p {
  margin: 6px 0 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--steel-500);
}

/* 提示块 */
.page-about .about-callout {
  margin-top: 30px;
  padding: 20px 22px;
}

.page-about .about-callout p {
  margin: 0;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--fog-100);
}

.page-about .about-callout__links {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin-top: 14px !important;
  font-family: var(--font-mono);
  font-size: var(--fs-14) !important;
}

.page-about .about-callout__links a {
  color: var(--gold-400);
  text-decoration: none;
  border-bottom: 1px solid var(--gold-600);
  transition: color .25s var(--ease), border-color .25s var(--ease);
}

.page-about .about-callout__links a:hover,
.page-about .about-callout__links a:focus-visible {
  color: var(--cyan-400);
  border-bottom-color: var(--cyan-400);
}

/* 结尾入口 */
.page-about .about-next {
  padding-top: var(--about-pad);
  padding-bottom: calc(var(--about-pad) + 16px);
}

.page-about .about-next__head {
  max-width: var(--about-body);
}

.page-about .about-next__list {
  display: grid;
  gap: 14px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-next__card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px 20px;
  border: 1px solid var(--grid-300);
  border-radius: var(--radius);
  background: var(--ink-800);
  text-decoration: none;
  transition: border-color .28s var(--ease), background .28s var(--ease);
}

.page-about .about-next__card:hover,
.page-about .about-next__card:focus-visible {
  border-color: var(--cyan-600);
  background: var(--ink-700);
}

.page-about .about-next__k {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .06em;
  color: var(--cyan-400);
}

.page-about .about-next__t {
  font-size: var(--fs-17);
  line-height: 1.6;
  color: var(--fog-100);
}

/* 中等屏幕 */
@media (min-width: 760px) {
  .page-about .about-rules {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

/* 桌面双栏 */
@media (min-width: 900px) {
  .page-about .about-lede {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(40px, 5vw, 88px);
    align-items: start;
  }

  .page-about .about-lede__side {
    padding-top: 8px;
  }

  .page-about .about-chapter__mark {
    right: 8px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .about-split--reverse .about-split__text {
    order: 2;
  }

  .page-about .about-split--reverse .about-figure--side {
    order: 1;
  }
}

/* 动效降级 */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-rule,
  .page-about .about-rule::before,
  .page-about .about-next__card,
  .page-about .about-crumb a,
  .page-about .about-callout__links a {
    transition: none;
  }
}