.page-about {
  --about-rule: rgba(75, 31, 115, 0.16);
  --about-rule-soft: rgba(169, 127, 212, 0.32);
  background: var(--paper);
  color: var(--ink);
  padding-bottom: clamp(64px, 8vw, 112px);
  overflow-x: clip;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  padding-top: clamp(20px, 3vw, 36px);
  font-size: 13px;
}

.page-about .crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  color: var(--ink-mute);
}

.page-about .crumbs li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--grape-300);
}

.page-about .crumbs a {
  color: var(--ink-mute);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--grape-700);
  border-bottom-color: var(--grape-300);
}

.page-about .crumbs [aria-current="page"] {
  color: var(--grape-700);
  font-weight: 600;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 24px;
  padding: clamp(28px, 5vw, 60px) 0 clamp(30px, 4vw, 48px);
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(34px, 7.8vw, 76px);
  line-height: 1.02;
  letter-spacing: -0.025em;
  color: var(--grape-900);
  margin: 12px 0 0;
}

.page-about .about-hero__title-b {
  display: block;
  font-weight: 700;
  color: var(--grape-500);
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 42ch;
}

@media (min-width: 960px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    align-items: end;
    gap: 72px;
  }

  .page-about .about-hero__lede {
    padding-bottom: 8px;
  }
}

/* ---------- 规模数据条 ---------- */
.page-about .about-figures {
  list-style: none;
  margin: 0 0 clamp(48px, 7vw, 88px);
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-rule);
  border-top: 1px solid var(--about-rule);
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-figure {
  background: var(--paper);
  padding: 20px 16px 22px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-figure__num {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.2vw, 46px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--grape-700);
}

.page-about .about-figure__label {
  font-size: 13px;
  line-height: 1.55;
  color: var(--ink-mute);
}

@media (min-width: 800px) {
  .page-about .about-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-figure {
    padding: 26px 22px 28px;
  }
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  margin-bottom: clamp(56px, 8vw, 104px);
}

.page-about .about-sec__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 16px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--about-rule);
  margin-bottom: 20px;
}

.page-about .about-sec__title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.5vw, 34px);
  line-height: 1.2;
  letter-spacing: -0.015em;
  color: var(--grape-900);
  margin: 0;
}

.page-about .about-sec__lead {
  max-width: 64ch;
  margin: 0 0 28px;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink-mute);
}

.page-about .about-fig {
  margin-top: 30px;
}

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

.page-about .about-fig--deep {
  background: var(--night);
  padding: clamp(14px, 2.4vw, 24px);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
}

/* ---------- 01 五个小组 ---------- */
.page-about .crew-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .crew-item {
  display: grid;
  grid-template-columns: 2.6rem minmax(0, 1fr) auto;
  grid-template-areas:
    "idx name count"
    "duty duty duty";
  align-items: baseline;
  column-gap: 12px;
  row-gap: 8px;
  padding: 18px 10px;
  margin: 0 -10px;
  border-top: 1px solid var(--about-rule);
  transition: background-color 180ms var(--ease);
}

.page-about .crew-item:hover,
.page-about .crew-item:focus {
  background: var(--grape-050);
  outline: none;
}

.page-about .crew-item:focus-visible {
  outline: 2px solid var(--green-600);
  outline-offset: -2px;
}

.page-about .crew-item__idx {
  grid-area: idx;
  font-size: 13px;
  color: var(--grape-300);
}

.page-about .crew-item__name {
  grid-area: name;
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(18px, 2.4vw, 22px);
  color: var(--grape-900);
}

.page-about .crew-item__count {
  grid-area: count;
  font-size: 13px;
  color: var(--grape-700);
  white-space: nowrap;
}

.page-about .crew-item__duty {
  grid-area: duty;
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.72;
  color: var(--ink-mute);
}

@media (min-width: 900px) {
  .page-about .crew-item {
    grid-template-columns: 3.4rem minmax(0, 1fr) auto;
    column-gap: 20px;
    padding: 22px 14px;
    margin: 0 -14px;
  }

  .page-about .crew-item__duty {
    overflow: hidden;
    max-height: 0;
    opacity: 0;
    transition: max-height 320ms var(--ease), opacity 220ms var(--ease), margin-top 320ms var(--ease);
  }

  .page-about .crew-item:hover .crew-item__duty,
  .page-about .crew-item:focus .crew-item__duty,
  .page-about .crew-item:focus-within .crew-item__duty {
    max-height: 200px;
    opacity: 1;
    margin-top: 4px;
  }
}

/* ---------- 02 五步流程 ---------- */
.page-about .flow {
  list-style: none;
  margin: 0;
  padding: 0 0 0 24px;
  border-left: 1px solid var(--about-rule-soft);
}

.page-about .flow-node {
  position: relative;
  padding: 0 0 26px;
}

.page-about .flow-node:last-child {
  padding-bottom: 0;
}

.page-about .flow-node::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 5px;
  width: 9px;
  height: 9px;
  transform: rotate(45deg);
  background: var(--paper);
  border: 2px solid var(--grape-500);
}

.page-about .flow-node__idx {
  display: block;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--grape-500);
}

.page-about .flow-node__title {
  margin: 5px 0 6px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 19px;
  color: var(--grape-900);
}

.page-about .flow-node__desc {
  margin: 0;
  max-width: 56ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-mute);
}

@media (min-width: 900px) {
  .page-about .flow {
    display: grid;
    grid-template-columns: 1.2fr 1fr 1.05fr 0.9fr 1.1fr;
    column-gap: 22px;
    padding: 34px 0 0;
    border-left: 0;
    border-top: 1px solid var(--about-rule);
  }

  .page-about .flow-node {
    padding: 0;
  }

  .page-about .flow-node:last-child {
    padding-bottom: 0;
  }

  .page-about .flow-node::before {
    left: 0;
    top: -38px;
  }
}

/* ---------- 03 版本年表 ---------- */
.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 26px;
  width: 1px;
  background: linear-gradient(to bottom, var(--grape-500), var(--grape-300) 68%, rgba(169, 127, 212, 0));
}

.page-about .tl-item {
  position: relative;
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  column-gap: 18px;
  padding: 0 0 26px 26px;
}

.page-about .tl-item:last-child {
  padding-bottom: 0;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 7px;
  width: 9px;
  height: 9px;
  transform: rotate(45deg);
  background: var(--green-600);
}

.page-about .tl-item__year {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--grape-700);
  padding-top: 1px;
}

.page-about .tl-item__title {
  margin: 0 0 5px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--grape-900);
}

.page-about .tl-item__desc {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.72;
  color: var(--ink-mute);
}

@media (min-width: 900px) {
  .page-about .tl-item {
    grid-template-columns: 92px minmax(0, 1fr);
    column-gap: 34px;
    padding: 0 0 36px 44px;
    align-items: start;
  }

  .page-about .tl-item:nth-child(even) {
    padding-left: 68px;
  }

  .page-about .tl-item__year {
    font-size: 21px;
    letter-spacing: 0.01em;
  }
}

/* ---------- 04 术语与校对 ---------- */
.page-about .terms-split {
  display: grid;
  gap: 26px;
}

.page-about .terms-split .prose p {
  margin: 0 0 18px;
  max-width: 40ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ink);
}

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

.page-about .terms-note {
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--ink-mute);
}

.page-about .terms-note p {
  margin: 0;
}

@media (min-width: 900px) {
  .page-about .terms-split {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 60px;
    align-items: start;
  }
}

/* ---------- 05 伙伴（深底） ---------- */
.page-about .about-sec--night {
  background: var(--night);
  color: var(--paper);
  padding: clamp(30px, 5vw, 58px) clamp(22px, 4vw, 52px);
  margin-inline: calc(var(--gutter) * -1);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

.page-about .about-sec--night .about-sec__head {
  border-bottom-color: var(--about-rule-soft);
}

.page-about .about-sec--night .about-sec__title {
  color: var(--paper);
}

.page-about .about-sec--night .section-index {
  color: var(--gold-500);
}

.page-about .about-sec--night .about-sec__lead {
  color: var(--grape-300);
}

.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 28px;
}

.page-about .partner-item__num {
  display: block;
  margin-bottom: 10px;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold-500);
}

.page-about .partner-item__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--paper);
}

.page-about .partner-item__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--grape-300);
}

@media (min-width: 800px) {
  .page-about .partner-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 40px;
  }
}

/* ---------- 结尾入口 ---------- */
.page-about .about-cta {
  margin-top: clamp(48px, 7vw, 88px);
  padding-top: clamp(30px, 4.5vw, 48px);
  border-top: 1px solid var(--about-rule);
}

.page-about .about-cta__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.5vw, 34px);
  line-height: 1.2;
  color: var(--grape-900);
}

.page-about .about-cta__text {
  max-width: 62ch;
  margin: 0 0 26px;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--ink-mute);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .crew-item,
  .page-about .crew-item__duty,
  .page-about .crumbs a {
    transition: none;
  }
}
</style>