/* ============================================================
   平台介绍 /introduction/ · page-about
   低饱和墨蓝 + 纸白，纵向时间线 + 右侧旁注双层结构
   ============================================================ */

.page-about {
  --accent: var(--paper);
  --about-stroke: 1px solid var(--rule);
  display: block;
  background: var(--ink-0);
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-top: 28px;
  padding-bottom: 20px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

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

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

.page-about .crumbs__sep {
  color: var(--rule);
}

.page-about .crumbs [aria-current="page"] {
  color: var(--paper);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-top: 8px;
  border-top: 0;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 48px);
}

@media (min-width: 980px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }
}

.page-about .about-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--mist);
}

.page-about .about-kicker::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--accent);
}

.page-about .about-hero__title {
  margin: 0 0 24px;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(34px, 6vw, 72px);
  line-height: 1.04;
  letter-spacing: -0.03em;
  color: var(--paper);
  max-width: 13em;
}

.page-about .about-hero__lede {
  max-width: 46ch;
  margin: 0;
}

.page-about .about-hero__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.page-about .about-hero__side {
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}

.page-about .about-side__cap {
  margin: 0;
  padding: 14px 18px;
  background: var(--ink-2);
  border-bottom: var(--about-stroke);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule);
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 18px 22px;
  background: var(--ink-1);
}

.page-about .about-facts b {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: clamp(24px, 3vw, 32px);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-facts span {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.1em;
  color: var(--mist);
}

/* ---------- 起点 ---------- */
.page-about .about-origin__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

@media (min-width: 900px) {
  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 1fr) 96px;
    gap: clamp(28px, 4vw, 56px);
  }
}

.page-about .about-origin__body {
  margin-top: 22px;
  max-width: 74ch;
}

.page-about .about-origin__body p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

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

.page-about .about-origin__note {
  display: flex;
  align-items: flex-start;
  justify-content: flex-start;
  padding-top: 6px;
  border-left: 2px solid var(--rule);
  padding-left: 14px;
}

.page-about .about-origin__note .annot {
  margin: 0;
  letter-spacing: 0.16em;
  color: var(--mist);
}

@media (min-width: 900px) {
  .page-about .about-origin__note {
    justify-content: center;
    padding-left: 0;
    border-left: 0;
    border-right: 2px solid var(--rule);
    padding-right: 18px;
  }

  .page-about .about-origin__note .annot {
    writing-mode: vertical-rl;
    letter-spacing: 0.22em;
  }
}

/* ---------- 时间线 ---------- */
.page-about .about-stages__intro {
  margin: 16px 0 40px;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-track {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 4px 0 4px 34px;
}

.page-about .about-track::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 16px;
  bottom: 16px;
  width: 1px;
  background: var(--rule);
}

.page-about .about-step {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  padding-bottom: 42px;
}

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

.page-about .about-step::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-0);
  border: 1px solid var(--mist);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-step:hover::before,
.page-about .about-step:focus-within::before {
  background: var(--accent);
  border-color: var(--accent);
  transform: scale(1.18);
}

@media (min-width: 820px) {
  .page-about .about-step {
    grid-template-columns: minmax(170px, 4fr) minmax(0, 8fr);
    gap: clamp(24px, 4vw, 56px);
    align-items: start;
  }
}

.page-about .about-step__label {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .about-step__index {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.page-about .about-step__title {
  margin: 0;
  font-size: clamp(18px, 2vw, 22px);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-step__body p {
  margin: 0 0 12px;
  font-size: 15px;
  line-height: 1.82;
  color: var(--mist);
  max-width: 62ch;
}

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

.page-about .about-step__data {
  display: inline-block;
  margin-top: 4px;
  padding: 6px 12px;
  border: var(--about-stroke);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

/* ---------- 维护分工 ---------- */
.page-about .about-team__intro {
  margin: 16px 0 32px;
  max-width: 66ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-figure {
  margin: 0 0 36px;
}

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

.page-about .about-figure .figure__cap {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

@media (min-width: 820px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
    align-items: start;
  }

  .page-about .about-roles > li:nth-child(2) {
    margin-top: 28px;
  }

  .page-about .about-roles > li:nth-child(3) {
    margin-top: 56px;
  }
}

.page-about .about-role {
  padding: 24px 22px 26px;
  background: var(--ink-1);
  border: var(--about-stroke);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.page-about .about-role__head {
  display: flex;
  align-items: center;
  gap: 10px;
}

.page-about .about-role__name {
  margin: 0;
  flex: 1 1 auto;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-role__count {
  font-size: 13px;
  color: var(--mist);
}

.page-about .about-dot {
  flex: 0 0 auto;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.page-about .about-dot--green {
  background: var(--green);
}

.page-about .about-dot--cyan {
  background: var(--cyan);
}

.page-about .about-dot--amber {
  background: var(--amber);
}

.page-about .about-role .list {
  font-size: 14px;
  line-height: 1.8;
}

/* ---------- 更新节奏 ---------- */
.page-about .about-cycle__wrap {
  position: relative;
}

.page-about .about-cycle__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

@media (min-width: 900px) {
  .page-about .about-cycle__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }
}

.page-about .about-cycle__text p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
  max-width: 60ch;
}

.page-about .about-cycle__cta {
  margin-top: 26px;
}

.page-about .about-metrics {
  margin: 0;
  border: var(--about-stroke);
  background: var(--ink-1);
}

.page-about .about-metrics > div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 18px;
  border-bottom: var(--about-stroke);
}

.page-about .about-metrics > div:last-child {
  border-bottom: 0;
}

.page-about .about-metrics dt {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .about-metrics dd {
  margin: 0;
  font-size: 16px;
  color: var(--paper);
}

/* ---------- 标签体系 ---------- */
.page-about .about-labels__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  padding: clamp(22px, 3vw, 34px);
  border: var(--about-stroke);
  background:
    linear-gradient(135deg, rgba(241, 245, 249, 0.05), transparent 58%),
    var(--ink-1);
}

@media (min-width: 860px) {
  .page-about .about-labels__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: center;
  }
}

.page-about .about-labels__text p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

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

.page-about .about-labels__chips {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}

.page-about .about-labels__chips li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  padding: 14px 0;
  border-top: var(--about-stroke);
}

.page-about .about-labels__chips li:last-child {
  border-bottom: var(--about-stroke);
}

.page-about .about-labels__chips em {
  font-style: normal;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
  flex: 1 1 180px;
}

/* ---------- 使用者 ---------- */
.page-about .about-audience__intro {
  margin: 16px 0 32px;
  max-width: 66ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-people {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--rule);
  border: var(--about-stroke);
}

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

.page-about .about-people li {
  background: var(--ink-1);
  padding: 26px 22px 28px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  border-top: 2px solid transparent;
}

.page-about .about-people li:nth-child(1) {
  border-top-color: var(--paper);
}

.page-about .about-people li:nth-child(2) {
  border-top-color: var(--mist);
}

.page-about .about-people li:nth-child(3) {
  border-top-color: var(--rule);
}

.page-about .about-people h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.45;
  letter-spacing: -0.01em;
  color: var(--paper);
}

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

/* ---------- 下一步 ---------- */
.page-about .about-next {
  border-top: var(--about-stroke);
}

.page-about .about-next__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

@media (min-width: 900px) {
  .page-about .about-next__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: clamp(32px, 5vw, 64px);
    align-items: start;
  }
}

.page-about .about-next__lead p {
  margin: 16px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
  max-width: 52ch;
}

.page-about .about-next__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--rule);
  border: var(--about-stroke);
}

@media (min-width: 620px) {
  .page-about .about-next__links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-next__links li {
  background: var(--ink-1);
}

.page-about .about-next__links a {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 22px 46px 22px 18px;
  text-decoration: none;
  color: var(--paper);
  font-size: 16px;
  font-weight: 700;
  transition: background var(--dur) var(--ease);
}

.page-about .about-next__links a span {
  font-size: 13px;
  font-weight: 400;
  line-height: 1.6;
  color: var(--mist);
  transition: color var(--dur) var(--ease);
}

.page-about .about-next__links a::after {
  content: "→";
  position: absolute;
  top: 22px;
  right: 18px;
  font-size: 14px;
  color: var(--mist);
  transition: transform var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-next__links a:hover,
.page-about .about-next__links a:focus-visible {
  background: var(--ink-2);
}

.page-about .about-next__links a:hover::after,
.page-about .about-next__links a:focus-visible::after {
  transform: translateX(4px);
  color: var(--paper);
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-step::before,
  .page-about .about-next__links a,
  .page-about .about-next__links a::after,
  .page-about .crumbs a {
    transition: none;
  }

  .page-about .about-step:hover::before,
  .page-about .about-step:focus-within::before {
    transform: none;
  }
}