.page-about {
  --about-rule: rgba(30, 42, 66, 0.9);
  --about-body: #C4D0E6;
  --about-panel: linear-gradient(158deg, rgba(16, 27, 46, 0.94), rgba(11, 18, 32, 0.72));
  position: relative;
  padding-bottom: clamp(64px, 9vw, 112px);
  overflow-x: hidden;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  padding-top: 28px;
  padding-bottom: 6px;
}

.page-about .crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 13px;
  color: var(--muted);
}

.page-about .crumbs li {
  display: inline-flex;
  align-items: center;
}

.page-about .crumbs li + li::before {
  content: "/";
  margin: 0 10px;
  color: var(--line);
}

.page-about .crumbs a {
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s var(--ease);
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--aqua);
}

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

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(26px, 5vw, 52px) 0 clamp(34px, 5vw, 60px);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(30, 42, 66, 0.55) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(30, 42, 66, 0.3) 1px, transparent 1px);
  background-size: 96px 96px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), transparent 84%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), transparent 84%);
  pointer-events: none;
  opacity: 0.55;
}

.page-about .about-hero__grid {
  position: relative;
  display: grid;
  gap: 32px;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(36px, 6vw, 68px);
  font-weight: 800;
  line-height: 1.07;
  letter-spacing: -0.022em;
  color: var(--text);
  margin: 16px 0 20px;
  max-width: 15em;
}

.page-about .about-hero .lead {
  font-size: clamp(16px, 1.6vw, 18px);
  line-height: 1.78;
  color: var(--about-body);
  max-width: 64ch;
  margin: 0 0 18px;
}

.page-about .about-hero__note {
  margin: 0;
  padding-left: 16px;
  border-left: 2px solid var(--signal);
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--muted);
  max-width: 56ch;
}

/* ---------- 索引面板 ---------- */
.page-about .about-index {
  border-radius: var(--radius-l);
  padding: 20px 18px 22px;
}

.page-about .about-index__title {
  margin: 0 0 14px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-index ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-index a {
  display: grid;
  grid-template-columns: 32px 1fr;
  align-items: baseline;
  gap: 8px;
  padding: 9px 10px;
  border-left: 2px solid transparent;
  border-radius: var(--radius-s);
  color: var(--text);
  text-decoration: none;
  font-size: 15px;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease), color 0.2s var(--ease);
}

.page-about .about-index a:hover,
.page-about .about-index a:focus-visible {
  background: rgba(53, 224, 198, 0.09);
  border-left-color: var(--aqua);
  color: var(--aqua);
}

.page-about .about-index .idx {
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--signal);
}

/* ---------- 首图 ---------- */
.page-about .about-figure {
  padding: 0 0 clamp(30px, 5vw, 56px);
}

.page-about .about-figure .media-frame {
  border-radius: var(--radius-l);
  border: 1px solid var(--about-rule);
  background: var(--glass);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  position: relative;
  padding: clamp(44px, 6vw, 88px) 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-chapter::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  height: 1px;
  width: 0;
  background: linear-gradient(90deg, var(--signal), rgba(185, 242, 74, 0));
  transition: width 0.9s var(--ease);
}

.page-about .about-chapter.is-in::before {
  width: min(100%, 420px);
}

.page-about .about-chapter__grid {
  display: grid;
  gap: 22px;
}

.page-about .about-chapter .index-num {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--signal);
}

.page-about .about-chapter .index-num::after {
  content: "";
  width: 48px;
  height: 1px;
  background: linear-gradient(90deg, var(--signal), rgba(185, 242, 74, 0));
}

.page-about .about-chapter h2 {
  font-family: var(--font-display);
  font-size: clamp(25px, 3.3vw, 42px);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.016em;
  color: var(--text);
  margin: 12px 0 0;
  max-width: 16em;
}

.page-about .about-chapter__body > p {
  font-size: 16.5px;
  line-height: 1.8;
  color: var(--about-body);
  max-width: 68ch;
  margin: 0 0 18px;
}

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

/* ---------- 角色分工卡 ---------- */
.page-about .about-roles {
  display: grid;
  gap: 14px;
  margin: 28px 0 26px;
}

.page-about .about-role {
  padding: 20px 18px 22px;
  border-radius: var(--radius-m);
  border: 1px solid var(--about-rule);
  border-top: 2px solid var(--aqua);
  background: var(--about-panel);
}

.page-about .about-role:nth-child(2) {
  border-top-color: var(--orange);
}

.page-about .about-role:nth-child(3) {
  border-top-color: var(--violet);
}

.page-about .about-role__figure {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 0;
}

.page-about .about-role__num {
  font-family: var(--font-data);
  font-size: 42px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--text);
}

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

.page-about .about-role h3 {
  margin: 14px 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-role p:not(.about-role__figure) {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--about-body);
}

/* ---------- 旁注 ---------- */
.page-about .about-aside {
  margin: 26px 0;
  padding: 16px 18px;
  border-left: 2px solid var(--violet);
  border-radius: 0 var(--radius-m) var(--radius-m) 0;
  background: rgba(108, 124, 255, 0.07);
}

.page-about .about-aside__label {
  margin: 0 0 6px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--violet);
}

.page-about .about-aside p:last-child {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--about-body);
}

/* ---------- 流程 ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 28px 0 8px;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-flow__step {
  position: relative;
  padding: 18px 0 18px 0;
  border-bottom: 1px solid var(--about-rule);
  outline: none;
}

.page-about .about-flow__step:last-child {
  border-bottom: 0;
}

.page-about .about-flow__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--signal);
  background: var(--ink-900);
  color: var(--signal);
  font-family: var(--font-data);
  font-size: 12px;
  transition: background 0.22s var(--ease), color 0.22s var(--ease);
}

.page-about .about-flow__step:hover .about-flow__num,
.page-about .about-flow__step:focus-within .about-flow__num,
.page-about .about-flow__step:focus .about-flow__num {
  background: var(--signal);
  color: var(--on-signal);
}

.page-about .about-flow__title {
  margin: 10px 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-flow__more {
  max-height: 12em;
  opacity: 1;
  overflow: hidden;
  transition: max-height 0.32s var(--ease), opacity 0.26s var(--ease);
}

.page-about .about-flow__more p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--about-body);
  max-width: 40ch;
}

.page-about .about-flow-figure {
  margin: clamp(26px, 4vw, 40px) 0 0;
  border-radius: var(--radius-l);
  border: 1px solid var(--about-rule);
  background: var(--glass);
}

/* ---------- 更新节奏 ---------- */
.page-about .about-cadence {
  list-style: none;
  margin: 30px 0 8px;
  padding: 0 0 0 26px;
  border-left: 1px solid var(--about-rule);
  display: grid;
  gap: 0;
}

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

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

.page-about .about-cadence__item::before {
  content: "";
  position: absolute;
  left: -31px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--aqua);
}

.page-about .about-cadence__item--signal::before {
  background: var(--signal);
  border-color: var(--signal);
  box-shadow: 0 0 0 4px rgba(185, 242, 74, 0.14);
}

.page-about .about-cadence__name {
  margin: 0 0 5px;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-cadence__item--signal .about-cadence__name {
  color: var(--signal);
}

.page-about .about-cadence__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--about-body);
  max-width: 56ch;
}

.page-about .about-cadence-figure {
  margin: clamp(26px, 4vw, 40px) 0 0;
  border-radius: var(--radius-l);
  border: 1px solid var(--about-rule);
  background: var(--glass);
}

/* ---------- 成长阶段 ---------- */
.page-about .about-stages {
  list-style: none;
  margin: 28px 0 26px;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 14px;
  padding: 18px 0;
  border-bottom: 1px solid rgba(30, 42, 66, 0.7);
}

.page-about .about-stage:last-child {
  border-bottom: 0;
}

.page-about .about-stage__id {
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--aqua);
  padding-top: 4px;
}

.page-about .about-stage h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-stage p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--about-body);
  max-width: 60ch;
}

/* ---------- 三件事 ---------- */
.page-about .about-principles {
  display: grid;
  gap: 14px;
  margin: 26px 0 24px;
}

.page-about .about-principle {
  padding: 22px 20px 24px;
  border-radius: var(--radius-m);
  border: 1px solid var(--about-rule);
  background: var(--about-panel);
}

.page-about .about-principle--light {
  background: var(--paper);
  border-color: transparent;
}

.page-about .about-principle h3 {
  margin: 0 0 9px;
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-principle--light h3 {
  color: var(--ink-900);
}

.page-about .about-principle p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--about-body);
}

.page-about .about-principle--light p {
  color: #3B4763;
}

.page-about .about-chapter--last {
  border-bottom: 1px solid var(--about-rule);
}

/* ---------- 收束 ---------- */
.page-about .about-close {
  padding: clamp(48px, 7vw, 96px) 0 0;
}

.page-about .about-close__inner {
  padding: clamp(28px, 4vw, 48px);
  border-radius: var(--radius-l);
  border: 1px solid var(--about-rule);
  background:
    radial-gradient(120% 140% at 100% 0%, rgba(53, 224, 198, 0.1), transparent 62%),
    linear-gradient(160deg, rgba(16, 27, 46, 0.92), rgba(5, 7, 14, 0.9));
}

.page-about .about-close__kicker {
  margin: 0 0 12px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--aqua);
}

.page-about .about-close h2 {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.015em;
  color: var(--text);
  max-width: 20em;
}

.page-about .about-close p {
  margin: 0 0 24px;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--about-body);
  max-width: 62ch;
}

.page-about .about-close__links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 20px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-principles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-chapter__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 2.05fr);
    gap: clamp(30px, 4.5vw, 68px);
  }

  .page-about .about-chapter__head {
    position: sticky;
    top: calc(var(--header-h) + 30px);
    align-self: start;
  }

  .page-about .about-chapter h2 {
    font-size: clamp(26px, 2.5vw, 38px);
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(250px, 0.84fr);
    gap: clamp(32px, 5vw, 76px);
    align-items: start;
  }
}

@media (min-width: 1000px) and (hover: hover) {
  .page-about .about-flow {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    padding-top: 28px;
    position: relative;
  }

  .page-about .about-flow::before {
    content: "";
    position: absolute;
    top: 14px;
    left: 3%;
    right: 3%;
    height: 1px;
    background: linear-gradient(90deg, var(--signal), var(--aqua) 52%, var(--violet));
    opacity: 0.5;
  }

  .page-about .about-flow__step {
    border-bottom: 0;
    padding: 0 20px 0 0;
  }

  .page-about .about-flow__more {
    max-height: 0;
    opacity: 0;
  }

  .page-about .about-flow__step:hover .about-flow__more,
  .page-about .about-flow__step:focus-within .about-flow__more,
  .page-about .about-flow__step:focus .about-flow__more {
    max-height: 12em;
    opacity: 1;
  }
}

@media (max-width: 479px) {
  .page-about .about-hero h1 {
    font-size: 32px;
  }

  .page-about .about-role__num {
    font-size: 36px;
  }

  .page-about .about-cadence {
    padding-left: 20px;
  }

  .page-about .about-cadence__item::before {
    left: -25px;
  }

  .page-about .about-stage {
    grid-template-columns: 40px 1fr;
    gap: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-chapter::before,
  .page-about .about-flow__more,
  .page-about .about-flow__num,
  .page-about .about-index a {
    transition: none;
  }

  .page-about .about-chapter::before {
    width: 100%;
  }
}