.page-about {
  --about-rail: clamp(28px, 5vw, 44px);
}

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

.page-about section[id],
.page-about .tl-item {
  scroll-margin-top: 132px;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: clamp(18px, 3vw, 34px) 0 clamp(44px, 7vw, 96px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(28px, 5vw, 52px);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-size: var(--step-4);
  line-height: 1.05;
  font-weight: 900;
  letter-spacing: -0.025em;
  color: var(--white);
  max-width: 18ch;
}

.page-about .about-hero__lead {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  max-width: 58ch;
  font-size: var(--step-1);
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-hero__actions {
  margin-top: clamp(22px, 3vw, 32px);
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero__panel {
  border: 1px solid var(--line);
  padding: clamp(16px, 2.6vw, 22px);
  display: flex;
  flex-direction: column;
  gap: clamp(14px, 2vw, 18px);
  background:
    radial-gradient(140% 100% at 0% 0%, rgba(79, 240, 200, 0.1), transparent 62%),
    var(--panel);
}

.page-about .about-hero__panel-label {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-num);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .about-hero__panel-label::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--cyan);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .stat {
  background: var(--panel);
  padding: clamp(12px, 2.2vw, 18px);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .stat__num {
  font-family: var(--font-num);
  font-size: clamp(24px, 4.6vw, 38px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--amber);
}

.page-about .stat__label {
  font-size: var(--step--1);
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* ---------- 通用章节微调 ---------- */

.page-about .section-head {
  margin-bottom: clamp(24px, 4vw, 40px);
}

/* ---------- 01 起点 ---------- */

.page-about .origin-grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
}

.page-about .origin-points {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .origin-points li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .origin-points__k {
  font-family: var(--font-num);
  font-size: var(--step--1);
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .origin-points__v {
  font-size: var(--step-0);
  color: var(--text);
  line-height: 1.7;
}

/* ---------- 02 时间线 ---------- */

.page-about .timeline-visual {
  margin: 0 0 clamp(30px, 5vw, 52px);
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 clamp(26px, 4vw, 42px) var(--about-rail);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 24px;
  bottom: 0;
  width: 1px;
  background: var(--line);
}

.page-about .tl-item:last-child::before {
  display: none;
}

.page-about .tl-item::after {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 15px;
  height: 15px;
  background: var(--ink);
  border: 1px solid var(--cyan);
  transform: rotate(45deg);
  transition: background-color 0.18s ease, border-color 0.18s ease;
}

.page-about .tl-item:hover::after,
.page-about .tl-item:focus-within::after {
  background: var(--amber);
  border-color: var(--amber);
}

.page-about .tl-node {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.page-about .tl-node__coord {
  font-family: var(--font-num);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  color: var(--amber);
}

.page-about .tl-node__title {
  font-size: var(--step-2);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.28;
  color: var(--white);
  transition: color 0.18s ease;
}

.page-about .tl-node:hover .tl-node__title,
.page-about .tl-node:focus-visible .tl-node__title {
  color: var(--cyan);
}

.page-about .tl-note {
  margin: 10px 0 0;
  max-width: 62ch;
  font-size: var(--step-0);
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 03 团队 ---------- */

.page-about .team-visual {
  margin: 0 0 clamp(26px, 4vw, 42px);
}

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

.page-about .team-card {
  background: var(--panel);
  padding: clamp(18px, 2.6vw, 26px);
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: background-color 0.18s ease;
}

.page-about .team-card:hover {
  background: var(--panel-2);
}

.page-about .team-card__idx {
  margin: 0;
  font-family: var(--font-num);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .team-card__title {
  margin: 0;
  font-size: var(--step-2);
  font-weight: 800;
  color: var(--white);
}

.page-about .team-card__body {
  margin: 0;
  font-size: var(--step-0);
  line-height: 1.82;
  color: var(--muted);
}

/* ---------- 04 工序 ---------- */

.page-about .workflow-grid {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
}

.page-about .steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .step {
  background: var(--panel);
  padding: clamp(16px, 2.4vw, 22px);
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  grid-template-areas:
    "num title"
    "num body"
    "num extra";
  column-gap: clamp(14px, 2vw, 22px);
  row-gap: 8px;
  transition: background-color 0.18s ease, box-shadow 0.18s ease;
}

.page-about .step__num {
  grid-area: num;
  font-family: var(--font-num);
  font-size: var(--step-1);
  font-weight: 700;
  color: var(--amber);
  line-height: 1.4;
}

.page-about .step__title {
  grid-area: title;
  margin: 0;
  font-size: var(--step-1);
  font-weight: 800;
  color: var(--white);
}

.page-about .step__body {
  grid-area: body;
  margin: 0;
  font-size: var(--step-0);
  line-height: 1.78;
  color: var(--text);
}

.page-about .step__extra {
  grid-area: extra;
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.7;
  color: var(--muted);
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, opacity 0.3s ease, margin-top 0.3s ease;
}

.page-about .step:hover,
.page-about .step:focus-within {
  background: var(--panel-2);
  box-shadow: inset 2px 0 0 var(--cyan);
}

.page-about .step:hover .step__extra,
.page-about .step:focus-within .step__extra {
  max-height: 220px;
  opacity: 1;
  margin-top: 4px;
}

.page-about .workflow-visual {
  margin: 0;
}

/* ---------- 05 合作 ---------- */

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

.page-about .partner-card {
  background: var(--panel);
  padding: clamp(18px, 2.6vw, 26px);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.page-about .partner-card__type {
  margin: 0;
  font-family: var(--font-num);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .partner-card__title {
  margin: 0;
  font-size: var(--step-2);
  font-weight: 800;
  color: var(--white);
}

.page-about .partner-card__body {
  margin: 0;
  font-size: var(--step-0);
  line-height: 1.82;
  color: var(--muted);
}

.page-about .partner-cta {
  margin: clamp(20px, 3vw, 30px) 0 0;
  max-width: 72ch;
  font-size: var(--step-0);
  line-height: 1.85;
  color: var(--text);
}

.page-about .partner-cta a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan);
}

/* ---------- 06 原则 ---------- */

.page-about .principle-grid {
  display: grid;
  gap: clamp(22px, 3vw, 34px);
}

.page-about .principle {
  border-top: 2px solid var(--cyan);
  padding-top: clamp(14px, 2vw, 20px);
}

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

.page-about .principle:nth-child(3) {
  border-top-color: var(--line-strong);
}

.page-about .principle__num {
  font-family: var(--font-num);
  font-size: var(--step-1);
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .principle h3 {
  margin: 10px 0 0;
  font-size: var(--step-2);
  font-weight: 800;
  color: var(--white);
}

.page-about .principle p {
  margin: 10px 0 0;
  font-size: var(--step-0);
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 归档尾 ---------- */

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

.page-about .next-card {
  background: var(--panel);
  padding: clamp(18px, 2.6vw, 26px);
  display: flex;
  flex-direction: column;
  gap: 10px;
  text-decoration: none;
  transition: background-color 0.18s ease;
}

.page-about .next-card:hover,
.page-about .next-card:focus-visible {
  background: var(--hover);
}

.page-about .next-card__k {
  font-family: var(--font-num);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .next-card__t {
  font-size: var(--step-1);
  font-weight: 600;
  line-height: 1.55;
  color: var(--text);
}

/* ---------- 响应式 ---------- */

@media (hover: none) {
  .page-about .step__extra {
    max-height: none;
    opacity: 1;
    margin-top: 4px;
  }
}

@media (min-width: 640px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 780px) {
  .page-about .partner-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 860px) {
  .page-about .principle-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }

  .page-about .origin-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
    gap: clamp(32px, 5vw, 60px);
  }
}

@media (min-width: 1000px) {
  .page-about .workflow-grid {
    grid-template-columns: minmax(0, 1.28fr) minmax(0, 0.72fr);
    align-items: start;
    gap: clamp(32px, 4vw, 56px);
  }
}

@media (min-width: 1080px) {
  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .tl-node__title {
    font-size: var(--step-3);
  }
}