.page-about {
  --about-rail-x: 2.4rem;
  --about-head-pad: 0rem;
  background: var(--ink-deep);
  color: var(--paper);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  padding-bottom: clamp(2.5rem, 6vw, 4.5rem);
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
}

.page-about .about-hero__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 40%;
  opacity: 0.42;
}

.page-about .about-hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(11, 16, 38, 0.6) 0%, rgba(11, 16, 38, 0.88) 58%, var(--ink-deep) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(92, 225, 230, 0.07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(92, 225, 230, 0.07) 1px, transparent 1px);
  background-size: 96px 96px;
  -webkit-mask-image: radial-gradient(120% 90% at 72% 0%, #000 0%, transparent 76%);
  mask-image: radial-gradient(120% 90% at 72% 0%, #000 0%, transparent 76%);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 2;
  padding-top: clamp(1.25rem, 3.5vw, 2.25rem);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
  margin-top: clamp(1.75rem, 5vw, 3rem);
}

.page-about h1 {
  font-family: var(--font-head);
  font-size: clamp(2.25rem, 7.5vw, 5rem);
  line-height: 1.06;
  letter-spacing: -0.03em;
  margin: 0.45rem 0 0;
  max-width: 11em;
}

.page-about .about-hero__lede {
  margin: clamp(1rem, 2.5vw, 1.5rem) 0 0;
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.85;
  color: var(--silver);
  max-width: 34em;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: clamp(1.5rem, 3vw, 2rem);
}

.page-about .about-note {
  display: grid;
  gap: 0.5rem;
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.page-about .about-note__label {
  font-family: var(--font-mono);
  font-size: var(--fs-1);
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.page-about .about-note__text {
  margin: 0;
  font-size: var(--fs-2);
  line-height: 1.7;
  color: var(--silver);
  max-width: 18em;
}

/* ---------- 区块骨架 ---------- */
.page-about .about-sec {
  position: relative;
  padding-block: clamp(2.5rem, 6vw, 4.5rem);
  border-top: 1px solid var(--line);
}

.page-about .about-sec:first-of-type {
  border-top: 0;
}

.page-about .about-sec__head {
  position: relative;
  display: grid;
  gap: 0.75rem;
  margin-bottom: clamp(1.75rem, 4vw, 3rem);
  max-width: 44rem;
}

.page-about .about-sec__head .coord {
  color: var(--cyan);
}

.page-about .about-sec h2 {
  font-family: var(--font-head);
  font-size: clamp(1.7rem, 4.2vw, 3rem);
  line-height: 1.16;
  letter-spacing: -0.025em;
  margin: 0;
}

.page-about .about-sec__intro {
  margin: 0;
  color: var(--silver);
  font-size: var(--fs-2);
  line-height: 1.8;
}

.page-about .about-copy {
  max-width: 40em;
}

.page-about .about-copy p {
  margin: 0;
  color: var(--silver);
  font-size: var(--fs-2);
  line-height: 1.85;
}

.page-about .about-copy p + p {
  margin-top: 1rem;
}

.page-about .about-copy a {
  color: var(--cyan);
  text-decoration-color: rgba(92, 225, 230, 0.45);
  text-underline-offset: 0.22em;
}

.page-about .about-copy a:hover {
  color: var(--signal);
}

/* ---------- 使命双栏 ---------- */
.page-about .about-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-quote {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.25rem, 2.6vw, 1.75rem);
  line-height: 1.45;
  letter-spacing: -0.02em;
  color: var(--paper);
  border-left: 3px solid var(--signal);
  padding-left: 1rem;
}

/* ---------- 数据坐标卡 ---------- */
.page-about .coord-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
}

.page-about .coord-card {
  display: grid;
  align-content: start;
  gap: 0.3rem;
  padding: clamp(1rem, 2.5vw, 1.5rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--ink-panel);
  transition: border-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.page-about .coord-card:hover,
.page-about .coord-card:focus-within {
  border-color: var(--cyan);
  transform: translateY(-3px);
}

.page-about .coord-card__id {
  font-family: var(--font-mono);
  font-size: var(--fs-1);
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .coord-card__num {
  font-family: var(--font-head);
  font-size: clamp(1.6rem, 4.5vw, 2.5rem);
  line-height: 1.05;
  letter-spacing: -0.04em;
  color: var(--paper);
}

.page-about .coord-card__num em {
  font-style: normal;
  font-size: 0.5em;
  margin-left: 0.14em;
  letter-spacing: 0;
  color: var(--signal);
}

.page-about .coord-card__label {
  font-size: var(--fs-2);
  font-weight: 600;
  color: var(--paper);
}

.page-about .coord-card__note {
  font-size: var(--fs-1);
  line-height: 1.65;
  color: var(--silver);
}

.page-about .about-figure {
  margin: clamp(1.75rem, 4vw, 2.5rem) 0 0;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
}

/* ---------- 三条原则 ---------- */
.page-about .principles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

.page-about .principle {
  position: relative;
  display: grid;
  align-content: start;
  gap: 0.55rem;
  padding: clamp(1.5rem, 3vw, 1.9rem) clamp(1.15rem, 3vw, 1.6rem) clamp(1.15rem, 3vw, 1.6rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: linear-gradient(160deg, var(--ink-panel) 0%, rgba(20, 27, 61, 0.45) 100%);
}

.page-about .principle::before {
  content: "";
  position: absolute;
  left: clamp(1.15rem, 3vw, 1.6rem);
  top: 0;
  width: 3.25rem;
  height: 2px;
  border-radius: 2px;
  background: var(--cyan);
}

.page-about .principle:nth-child(2)::before {
  background: var(--signal);
}

.page-about .principle:nth-child(3)::before {
  background: var(--violet);
}

.page-about .principle__id {
  font-family: var(--font-mono);
  font-size: var(--fs-1);
  letter-spacing: 0.12em;
  color: var(--silver);
}

.page-about .principle__title {
  margin: 0;
  font-family: var(--font-head);
  font-size: var(--fs-3);
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .principle__text {
  margin: 0;
  font-size: var(--fs-2);
  line-height: 1.8;
  color: var(--silver);
}

/* ---------- 双端 ---------- */
.page-about .dual {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

.page-about .dual__card {
  padding: clamp(1.25rem, 3vw, 1.75rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--ink-panel);
}

.page-about .dual__card--pc {
  border-color: rgba(92, 225, 230, 0.34);
  background:
    linear-gradient(150deg, rgba(92, 225, 230, 0.13), rgba(20, 27, 61, 0) 62%),
    var(--ink-panel);
}

.page-about .dual__card h3 {
  margin: 0.8rem 0 0.7rem;
  font-family: var(--font-head);
  font-size: var(--fs-3);
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .dual__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.page-about .dual__list li {
  position: relative;
  padding-left: 1.05rem;
  font-size: var(--fs-2);
  line-height: 1.7;
  color: var(--silver);
}

.page-about .dual__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 0.4rem;
  height: 0.4rem;
  border-radius: 50%;
  background: var(--cyan);
}

.page-about .dual__card--pc .dual__list li::before {
  background: var(--signal);
}

.page-about .checklist {
  margin-top: clamp(1.5rem, 4vw, 2.5rem);
  padding: clamp(1.15rem, 3vw, 1.9rem);
  border: 1px dashed var(--line);
  border-radius: var(--radius-lg);
  background: rgba(5, 7, 18, 0.55);
}

.page-about .checklist__head h3 {
  margin: 0;
  font-family: var(--font-head);
  font-size: var(--fs-3);
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .checklist__head p {
  margin: 0.5rem 0 1.15rem;
  font-size: var(--fs-1);
  line-height: 1.75;
  color: var(--silver);
}

.page-about .checklist__grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.6rem 1rem;
}

.page-about .checklist__item {
  display: flex;
  align-items: baseline;
  gap: 0.55rem;
  padding: 0.5rem 0;
  border-top: 1px solid var(--line);
  font-size: var(--fs-2);
  color: var(--paper);
}

.page-about .checklist__id {
  font-family: var(--font-mono);
  font-size: var(--fs-1);
  letter-spacing: 0.1em;
  color: var(--cyan);
}

/* ---------- 团队 ---------- */
.page-about .team-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .team-list {
  list-style: none;
  margin: 1.25rem 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.55rem;
}

.page-about .team-list li {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.55rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: var(--pill);
  background: var(--ink-panel);
  font-size: var(--fs-1);
  color: var(--paper);
}

.page-about .team-list__id {
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  color: var(--violet);
}

.page-about .team-layout__media {
  margin: 0;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
}

/* ---------- 阶段星轨 ---------- */
.page-about .stage-switch {
  position: relative;
}

.page-about .stage-radio {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.page-about .stage-nodes {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.page-about .stage-node {
  display: inline-flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.62rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--pill);
  background: transparent;
  color: var(--silver);
  font-size: var(--fs-1);
  cursor: pointer;
  user-select: none;
  transition: background 0.25s var(--ease), color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .stage-node:hover {
  border-color: var(--cyan);
  color: var(--paper);
}

.page-about .stage-node__id {
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about #stage-1:checked ~ .stage-nodes label[for="stage-1"],
.page-about #stage-2:checked ~ .stage-nodes label[for="stage-2"],
.page-about #stage-3:checked ~ .stage-nodes label[for="stage-3"],
.page-about #stage-4:checked ~ .stage-nodes label[for="stage-4"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink-black);
}

.page-about #stage-1:checked ~ .stage-nodes label[for="stage-1"] .stage-node__id,
.page-about #stage-2:checked ~ .stage-nodes label[for="stage-2"] .stage-node__id,
.page-about #stage-3:checked ~ .stage-nodes label[for="stage-3"] .stage-node__id,
.page-about #stage-4:checked ~ .stage-nodes label[for="stage-4"] .stage-node__id {
  color: var(--ink-black);
}

.page-about #stage-1:focus-visible ~ .stage-nodes label[for="stage-1"],
.page-about #stage-2:focus-visible ~ .stage-nodes label[for="stage-2"],
.page-about #stage-3:focus-visible ~ .stage-nodes label[for="stage-3"],
.page-about #stage-4:focus-visible ~ .stage-nodes label[for="stage-4"] {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .stage-panels {
  margin-top: clamp(1.15rem, 3vw, 1.75rem);
}

.page-about .stage-panel {
  display: none;
  gap: 0.65rem;
  align-content: start;
  padding: clamp(1.25rem, 3vw, 2rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(135deg, rgba(92, 225, 230, 0.08), rgba(20, 27, 61, 0) 55%),
    var(--ink-panel);
}

.page-about #stage-1:checked ~ .stage-panels .stage-panel--1,
.page-about #stage-2:checked ~ .stage-panels .stage-panel--2,
.page-about #stage-3:checked ~ .stage-panels .stage-panel--3,
.page-about #stage-4:checked ~ .stage-panels .stage-panel--4 {
  display: grid;
}

.page-about .stage-panel .coord {
  color: var(--violet);
}

.page-about .stage-panel h3 {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.25rem, 2.8vw, 1.75rem);
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .stage-panel p {
  margin: 0;
  max-width: 42em;
  font-size: var(--fs-2);
  line-height: 1.85;
  color: var(--silver);
}

/* ---------- 收束 ---------- */
.page-about .about-cta {
  border-top: 1px solid var(--line);
  padding-block: clamp(2.5rem, 6vw, 4.5rem);
  background:
    radial-gradient(120% 140% at 12% 0%, rgba(92, 225, 230, 0.14), transparent 62%),
    var(--ink-deep);
}

.page-about .about-cta__inner {
  display: grid;
  justify-items: start;
  gap: 0.9rem;
}

.page-about .about-cta__inner .eyebrow {
  color: var(--cyan);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.6rem, 4vw, 2.75rem);
  line-height: 1.16;
  letter-spacing: -0.025em;
  color: var(--paper);
}

.page-about .about-cta p {
  margin: 0;
  max-width: 38em;
  font-size: var(--fs-2);
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.6rem;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .coord-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
  }

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

@media (min-width: 860px) {
  .page-about .principles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.25rem;
  }

  .page-about .dual {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.25rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
    gap: clamp(2rem, 5vw, 4rem);
  }

  .page-about .about-note {
    justify-self: end;
    align-self: stretch;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    gap: 0.85rem;
    border-top: 0;
    border-left: 1px solid var(--line);
    padding: 0 0 0 1.25rem;
  }

  .page-about .about-note__text {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    max-height: 16em;
    max-width: none;
  }

  .page-about .about-cols {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    gap: clamp(2rem, 5vw, 4rem);
    align-items: start;
  }

  .page-about .team-layout {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }
}

@media (min-width: 1100px) {
  .page-about .about-sec__head {
    padding-left: 4.25rem;
  }

  .page-about .about-sec__head .coord {
    position: absolute;
    left: 0;
    top: 0.2rem;
    writing-mode: vertical-rl;
    text-orientation: mixed;
    letter-spacing: 0.2em;
  }

  .page-about .about-sec__head::before {
    content: "";
    position: absolute;
    left: var(--about-rail-x);
    top: 0.35rem;
    bottom: 0.35rem;
    width: 1px;
    background: linear-gradient(to bottom, var(--cyan), transparent 88%);
    opacity: 0.7;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .coord-card,
  .page-about .stage-node {
    transition: none;
  }

  .page-about .coord-card:hover,
  .page-about .coord-card:focus-within {
    transform: none;
  }
}