/* ===== 我们是谁 · 页面专属样式 ===== */
.page-about {
  --about-rail: 15rem;
  --about-ink-soft: rgba(233, 242, 250, 0.74);
  display: block;
  overflow-x: clip;
  background: var(--yb-void);
  color: var(--yb-body-text);
  font-family: var(--yb-font-body);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(1.5rem, 4vw, 2.75rem) 0 clamp(2.25rem, 5vw, 3.5rem);
  border-bottom: 1px solid var(--yb-line);
  background:
    radial-gradient(120% 95% at 88% 0%, rgba(18, 33, 58, 0.95) 0%, rgba(5, 9, 15, 0) 62%),
    linear-gradient(180deg, rgba(11, 20, 32, 0.92) 0%, rgba(5, 9, 15, 0) 100%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(to right, var(--yb-line-soft) 1px, transparent 1px);
  background-size: 96px 100%;
  opacity: 0.5;
  pointer-events: none;
}

.page-about .about-hero > .yb-wrap {
  position: relative;
  z-index: 1;
}

.page-about .yb-crumbs {
  margin-bottom: clamp(1.25rem, 3vw, 2rem);
}

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

.page-about .about-hero__lede .yb-h1 {
  margin: 0 0 1.1rem;
  max-width: 16em;
  color: var(--yb-ink);
}

.page-about .about-hero__lede .yb-lede {
  max-width: 36em;
  color: var(--about-ink-soft);
}

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

.page-about .about-metric {
  min-width: 0;
  padding: 1rem 0.95rem 1.15rem;
  background: var(--yb-void);
}

.page-about .about-metric--wide {
  grid-column: 1 / -1;
}

.page-about .about-metric__figure {
  display: flex;
  align-items: baseline;
  gap: 0.3rem;
}

.page-about .about-metric__num {
  font-size: clamp(2rem, 5.4vw, 3.15rem);
  font-weight: 700;
  line-height: 0.95;
  color: var(--yb-signal);
}

.page-about .about-metric__unit {
  font-size: 0.85rem;
  letter-spacing: 0.1em;
  color: var(--yb-muted);
}

.page-about .about-metric__label {
  margin: 0.6rem 0 0;
  max-width: 24em;
  font-size: 0.8rem;
  line-height: 1.6;
  color: var(--yb-muted);
}

/* ---------- 画布与轨道 ---------- */
.page-about .about-canvas {
  padding: clamp(2.5rem, 6vw, 4.5rem) 0 clamp(3rem, 7vw, 5.5rem);
}

.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 3rem);
}

.page-about .about-track {
  min-width: 0;
}

.page-about .about-track__title {
  margin: 0 0 0.75rem;
  font-family: var(--yb-font-serif);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--yb-muted);
}

.page-about .about-track__list {
  display: flex;
  gap: 0.5rem;
  margin: 0;
  padding: 0 0 0.5rem;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-track__list > li {
  flex: 0 0 auto;
}

.page-about .about-track__node {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  min-height: var(--yb-tap);
  padding: 0 0.85rem;
  border: 1px solid var(--yb-line);
  background: var(--yb-panel);
  color: var(--yb-muted);
  font-size: 0.85rem;
  text-decoration: none;
  white-space: nowrap;
  transition: color 160ms ease, border-color 160ms ease, background-color 160ms ease;
}

.page-about .about-track__dot {
  flex: 0 0 auto;
  width: 7px;
  height: 7px;
  background: var(--yb-muted);
  transition: background-color 160ms ease;
}

.page-about .about-track__num {
  font-size: 0.72rem;
  color: var(--yb-signal-dim);
}

.page-about .about-track__node:hover {
  color: var(--yb-ink);
  border-color: var(--yb-signal-a35);
}

.page-about .about-track__node[aria-current="true"] {
  color: var(--yb-ink);
  border-color: var(--yb-signal-a35);
  background: var(--yb-elevated);
}

.page-about .about-track__node[aria-current="true"] .about-track__dot {
  background: var(--yb-signal);
}

/* ---------- 叙事流 ---------- */
.page-about .about-flow {
  display: grid;
  min-width: 0;
  gap: clamp(3rem, 7vw, 5.5rem);
}

.page-about .about-chapter {
  min-width: 0;
  scroll-margin-top: 7rem;
}

.page-about .about-chapter__head {
  margin-bottom: clamp(1.25rem, 3vw, 2rem);
  padding-top: 1.25rem;
  border-top: 1px solid var(--yb-line-strong);
}

.page-about .about-chapter__head .yb-eyebrow {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0 0 0.7rem;
  color: var(--yb-muted);
}

.page-about .about-chapter__head .yb-eyebrow .yb-num {
  color: var(--yb-signal);
  font-size: 0.78rem;
}

.page-about .about-chapter__head .yb-h2 {
  margin: 0;
  color: var(--yb-ink);
  max-width: 20em;
}

.page-about .about-chapter__intro {
  margin: 0 0 1.75rem;
  max-width: 34em;
  font-size: 0.98rem;
  line-height: 1.75;
  color: var(--about-ink-soft);
}

.page-about .about-chapter__body {
  display: grid;
  max-width: 40em;
  gap: 1rem;
}

.page-about .about-chapter__body p {
  margin: 0;
  font-size: 1rem;
  line-height: 1.75;
}

.page-about .about-chapter__link {
  margin-top: 0.5rem;
}

.page-about .about-banner {
  margin: 0 0 1.75rem;
}

/* ---------- 分工条 ---------- */
.page-about .about-roles {
  margin-top: 2rem;
}

.page-about .about-roles__bar {
  display: flex;
  gap: 2px;
  height: 14px;
  background: var(--yb-line-soft);
}

.page-about .about-roles__seg {
  display: block;
  height: 100%;
}

.page-about .about-roles__seg--field {
  flex: 18 1 0;
  background: var(--yb-signal);
}

.page-about .about-roles__seg--desk {
  flex: 14 1 0;
  background: var(--yb-signal-dim);
}

.page-about .about-roles__seg--build {
  flex: 14 1 0;
  background: var(--yb-elevated);
  border: 1px solid var(--yb-line);
}

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

.page-about .about-roles__key {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding: 0.9rem 1rem;
  background: var(--yb-panel);
}

.page-about .about-roles__key-num {
  flex: 0 0 auto;
  min-width: 2.2rem;
  font-size: 1.35rem;
  font-weight: 600;
}

.page-about .about-roles__key--field .about-roles__key-num {
  color: var(--yb-signal);
}

.page-about .about-roles__key--desk .about-roles__key-num {
  color: var(--yb-signal-dim);
}

.page-about .about-roles__key--build .about-roles__key-num {
  color: var(--yb-ink);
}

.page-about .about-roles__key-text {
  font-size: 0.85rem;
  line-height: 1.65;
  color: var(--yb-muted);
}

@media (prefers-reduced-motion: no-preference) {
  .page-about .about-roles__seg {
    transform: scaleX(0);
    transform-origin: left center;
    transition: transform 560ms cubic-bezier(0.2, 0.7, 0.2, 1);
  }

  .page-about .about-roles.is-in .about-roles__seg {
    transform: scaleX(1);
  }

  .page-about .about-roles.is-in .about-roles__seg--desk {
    transition-delay: 80ms;
  }

  .page-about .about-roles.is-in .about-roles__seg--build {
    transition-delay: 160ms;
  }
}

/* ---------- 流程四步 ---------- */
.page-about .about-flowline {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
  background: var(--yb-line);
  border: 1px solid var(--yb-line);
}

.page-about .about-flowline__step {
  padding: 1.15rem 1.1rem 1.35rem;
  background: var(--yb-panel);
}

.page-about .about-flowline__num {
  display: block;
  margin-bottom: 0.6rem;
  font-size: 0.78rem;
  color: var(--yb-signal);
}

.page-about .about-flowline__step .yb-h3 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  color: var(--yb-ink);
}

.page-about .about-flowline__step p {
  margin: 0;
  font-size: 0.87rem;
  line-height: 1.7;
  color: var(--yb-muted);
}

/* ---------- 反馈 ---------- */
.page-about .about-feedback-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 4vw, 2.75rem);
  align-items: start;
}

.page-about .about-donut-wrap {
  display: grid;
  justify-items: center;
  gap: 1.1rem;
}

.page-about .about-donut {
  position: relative;
  display: grid;
  place-items: center;
  width: min(210px, 60vw);
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  background: conic-gradient(var(--yb-signal) 0deg 187deg, var(--yb-elevated) 187deg 360deg);
}

.page-about .about-donut::after {
  content: "";
  position: absolute;
  inset: 22%;
  border-radius: 50%;
  background: var(--yb-void);
  border: 1px solid var(--yb-line);
}

.page-about .about-donut__center {
  position: relative;
  z-index: 1;
  display: grid;
  justify-items: center;
  gap: 0.25rem;
  text-align: center;
}

.page-about .about-donut__value {
  font-family: var(--yb-font-display);
  font-size: clamp(1.5rem, 4.4vw, 1.9rem);
  font-weight: 700;
  color: var(--yb-signal);
  letter-spacing: -0.01em;
}

.page-about .about-donut__unit {
  font-family: var(--yb-font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--yb-muted);
}

.page-about .about-donut__cap {
  margin: 0;
  max-width: 26em;
  font-size: 0.88rem;
  line-height: 1.75;
  color: var(--yb-muted);
  text-align: center;
}

.page-about .about-donut__cap .yb-num {
  color: var(--yb-signal);
  font-weight: 600;
}

.page-about .about-fb {
  border-top: 1px solid var(--yb-line);
}

.page-about .about-fb:last-child {
  border-bottom: 1px solid var(--yb-line);
}

.page-about .about-fb__sum {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 56px;
  padding: 0.75rem 0.2rem;
  cursor: pointer;
  list-style: none;
  font-size: 0.96rem;
  color: var(--yb-ink);
}

.page-about .about-fb__sum::-webkit-details-marker {
  display: none;
}

.page-about .about-fb__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--yb-font-mono);
  font-size: 1.05rem;
  color: var(--yb-signal);
}

.page-about .about-fb[open] .about-fb__sum::after {
  content: "–";
}

.page-about .about-fb__sum:hover {
  color: var(--yb-signal);
}

.page-about .about-fb__idx {
  flex: 0 0 auto;
  padding: 0.15rem 0.4rem;
  border: 1px solid var(--yb-line);
  font-size: 0.72rem;
  color: var(--yb-signal-dim);
}

.page-about .about-fb__body {
  padding: 0 0.2rem 1.35rem;
}

.page-about .about-fb__body p {
  margin: 0;
  max-width: 44em;
  font-size: 0.9rem;
  line-height: 1.78;
  color: var(--yb-muted);
}

/* ---------- 版图 ---------- */
.page-about .about-coverage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 4vw, 2.5rem);
}

.page-about .about-coverage__text p {
  margin: 0 0 1rem;
  max-width: 36em;
  font-size: 0.98rem;
  line-height: 1.78;
}

.page-about .about-coverage__facts {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
  background: var(--yb-line);
  border: 1px solid var(--yb-line);
}

.page-about .about-coverage__facts li {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding: 0.85rem 1rem;
  background: var(--yb-panel);
  font-size: 0.86rem;
  line-height: 1.6;
  color: var(--yb-muted);
}

.page-about .about-coverage__facts .yb-num {
  flex: 0 0 auto;
  min-width: 2rem;
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--yb-signal);
}

.page-about .about-coverage__media {
  margin: 0;
}

/* ---------- 版本刻度 ---------- */
.page-about .about-scale {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.5rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-scale__item {
  position: relative;
  padding: 0;
}

.page-about .about-scale__tick {
  display: block;
  width: 9px;
  height: 9px;
  margin-bottom: 0.85rem;
  background: var(--yb-signal-dim);
  transition: background-color 160ms ease;
}

.page-about .about-scale__ver {
  display: block;
  font-size: clamp(1.3rem, 2.6vw, 1.7rem);
  font-weight: 600;
  line-height: 1.1;
  color: var(--yb-signal);
}

.page-about .about-scale__season {
  display: block;
  margin-top: 0.35rem;
  font-family: var(--yb-font-serif);
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  color: var(--yb-muted);
}

.page-about .about-scale__note {
  margin: 0.75rem 0 0;
  max-width: 26em;
  font-size: 0.85rem;
  line-height: 1.72;
  color: var(--yb-body-text);
  transition: color 160ms ease;
}

@media (hover: hover) {
  .page-about .about-scale__item:hover .about-scale__tick {
    background: var(--yb-signal);
  }

  .page-about .about-scale__item:hover .about-scale__note {
    color: var(--yb-ink);
  }
}

.page-about .about-scale-figure {
  margin: 2.5rem 0 0;
}

/* ---------- 做法 ---------- */
.page-about .about-principles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--yb-line);
}

.page-about .about-principles__item {
  display: grid;
  grid-template-columns: 2.6rem minmax(0, 1fr);
  gap: 0.75rem;
  padding: 1.35rem 0;
  border-bottom: 1px solid var(--yb-line);
}

.page-about .about-principles__idx {
  padding-top: 0.3rem;
  font-size: 0.76rem;
  color: var(--yb-signal-dim);
}

.page-about .about-principles__item .yb-h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
  color: var(--yb-ink);
}

.page-about .about-principles__item p {
  margin: 0;
  max-width: 44em;
  font-size: 0.92rem;
  line-height: 1.78;
  color: var(--yb-muted);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  margin-top: clamp(3rem, 7vw, 5rem);
  padding: clamp(2.5rem, 6vw, 4rem) 0 clamp(3rem, 7vw, 5rem);
  border-top: 1px solid var(--yb-line-strong);
  background: linear-gradient(180deg, var(--yb-panel) 0%, var(--yb-void) 100%);
}

.page-about .about-cta__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.75rem;
}

.page-about .about-cta__text .yb-h2 {
  margin: 0 0 0.85rem;
  color: var(--yb-ink);
}

.page-about .about-cta__text .yb-lede {
  max-width: 40em;
  color: var(--about-ink-soft);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-flowline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .page-about .about-principles__item {
    grid-template-columns: 5rem minmax(0, 1fr);
    gap: 1.5rem;
  }

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

@media (min-width: 820px) {
  .page-about .about-feedback-grid {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 3rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
    gap: clamp(2rem, 4vw, 3.5rem);
  }

  .page-about .about-coverage {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: center;
  }

  .page-about .about-scale {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
  }

  .page-about .about-scale__item {
    padding: 1.5rem 1.4rem 0 0;
    border-top: 1px solid var(--yb-line-strong);
  }

  .page-about .about-scale__item .about-scale__tick {
    position: absolute;
    top: -5px;
    left: 0;
    margin: 0;
  }

  .page-about .about-scale__note {
    margin-top: 0.85rem;
  }
}

@media (min-width: 1040px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2.5rem, 5vw, 4.5rem);
    align-items: start;
  }

  .page-about .about-track {
    position: sticky;
    top: 7rem;
  }

  .page-about .about-track__list {
    flex-direction: column;
    gap: 0;
    padding: 0;
    overflow: visible;
    border-left: 1px solid var(--yb-line);
  }

  .page-about .about-track__list > li {
    flex: 1 1 auto;
  }

  .page-about .about-track__node {
    width: 100%;
    margin-left: -1px;
    padding: 0.65rem 0.5rem 0.65rem 0.9rem;
    border: 0;
    border-left: 2px solid transparent;
    background: transparent;
    white-space: normal;
  }

  .page-about .about-track__node:hover {
    background: rgba(47, 243, 192, 0.06);
  }

  .page-about .about-track__node[aria-current="true"] {
    border-left-color: var(--yb-signal);
    background: linear-gradient(90deg, var(--yb-signal-a12), rgba(47, 243, 192, 0) 88%);
  }
}