.page-about {
  --about-axis: 118px;
  --about-accent: var(--silver);
}

.page-about .about-crumb {
  padding-top: clamp(1.1rem, 3vw, 1.9rem);
}

/* ---- 首屏 ---- */
.page-about .about-hero {
  padding: clamp(1.6rem, 4vw, 3rem) 0 clamp(2.2rem, 5vw, 3.6rem);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-hero .display-title {
  margin: 0.5rem 0 1.6rem;
  max-width: 18em;
}

.page-about .about-hero__body {
  align-items: start;
  gap: clamp(1.6rem, 4vw, 3rem);
}

.page-about .about-hero__note {
  border: 2px solid var(--line);
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  padding: 18px 20px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--silver);
}

.page-about .about-hero__note-tag {
  color: var(--summer);
  margin: 0 0 0.55rem;
  letter-spacing: 0.1em;
}

.page-about .about-hero__note p {
  margin: 0;
}

.page-about .about-facts {
  list-style: none;
  margin: 2.2rem 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.page-about .about-facts__i {
  border: 2px solid var(--line);
  border-top: 5px solid var(--about-fact-c, var(--silver));
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  padding: 16px 16px 14px;
}

.page-about .about-facts__i--spring { --about-fact-c: var(--spring); }
.page-about .about-facts__i--summer { --about-fact-c: var(--summer); }
.page-about .about-facts__i--autumn { --about-fact-c: var(--autumn); }
.page-about .about-facts__i--winter { --about-fact-c: var(--winter); }

.page-about .about-facts__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4.4vw, 38px);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--silver);
  font-variant-numeric: tabular-nums;
}

.page-about .about-facts__label {
  display: block;
  margin-top: 9px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--rock);
}

/* ---- 纵向时间轴 ---- */
.page-about .about-axis {
  padding: clamp(1.2rem, 3vw, 2.2rem) 0 clamp(2.4rem, 6vw, 4.5rem);
}

.page-about .tl-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.1rem;
  padding: clamp(2rem, 5.5vw, 3.6rem) 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .tl-item:first-child {
  border-top: 0;
  padding-top: clamp(1.4rem, 3vw, 2.4rem);
}

.page-about .tl-rail {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--rock);
}

.page-about .tl-rail--spring { --tl-dot: var(--spring); }
.page-about .tl-rail--summer { --tl-dot: var(--summer); }
.page-about .tl-rail--autumn { --tl-dot: var(--autumn); }
.page-about .tl-rail--winter { --tl-dot: var(--winter); }

.page-about .tl-rail__num {
  color: var(--silver);
  font-size: 15px;
  font-variant-numeric: tabular-nums;
}

.page-about .tl-rail__dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--tl-dot, var(--silver));
  flex: none;
}

.page-about .tl-rail__tag {
  text-transform: uppercase;
}

.page-about .sec-title {
  font-family: var(--font-display);
  font-size: clamp(23px, 3.4vw, 35px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--silver);
  margin: 0 0 1.1rem;
}

.page-about .tl-body p {
  max-width: 38em;
  margin: 0 0 1rem;
}

.page-about .tl-note {
  max-width: 38em;
  margin-top: 0.4rem;
  padding-left: 16px;
  border-left: 4px solid var(--summer);
  color: var(--rock);
  font-size: 15px;
}

/* ---- 四季折叠面板 ---- */
.page-about .acc-group {
  margin: 1.6rem 0 1.9rem;
}

.page-about .acc {
  border: 2px solid var(--line);
  border-left-width: 7px;
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  margin-bottom: 12px;
}

.page-about .acc--spring { border-left-color: var(--spring); }
.page-about .acc--summer { border-left-color: var(--summer); }
.page-about .acc--autumn { border-left-color: var(--autumn); }
.page-about .acc--winter { border-left-color: var(--winter); }

.page-about .acc__sum {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--silver);
}

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

.page-about .acc__sum::after {
  content: "+";
  margin-left: auto;
  font-size: 19px;
  line-height: 1;
  color: var(--rock);
}

.page-about .acc[open] > .acc__sum::after {
  content: "–";
}

.page-about .acc__sum:hover {
  background: rgba(220, 232, 242, 0.05);
}

.page-about .acc[open] > .acc__sum {
  border-bottom: 1px solid var(--line);
}

.page-about .acc__sum:focus-visible {
  outline: 2px solid var(--summer);
  outline-offset: -2px;
}

.page-about .acc__body {
  padding: 16px 18px 18px;
}

.page-about .acc__body p {
  margin: 0;
  max-width: 40em;
  font-size: 15.5px;
  line-height: 1.75;
}

/* ---- 图片 ---- */
.page-about .about-figure {
  margin: 1.9rem 0 0;
  max-width: 100%;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
}

.page-about .img-frame--tall.about-figure {
  max-width: 520px;
}

/* ---- 团队分工 ---- */
.page-about .team-grid {
  list-style: none;
  margin: 1.7rem 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .team-card {
  border: 2px solid var(--line);
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  padding: 18px 18px 20px;
}

.page-about .team-card__num {
  display: block;
  font-size: clamp(30px, 5vw, 46px);
  line-height: 1;
  color: var(--summer);
  font-variant-numeric: tabular-nums;
}

.page-about .team-card__title {
  margin: 0.7rem 0 0.5rem;
  font-size: 17px;
  color: var(--silver);
  letter-spacing: 0.01em;
}

.page-about .team-card__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--rock);
}

.page-about .quote-block {
  margin: 1.9rem 0 0;
  border: 2px solid var(--silver);
  border-left-width: 9px;
  border-left-color: var(--spring);
  background: var(--ink-3);
  box-shadow: var(--shadow);
  padding: 20px 22px;
}

.page-about .quote-block p {
  margin: 0;
  max-width: 36em;
  font-size: clamp(16px, 2.1vw, 19px);
  line-height: 1.7;
  color: var(--silver);
}

/* ---- 数据工序 ---- */
.page-about .step-list {
  margin: 1.7rem 0 1.2rem;
}

.page-about .step {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.5rem;
  padding: 22px 0;
  border-top: 1px solid var(--line-soft);
}

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

.page-about .step--spring { --about-accent: var(--spring); }
.page-about .step--summer { --about-accent: var(--summer); }
.page-about .step--autumn { --about-accent: var(--autumn); }

.page-about .step__num {
  font-size: clamp(28px, 4.4vw, 44px);
  line-height: 1;
  color: var(--about-accent, var(--silver));
  font-variant-numeric: tabular-nums;
}

.page-about .step__title {
  margin: 0 0 0.45rem;
  font-size: 18px;
  color: var(--silver);
}

.page-about .step__text p {
  margin: 0;
  max-width: 40em;
  font-size: 15.5px;
  line-height: 1.75;
}

/* ---- 覆盖范围 ---- */
.page-about .cov-belt {
  list-style: none;
  margin: 1.5rem 0 1rem;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .cov-belt__item {
  flex: 1 1 108px;
  border: 2px solid var(--line);
  border-bottom: 6px solid var(--cov-c, var(--silver));
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  padding: 13px 14px;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.06em;
  color: var(--silver);
}

.page-about .cov-belt__item--spring { --cov-c: var(--spring); }
.page-about .cov-belt__item--summer { --cov-c: var(--summer); }
.page-about .cov-belt__item--autumn { --cov-c: var(--autumn); }
.page-about .cov-belt__item--moss { --cov-c: var(--moss); }
.page-about .cov-belt__item--clay { --cov-c: var(--clay); }

.page-about .cov-note {
  max-width: 40em;
  font-size: 15px;
  color: var(--rock);
  line-height: 1.75;
}

/* ---- 合作 ---- */
.page-about .coop-split {
  display: grid;
  gap: 18px;
  grid-template-columns: minmax(0, 1fr);
  margin: 1.6rem 0 1.8rem;
}

.page-about .coop-col {
  border: 2px solid var(--line);
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  padding: 18px 18px 20px;
}

.page-about .coop-col .eyebrow {
  display: block;
  margin-bottom: 0.9rem;
  color: var(--rock);
}

.page-about .coop-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.6rem;
}

.page-about .coop-list li {
  position: relative;
  padding-left: 18px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--silver);
}

.page-about .coop-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 8px;
  height: 2px;
  background: var(--rock);
}

.page-about .coop-list--accent li::before {
  background: var(--spring);
}

.page-about .coop-hint {
  max-width: 38em;
  font-size: 15px;
  color: var(--rock);
}

.page-about .check-list {
  list-style: none;
  margin: 1.2rem 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .check-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 13px;
  align-items: start;
  border: 2px solid var(--line);
  background: var(--ink-2);
  box-shadow: var(--shadow-sm);
  padding: 14px 16px;
}

.page-about .check-item input {
  appearance: none;
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  margin: 2px 0 0;
  border: 2px solid var(--rock);
  background: transparent;
  cursor: pointer;
  position: relative;
  flex: none;
}

.page-about .check-item input:checked {
  background: var(--spring);
  border-color: var(--spring);
}

.page-about .check-item input:checked::after {
  content: "✓";
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .check-item input:focus-visible {
  outline: 2px solid var(--summer);
  outline-offset: 2px;
}

.page-about .check-item__label {
  cursor: pointer;
  display: block;
}

.page-about .check-item__title {
  display: block;
  font-size: 16px;
  color: var(--silver);
  margin-bottom: 0.35rem;
}

.page-about .check-item__text {
  display: block;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--rock);
}

/* ---- 尾部行动区 ---- */
.page-about .about-cta {
  margin-top: clamp(1.6rem, 4vw, 3rem);
  padding: clamp(2.4rem, 6vw, 4.4rem) 0 clamp(3rem, 7vw, 5rem);
  border-top: 1px solid var(--line-soft);
  background: linear-gradient(180deg, rgba(255, 122, 41, 0.10), transparent 62%);
}

.page-about .about-cta__box {
  display: grid;
  gap: 1.6rem;
  grid-template-columns: minmax(0, 1fr);
  border: 2px solid var(--line);
  background: var(--ink-2);
  box-shadow: var(--shadow);
  padding: clamp(20px, 4vw, 34px);
}

.page-about .about-cta__text p {
  max-width: 36em;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--rock);
}

.page-about .about-cta__text .sec-title {
  margin: 0.35rem 0 0.8rem;
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}

/* ---- 响应式 ---- */
@media (min-width: 680px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-cta__box {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
  }

  .page-about .step {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 0 clamp(1.6rem, 4vw, 3rem);
    align-items: start;
  }
}

@media (min-width: 980px) {
  .page-about .tl-item {
    grid-template-columns: var(--about-axis) minmax(0, 1fr);
    gap: clamp(1.8rem, 5vw, 4rem);
  }

  .page-about .tl-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.95rem;
    position: sticky;
    top: 108px;
  }

  .page-about .tl-rail::after {
    content: "";
    display: block;
    width: 1px;
    height: 76px;
    background: linear-gradient(var(--line), transparent);
  }

  .page-about .tl-rail__dot {
    order: -1;
  }
}

@media (prefers-reduced-motion: no-preference) {
  .page-about .tl-item {
    transition: opacity 220ms var(--ease), transform 220ms var(--ease);
  }

  .page-about .acc__sum::after {
    transition: color 120ms var(--ease);
  }
}