.page-about {
  --about-mark-w: 152px;
  --about-line: 2px solid var(--gold-line);
  --about-paper-dim: rgba(27, 26, 23, 0.72);
  --about-paper-rule: rgba(27, 26, 23, 0.18);
  --about-paper-link: #8a5312;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(20px, 3.4vw, 44px) clamp(20px, 3vw, 36px);
}

.page-about .about-hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 2.4vw, 32px);
}

.page-about .about-hero__rail {
  display: none;
}

.page-about .about-hero h1 {
  margin: 10px 0 0;
  font-size: clamp(30px, 5.4vw, 62px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  font-weight: 900;
  color: var(--text-hi);
}

.page-about .about-hero__lede {
  max-width: 34em;
  margin: 18px 0 0;
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.9;
  color: var(--silver);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 12px;
  border-top: var(--about-line);
}

.page-about .about-stat__num {
  font-size: clamp(26px, 3.4vw, 40px);
  line-height: 1;
  font-weight: 600;
  color: var(--gold);
}

.page-about .about-stat__txt {
  font-size: 13px;
  line-height: 1.6;
  color: var(--silver-dim);
  letter-spacing: 0.02em;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: clamp(20px, 3vw, 36px) 0 0;
  border: var(--about-line);
  background: var(--panel);
  overflow: hidden;
}

.page-about .about-figure--spaced {
  margin-top: clamp(24px, 3.4vw, 40px);
}

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

/* ---------- 章节通用 ---------- */
.page-about .about-chapter {
  padding-block: clamp(36px, 5.6vw, 76px);
}

.page-about .about-chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

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

.page-about .about-mark__year {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--gold);
}

.page-about .about-mark__dot {
  width: 10px;
  height: 10px;
  flex: 0 0 auto;
  background: var(--cyan);
}

.page-about .about-mark__idx {
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--silver-dim);
}

.page-about .about-chapter h2 {
  margin: 0 0 14px;
  font-size: clamp(22px, 3vw, 34px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  font-weight: 800;
  color: var(--text-hi);
}

.page-about .about-chapter p {
  max-width: 34em;
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.9;
  color: var(--silver);
}

/* ---------- 四代版本 ---------- */
.page-about .filter-bar {
  margin: 22px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-versions {
  margin-top: 20px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--bento-gap);
}

.page-about .about-version {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px 16px 20px;
  border: var(--about-line);
  background: var(--panel);
  transition: border-color 220ms var(--ease), transform 220ms var(--ease),
    box-shadow 220ms var(--ease);
}

.page-about .about-version:hover {
  border-color: var(--cyan);
  transform: translateY(-3px);
}

.page-about .about-version--current {
  border-color: var(--gold);
  background: var(--panel-2);
  box-shadow: var(--shadow-gold);
}

.page-about .about-version--current:hover {
  border-color: var(--gold);
}

.page-about .about-version__idx {
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--gold);
}

.page-about .about-version__name {
  margin: 0;
  font-size: 19px;
  line-height: 1.3;
  font-weight: 800;
  color: var(--text-hi);
}

.page-about .about-version__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--silver);
}

.page-about [data-filter-item][hidden] {
  display: none;
}

/* ---------- 暖纸区：团队与流程 ---------- */
.page-about .about-paper {
  background: var(--paper);
  color: var(--paper-ink);
  padding-block: clamp(40px, 6vw, 84px);
  border-top: var(--about-line);
  border-bottom: var(--about-line);
}

.page-about .about-paper h2 {
  margin: 0 0 14px;
  font-size: clamp(22px, 3vw, 34px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  font-weight: 800;
  color: var(--paper-ink);
}

.page-about .about-paper p {
  max-width: 34em;
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.9;
  color: var(--about-paper-dim);
}

.page-about .about-paper .about-mark__year {
  color: var(--about-paper-link);
}

.page-about .about-paper .about-mark__dot {
  background: var(--teal);
}

.page-about .about-paper .about-mark__idx {
  color: rgba(27, 26, 23, 0.55);
}

.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 40px);
  padding-bottom: clamp(30px, 4vw, 52px);
  border-bottom: 1px solid var(--about-paper-rule);
}

.page-about .about-badge {
  margin: 0;
  padding: 14px;
  border: 2px solid var(--paper-ink);
  background: rgba(27, 26, 23, 0.05);
  box-shadow: 6px 6px 0 rgba(27, 26, 23, 0.14);
}

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

.page-about .about-badge figcaption {
  margin-top: 12px;
  font-size: 12px;
  letter-spacing: 0.14em;
  line-height: 1.7;
  color: var(--about-paper-dim);
}

.page-about .about-chapter__grid--flow {
  padding-top: clamp(30px, 4vw, 52px);
}

/* ---------- 流程步骤 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.page-about .about-steps__item {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 4px 12px;
  padding: 16px 10px 16px 4px;
  border-top: 1px solid var(--about-paper-rule);
  transition: background-color 200ms var(--ease);
}

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

.page-about .about-steps__item:hover,
.page-about .about-steps__item:focus-within {
  background-color: rgba(245, 160, 60, 0.2);
}

.page-about .about-steps__num {
  grid-column: 1;
  grid-row: 1;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--about-paper-link);
}

.page-about .about-steps__main {
  grid-column: 2;
  grid-row: 1;
}

.page-about .about-steps__name {
  margin: 0 0 4px;
  font-size: 17px;
  line-height: 1.4;
  font-weight: 800;
  color: var(--paper-ink);
}

.page-about .about-steps__desc {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--about-paper-dim);
}

.page-about .about-steps__time {
  grid-column: 2;
  grid-row: 2;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: rgba(27, 26, 23, 0.5);
  transition: color 200ms var(--ease), transform 200ms var(--ease);
}

.page-about .about-steps__item:hover .about-steps__time,
.page-about .about-steps__item:focus-within .about-steps__time {
  color: var(--about-paper-link);
  transform: translateX(4px);
}

.page-about .about-steps__note {
  margin-top: 20px;
  padding-left: 12px;
  border-left: 3px solid var(--about-paper-link);
  color: var(--about-paper-dim);
}

/* ---------- 合作数据 ---------- */
.page-about .about-partners {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--bento-gap);
}

.page-about .about-partner {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 16px 18px;
  border: var(--about-line);
  border-left: 6px solid var(--gold);
  background: var(--panel);
}

.page-about .about-partner__num {
  font-size: clamp(24px, 2.8vw, 34px);
  line-height: 1;
  font-weight: 600;
  color: var(--cyan);
}

.page-about .about-partner__txt {
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--silver);
}

/* ---------- 下一步 ---------- */
.page-about .about-chapter--next {
  border-top: 1px solid rgba(169, 106, 28, 0.4);
}

.page-about .about-chapter--next h2::after {
  content: "";
  display: block;
  width: 64px;
  height: 3px;
  margin-top: 14px;
  background: var(--cyan);
}

/* ---------- 收束 ---------- */
.page-about .about-cta {
  padding-block: clamp(36px, 5vw, 72px);
  border-top: var(--about-line);
  background: var(--ink-2);
}

.page-about .about-cta__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
  align-items: end;
}

.page-about .about-cta h2 {
  margin: 8px 0 12px;
  font-size: clamp(22px, 3vw, 34px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  font-weight: 900;
  color: var(--text-hi);
}

.page-about .about-cta__text p {
  max-width: 34em;
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--silver);
}

.page-about .about-cta__text .label {
  color: var(--gold);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

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

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

@media (min-width: 720px) {
  .page-about .about-steps__item {
    grid-template-columns: 56px minmax(0, 1fr) auto;
    align-items: baseline;
    gap: 4px 18px;
  }

  .page-about .about-steps__time {
    grid-column: 3;
    grid-row: 1;
    margin-top: 0;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: var(--about-mark-w) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 56px);
  }

  .page-about .about-hero__rail {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    padding-left: 14px;
    border-left: var(--about-line);
  }

  .page-about .about-hero__rail-num {
    font-size: 13px;
    letter-spacing: 0.22em;
    color: var(--silver-dim);
  }

  .page-about .about-hero__rail-num:first-child {
    color: var(--gold);
    font-weight: 600;
  }

  .page-about .about-hero__rail-line {
    width: 2px;
    height: 64px;
    background: var(--gold-line);
  }

  .page-about .about-chapter__grid {
    grid-template-columns: var(--about-mark-w) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 56px);
  }

  .page-about .about-mark {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    align-self: start;
    position: sticky;
    top: 28px;
    padding-left: 14px;
    border-left: var(--about-line);
  }

  .page-about .about-mark__year {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    font-size: 19px;
    letter-spacing: 0.3em;
  }

  .page-about .about-paper .about-mark {
    border-left-color: rgba(27, 26, 23, 0.35);
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.75fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-team__main .about-chapter__grid {
    grid-template-columns: var(--about-mark-w) minmax(0, 1fr);
  }

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

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  }

  .page-about .about-cta__actions {
    justify-content: flex-end;
  }
}

@media (min-width: 1180px) {
  .page-about .about-partners {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-version,
  .page-about .about-steps__item,
  .page-about .about-steps__time {
    transition: none;
  }

  .page-about .about-version:hover {
    transform: none;
  }

  .page-about .about-steps__item:hover .about-steps__time,
  .page-about .about-steps__item:focus-within .about-steps__time {
    transform: none;
  }
}