.page-about {
  --about-space: clamp(48px, 8vw, 92px);
  --about-gap: clamp(18px, 2.6vw, 26px);
  background: var(--floodlight-white);
  color: var(--night-ink);
  font-family: var(--font-body);
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--night-ink);
  margin: 0;
}

.page-about p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
}

.page-about .title-lg {
  font-size: clamp(26px, 4.4vw, 38px);
  line-height: 1.2;
}

.page-about .title-sm {
  font-size: clamp(18px, 2.4vw, 21px);
  line-height: 1.36;
}

.page-about .about-crumb {
  padding-block: 16px;
}

/* ---------- 报头 ---------- */
.page-about .about-masthead {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--night-ink);
  color: var(--floodlight-white);
  padding: clamp(38px, 6.5vw, 76px) 0 clamp(30px, 4.5vw, 52px);
  border-bottom: 2px solid var(--pitch-green);
}

.page-about .about-masthead::before {
  content: "";
  position: absolute;
  inset: -25% -8% auto;
  height: 150%;
  z-index: -1;
  background:
    radial-gradient(58% 52% at 50% 0%, rgba(31, 107, 74, 0.62), transparent 72%),
    repeating-linear-gradient(90deg, rgba(174, 184, 178, 0.07) 0 1px, transparent 1px 96px);
  pointer-events: none;
}

.page-about .about-masthead__frame {
  max-width: 880px;
  margin-inline: auto;
  padding-inline: var(--gutter);
  text-align: center;
}

.page-about .about-masthead__kicker {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--whistle-yellow);
  margin-bottom: 16px;
}

.page-about .about-masthead__title {
  font-size: clamp(34px, 7vw, 66px);
  line-height: 1.06;
  color: var(--floodlight-white);
  margin-bottom: 20px;
}

.page-about .about-masthead__title span {
  display: block;
}

.page-about .about-masthead__title em {
  font-style: normal;
  color: var(--whistle-yellow);
}

.page-about .about-masthead__lede {
  max-width: 620px;
  margin-inline: auto;
  font-size: clamp(15px, 2.1vw, 18px);
  line-height: 1.8;
  color: rgba(247, 250, 247, 0.82);
}

.page-about .about-masthead__index {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 26px;
  margin: 30px 0 0;
  padding: 20px 0 0;
  border-top: 1px solid rgba(174, 184, 178, 0.28);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
}

.page-about .about-masthead__index a {
  color: var(--floodlight-white);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-masthead__index a:hover,
.page-about .about-masthead__index a:focus-visible {
  color: var(--electric-teal);
  border-bottom-color: var(--electric-teal);
}

/* ---------- 主图 ---------- */
.page-about .about-hero {
  margin: 0;
  background: var(--night-ink);
}

.page-about .about-hero img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 540px;
  object-fit: cover;
  object-position: center;
  max-width: 100%;
}

.page-about .about-hero__cap {
  max-width: var(--maxw);
  margin-inline: auto;
  padding: 12px var(--gutter) 0;
  font-size: 13px;
  color: var(--slate-blue);
  text-align: center;
}

/* ---------- 数据条 ---------- */
.page-about .about-stats {
  background: var(--pitch-green);
  color: var(--floodlight-white);
  padding: clamp(28px, 4.6vw, 44px) 0;
}

.page-about .about-stats__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 16px;
}

.page-about .about-stats__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(28px, 4.2vw, 40px);
  line-height: 1;
  color: var(--floodlight-white);
  letter-spacing: -0.02em;
}

.page-about .about-stats__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  color: rgba(247, 250, 247, 0.78);
  letter-spacing: 0.02em;
}

/* ---------- 筛选条 ---------- */
.page-about .about-filter-band {
  background: var(--archive-paper);
  border-bottom: 1px solid var(--line-gray);
}

.page-about .about-filter {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  padding-block: 16px;
}

.page-about .about-filter .filter-bar__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--slate-blue);
}

.page-about .about-filter__group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-filter .filter-btn {
  font-family: var(--font-body);
  font-size: 13px;
  line-height: 1.2;
  padding: 7px 15px;
  border: 1px solid var(--line-gray);
  border-radius: 999px;
  background: transparent;
  color: var(--night-ink);
  cursor: pointer;
  transition: background-color 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.page-about .about-filter .filter-btn:hover {
  border-color: var(--pitch-green);
  background: rgba(0, 194, 168, 0.14);
}

.page-about .about-filter .filter-btn[aria-pressed="true"] {
  background: var(--whistle-yellow);
  border-color: var(--whistle-yellow);
  box-shadow: inset 0 -2px 0 var(--signal-orange);
}

.page-about .about-filter .filter-btn:focus-visible {
  outline: 2px solid var(--electric-teal);
  outline-offset: 2px;
}

.page-about .about-filter .filter-bar__status {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--slate-blue);
  margin-left: auto;
}

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

/* ---------- 通用章节头 ---------- */
.page-about .about-sec-head__no {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--pitch-green);
  margin: 0 0 12px;
}

.page-about .about-sec-head__no::after {
  content: "";
  width: 36px;
  height: 2px;
  background: var(--whistle-yellow);
}

.page-about .about-sec-head__sub,
.page-about .about-league__sub,
.page-about .about-principles__head .about-sec-head__sub {
  margin-top: 14px;
  max-width: 56ch;
  color: var(--slate-blue);
}

/* ---------- 三张工作台 ---------- */
.page-about .about-methods {
  background: var(--archive-paper);
  padding: var(--about-space) 0;
}

.page-about .about-sec-head--split {
  display: grid;
  gap: var(--about-gap);
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .about-sec-head__figure {
  margin: 0;
  border: 1px solid var(--line-gray);
  background: var(--mist-gray);
  padding: 8px;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sticker);
  transform: rotate(-1.2deg);
}

.page-about .about-sec-head__figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: 2px;
}

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

.page-about .workbench__card {
  --shift: 0px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--floodlight-white);
  border: 1px solid var(--line-gray);
  border-radius: var(--radius);
  padding: 22px 20px 20px;
  transform: translateY(var(--shift));
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
}

.page-about .workbench__tag {
  align-self: flex-start;
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.1em;
  padding: 4px 10px;
  background: var(--whistle-yellow);
  color: var(--night-ink);
  border-radius: 2px;
  box-shadow: inset 0 -2px 0 rgba(11, 21, 18, 0.16);
}

.page-about .workbench__card p {
  color: rgba(11, 21, 18, 0.86);
}

.page-about .workbench__card .workbench__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate-blue);
}

.page-about .workbench__link {
  margin-top: auto;
  align-self: flex-start;
  font-size: 14px;
  font-weight: 600;
  color: var(--pitch-green);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid var(--electric-teal);
  transition: color 0.18s ease, background-color 0.18s ease;
}

.page-about .workbench__link:hover,
.page-about .workbench__link:focus-visible {
  color: var(--night-ink);
  background: rgba(244, 197, 66, 0.32);
}

/* ---------- 里程碑 ---------- */
.page-about .about-milestones {
  background: var(--mist-gray);
  padding: var(--about-space) 0;
}

.page-about .about-milestones__head {
  margin-bottom: clamp(26px, 4vw, 42px);
}

.page-about .about-milestones__grid {
  display: grid;
  gap: clamp(28px, 4vw, 46px);
  grid-template-columns: minmax(0, 1fr);
}

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--pitch-green), var(--line-gray));
}

.page-about .tl-node {
  position: relative;
  padding-bottom: clamp(22px, 3.4vw, 34px);
  outline-offset: 6px;
}

.page-about .tl-node:last-child {
  padding-bottom: 0;
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 7px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--archive-paper);
  border: 2px solid var(--pitch-green);
  box-sizing: border-box;
}

.page-about .tl-node--live::before {
  background: var(--signal-orange);
  border-color: var(--signal-orange);
  box-shadow: 0 0 0 4px rgba(255, 107, 44, 0.18);
}

.page-about .tl-node__year {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  padding: 2px 8px;
  margin-bottom: 8px;
  border-radius: 2px;
  color: var(--pitch-green);
  background: rgba(31, 107, 74, 0.1);
}

.page-about .tl-node--live .tl-node__year {
  color: var(--night-ink);
  background: rgba(255, 107, 44, 0.22);
}

.page-about .tl-node__more {
  margin-top: 6px;
  font-size: 14px;
  color: var(--slate-blue);
}

.page-about .about-milestones__figure {
  margin: 0;
  padding: 10px;
  background: var(--archive-paper);
  border: 1px solid var(--line-gray);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sticker);
  transform: rotate(1.1deg);
}

.page-about .about-milestones__figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: 2px;
}

.page-about .about-milestones__figure figcaption {
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--slate-blue);
}

/* ---------- 联赛合作 ---------- */
.page-about .about-league {
  background: var(--night-ink);
  color: var(--floodlight-white);
  padding: var(--about-space) 0;
}

.page-about .about-league h2,
.page-about .about-league h3 {
  color: var(--floodlight-white);
}

.page-about .about-league .about-sec-head__no {
  color: var(--whistle-yellow);
}

.page-about .about-league__head {
  margin-bottom: clamp(20px, 3vw, 32px);
}

.page-about .about-league__sub {
  color: rgba(247, 250, 247, 0.76);
  max-width: 62ch;
}

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

.page-about .league-row {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 6px 14px;
  padding: clamp(18px, 3vw, 26px) 0;
  border-top: 1px solid rgba(174, 184, 178, 0.24);
}

.page-about .league-row:last-child {
  border-bottom: 1px solid rgba(174, 184, 178, 0.24);
}

.page-about .league-row__no {
  grid-row: 1;
  grid-column: 1;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--whistle-yellow);
  letter-spacing: 0.1em;
}

.page-about .league-row__title {
  grid-column: 2;
}

.page-about .league-row__text {
  grid-column: 2;
  font-size: 14px;
  color: rgba(247, 250, 247, 0.78);
}

/* ---------- 原则 ---------- */
.page-about .about-principles {
  background: var(--archive-paper);
  padding: var(--about-space) 0;
}

.page-about .about-principles__head {
  margin-bottom: clamp(24px, 3.6vw, 40px);
}

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

.page-about .principle {
  background: var(--floodlight-white);
  border: 1px solid var(--line-gray);
  border-left: 3px solid var(--pitch-green);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 20px 18px;
  transition: border-left-color 0.2s ease, box-shadow 0.2s ease;
}

.page-about .principle:hover {
  border-left-color: var(--signal-orange);
  box-shadow: var(--shadow-sticker);
}

.page-about .principle__no {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--slate-blue);
  margin-bottom: 8px;
}

.page-about .principle p {
  margin-top: 8px;
  font-size: 14px;
  color: rgba(11, 21, 18, 0.84);
}

/* ---------- 下一步 ---------- */
.page-about .about-next {
  background: var(--pitch-green);
  color: var(--floodlight-white);
  padding: var(--about-space) 0;
}

.page-about .about-next__inner {
  max-width: 760px;
}

.page-about .about-next__kicker {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--whistle-yellow);
  margin-bottom: 12px;
}

.page-about .about-next h2 {
  color: var(--floodlight-white);
}

.page-about .about-next__lede {
  margin-top: 14px;
  font-size: 15px;
  color: rgba(247, 250, 247, 0.84);
  max-width: 58ch;
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 26px;
}

/* ---------- 媒体查询 ---------- */
@media (hover: hover) and (min-width: 861px) {
  .page-about .tl-node__more {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.28s ease, opacity 0.28s ease, margin-top 0.28s ease;
    margin-top: 0;
  }

  .page-about .tl-node:hover .tl-node__more,
  .page-about .tl-node:focus-within .tl-node__more {
    max-height: 7em;
    opacity: 1;
    margin-top: 6px;
  }
}

@media (min-width: 641px) {
  .page-about .about-stats__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 861px) {
  .page-about .about-sec-head--split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: end;
  }

  .page-about .about-milestones__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .league-row {
    grid-template-columns: 56px minmax(0, 0.9fr) minmax(0, 1.6fr);
    align-items: baseline;
    gap: 6px 22px;
  }

  .page-about .league-row__title {
    grid-column: 2;
  }

  .page-about .league-row__text {
    grid-column: 3;
  }
}

@media (min-width: 981px) {
  .page-about .workbench {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    padding-bottom: 54px;
  }

  .page-about .workbench__card:nth-child(2) {
    --shift: 26px;
  }

  .page-about .workbench__card:nth-child(3) {
    --shift: 52px;
  }

  .page-about .workbench__card:hover {
    transform: translateY(calc(var(--shift) - 3px));
    border-color: var(--pitch-green);
    box-shadow: var(--shadow-sticker);
  }
}

@media (max-width: 420px) {
  .page-about .about-masthead__index {
    gap: 8px 18px;
    font-size: 10px;
  }

  .page-about .about-filter .filter-bar__status {
    margin-left: 0;
    width: 100%;
  }

  .page-about .about-next__actions .btn {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .workbench__card,
  .page-about .tl-node__more,
  .page-about .about-filter .filter-btn,
  .page-about .principle {
    transition: none !important;
  }
}