.page-about {
  --about-card-bg: var(--steel);
  --about-card-bg-deep: var(--carbon);
  --about-radius: var(--radius-md);
}

/* ===== 首屏信息板 ===== */
.page-about .about-intro {
  padding-top: 8px;
  padding-bottom: 8px;
}

.page-about .about-intro__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

.page-about .about-intro__main .eyebrow {
  color: var(--cyan);
  letter-spacing: .18em;
  margin-bottom: 14px;
}

.page-about .about-intro__main .display-title {
  margin: 0 0 20px;
  max-width: 16ch;
}

.page-about .about-intro__main .lede {
  max-width: 56ch;
  color: var(--text-soft);
}

.page-about .about-intro__main .btn-row {
  margin-top: 28px;
}

.page-about .about-panel {
  position: relative;
  background: var(--about-card-bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 24px 22px;
  overflow: hidden;
}

.page-about .about-panel::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 4px;
  background: var(--lime);
}

.page-about .about-panel__head {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--lime);
  margin: 0 0 20px;
}

.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 14px;
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.page-about .about-stats__num {
  font-size: 30px;
  line-height: 1.1;
  color: var(--mist);
  letter-spacing: -0.02em;
}

.page-about .about-stats__item:nth-child(2) .about-stats__num {
  color: var(--lime);
}

.page-about .about-stats__item:nth-child(3) .about-stats__num {
  color: var(--amber);
}

.page-about .about-stats__item:nth-child(4) .about-stats__num {
  color: var(--cyan);
}

.page-about .about-stats__label {
  font-size: 13px;
  color: var(--text-mute);
}

.page-about .about-panel__foot {
  margin: 22px 0 0;
  padding-top: 16px;
  border-top: 1px dashed var(--line);
}

/* ===== 团队分工 ===== */
.page-about .about-roles .section-head {
  margin-bottom: 36px;
}

.page-about .roles-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

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

.page-about .role-card {
  background: var(--about-card-bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  transition: border-color 160ms var(--ease), transform 160ms var(--ease);
}

.page-about .role-card:hover,
.page-about .role-card[open] {
  border-color: var(--lime);
}

.page-about .role-card[open] {
  background: var(--about-card-bg);
}

.page-about .role-card__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 4px 14px;
  padding: 20px 20px 18px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .role-card__head::after {
  content: "＋";
  grid-column: 3;
  grid-row: 1;
  font-size: 18px;
  line-height: 1;
  color: var(--text-mute);
  transition: color 160ms var(--ease), transform 160ms var(--ease);
}

.page-about .role-card[open] .role-card__head::after {
  content: "－";
  color: var(--lime);
}

.page-about .role-card__num {
  font-size: 13px;
  color: var(--lime);
  letter-spacing: .08em;
}

.page-about .role-card__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 20px;
  letter-spacing: -0.01em;
  color: var(--mist);
}

.page-about .role-card__brief {
  grid-column: 2 / 4;
  font-size: 13px;
  color: var(--text-mute);
}

.page-about .role-card__body {
  padding: 0 20px 22px;
  border-top: 1px solid var(--line);
  margin-top: 2px;
  padding-top: 16px;
}

.page-about .role-card__body p {
  margin: 0 0 12px;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1.7;
}

.page-about .role-card__body ul {
  margin: 0;
  padding-left: 18px;
  color: var(--text-mute);
  font-size: 14px;
  line-height: 1.75;
}

.page-about .role-card__body li + li {
  margin-top: 6px;
}

.page-about .roles-figure {
  align-self: start;
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.page-about .roles-figure .media-frame__img {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

/* ===== 四步方法（横向色带） ===== */
.page-about .about-method .method-band {
  position: relative;
  overflow: hidden;
  background: var(--about-card-bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 32px 22px 34px;
}

.page-about .method-band::before {
  content: "";
  position: absolute;
  top: -70px;
  right: -80px;
  width: 220px;
  height: 220px;
  background: var(--lime);
  opacity: .1;
  border-radius: 40px;
  transform: rotate(20deg);
  pointer-events: none;
}

.page-about .method-band__head {
  position: relative;
  margin-bottom: 30px;
}

.page-about .method-band__head .section-title {
  max-width: 22ch;
}

.page-about .method-band__head .section-desc {
  color: var(--text-mute);
  margin-top: 10px;
}

.page-about .method-steps {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .method-step {
  padding: 20px 0 22px;
  border-top: 1px solid var(--line);
}

.page-about .method-step__num {
  display: inline-block;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--ink);
  background: var(--lime);
  border-radius: var(--pill);
  padding: 3px 10px;
  margin-bottom: 12px;
}

.page-about .method-step__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 20px;
  color: var(--mist);
}

.page-about .method-step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--text-soft);
}

/* ===== 版本维护 ===== */
.page-about .about-versions .section-head {
  margin-bottom: 32px;
}

.page-about .versions-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

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

.page-about .version-card {
  background: var(--about-card-bg);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  padding: 22px 20px;
  transition: border-color 160ms var(--ease), transform 160ms var(--ease);
}

.page-about .version-card:hover {
  border-color: var(--amber);
  transform: translateY(-2px);
}

.page-about .version-card__code {
  display: inline-block;
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--ink);
  background: var(--amber);
  border-radius: var(--radius-sm);
  padding: 3px 9px;
  margin: 0 0 14px;
}

.page-about .version-card__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 21px;
  color: var(--mist);
}

.page-about .version-card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--text-soft);
}

.page-about .versions-figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: 0;
}

.page-about .versions-figure .media-frame__img {
  width: 100%;
  height: auto;
  display: block;
}

.page-about .cadence {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .cadence__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .cadence__key {
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--amber);
}

.page-about .cadence__val {
  font-size: 15px;
  line-height: 1.7;
  color: var(--text-soft);
}

/* ===== 质量校验 ===== */
.page-about .about-quality .section-head {
  margin-bottom: 26px;
}

.page-about .quality-flow {
  display: block;
  width: 100%;
  height: auto;
  max-width: 760px;
  margin: 0 0 28px;
}

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

.page-about .quality-item {
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  background: var(--about-card-bg-deep);
}

.page-about .quality-item__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  color: var(--mist);
}

.page-about .quality-item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--text-mute);
}

.page-about .quality-copy {
  margin-top: 26px;
  padding: 20px 20px 22px;
  border-left: 3px solid var(--coral);
  background: var(--about-card-bg);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.page-about .quality-copy__text {
  margin: 0 0 14px;
  font-size: 15px;
  color: var(--text-soft);
}

.page-about .quality-id {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 10px;
}

.page-about .quality-id .mono {
  font-size: 14px;
  letter-spacing: .08em;
  color: var(--mist);
  background: var(--ink-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
}

/* ===== 发展阶段时间线 ===== */
.page-about .about-stages .section-head {
  margin-bottom: 34px;
}

.page-about .stages-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  border-left: 2px solid var(--line);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .stage {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 18px 18px 20px;
  background: var(--about-card-bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  transition: border-color 160ms var(--ease), background 160ms var(--ease);
}

.page-about .stage::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 24px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--cyan);
  transition: background 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .stage:hover {
  border-color: var(--cyan);
  background: var(--about-card-bg);
}

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

.page-about .stage__num {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--cyan);
}

.page-about .stage__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 19px;
  color: var(--mist);
}

.page-about .stage__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--text-soft);
}

/* ===== 会员支持场景 ===== */
.page-about .about-support .section-head {
  margin-bottom: 32px;
}

.page-about .support-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .support-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .support-card {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: 14px;
  padding: 18px 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  background: var(--about-card-bg-deep);
  transition: border-color 160ms var(--ease);
}

.page-about .support-card:hover {
  border-color: var(--lime);
}

.page-about .support-card__num {
  grid-row: 1 / 3;
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  font-size: 13px;
  color: var(--ink);
  background: var(--lime);
  border-radius: var(--radius-sm);
  transition: transform 160ms var(--ease);
}

.page-about .support-card:hover .support-card__num {
  transform: translateY(-2px);
}

.page-about .support-card h3 {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 18px;
  color: var(--mist);
  align-self: center;
}

.page-about .support-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-mute);
}

.page-about .support-figure {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.page-about .support-figure .media-frame__img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

/* ===== 协作与联系 ===== */
.page-about .about-collab .section-head {
  margin-bottom: 30px;
}

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

.page-about .collab-col {
  padding: 22px 20px 24px;
  border-radius: var(--about-radius);
  background: var(--about-card-bg);
  border: 1px solid var(--line);
  border-top: 3px solid var(--violet);
}

.page-about .collab-col:nth-child(2) {
  border-top-color: var(--amber);
}

.page-about .collab-col:nth-child(3) {
  border-top-color: var(--cyan);
}

.page-about .collab-col__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 19px;
  color: var(--mist);
}

.page-about .collab-col p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--text-soft);
}

.page-about .contact-strip {
  margin-top: 30px;
  padding: 26px 22px 28px;
  border-radius: var(--radius-lg);
  background: var(--about-card-bg-deep);
  border: 1px solid var(--line);
}

.page-about .contact-strip__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  margin: 0 0 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.page-about .contact-strip__key {
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--text-mute);
}

.page-about .contact-strip__val {
  font-size: 15px;
  color: var(--mist);
  line-height: 1.6;
  overflow-wrap: anywhere;
}

.page-about .contact-strip__note {
  margin: 16px 0 20px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-mute);
}

.page-about .contact-strip .btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ===== 响应式 ===== */
@media (min-width: 640px) {
  .page-about .quality-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

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

  .page-about .cadence__item {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
    gap: 18px;
  }

  .page-about .contact-strip__item {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }
}

@media (min-width: 900px) {
  .page-about .about-intro__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, .7fr);
    gap: 56px;
    padding-right: 2%;
  }

  .page-about .about-intro__main .display-title {
    font-size: clamp(40px, 4.6vw, 60px);
  }

  .page-about .roles-layout {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 40px;
    align-items: start;
  }

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

  .page-about .roles-figure {
    position: sticky;
    top: 130px;
  }

  .page-about .method-band {
    padding: 42px 40px 44px;
  }

  .page-about .method-steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 26px;
  }

  .page-about .method-step {
    border-top: 1px solid var(--line);
    padding-right: 8px;
  }

  .page-about .versions-layout {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
    gap: 32px;
    align-items: start;
  }

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

  .page-about .support-layout {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 34px;
    align-items: start;
  }

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

  .page-about .support-card:first-child {
    grid-column: 1 / -1;
  }

  .page-about .collab-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .stages-timeline {
    padding-left: 34px;
  }

  .page-about .stage {
    grid-template-columns: 64px minmax(0, 1fr);
    column-gap: 20px;
    align-items: start;
    padding: 22px 24px 24px;
  }

  .page-about .stage::before {
    left: -43px;
  }
}

@media (min-width: 1100px) {
  .page-about .quality-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .quality-item {
    padding: 22px 20px;
  }

  .page-about .quality-copy {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto auto;
    align-items: center;
    gap: 18px;
  }

  .page-about .quality-copy__text {
    margin: 0;
  }

  .page-about .quality-id {
    margin: 0;
  }
}