.page-about {
  --about-mint-soft: rgba(23, 242, 196, 0.12);
  --about-orange-soft: rgba(255, 139, 61, 0.16);
  --about-hair: rgba(43, 58, 92, 0.62);
  display: block;
}

/* ---------- 首屏 ---------- */

.about-hero {
  padding: clamp(22px, 4vw, 44px) 0 clamp(42px, 7vw, 84px);
  background:
    radial-gradient(120% 96% at 6% 0%, rgba(27, 60, 122, 0.62), transparent 62%),
    linear-gradient(180deg, rgba(15, 27, 56, 0.92), rgba(7, 14, 34, 0) 82%);
  border-bottom: 1px solid var(--about-hair);
}

.about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 48px);
  margin-top: clamp(28px, 5vw, 56px);
}

.about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(2.2rem, 8vw, 5rem);
  line-height: 1.04;
  letter-spacing: 0.01em;
  color: var(--ob-fog);
}

.about-hero__text {
  margin: clamp(16px, 2vw, 24px) 0 0;
  max-width: 40em;
  font-size: clamp(1rem, 1.5vw, 1.08rem);
  line-height: 1.85;
  color: var(--ob-silver);
}

.about-hero__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
  align-content: end;
}

.about-fact {
  padding-left: 16px;
  border-left: 2px solid var(--ob-line);
}

.about-fact:nth-child(2) {
  border-left-color: var(--ob-orange);
}

.about-fact:nth-child(3) {
  border-left-color: var(--ob-mint-dim);
}

.about-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.35rem, 3vw, 1.75rem);
  letter-spacing: 0.04em;
  color: var(--ob-fog);
}

.about-fact__label {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  letter-spacing: 0.1em;
  line-height: 1.7;
  color: var(--ob-silver);
}

/* ---------- 章节骨架 ---------- */

.about-chapter {
  padding: clamp(46px, 7vw, 100px) 0;
  border-top: 1px solid var(--about-hair);
}

.about-hero + .about-chapter {
  border-top: 0;
}

.about-chapter__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 3vw, 32px);
}

.about-chapter__rail .section-no {
  display: block;
  line-height: 0.86;
}

.about-chapter__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(1.65rem, 4.4vw, 3.05rem);
  line-height: 1.16;
  letter-spacing: 0.01em;
  color: var(--ob-fog);
}

.about-chapter__body .prose {
  margin-top: clamp(16px, 2vw, 24px);
}

.about-chapter__body .prose p {
  color: var(--ob-silver);
  line-height: 1.85;
}

/* ---------- 图注与图片 ---------- */

.about-team-figure,
.about-timeline-figure {
  margin: clamp(24px, 4vw, 40px) 0 0;
}

.about-team-figure .figure__media img,
.about-timeline-figure .figure__media img,
.about-collab__figure .figure__media img {
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 团队卡片 ---------- */

.about-roles {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: clamp(20px, 3vw, 32px);
}

.about-role {
  border: 1px solid var(--ob-line);
  border-radius: var(--ob-radius);
  background: linear-gradient(168deg, rgba(15, 27, 56, 0.96), rgba(7, 14, 34, 0.92));
  box-shadow: var(--ob-shadow);
  overflow: hidden;
  transition: border-color 0.22s var(--ob-ease);
}

.about-role[open] {
  border-color: var(--ob-mint-dim);
}

.about-role__summary {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 18px;
  cursor: pointer;
  list-style: none;
}

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

.about-role__summary::after {
  content: "展开职责";
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ob-mint);
}

.about-role[open] .about-role__summary::after {
  content: "收起职责";
}

.about-role__name {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 1.2rem;
  letter-spacing: 0.02em;
  color: var(--ob-fog);
}

.about-role__body {
  padding: 0 18px 20px;
  border-top: 1px solid var(--about-hair);
}

.about-role__body p {
  margin: 16px 0 0;
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--ob-silver);
}

/* ---------- 时间线 ---------- */

.about-timeline {
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0;
}

.about-timeline__item {
  position: relative;
  padding: 0 0 clamp(24px, 4vw, 40px) clamp(24px, 4vw, 38px);
  border-left: 1px solid var(--ob-line);
}

.about-timeline__item:last-child {
  border-left-color: transparent;
  padding-bottom: 0;
}

.about-timeline__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 6px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ob-orange);
  box-shadow: 0 0 0 4px var(--about-orange-soft);
}

.about-timeline__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ob-amber);
}

.about-timeline__meta span + span {
  color: var(--ob-silver);
}

.about-timeline__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.1rem, 2.4vw, 1.45rem);
  line-height: 1.35;
  color: var(--ob-fog);
}

.about-timeline__text {
  margin: 10px 0 0;
  max-width: 42em;
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--ob-silver);
}

/* ---------- 五道环节 ---------- */

.about-flow {
  display: block;
  width: 100%;
  max-width: 640px;
  height: auto;
  margin: clamp(24px, 4vw, 36px) 0 0;
}

.about-steps {
  list-style: none;
  margin: clamp(18px, 3vw, 28px) 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.about-step {
  border: 1px solid var(--ob-line);
  border-left: 3px solid var(--ob-mint-dim);
  border-radius: var(--ob-radius-sm);
  background: rgba(15, 27, 56, 0.72);
  transition: border-color 0.22s var(--ob-ease);
}

.about-step[open] {
  border-left-color: var(--ob-mint);
}

.about-step__summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

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

.about-step__no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ob-amber);
}

.about-step__name {
  font-size: 1rem;
  font-weight: 500;
  color: var(--ob-fog);
}

.about-step__toggle {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ob-silver);
}

.about-step__toggle::after {
  content: "展开";
}

.about-step[open] .about-step__toggle {
  color: var(--ob-mint);
}

.about-step[open] .about-step__toggle::after {
  content: "收起";
}

.about-step__body {
  padding: 0 16px 16px;
}

.about-step__body p {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.85;
  color: var(--ob-silver);
}

/* ---------- 协作 ---------- */

.about-collab {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(20px, 3vw, 36px);
  margin-top: clamp(24px, 4vw, 40px);
}

.about-collab__figure {
  margin: 0;
}

.about-collab__text p {
  color: var(--ob-silver);
  line-height: 1.85;
}

.about-collab__text p + p {
  margin-top: 16px;
}

/* ---------- 会员等级 ---------- */

.about-tiers {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: clamp(24px, 4vw, 36px);
}

.about-tier {
  position: relative;
  padding: clamp(20px, 3vw, 28px);
  border: 1px solid var(--ob-line);
  border-radius: var(--ob-radius-lg);
  background: linear-gradient(160deg, rgba(15, 27, 56, 0.95) 0%, rgba(7, 14, 34, 0.92) 72%);
  box-shadow: var(--ob-shadow);
  overflow: hidden;
}

.about-tier::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 4px;
  background: var(--ob-line);
}

.about-tier--v1::before {
  background: var(--ob-mint-dim);
}

.about-tier--v2::before {
  background: var(--ob-orange);
}

.about-tier--v3::before {
  background: var(--ob-mint);
}

.about-tier__code {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5vw, 2.8rem);
  letter-spacing: 0.06em;
  color: var(--ob-fog);
}

.about-tier__name {
  margin: 6px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 1.05rem;
  letter-spacing: 0.06em;
  color: var(--ob-amber);
}

.about-tier__list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.about-tier__list li {
  position: relative;
  padding-left: 18px;
  font-size: 0.93rem;
  line-height: 1.75;
  color: var(--ob-silver);
}

.about-tier__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 7px;
  height: 7px;
  border: 1px solid var(--ob-line);
  transform: rotate(45deg);
}

.about-tier--v3 .about-tier__list li::before {
  border-color: var(--ob-mint-dim);
}

/* ---------- 末尾指引 ---------- */

.about-cta {
  padding: clamp(46px, 7vw, 92px) 0;
  border-top: 1px solid var(--about-hair);
}

.about-cta__panel {
  padding: clamp(22px, 4vw, 48px);
  border: 1px solid var(--ob-line);
  border-radius: var(--ob-radius-lg);
  background:
    radial-gradient(110% 130% at 0% 0%, rgba(27, 60, 122, 0.6), transparent 60%),
    rgba(15, 27, 56, 0.88);
  box-shadow: var(--ob-shadow-lift);
}

.about-cta__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3vw, 40px);
}

.about-cta__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(1.5rem, 3.6vw, 2.4rem);
  line-height: 1.2;
  color: var(--ob-fog);
}

.about-cta__text {
  margin: 14px 0 0;
  max-width: 34em;
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--ob-silver);
}

.about-cta__links {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.about-cta__link {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px;
  border: 1px solid var(--ob-line);
  border-radius: var(--ob-radius);
  background: rgba(7, 14, 34, 0.62);
  text-decoration: none;
  transition: border-color 0.22s var(--ob-ease), transform 0.22s var(--ob-ease);
}

.about-cta__link:hover,
.about-cta__link:focus-visible {
  border-color: var(--ob-mint);
  transform: translateY(-2px);
}

.about-cta__link-title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 1.05rem;
  letter-spacing: 0.04em;
  color: var(--ob-fog);
}

.about-cta__link-text {
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--ob-silver);
}

.about-cta__link-go {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ob-mint);
}

/* ---------- 响应式 ---------- */

@media (min-width: 620px) {
  .about-cta__links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }

  .about-role:nth-child(2) {
    transform: translateY(16px);
  }

  .about-role:nth-child(3) {
    transform: translateY(32px);
  }

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

@media (min-width: 900px) {
  .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    align-items: end;
  }

  .about-chapter__grid {
    grid-template-columns: minmax(76px, 112px) minmax(0, 1fr);
    column-gap: clamp(24px, 4vw, 60px);
  }

  .about-chapter__rail {
    position: sticky;
    top: 108px;
    align-self: start;
  }

  .about-collab {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    align-items: start;
  }

  .about-cta__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
    align-items: center;
  }
}

@media (min-width: 1080px) {
  .about-chapter__rail {
    top: 120px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .about-cta__link,
  .about-role,
  .about-step {
    transition: none;
  }

  .about-cta__link:hover,
  .about-cta__link:focus-visible {
    transform: none;
  }

  .about-role:nth-child(2),
  .about-role:nth-child(3) {
    transform: none;
  }
}
<<<END>>>