.page-about {
  --about-line: var(--hairline);
  --about-sticky-top: 6rem;
  background: var(--deep-space);
  color: var(--ice-text);
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(6rem, 14vh, 9.5rem) clamp(2.75rem, 7vw, 5rem);
  background:
    radial-gradient(120% 90% at 88% -12%, rgba(37, 201, 255, 0.22), transparent 62%),
    radial-gradient(90% 80% at 4% 0%, rgba(43, 240, 160, 0.16), transparent 64%),
    var(--ink-navy);
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -12%;
  bottom: -50%;
  width: 62%;
  height: 130%;
  background: linear-gradient(
    115deg,
    transparent 44%,
    rgba(43, 240, 160, 0.09) 44%,
    rgba(43, 240, 160, 0.09) 45.4%,
    transparent 45.4%
  );
  pointer-events: none;
}

.page-about .about-hero .container {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: var(--step-13);
  letter-spacing: 0.02em;
  color: var(--mist-text);
}

.page-about .breadcrumb ol > li + li::before {
  content: "/";
  margin-right: 0.55rem;
  color: var(--hairline);
}

.page-about .breadcrumb a {
  color: var(--mist-text);
  text-decoration: none;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--pulse-green);
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--electric-cyan);
  font-family: var(--font-mono);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(2rem, 5vw, 3.5rem);
  margin-top: clamp(2rem, 5vw, 3.5rem);
}

.page-about h1 {
  margin: 0.7rem 0 0;
  font-family: var(--font-heading);
  font-size: var(--step-64);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.005em;
  transform: rotate(-1.4deg);
  transform-origin: left center;
}

.page-about .about-lede {
  margin: 1.25rem 0 0;
  max-width: 56ch;
  font-size: var(--step-17);
  line-height: 1.9;
  color: color-mix(in srgb, var(--ice-text) 82%, var(--mist-text));
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--about-line);
  align-self: end;
}

.page-about .about-facts li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .fact-num {
  font-family: var(--font-mono);
  font-size: var(--step-28);
  font-weight: 700;
  line-height: 1;
  color: var(--pulse-green);
  font-variant-numeric: tabular-nums;
}

.page-about .fact-label {
  max-width: 13ch;
  text-align: right;
  font-size: var(--step-13);
  line-height: 1.55;
  color: var(--mist-text);
}

/* ============ 章节骨架 ============ */
.page-about .about-section {
  position: relative;
  padding-block: clamp(3.25rem, 8vw, 6.5rem);
}

.page-about .about-section + .about-section::before {
  content: "";
  position: absolute;
  inset-inline: 0;
  top: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--about-line) 16%, var(--about-line) 84%, transparent);
}

.page-about .about-section-head {
  max-width: 64ch;
  margin-bottom: clamp(1.75rem, 4vw, 3rem);
}

.page-about .about-section-head h2 {
  margin: 0.5rem 0 0.85rem;
  font-family: var(--font-heading);
  font-size: var(--step-40);
  font-weight: 900;
  line-height: 1.15;
}

.page-about .about-section-lede {
  margin: 0;
  max-width: 60ch;
  font-size: var(--step-17);
  line-height: 1.85;
  color: var(--mist-text);
}

.page-about .about-history-figure,
.page-about .about-flow-figure,
.page-about .about-crew-figure {
  margin: 0 0 clamp(2rem, 5vw, 3.25rem);
}

.page-about .about-crew-figure {
  margin-top: clamp(2rem, 5vw, 3rem);
  margin-bottom: 0;
}

.page-about .about-flow-figure {
  margin-top: clamp(2rem, 5vw, 3rem);
  margin-bottom: 0;
}

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

/* ============ 标签页 ============ */
.page-about .tablist {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding-bottom: 0.5rem;
  scrollbar-width: thin;
  scrollbar-color: var(--hairline) transparent;
}

.page-about .tab {
  flex: 0 0 auto;
  padding: 0.65rem 1.1rem;
  font-family: var(--font-mono);
  font-size: var(--step-13);
  letter-spacing: 0.05em;
  color: var(--mist-text);
  background: transparent;
  border: 1px solid var(--about-line);
  clip-path: var(--clip-btn);
  cursor: pointer;
  transition: background-color 180ms ease, color 180ms ease, border-color 180ms ease;
}

.page-about .tab:hover,
.page-about .tab:focus-visible {
  color: var(--ice-text);
  border-color: var(--pulse-green);
}

.page-about .tab[aria-selected="true"] {
  color: var(--on-green);
  background: var(--pulse-green);
  border-color: var(--pulse-green);
  font-weight: 700;
}

.page-about .tabpanel {
  animation: about-fade 180ms ease both;
}

@keyframes about-fade {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ============ 时间轴 ============ */
.page-about .about-tabs {
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .chronicle {
  list-style: none;
  margin: clamp(1.5rem, 4vw, 2.25rem) 0 0;
  padding: 0;
}

.page-about .chronicle-item {
  position: relative;
  padding-left: 1.75rem;
  padding-bottom: clamp(1.75rem, 4vw, 2.75rem);
}

.page-about .chronicle-item::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 0.65rem;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--pulse-green), var(--electric-cyan));
  opacity: 0.5;
}

.page-about .chronicle-item:last-child::before {
  background: linear-gradient(180deg, var(--electric-cyan), transparent);
}

.page-about .chronicle-item::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0.45rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--pulse-green);
  box-shadow: 0 0 0 4px rgba(43, 240, 160, 0.14);
}

.page-about .chronicle-item:last-child::after {
  background: var(--electric-cyan);
  box-shadow: 0 0 0 4px rgba(37, 201, 255, 0.14);
}

.page-about .chronicle-mark span {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--step-20);
  font-weight: 700;
  line-height: 1.2;
  color: var(--electric-cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .chronicle-body h3 {
  margin: 0.6rem 0 0.5rem;
  font-family: var(--font-heading);
  font-size: var(--step-20);
  font-weight: 800;
  line-height: 1.35;
}

.page-about .chronicle-body > p {
  margin: 0;
  max-width: 62ch;
  font-size: var(--step-17);
  line-height: 1.85;
  color: color-mix(in srgb, var(--ice-text) 78%, var(--mist-text));
}

.page-about .chronicle-note {
  margin-top: 0.9rem;
  border-left: 2px solid var(--amber-rule);
  padding-left: 0.9rem;
}

.page-about .chronicle-note summary {
  cursor: pointer;
  list-style: none;
  font-size: var(--step-13);
  letter-spacing: 0.04em;
  color: var(--amber-rule);
}

.page-about .chronicle-note summary::-webkit-details-marker {
  display: none;
}

.page-about .chronicle-note summary::before {
  content: "+";
  display: inline-block;
  width: 1em;
  font-family: var(--font-mono);
}

.page-about .chronicle-note[open] summary::before {
  content: "–";
}

.page-about .chronicle-note p {
  margin: 0.5rem 0 0;
  max-width: 60ch;
  font-size: var(--step-15);
  line-height: 1.8;
  color: var(--mist-text);
}

/* ============ 数据流程 ============ */
.page-about .about-flow-tabs {
  display: grid;
  gap: 1.25rem;
}

.page-about .about-flow-tabs .tabpanel {
  background: var(--panel-slate);
  border: 1px solid var(--about-line);
  clip-path: var(--clip-panel);
  padding: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-flow-tabs .tabpanel h3 {
  margin: 0 0 0.75rem;
  font-family: var(--font-heading);
  font-size: var(--step-28);
  font-weight: 800;
  line-height: 1.25;
}

.page-about .about-flow-tabs .tabpanel > p {
  margin: 0;
  max-width: 58ch;
  font-size: var(--step-17);
  line-height: 1.85;
  color: color-mix(in srgb, var(--ice-text) 80%, var(--mist-text));
}

.page-about .flow-points {
  list-style: none;
  margin: 1.25rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.page-about .flow-points li {
  position: relative;
  padding-left: 1.4rem;
  font-size: var(--step-15);
  line-height: 1.8;
  color: var(--mist-text);
}

.page-about .flow-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 7px;
  height: 7px;
  background: var(--pulse-green);
  transform: rotate(45deg);
}

/* ============ 团队与协作 ============ */
.page-about .crew-grid {
  display: grid;
  gap: 1rem;
}

.page-about .crew-card {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  padding: clamp(1.35rem, 3vw, 1.9rem);
  background: var(--panel-slate);
  border: 1px solid var(--about-line);
  clip-path: var(--clip-panel);
}

.page-about .crew-card:nth-child(2) {
  border-top: 2px solid var(--electric-cyan);
}

.page-about .crew-card:nth-child(3) {
  border-top: 2px solid var(--amber-rule);
}

.page-about .crew-card:nth-child(1) {
  border-top: 2px solid var(--pulse-green);
}

.page-about .crew-index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--step-13);
  letter-spacing: 0.12em;
  color: var(--mist-text);
}

.page-about .crew-card h3 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--step-20);
  font-weight: 800;
}

.page-about .crew-card p:last-child {
  margin: 0;
  font-size: var(--step-15);
  line-height: 1.85;
  color: var(--mist-text);
}

.page-about .crew-subtitle {
  margin: clamp(2.25rem, 5vw, 3.25rem) 0 1rem;
  font-family: var(--font-heading);
  font-size: var(--step-28);
  font-weight: 800;
  line-height: 1.25;
}

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

.page-about .partner-list li {
  display: grid;
  gap: 0.4rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .partner-count {
  font-family: var(--font-mono);
  font-size: var(--step-20);
  font-weight: 700;
  line-height: 1.2;
  color: var(--electric-cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .partner-desc {
  font-size: var(--step-15);
  line-height: 1.8;
  color: var(--mist-text);
}

/* ============ 赛季节奏 ============ */
.page-about .season-track {
  display: grid;
  gap: 1rem;
}

.page-about .season-card {
  padding: 1.5rem 1.5rem 1.6rem 1.6rem;
  background: linear-gradient(135deg, rgba(18, 34, 74, 0.92), rgba(10, 23, 51, 0.92));
  border: 1px solid var(--about-line);
  border-left-width: 3px;
  border-left-color: var(--pulse-green);
}

.page-about .season-card:nth-child(2) {
  border-left-color: var(--electric-cyan);
}

.page-about .season-card:nth-child(3) {
  border-left-color: var(--amber-rule);
}

.page-about .season-card:nth-child(4) {
  border-left-color: var(--spark-orange);
}

.page-about .season-tag {
  margin: 0 0 0.65rem;
  font-family: var(--font-mono);
  font-size: var(--step-13);
  letter-spacing: 0.06em;
  color: var(--mist-text);
}

.page-about .season-card h3 {
  margin: 0 0 0.6rem;
  font-family: var(--font-heading);
  font-size: var(--step-20);
  font-weight: 800;
  line-height: 1.35;
}

.page-about .season-card p:last-child {
  margin: 0;
  font-size: var(--step-15);
  line-height: 1.85;
  color: color-mix(in srgb, var(--ice-text) 74%, var(--mist-text));
}

/* ============ 合作引导 ============ */
.page-about .about-cta {
  display: grid;
  gap: 1.75rem;
  padding: clamp(2rem, 5vw, 3.5rem);
  background:
    linear-gradient(118deg, rgba(43, 240, 160, 0.13), transparent 56%),
    var(--panel-slate);
  border: 1px solid var(--about-line);
  clip-path: var(--clip-panel);
}

.page-about .about-cta h2 {
  margin: 0.5rem 0 0.85rem;
  font-family: var(--font-heading);
  font-size: var(--step-40);
  font-weight: 900;
  line-height: 1.15;
}

.page-about .about-cta-copy p:last-child {
  margin: 0;
  max-width: 62ch;
  font-size: var(--step-17);
  line-height: 1.85;
  color: color-mix(in srgb, var(--ice-text) 80%, var(--mist-text));
}

.page-about .about-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-content: start;
}

/* ============ 响应式 ============ */
@media (min-width: 48rem) {
  .page-about .crew-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .partner-list li {
    grid-template-columns: 11rem minmax(0, 1fr);
    align-items: baseline;
    gap: 1.5rem;
  }

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

  .page-about .chronicle-item {
    display: grid;
    grid-template-columns: 7.5rem minmax(0, 1fr);
    gap: clamp(1.5rem, 4vw, 3rem);
  }

  .page-about .chronicle-mark {
    position: sticky;
    top: var(--about-sticky-top);
    align-self: start;
  }

  .page-about .chronicle-body h3 {
    margin-top: 0;
  }
}

@media (min-width: 62rem) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
  }

  .page-about .about-flow-tabs {
    grid-template-columns: 14rem minmax(0, 1fr);
    gap: clamp(1.75rem, 4vw, 3rem);
    align-items: start;
  }

  .page-about .about-flow-tabs .tablist {
    flex-direction: column;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-flow-tabs .tab {
    width: 100%;
    text-align: left;
  }

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

@media (min-width: 76rem) {
  .page-about .season-track {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 30rem) {
  .page-about h1 {
    transform: none;
  }

  .page-about .about-facts li {
    align-items: flex-start;
  }

  .page-about .fact-label {
    max-width: 11ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tabpanel {
    animation: none;
  }

  .page-about .tab,
  .page-about .partner-list li,
  .page-about .chronicle-note summary {
    transition: none;
  }
}