.page-about {
  --about-rail-w: 2px;
  --about-node: 14px;
  background: var(--ink-950);
  color: var(--mist);
}

/* ---------- Hero ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(5.5rem, 14vw, 9rem) 0 clamp(2.6rem, 5vw, 4rem);
  border-bottom: 1px solid var(--border-soft);
  background:
    radial-gradient(110% 80% at 82% 4%, rgba(69, 244, 208, .20), transparent 62%),
    radial-gradient(90% 70% at 0% 100%, rgba(255, 90, 54, .12), transparent 60%),
    linear-gradient(180deg, var(--ink-950) 0%, var(--ink-900) 58%, var(--ink-950) 100%);
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
  z-index: -2;
}

.page-about .about-hero__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 30%;
  opacity: .22;
  filter: saturate(.85) contrast(1.05);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(0deg, rgba(69, 244, 208, .055) 0 1px, transparent 1px 68px),
    repeating-linear-gradient(90deg, rgba(69, 244, 208, .055) 0 1px, transparent 1px 68px),
    linear-gradient(180deg, rgba(4, 26, 20, .58) 0%, rgba(4, 26, 20, .88) 64%, var(--ink-950) 100%);
}

.page-about .about-hero__inner {
  position: relative;
}

.page-about .about-hero__eyebrow {
  margin: 1.4rem 0 0;
  color: var(--teal);
  letter-spacing: .18em;
}

.page-about .about-hero__title {
  margin: .7rem 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.3rem, 8.4vw, 5.1rem);
  line-height: 1.02;
  letter-spacing: -.01em;
  color: var(--mist);
}

.page-about .about-hero__title-mark {
  display: block;
  margin-top: .18em;
  color: var(--neon);
}

.page-about .about-hero__lede {
  max-width: 46ch;
  margin: 1.3rem 0 0;
  font-size: var(--step-body);
  line-height: 1.85;
  color: rgba(234, 247, 242, .82);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
  margin-top: 1.7rem;
}

.page-about .about-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .75rem;
  margin: clamp(1.9rem, 5vw, 2.8rem) 0 0;
  padding: 0;
}

.page-about .about-figures__item {
  padding: .85rem 1rem;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  background: var(--surface-glass);
  backdrop-filter: blur(10px);
}

.page-about .about-figures__item dt {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .14em;
  color: var(--teal);
}

.page-about .about-figures__item dd {
  margin: .35rem 0 0;
  font-size: .9rem;
  color: rgba(234, 247, 242, .78);
}

.page-about .about-figures__item .data-figure {
  font-size: 1.6rem;
  color: var(--neon);
  vertical-align: baseline;
}

/* ---------- 章节色带 ---------- */
.page-about .about-band {
  display: flex;
  align-items: center;
  gap: .9rem;
  margin-bottom: clamp(1.4rem, 3vw, 2.2rem);
  padding-bottom: .8rem;
  border-bottom: 1px solid var(--border-soft);
}

.page-about .about-band::after {
  content: "";
  flex: 1 1 auto;
  height: 1px;
  background: linear-gradient(90deg, var(--border-neon), transparent);
}

.page-about .about-band__num {
  font-family: var(--font-mono);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--neon);
}

.page-about .about-band__label {
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .22em;
  color: var(--teal);
}

.page-about .about-sublede {
  margin: .6rem 0 0;
  max-width: 60ch;
  font-size: .95rem;
  line-height: 1.8;
  color: rgba(234, 247, 242, .74);
}

.page-about .about-inline-link {
  display: inline-block;
  margin-top: 1.1rem;
  font-family: var(--font-mono);
  font-size: .8rem;
  letter-spacing: .06em;
  color: var(--neon);
  text-decoration: none;
  border-bottom: 1px solid var(--border-neon);
  padding-bottom: 2px;
}

.page-about .about-inline-link:hover {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 01 起点与定位 ---------- */
.page-about .about-origin__grid {
  align-items: start;
  gap: clamp(1.6rem, 4vw, 3rem);
}

.page-about .about-origin__main h2 {
  margin: 0 0 1rem;
  font-size: var(--step-h2);
  line-height: 1.2;
  color: var(--mist);
}

.page-about .about-origin__main p {
  margin: 0 0 1rem;
  font-size: var(--step-body);
  line-height: 1.9;
  color: rgba(234, 247, 242, .8);
}

.page-about .about-origin__aside {
  padding: clamp(1.1rem, 3vw, 1.6rem);
}

.page-about .about-facts {
  list-style: none;
  margin: .9rem 0 0;
  padding: 0;
  display: grid;
  gap: .8rem;
}

.page-about .about-facts li {
  padding-bottom: .8rem;
  border-bottom: 1px dashed rgba(44, 113, 96, .55);
}

.page-about .about-facts li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-facts__key {
  display: block;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .14em;
  color: var(--teal);
  margin-bottom: .25rem;
}

.page-about .about-facts__val {
  display: block;
  font-size: .92rem;
  line-height: 1.7;
  color: rgba(234, 247, 242, .86);
}

/* ---------- 02 时间线 ---------- */
.page-about .about-history__head {
  display: block;
}

.page-about .about-history__head h2 {
  margin: 0;
  font-size: var(--step-h2);
  line-height: 1.2;
}

.page-about .about-timeline__index {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem;
  margin: 1.2rem 0 1.4rem;
}

.page-about .about-timeline__index a {
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .05em;
  padding: .42rem .8rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-soft);
  color: rgba(234, 247, 242, .82);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-timeline__index a:hover,
.page-about .about-timeline__index a:focus-visible {
  color: var(--ink-950);
  background: var(--neon);
  border-color: var(--neon);
}

.page-about .about-timeline-wrap {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  padding: clamp(1rem, 3vw, 1.8rem);
  background: linear-gradient(160deg, var(--ink-900), var(--ink-800) 70%, var(--ink-900));
  border: 1px solid var(--border-soft);
}

.page-about .about-timeline__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-about .about-timeline__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: .16;
}

.page-about .about-timeline {
  position: relative;
  z-index: 1;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .8rem;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 11px;
  top: .8rem;
  bottom: .8rem;
  width: var(--about-rail-w);
  background: linear-gradient(180deg, var(--neon), var(--teal) 58%, transparent);
}

.page-about .about-phase {
  position: relative;
  padding-left: 2.3rem;
}

.page-about .about-phase::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 1.05rem;
  width: var(--about-node);
  height: var(--about-node);
  border-radius: 50%;
  background: var(--ink-950);
  border: 2px solid var(--neon);
  box-shadow: 0 0 0 4px rgba(69, 244, 208, .14);
}

.page-about .about-phase__details {
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  background: var(--surface-glass);
  backdrop-filter: blur(10px);
  overflow: hidden;
}

.page-about .about-phase__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .55rem;
  padding: .85rem 1rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-phase__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  color: var(--neon);
  line-height: 1;
}

.page-about .about-phase__details[open] .about-phase__summary::after {
  content: "–";
  color: var(--amber);
}

.page-about .about-phase__num {
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--teal);
  letter-spacing: .1em;
}

.page-about .about-phase__name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--mist);
}

.page-about .about-phase__body {
  padding: 0 1rem 1rem;
}

.page-about .about-phase__body p {
  margin: 0;
  font-size: .93rem;
  line-height: 1.85;
  color: rgba(234, 247, 242, .78);
}

/* ---------- 03 内容体系 ---------- */
.page-about .about-systems__grid {
  align-items: start;
  gap: clamp(1.6rem, 4vw, 2.8rem);
}

.page-about .about-systems__main h2 {
  margin: 0;
  font-size: var(--step-h2);
  line-height: 1.2;
}

.page-about .tabset {
  margin-top: 1.4rem;
}

.page-about .tablist {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  padding-bottom: .7rem;
  border-bottom: 1px solid var(--border-soft);
}

.page-about .tab {
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .08em;
  padding: .52rem .95rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-soft);
  background: transparent;
  color: rgba(234, 247, 242, .8);
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .tab:hover {
  border-color: var(--border-neon);
  color: var(--neon);
}

.page-about .tab[aria-selected="true"] {
  background: rgba(69, 244, 208, .14);
  border-color: var(--border-neon);
  color: var(--neon);
}

.page-about .tab-panel {
  padding-top: 1.2rem;
}

.page-about .tab-panel[hidden] {
  display: none;
}

.page-about .about-sys-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .7rem;
}

.page-about .about-sys-item {
  padding: .95rem 1rem;
  border-left: 2px solid var(--border-neon);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: rgba(12, 59, 46, .62);
}

.page-about .about-sys-item h3 {
  margin: 0 0 .35rem;
  font-size: 1rem;
  color: var(--neon);
}

.page-about .about-sys-item p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.8;
  color: rgba(234, 247, 242, .78);
}

.page-about .about-systems__media {
  margin: 1.4rem 0 0;
}

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

/* ---------- 04 团队 ---------- */
.page-about .about-team__head {
  display: block;
}

.page-about .about-team__head h2 {
  margin: 0;
  font-size: var(--step-h2);
  line-height: 1.2;
}

.page-about .about-team__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: .8rem;
  margin-top: 1.4rem;
}

.page-about .about-team__card {
  padding: 1.1rem 1.1rem 1.2rem;
  position: relative;
  overflow: hidden;
}

.page-about .about-team__card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 44px;
  height: 2px;
  background: var(--neon);
}

.page-about .about-team__card h3 {
  margin: .4rem 0 .5rem;
  font-size: 1.1rem;
  color: var(--mist);
}

.page-about .about-team__card p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.78;
  color: rgba(234, 247, 242, .78);
}

.page-about .about-team__note {
  margin-top: 1rem;
  padding: clamp(1.1rem, 3vw, 1.6rem);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  background: linear-gradient(140deg, rgba(69, 244, 208, .10), transparent 62%), var(--ink-900);
}

.page-about .about-team__note p {
  margin: 0 0 1rem;
  font-size: .95rem;
  line-height: 1.9;
  color: rgba(234, 247, 242, .82);
}

.page-about .about-team__note a {
  color: var(--neon);
  text-decoration: none;
  border-bottom: 1px solid var(--border-neon);
}

.page-about .about-team__note a:hover {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 05 合作 ---------- */
.page-about .about-coop__grid {
  align-items: start;
  gap: clamp(1.6rem, 4vw, 2.8rem);
}

.page-about .about-coop__main h2 {
  margin: 0;
  font-size: var(--step-h2);
  line-height: 1.2;
}

.page-about .about-coop__cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: .7rem;
  margin-top: 1.4rem;
}

.page-about .about-coop__card {
  padding: 1rem 1.05rem;
  background: var(--ink-800);
}

.page-about .about-coop__card h3 {
  margin: 0 0 .4rem;
  font-size: 1rem;
  color: var(--amber);
}

.page-about .about-coop__card p {
  margin: 0;
  font-size: .89rem;
  line-height: 1.78;
  color: rgba(234, 247, 242, .78);
}

.page-about .about-coop__aside {
  padding: clamp(1.1rem, 3vw, 1.6rem);
}

.page-about .about-flow {
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
  display: grid;
  gap: .65rem;
}

.page-about .about-flow li {
  display: flex;
  gap: .7rem;
  align-items: flex-start;
  padding-bottom: .65rem;
  border-bottom: 1px dashed rgba(44, 113, 96, .55);
}

.page-about .about-flow li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-flow__num {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--neon);
  flex: 0 0 auto;
  padding-top: 2px;
}

.page-about .about-flow__text {
  font-size: .88rem;
  line-height: 1.7;
  color: rgba(234, 247, 242, .82);
}

.page-about .about-coop__contact {
  margin: 1.1rem 0 1.1rem;
  font-size: .84rem;
  line-height: 1.75;
  color: rgba(234, 247, 242, .7);
}

.page-about .about-coop__contact a {
  color: var(--teal);
  text-decoration: none;
  border-bottom: 1px solid var(--border-soft);
  word-break: break-all;
}

.page-about .about-coop__contact a:hover {
  color: var(--neon);
  border-bottom-color: var(--border-neon);
}

.page-about .about-principles {
  display: grid;
  grid-template-columns: 1fr;
  gap: .7rem;
  margin-top: clamp(1.6rem, 4vw, 2.4rem);
  padding-top: clamp(1.4rem, 3vw, 2rem);
  border-top: 1px solid var(--border-soft);
}

.page-about .about-principles__item {
  padding: .9rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(7, 39, 30, .8);
  border: 1px solid rgba(44, 113, 96, .4);
}

.page-about .about-principles__item p {
  margin: 0;
}

.page-about .about-principles__item .data-figure {
  font-size: 1.15rem;
  letter-spacing: .04em;
  color: var(--neon);
}

.page-about .about-principles__item p + p {
  margin-top: .4rem;
  font-size: .87rem;
  line-height: 1.75;
  color: rgba(234, 247, 242, .76);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 960px) {
  .page-about .about-hero {
    padding-top: clamp(7rem, 9vw, 9.5rem);
  }

  .page-about .about-timeline-wrap {
    padding: clamp(1.6rem, 2.4vw, 2.4rem);
  }

  .page-about .about-timeline {
    gap: .75rem;
  }

  .page-about .about-phase__body {
    padding-left: 1rem;
    padding-right: 2.5rem;
  }

  .page-about .about-systems__media {
    position: sticky;
    top: 6rem;
    margin-top: 2.4rem;
  }

  .page-about .about-team__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-principles {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tab,
  .page-about .about-timeline__index a {
    transition: none;
  }
}