.page-about {
  --about-gap: clamp(16px, 2.8vw, 30px);
  background: var(--ink);
  color: var(--on-dark);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--navy);
  border-bottom: 3px solid var(--red);
}

.page-about .about-hero__bg {
  position: absolute;
  inset: 0;
}

.page-about .about-hero__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.34;
  filter: saturate(0.82);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(104deg, rgba(7, 19, 36, 0.96) 0%, rgba(7, 19, 36, 0.84) 46%, rgba(143, 24, 17, 0.56) 100%);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  padding-block: clamp(20px, 3.4vw, 38px) clamp(32px, 5.6vw, 72px);
}

.page-about .about-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0 0 clamp(16px, 3vw, 28px);
  padding: 0;
  font-size: 13px;
  color: var(--on-dark-dim);
}

.page-about .about-crumbs li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--red);
}

.page-about .about-crumbs a {
  color: var(--on-dark-dim);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-crumbs a:hover,
.page-about .about-crumbs a:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.page-about .about-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--lime);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  max-width: 18em;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(30px, 5.4vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.008em;
  color: var(--white);
}

.page-about .about-lead {
  max-width: 62ch;
  margin: 0 0 clamp(22px, 3.2vw, 34px);
  font-size: clamp(15px, 1.9vw, 17.5px);
  line-height: 1.8;
  color: #DCE1E8;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
  max-width: 760px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-hero__facts li {
  padding: 10px 14px 12px;
  border-left: 3px solid var(--red);
  background: rgba(38, 42, 50, 0.62);
}

.page-about .about-stat {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(19px, 2.5vw, 26px);
  font-weight: 700;
  line-height: 1.2;
  color: var(--lime);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 3px;
  font-size: 12.5px;
  color: var(--on-dark-dim);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-layout {
  display: grid;
  gap: clamp(18px, 3.2vw, 40px);
  max-width: var(--shell);
  margin-inline: auto;
  padding: clamp(22px, 4vw, 52px) var(--gutter) clamp(44px, 6vw, 86px);
}

.page-about .about-index {
  min-width: 0;
  padding: 16px 18px;
  border: 1px solid rgba(185, 191, 201, 0.28);
  background: var(--panel);
}

.page-about .about-index__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--on-dark-dim);
}

.page-about .about-index__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-index__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 10px;
  font-size: 13px;
  color: var(--on-dark);
  text-decoration: none;
  border: 1px solid rgba(185, 191, 201, 0.22);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-index__list a span {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 11px;
  color: var(--red);
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--lime);
  border-color: var(--blue);
  background: rgba(30, 91, 255, 0.12);
}

.page-about .about-index__list a:hover span,
.page-about .about-index__list a:focus-visible span {
  color: var(--lime);
}

.page-about .about-index__foot {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: 1px dashed rgba(185, 191, 201, 0.28);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--on-dark-dim);
}

.page-about .about-body {
  display: grid;
  gap: var(--about-gap);
  min-width: 0;
}

/* ---------- 面板 ---------- */
.page-about .about-panel {
  position: relative;
  min-width: 0;
  padding: clamp(20px, 3.2vw, 38px);
  background: var(--paper);
  color: var(--ink);
  border: 1px solid var(--line);
  box-shadow: 6px 6px 0 -1px rgba(185, 191, 201, 0.4), var(--shadow-paper);
}

.page-about .about-panel--dark {
  background: var(--ink);
  color: var(--on-dark);
  border-color: rgba(185, 191, 201, 0.28);
  box-shadow: 6px 6px 0 -1px rgba(212, 42, 31, 0.6), var(--shadow-lift);
}

.page-about .about-panel--red {
  background: var(--red-deep);
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.24);
  box-shadow: 6px 6px 0 -1px rgba(7, 19, 36, 0.7);
}

.page-about .about-sec__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 10px 14px;
  align-items: start;
  margin-bottom: clamp(14px, 2.4vw, 24px);
  padding-bottom: 13px;
  border-bottom: 1px dashed rgba(110, 116, 128, 0.45);
}

.page-about .about-panel--dark .about-sec__head,
.page-about .about-panel--red .about-sec__head {
  border-bottom-color: rgba(255, 255, 255, 0.24);
}

.page-about .about-sec__no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 2.8vw, 28px);
  font-weight: 700;
  line-height: 1;
  color: var(--red);
}

.page-about .about-panel--dark .about-sec__no {
  color: var(--lime);
}

.page-about .about-panel--red .about-sec__no {
  color: var(--lime);
}

.page-about .about-sec__kicker {
  display: block;
  margin-bottom: 5px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--mid);
}

.page-about .about-panel--dark .about-sec__kicker,
.page-about .about-panel--red .about-sec__kicker {
  color: rgba(255, 255, 255, 0.6);
}

.page-about .about-sec__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(20px, 3.1vw, 31px);
  line-height: 1.18;
}

.page-about .about-panel p {
  margin: 0 0 13px;
  font-size: clamp(14.5px, 1.7vw, 16px);
  line-height: 1.8;
}

.page-about .about-panel p:last-child {
  margin-bottom: 0;
}

.page-about .about-panel--dark p,
.page-about .about-panel--red p {
  color: rgba(245, 242, 234, 0.86);
}

.page-about .about-note {
  margin-top: 16px;
  padding: 11px 14px;
  border-left: 3px solid var(--blue);
  background: rgba(30, 91, 255, 0.07);
  font-size: 13.5px;
  line-height: 1.72;
  color: #3C424C;
}

.page-about .about-panel--dark .about-note {
  background: rgba(30, 91, 255, 0.18);
  color: rgba(245, 242, 234, 0.78);
}

/* ---------- 按钮 ---------- */
.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.page-about .about-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 18px;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.2;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform var(--dur) var(--ease), background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-btn--dark {
  background: var(--ink);
  color: var(--lime);
}

.page-about .about-btn--dark:hover,
.page-about .about-btn--dark:focus-visible {
  transform: translateY(-2px);
  background: var(--panel);
}

.page-about .about-btn--line {
  border-color: var(--line);
  color: var(--ink);
  background: transparent;
}

.page-about .about-btn--line:hover,
.page-about .about-btn--line:focus-visible {
  transform: translateY(-2px);
  border-color: var(--red);
  color: var(--red-deep);
}

.page-about .about-btn--solid {
  background: var(--ink);
  color: var(--lime);
}

.page-about .about-btn--solid:hover,
.page-about .about-btn--solid:focus-visible {
  transform: translateY(-2px);
  background: var(--navy);
}

.page-about .about-btn--outline {
  border-color: rgba(255, 255, 255, 0.62);
  color: var(--white);
}

.page-about .about-btn--outline:hover,
.page-about .about-btn--outline:focus-visible {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 0.14);
}

/* ---------- 时间轴 ---------- */
.page-about .about-tl {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 4px 0 4px 30px;
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, var(--red) 0%, var(--red-deep) 50%, var(--blue) 100%);
}

.page-about .about-tl > li {
  position: relative;
  margin-bottom: 10px;
}

.page-about .about-tl > li::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 16px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  border: 3px solid var(--red);
}

.page-about .about-tl > li:last-child::before {
  border-color: var(--blue);
}

.page-about .about-stage summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 12px;
  padding: 12px 14px;
  list-style: none;
  cursor: pointer;
  background: var(--panel);
  border: 1px solid rgba(185, 191, 201, 0.24);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

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

.page-about .about-stage summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  line-height: 1;
  color: var(--lime);
}

.page-about .about-stage[open] summary::after {
  content: "−";
}

.page-about .about-stage summary:hover {
  border-color: var(--blue);
  background: rgba(38, 42, 50, 0.92);
}

.page-about .about-stage summary:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 2px;
}

.page-about .about-stage__year {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 14.5px;
  font-weight: 700;
  color: var(--lime);
}

.page-about .about-stage__name {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  color: var(--on-dark);
}

.page-about .about-stage__body {
  padding: 13px 14px 5px;
  border: 1px solid rgba(185, 191, 201, 0.18);
  border-top: 0;
  background: rgba(38, 42, 50, 0.52);
  font-size: 13.5px;
  line-height: 1.78;
  color: rgba(245, 242, 234, 0.8);
}

/* ---------- 配图 ---------- */
.page-about .about-fig {
  margin: 20px 0 0;
  padding: 8px;
  background: var(--panel);
  border: 1px solid var(--line);
}

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

.page-about .about-fig figcaption {
  padding: 8px 2px 2px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--on-dark-dim);
}

.page-about .about-fig--square {
  max-width: 460px;
  margin-inline: auto;
}

/* ---------- 流程 ---------- */
.page-about .about-split {
  display: grid;
  gap: 18px;
}

.page-about .about-flow {
  display: grid;
  gap: 12px;
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
}

.page-about .about-flow > li {
  padding: 13px 15px 15px;
  background: var(--white);
  border: 1px solid var(--line);
  border-top: 3px solid var(--red);
}

.page-about .about-flow > li:nth-child(2) {
  border-top-color: var(--blue);
}

.page-about .about-flow > li:nth-child(3) {
  border-top-color: var(--ink);
}

.page-about .about-flow h3 {
  margin: 0 0 7px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-flow p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: #424853;
}

/* ---------- 团队数据条 ---------- */
.page-about .about-team {
  display: grid;
  gap: 15px;
  margin: 4px 0 18px;
}

.page-about .about-team__meta {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  font-size: 13.5px;
  line-height: 1.6;
  color: rgba(245, 242, 234, 0.82);
}

.page-about .about-team__val {
  flex: none;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
  font-weight: 700;
  color: var(--lime);
}

.page-about .about-bar {
  margin-top: 7px;
  height: 10px;
  overflow: hidden;
  background: rgba(185, 191, 201, 0.16);
}

.page-about .about-bar > span {
  display: block;
  height: 100%;
  background: var(--red);
}

.page-about .about-bar--blue > span {
  background: var(--blue);
}

.page-about .about-bar--lime > span {
  background: var(--lime);
}

.page-about .about-fill--100 {
  width: 100%;
}

.page-about .about-fill--43 {
  width: 43%;
}

.page-about .about-fill--62 {
  width: 62%;
}

/* ---------- 合作 ---------- */
.page-about .about-parts {
  display: grid;
  gap: 13px;
  list-style: none;
  margin: 16px 0;
  padding: 0;
}

.page-about .about-parts > li {
  padding: 15px 16px 16px;
  background: var(--white);
  border: 1px solid var(--line);
  border-left: 4px solid var(--blue);
}

.page-about .about-parts > li:nth-child(2) {
  border-left-color: var(--red);
}

.page-about .about-parts h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-parts p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: #424853;
}

/* ---------- 联系区 ---------- */
.page-about .about-contact {
  display: grid;
  gap: 8px;
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  font-size: 14px;
  line-height: 1.7;
}

.page-about .about-contact a {
  color: var(--white);
  text-decoration: underline;
  text-underline-offset: 3px;
  word-break: break-all;
}

.page-about .about-contact a:hover,
.page-about .about-contact a:focus-visible {
  color: var(--lime);
}

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

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

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) 268px;
    align-items: start;
    gap: 22px;
  }

  .page-about .about-split .about-fig {
    margin-top: 0;
  }
}

@media (min-width: 900px) {
  .page-about .about-layout {
    grid-template-columns: 206px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 18px);
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
  }

  .page-about .about-index__list li {
    width: 100%;
  }

  .page-about .about-index__list a {
    display: flex;
    width: 100%;
    padding: 9px 4px;
    border: 0;
    border-bottom: 1px solid rgba(185, 191, 201, 0.16);
    background: transparent;
  }

  .page-about .about-index__list a:hover,
  .page-about .about-index__list a:focus-visible {
    background: transparent;
    border-bottom-color: var(--blue);
  }

  .page-about .about-tl {
    padding-left: 38px;
  }

  .page-about .about-tl > li::before {
    left: -37px;
  }

  .page-about .about-stage__name {
    font-size: 18px;
  }
}

@media (min-width: 1080px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) 320px;
  }

  .page-about .about-hero__facts {
    gap: 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-btn,
  .page-about .about-index__list a,
  .page-about .about-stage summary {
    transition: none;
  }

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