.page-about {
  --about-rail: minmax(0, 3fr);
  --about-main: minmax(0, 9fr);
  background: var(--ink-900);
  color: var(--paper);
}

.page-about .breadcrumb {
  padding-top: clamp(14px, 2vw, 22px);
  padding-bottom: 4px;
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(22px, 3vw, 38px) 0 clamp(46px, 6vw, 84px);
  background:
    radial-gradient(120% 80% at 92% -20%, rgba(0, 240, 200, 0.14), transparent 62%),
    radial-gradient(80% 60% at 0% 110%, rgba(255, 138, 61, 0.1), transparent 60%),
    linear-gradient(165deg, var(--ink-800) 0%, var(--ink-900) 68%);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -12%;
  top: -30%;
  width: 54%;
  height: 165%;
  background: repeating-linear-gradient(115deg, rgba(201, 209, 206, 0.06) 0 1px, transparent 1px 15px);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 52px);
}

.page-about .about-hero__main { order: 1; }
.page-about .about-hero__rail { order: 2; }

.page-about .about-hero__kicker {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--signal);
  text-transform: uppercase;
}

.page-about .about-hero__stats {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-hero__stat {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-hero__stat dt {
  font-size: 13px;
  line-height: 1.5;
  color: var(--muted);
}

.page-about .about-hero__stat dd {
  margin: 0;
  white-space: nowrap;
}

.page-about .about-hero__num {
  font-family: var(--font-mono);
  font-size: 22px;
  color: var(--paper);
}

.page-about .about-hero__unit {
  margin-left: 4px;
  font-size: 12px;
  color: var(--muted);
}

.page-about .about-hero h1 {
  margin: 12px 0 0;
  max-width: 15em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(32px, 6.4vw, 64px);
  line-height: 1.03;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 44ch;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: var(--about-rail) var(--about-main);
    align-items: start;
  }
  .page-about .about-hero__main { order: 2; }
  .page-about .about-hero__rail { order: 1; }
}

/* 章节骨架 */
.page-about .chapter {
  padding: clamp(48px, 7vw, 92px) 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .chapter--deep {
  background: var(--ink-800);
}

.page-about .chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
}

.page-about .chapter__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3vw, 38px);
  line-height: 1;
  color: var(--signal);
}

.page-about .chapter__rail-note {
  margin: 12px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--line-strong);
  font-size: 13px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .chapter__body h2 {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.6vw, 40px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.page-about .chapter__body > p {
  margin: 0 0 16px;
  max-width: 62ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--silver);
}

.page-about .chapter__body a {
  color: var(--signal-soft);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .chapter__body a:hover {
  color: var(--paper);
}

@media (min-width: 900px) {
  .page-about .chapter__grid {
    grid-template-columns: var(--about-rail) var(--about-main);
    gap: clamp(24px, 4vw, 56px);
  }
  .page-about .chapter__rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    align-self: start;
  }
}

/* 图片 */
.page-about .figure {
  margin: 28px 0 0;
}

.page-about .figure__media {
  overflow: hidden;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: var(--ink-700);
}

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

.page-about .figure__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

/* 字段网格 */
.page-about .fields {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 28px 0 0;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
}

.page-about .field {
  position: relative;
  padding: 13px 14px 15px;
  background: var(--ink-700);
  transition: background 0.2s ease;
}

.page-about .field__name {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .field__desc {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .fields-note {
  margin: 14px 0 0;
  font-size: 13px;
  color: var(--muted);
}

@media (min-width: 620px) {
  .page-about .fields { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 1080px) {
  .page-about .fields { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .page-about .field:hover { background: var(--ink-600); }
  .page-about .field:hover .field__name { color: var(--signal-soft); }
  .page-about .field__desc {
    position: absolute;
    left: 8px;
    right: 8px;
    top: 100%;
    z-index: 6;
    margin: 0;
    padding: 10px 12px;
    background: var(--ink-800);
    border: 1px solid rgba(0, 240, 200, 0.35);
    border-radius: var(--radius);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s;
  }
  .page-about .field:hover .field__desc,
  .page-about .field:focus-within .field__desc {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
}

/* 路径对比 */
.page-about .paths {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: 26px;
}

.page-about .path-card {
  padding: 20px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: rgba(22, 54, 46, 0.55);
}

.page-about .path-card--new {
  border-color: rgba(0, 240, 200, 0.5);
  background: rgba(0, 240, 200, 0.07);
}

.page-about .path-card__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 14px;
}

.page-about .path-card__title {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--paper);
}

.page-about .path-card__count {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--warm);
}

.page-about .path-card--new .path-card__count {
  color: var(--signal);
}

.page-about .path-steps {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .path-step {
  padding: 9px 0;
  border-bottom: 1px dashed var(--line-soft);
  font-size: 14px;
  line-height: 1.6;
  color: var(--silver);
}

.page-about .path-step:last-child {
  border-bottom: 0;
}

.page-about .path-step::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-right: 10px;
  border-radius: 50%;
  background: var(--silver);
  vertical-align: middle;
}

.page-about .path-card--new .path-step::before {
  background: var(--signal);
}

.page-about .path-step:nth-child(2) { padding-left: 18px; }
.page-about .path-step:nth-child(3) { padding-left: 36px; }
.page-about .path-step:nth-child(4) { padding-left: 54px; }

@media (min-width: 760px) {
  .page-about .paths {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }
}

/* 更新节奏 */
.page-about .cadence {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 26px 0;
}

.page-about .cadence__item {
  padding: 18px 18px 20px;
  border: 1px solid var(--line-soft);
  border-left: 3px solid var(--signal);
  border-radius: var(--radius);
  background: var(--ink-700);
}

.page-about .cadence__item--warm {
  border-left-color: var(--warm);
}

.page-about .cadence__time {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--signal);
}

.page-about .cadence__item--warm .cadence__time {
  color: var(--warm);
}

.page-about .cadence__title {
  margin: 9px 0 7px;
  font-size: 16px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .cadence__text {
  margin: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--silver);
}

.page-about .cadence__text a {
  color: var(--signal-soft);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

/* 团队 */
.page-about .crew {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 26px;
}

.page-about .crew__card {
  padding: 20px 18px 22px;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: var(--ink-800);
}

.page-about .crew__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 34px;
  line-height: 1;
  color: var(--signal);
}

.page-about .crew__role {
  display: block;
  margin-top: 10px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.page-about .crew__text {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--muted);
}

@media (min-width: 700px) {
  .page-about .crew { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

/* 时间线 */
.page-about .timeline {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-top: 30px;
  padding-bottom: 8px;
}

.page-about .timeline__track {
  display: none;
}

.page-about .tl-node {
  position: relative;
  z-index: 1;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: rgba(22, 54, 46, 0.62);
}

.page-about .tl-node summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 14px 16px;
  list-style: none;
  cursor: pointer;
}

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

.page-about .tl-node summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--signal);
}

.page-about .tl-node[open] summary::after {
  content: "–";
}

.page-about .tl-node__year {
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--signal);
}

.page-about .tl-node__label {
  font-size: 14px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .tl-node__body {
  padding: 0 16px 16px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--silver);
}

.page-about .tl-node--now {
  border-color: rgba(255, 138, 61, 0.5);
}

.page-about .tl-node--now .tl-node__year {
  color: var(--warm);
}

.page-about .tl-node--now summary::after {
  color: var(--warm);
}

@media (min-width: 880px) {
  .page-about .timeline {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 16px;
    align-items: start;
    padding-bottom: 28px;
  }
  .page-about .timeline__track {
    display: block;
    position: absolute;
    left: 0;
    top: 0;
    z-index: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
  }
  .page-about .tl-node:nth-of-type(1) { margin-top: 0; }
  .page-about .tl-node:nth-of-type(2) { margin-top: 26px; }
  .page-about .tl-node:nth-of-type(3) { margin-top: 52px; }
  .page-about .tl-node:nth-of-type(4) { margin-top: 78px; }
  .page-about .tl-node:nth-of-type(5) { margin-top: 104px; }
}

/* 合作与安全 */
.page-about .eco {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 26px;
}

.page-about .eco__card {
  padding: 22px;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: linear-gradient(150deg, rgba(0, 240, 200, 0.09), transparent 72%), var(--ink-700);
}

.page-about .eco__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1;
  color: var(--paper);
}

.page-about .eco__label {
  display: block;
  margin-top: 10px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--silver);
}

.page-about .eco__list {
  margin-top: 20px;
}

.page-about .eco__list p {
  margin: 0 0 12px;
  max-width: 62ch;
  font-size: 14px;
  line-height: 1.85;
  color: var(--silver);
}

.page-about .eco__list strong {
  color: var(--paper);
}

.page-about .eco__list a {
  color: var(--signal-soft);
  text-decoration: underline;
  text-underline-offset: 3px;
}

@media (min-width: 760px) {
  .page-about .eco { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

/* 结尾 */
.page-about .about-cta {
  padding: clamp(46px, 6vw, 84px) 0 clamp(54px, 7vw, 96px);
  border-top: 1px solid var(--line-strong);
  background: linear-gradient(160deg, var(--ink-700) 0%, var(--ink-900) 78%);
}

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

.page-about .about-cta__lead h2 {
  margin: 10px 0 18px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.6vw, 40px);
  line-height: 1.16;
  letter-spacing: -0.01em;
}

.page-about .about-cta__lead > p {
  margin: 0 0 16px;
  max-width: 52ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-cta__contact {
  font-size: 13px !important;
  line-height: 1.8 !important;
  color: var(--muted) !important;
}

.page-about .about-cta__links {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  align-content: start;
}

.page-about .about-cta__links a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 13px 14px;
  border-bottom: 1px solid var(--line-soft);
  font-size: 14px;
  color: var(--paper);
  text-decoration: none;
  transition: background 0.18s ease, color 0.18s ease;
}

.page-about .about-cta__links a::after {
  content: "→";
  font-family: var(--font-mono);
  color: var(--signal);
}

.page-about .about-cta__links a:hover {
  background: rgba(0, 240, 200, 0.08);
  color: var(--signal-soft);
}

@media (min-width: 520px) {
  .page-about .about-cta__links { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 900px) {
  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    gap: 48px;
    align-items: start;
  }
}

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