.page-about {
  --about-max: 46rem;
  --about-heading: clamp(1.9rem, 4vw, 3rem);
  --about-hero-title: clamp(2.75rem, 8vw, 5.75rem);
  --about-lead: clamp(1.3rem, 2vw, 1.7rem);
  background: var(--color-black);
  color: var(--color-white);
}

/* 英雄区 */
.page-about .about-hero {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 620px;
  padding: 6rem 0 4rem;
  overflow: hidden;
  background: var(--color-black);
}

.page-about .about-hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.4;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(180deg, rgba(10, 14, 23, 0.72) 0%, rgba(10, 14, 23, 0.45) 50%, rgba(10, 14, 23, 0.92) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 4px;
  z-index: 2;
  background: linear-gradient(90deg, var(--color-cyan) 0%, var(--color-green) 35%, var(--color-orange) 70%, transparent 100%);
}

.page-about .about-hero__container {
  position: relative;
  z-index: 3;
}

.page-about .about-hero__inner {
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.page-about .about-hero__kicker {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--color-steel);
  text-transform: uppercase;
}

.page-about .about-hero__title {
  margin: 0 0 1.5rem;
  font-family: var(--font-display);
  font-size: var(--about-hero-title);
  font-weight: 700;
  line-height: 0.95;
  text-transform: uppercase;
  color: var(--color-white);
  transform: skewY(-3deg);
  text-shadow: 0 0 28px var(--glow-cyan);
}

.page-about .about-hero__lede {
  margin: 0 0 2.25rem;
  max-width: var(--about-max);
  margin-left: auto;
  margin-right: auto;
  font-size: clamp(1.0625rem, 1.6vw, 1.25rem);
  line-height: 1.7;
  color: var(--color-steel);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  max-width: 30rem;
}

.page-about .about-hero__stats li {
  padding: 1rem 0.5rem 0.85rem;
  border-top: 1px solid var(--color-border);
}

.page-about .about-hero__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 700;
  color: var(--color-cyan);
}

.page-about .about-hero__label {
  display: block;
  margin-top: 0.25rem;
  font-size: 0.75rem;
  color: var(--color-steel);
}

/* 面包屑区域不额外覆盖，使用站内共享 breadcrumb 样式 */

/* 起点 */
.page-about .about-origin {
  position: relative;
  padding: 4.5rem 0;
}

.page-about .about-origin__container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-origin__main {
  max-width: var(--about-max);
}

.page-about .about-origin__main h2,
.page-about .about-milestones__head h2,
.page-about .about-capability__main h2,
.page-about .about-commitment h2 {
  font-family: var(--font-display);
  font-size: var(--about-heading);
  line-height: 1.08;
  margin: 0 0 1.25rem;
  transform: skewY(-2deg);
}

.page-about .about-lead {
  margin: 0 0 1.25rem;
  font-size: var(--about-lead);
  font-weight: 500;
  line-height: 1.55;
  color: var(--color-white);
}

.page-about .about-origin__main > p:not(.about-lead) {
  margin: 0 0 1.25rem;
  color: var(--color-steel);
  line-height: 1.75;
}

.page-about .about-accent {
  color: var(--color-cyan);
  font-weight: 500;
}

.page-about .about-origin__quote {
  margin: 2rem 0 0;
  padding: 1.25rem 1.25rem 1.25rem 1.5rem;
  border-left: 3px solid var(--color-cyan);
  background: linear-gradient(90deg, var(--glow-cyan), transparent 70%);
  font-family: var(--font-display);
  font-size: 1.3rem;
  line-height: 1.45;
  color: var(--color-white);
  transform: skewY(-1deg);
}

.page-about .about-origin__side {
  display: grid;
  gap: 1rem;
}

.page-about .about-origin__cards {
  display: grid;
  gap: 0.75rem;
}

.page-about .about-origin__card {
  position: relative;
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.25rem 0.75rem;
  padding: 1.05rem 1.15rem;
  background: var(--color-night);
  border: 1px solid var(--color-border);
  border-radius: 2px;
  text-decoration: none;
  transition: border-color var(--transition), background var(--transition), box-shadow var(--transition), transform var(--transition);
}

.page-about .about-origin__card::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 0.75rem;
  bottom: 0.75rem;
  width: 3px;
  background: var(--color-border);
  transition: background var(--transition);
}

.page-about .about-origin__card-index {
  grid-column: 1;
  grid-row: 1 / span 2;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-steel);
  padding-top: 0.25rem;
}

.page-about .about-origin__card-title {
  grid-column: 2;
  grid-row: 1;
  font-weight: 700;
  font-size: 1rem;
  color: var(--color-white);
  transition: color var(--transition);
}

.page-about .about-origin__card-note {
  grid-column: 2;
  grid-row: 2;
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--color-steel);
}

.page-about .about-origin__card:hover,
.page-about .about-origin__card:focus-visible {
  border-color: var(--color-cyan);
  background: var(--color-black);
  box-shadow: 0 0 18px var(--glow-cyan);
  transform: translateX(4px);
}

.page-about .about-origin__card:hover::before,
.page-about .about-origin__card:focus-visible::before {
  background: var(--color-cyan);
}

.page-about .about-origin__card:hover .about-origin__card-title,
.page-about .about-origin__card:focus-visible .about-origin__card-title {
  color: var(--color-cyan);
}

/* 里程碑时间线 */
.page-about .about-milestones {
  padding: 4.5rem 0;
  background: var(--color-night);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.page-about .about-milestones__head {
  max-width: var(--about-max);
}

.page-about .about-milestones__intro {
  margin: 0;
  color: var(--color-steel);
  line-height: 1.7;
  max-width: var(--about-max);
}

.page-about .about-timeline {
  position: relative;
  margin: 3rem 0 0;
  max-width: 42rem;
  border-left: 2px solid var(--color-border);
  padding-left: 2rem;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  top: 2rem;
  left: -6rem;
  width: 12rem;
  height: 12rem;
  background: var(--glow-cyan);
  filter: blur(60px);
  z-index: 0;
  pointer-events: none;
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: 2.5rem;
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 0;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: calc(-2rem - 0.4rem);
  top: 0.4rem;
  width: 0.8rem;
  height: 0.8rem;
  background: var(--color-cyan);
  transform: rotate(45deg);
  box-shadow: 0 0 12px var(--glow-cyan);
  transition: background var(--transition), box-shadow var(--transition);
}

.page-about .about-timeline__item:nth-child(4n+2)::before {
  background: var(--color-green);
  box-shadow: 0 0 12px var(--glow-green);
}

.page-about .about-timeline__item:nth-child(4n+3)::before {
  background: var(--color-orange);
  box-shadow: 0 0 12px rgba(255, 61, 0, 0.18);
}

.page-about .about-timeline__item:nth-child(4n+4)::before {
  background: var(--color-cyan);
  box-shadow: 0 0 12px var(--glow-cyan);
}

.page-about .about-timeline__item[open]::before {
  background: var(--color-green);
  box-shadow: 0 0 16px var(--glow-green);
}

.page-about .about-timeline__item summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.4rem 0.9rem;
  margin: 0;
  padding: 0.25rem 3rem 0.25rem 0.25rem;
  position: relative;
  z-index: 1;
}

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

.page-about .about-timeline__item summary::marker {
  content: "";
}

.page-about .about-timeline__item summary:focus-visible {
  outline: 2px solid var(--color-cyan);
  outline-offset: 4px;
  border-radius: 2px;
}

.page-about .about-timeline__phase {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-steel);
  padding: 0.2rem 0.45rem;
  border: 1px solid var(--color-border);
  background: var(--color-data);
}

.page-about .about-timeline__title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  line-height: 1.2;
  color: var(--color-white);
  overflow-wrap: break-word;
  transition: color var(--transition);
}

.page-about .about-timeline__item:hover summary .about-timeline__title {
  color: var(--color-cyan);
}

.page-about .about-timeline__item summary::after {
  content: "＋";
  position: absolute;
  top: 0.7rem;
  right: 0.35rem;
  width: 2rem;
  height: 2rem;
  display: grid;
  place-items: center;
  color: var(--color-cyan);
  font-family: var(--font-mono);
  font-size: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  transition: color var(--transition), border-color var(--transition), transform 0.3s ease;
}

.page-about .about-timeline__item[open] summary::after {
  content: "−";
  color: var(--color-green);
  border-color: var(--color-green);
  transform: rotate(180deg);
}

.page-about .about-timeline__body {
  margin-top: 0.75rem;
  padding: 1rem 1.25rem 1.1rem;
  border-left: 3px solid var(--color-border);
  background: rgba(13, 27, 42, 0.6);
}

.page-about .about-timeline__body p {
  margin: 0 0 0.75rem;
  color: var(--color-steel);
  line-height: 1.7;
  font-size: 0.9375rem;
}

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

.page-about .about-timeline__tag {
  display: inline-block;
  margin-top: 0.5rem;
  padding: 0.2rem 0.55rem;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--color-cyan);
  border: 1px solid var(--color-border);
  background: var(--color-data);
}

/* 数据能力 */
.page-about .about-capability {
  padding: 4.5rem 0;
}

.page-about .about-capability__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-capability__main {
  max-width: var(--about-max);
}

.page-about .about-capability__main > p:not(.about-lead) {
  margin: 1.25rem 0 0;
  color: var(--color-steel);
  line-height: 1.75;
}

.page-about .about-capability__metrics {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin: 2rem 0;
}

.page-about .about-capability__metric {
  position: relative;
  padding: 1.25rem 1rem;
  background: var(--color-data);
  border: 1px solid var(--color-border);
  text-align: center;
  overflow: hidden;
}

.page-about .about-capability__metric::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--color-cyan);
  opacity: 0.7;
}

.page-about .about-capability__metric:nth-child(3)::after {
  background: var(--color-orange);
}

.page-about .about-capability__metric-label {
  display: block;
  font-size: 0.8125rem;
  color: var(--color-steel);
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

.page-about .about-capability__metric-value {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 700;
  color: var(--color-cyan);
}

.page-about .about-capability__metric:nth-child(3) .about-capability__metric-value {
  color: var(--color-orange);
}

.page-about .about-capability__media {
  margin: 0;
}

.page-about .about-capability__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--color-border);
}

.page-about .about-capability__media figcaption {
  padding-top: 0.6rem;
  font-size: 0.8125rem;
  color: var(--color-steel);
  line-height: 1.5;
}

/* 服务承诺 */
.page-about .about-commitment {
  padding: 4.5rem 0;
  background-image: linear-gradient(var(--color-grid) 1px, transparent 1px), linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
  background-size: 28px 28px;
  border-top: 1px solid var(--color-border);
}

.page-about .about-commitment h2 {
  margin-bottom: 2rem;
}

.page-about .about-commitment__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
}

.page-about .about-commitment__main {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.page-about .about-commitment__item {
  position: relative;
  padding: 1.5rem 1.5rem 1.5rem 1.75rem;
  background: rgba(20, 30, 51, 0.75);
  border: 1px solid var(--color-border);
}

.page-about .about-commitment__item::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 1rem;
  bottom: 1rem;
  width: 3px;
  background: var(--color-orange);
}

.page-about .about-commitment__item:nth-child(2)::before {
  background: var(--color-green);
}

.page-about .about-commitment__item:nth-child(3)::before {
  background: var(--color-cyan);
}

.page-about .about-commitment__item:nth-child(4)::before {
  background: var(--color-steel);
}

.page-about .about-commitment__item h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-body);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-white);
}

.page-about .about-commitment__item p {
  margin: 0;
  color: var(--color-steel);
  line-height: 1.7;
  font-size: 0.9375rem;
}

.page-about .about-commitment__media {
  margin: 0;
}

.page-about .about-commitment__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--color-border);
}

.page-about .about-commitment__media figcaption {
  padding-top: 0.6rem;
  font-size: 0.8125rem;
  color: var(--color-steel);
  line-height: 1.5;
}

/* 平板及以上 */
@media (min-width: 600px) {
  .page-about .about-capability__metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

/* 桌面 */
@media (min-width: 900px) {
  .page-about .about-hero {
    min-height: 76vh;
    padding: 7rem 0 4.5rem;
  }

  .page-about .about-origin,
  .page-about .about-capability,
  .page-about .about-commitment {
    padding: 6rem 0;
  }

  .page-about .about-milestones {
    padding: 6rem 0;
  }

  .page-about .about-origin__container {
    grid-template-columns: 290px minmax(0, 1fr);
    gap: 4rem;
  }

  .page-about .about-origin__main {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .about-origin__side {
    grid-column: 1;
    grid-row: 1;
    position: sticky;
    top: 2rem;
  }

  .page-about .about-capability__grid {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    gap: 4.5rem;
    align-items: center;
  }

  .page-about .about-capability__media {
    order: -1;
  }

  .page-about .about-commitment__layout {
    grid-template-columns: minmax(0, 1fr) minmax(0, 400px);
    gap: 3.5rem;
    align-items: center;
  }
}