.page-about {
  background: var(--paper-gradient);
  color: var(--color-ink);
}

.page-about img {
  max-width: 100%;
  height: auto;
}

/* ========== 页面头部 ========== */
.page-about .about-head {
  position: relative;
  padding: 2rem 0 2.75rem;
  overflow: hidden;
  border-bottom: 1px solid var(--color-gray-light);
  background:
    linear-gradient(135deg, rgba(11,45,92,.05) 0%, rgba(201,162,39,.07) 100%),
    var(--paper-gradient);
}

.page-about .about-head::before {
  content: "";
  position: absolute;
  right: -6%;
  top: -30%;
  width: 16rem;
  height: 16rem;
  border: 1px solid rgba(11,45,92,.10);
  border-radius: 2px;
  transform: rotate(18deg) skewX(-10deg);
}

.page-about .about-head::after {
  content: "HTH";
  position: absolute;
  right: 1.2rem;
  bottom: -1.6rem;
  font-family: var(--font-head);
  font-size: 5.5rem;
  font-weight: 700;
  line-height: 1;
  color: rgba(11,45,92,.05);
  letter-spacing: -.03em;
}

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

.page-about .about-head .breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .5rem;
  margin-bottom: 1.5rem;
  font-size: .88rem;
}

.page-about .about-head .breadcrumbs a {
  color: var(--color-blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--ease), color var(--ease);
}

.page-about .about-head .breadcrumbs a:hover,
.page-about .about-head .breadcrumbs a:focus-visible {
  border-color: var(--color-gold);
  color: var(--color-ink);
}

.page-about .about-head .breadcrumbs__sep {
  color: var(--color-gray-mid);
}

.page-about .about-head .breadcrumbs span[aria-current="page"] {
  color: var(--color-gray-mid);
}

.page-about .about-head .kicker {
  margin: .75rem 0 .35rem;
}

.page-about .about-head .page-title {
  margin: .4rem 0 1rem;
  max-width: 820px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(1.6rem, 4.8vw, 2.8rem);
  line-height: 1.2;
  letter-spacing: -.01em;
}

.page-about .about-head .page-description {
  max-width: 720px;
  margin: 0;
  font-size: .98rem;
  line-height: 1.75;
  color: var(--color-gray-dark);
}

/* ========== 章节元信息 ========== */
.page-about .about-section__meta {
  display: flex;
  align-items: center;
  gap: .65rem;
  margin-bottom: .45rem;
}

.page-about .about-section__meta .kicker {
  margin: 0;
}

.page-about .section-index {
  display: inline-block;
  padding: .18rem .55rem;
  background: linear-gradient(100deg, rgba(255,107,53,.14) 0%, rgba(201,162,39,.14) 100%);
  border-left: 2px solid var(--color-orange);
  font-family: var(--font-head);
  font-weight: 700;
  font-size: .88rem;
  color: var(--color-orange);
  letter-spacing: .1em;
  line-height: 1;
}

.page-about .section-index--light {
  background: rgba(255,255,255,.10);
  border-left-color: var(--color-gold);
  color: var(--color-gold);
}

/* ========== 01 品牌源起 ========== */
.page-about .about-origin {
  padding: 3rem 0 3.25rem;
}

.page-about .about-origin__grid {
  display: grid;
  gap: 2rem;
  align-items: center;
}

.page-about .about-origin__content {
  border-left: 2px solid var(--color-gold);
  padding-left: 1.25rem;
}

.page-about .about-origin__content h2,
.page-about .about-evolution__head h2,
.page-about .about-devices__content h2,
.page-about .about-commit__main h2 {
  font-family: var(--font-head);
  font-weight: 700;
  line-height: 1.32;
  margin: .25rem 0 1rem;
  letter-spacing: -.015em;
}

.page-about .about-origin__content h2 {
  font-size: 1.45rem;
}

.page-about .about-origin__content p {
  margin: 0 0 1rem;
  line-height: 1.75;
  color: var(--color-gray-dark);
}

.page-about .about-origin__content .callout {
  margin-top: 1.25rem;
}

.page-about .about-origin__media .figure {
  margin: 0;
}

/* ========== 02 数据服务演进 ========== */
.page-about .about-evolution {
  padding: 3.25rem 0;
  background: var(--color-white);
  border-top: 1px solid var(--color-gray-light);
  border-bottom: 3px solid var(--color-gold);
}

.page-about .about-evolution__head {
  margin-bottom: 2.25rem;
  max-width: 720px;
}

.page-about .about-evolution__head h2 {
  font-size: 1.45rem;
}

.page-about .about-evolution__lede {
  margin: 0;
  font-size: .96rem;
  line-height: 1.75;
  color: var(--color-gray-dark);
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.5rem;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(to bottom, var(--color-gold) 0%, var(--color-blue) 100%);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 2rem;
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -1.53rem;
  top: .85rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-white);
  border: 3px solid var(--color-gold);
  box-sizing: border-box;
}

.page-about .about-timeline__marker {
  display: inline-block;
  margin-bottom: .5rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: .92rem;
  letter-spacing: .06em;
  color: var(--color-orange);
  border-bottom: 2px solid var(--color-gold);
  padding-bottom: 2px;
}

.page-about .about-timeline__body h3 {
  font-family: var(--font-head);
  font-size: 1.05rem;
  margin: 0 0 .35rem;
}

.page-about .about-timeline__body p {
  margin: 0;
  font-size: .93rem;
  line-height: 1.7;
  color: var(--color-gray-dark);
}

/* ========== 03 多设备与数据保留 ========== */
.page-about .about-devices {
  position: relative;
  padding: 3.25rem 0;
  overflow: hidden;
  background: var(--color-blue);
  color: var(--color-white);
}

.page-about .about-devices::before {
  content: "";
  position: absolute;
  right: -4rem;
  top: 2rem;
  width: 18rem;
  height: 18rem;
  border: 1px solid rgba(255,255,255,.10);
  transform: rotate(18deg) skewX(-8deg);
}

.page-about .about-devices::after {
  content: "HTH";
  position: absolute;
  right: -1rem;
  bottom: -1.6rem;
  font-family: var(--font-head);
  font-size: 6rem;
  font-weight: 700;
  line-height: 1;
  color: rgba(255,255,255,.04);
  letter-spacing: -.05em;
}

.page-about .about-devices__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 2rem;
  align-items: center;
}

.page-about .about-devices__content h2 {
  font-size: 1.4rem;
}

.page-about .about-devices__content p {
  color: rgba(255,255,255,.82);
  line-height: 1.75;
  font-size: .95rem;
  margin: 0 0 1rem;
}

.page-about .about-devices__features {
  list-style: none;
  margin: 1.25rem 0 0;
  padding: 0;
}

.page-about .about-devices__features li {
  position: relative;
  padding: .6rem 0 .6rem 1.75rem;
  border-bottom: 1px solid rgba(255,255,255,.08);
  font-size: .95rem;
}

.page-about .about-devices__features li:last-child {
  border-bottom: none;
}

.page-about .about-devices__features li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .9rem;
  width: 8px;
  height: 8px;
  background: var(--color-gold);
  transform: skewX(-24deg);
}

.page-about .about-devices__features li strong {
  color: var(--color-white);
  font-weight: 600;
}

.page-about .about-devices__media {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,.14);
}

.page-about .about-devices__media::after {
  content: "登录中心 · 同步保留30天";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: .65rem .8rem;
  background: rgba(10,30,63,.72);
  color: var(--color-white);
  font-size: .8rem;
  text-align: center;
  transition: background-color var(--ease);
}

.page-about .about-devices__media:hover::after {
  background: rgba(10,30,63,.88);
}

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

/* ========== 04 品牌承诺 ========== */
.page-about .about-commit {
  padding: 3.25rem 0;
}

.page-about .about-commit__grid {
  display: grid;
  gap: 2.5rem;
  align-items: start;
}

.page-about .about-commit__main h2 {
  font-size: 1.45rem;
}

.page-about .about-commit__main > p {
  margin: 0 0 1rem;
  line-height: 1.75;
  color: var(--color-gray-dark);
}

.page-about .about-commit__stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: .55rem;
  margin-top: 1.5rem;
  border-top: 1px solid var(--color-gray-light);
  padding-top: 1.25rem;
}

.page-about .about-commit__stats .stat {
  border-left: 1px solid var(--color-gray-light);
  padding-left: .75rem;
}

.page-about .about-commit__stats .stat__value {
  display: block;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.35rem;
  line-height: 1.1;
  color: var(--color-blue);
}

.page-about .about-commit__stats .stat__label {
  display: block;
  margin-top: .3rem;
  font-size: .72rem;
  line-height: 1.4;
  color: var(--color-gray-dark);
}

.page-about .about-commit__aside {
  display: grid;
  gap: 1.25rem;
  align-content: start;
}

.page-about .about-cycle {
  border: 1px solid var(--color-gray-light);
  background: var(--color-white);
  padding: 1rem;
  box-shadow: var(--shadow-1);
}

.page-about .about-cycle img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  margin-bottom: .9rem;
}

.page-about .about-cycle h3 {
  font-family: var(--font-head);
  font-size: 1rem;
  margin: 0 0 .4rem;
}

.page-about .about-cycle p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--color-gray-dark);
}

.page-about .about-cycle__detail {
  margin-top: .8rem;
  border-top: 1px dashed var(--color-gray-light);
  padding-top: .6rem;
}

.page-about .about-cycle__detail summary {
  list-style: none;
  cursor: pointer;
  color: var(--color-blue);
  font-weight: 600;
  font-size: .88rem;
  transition: color var(--ease);
}

.page-about .about-cycle__detail summary:hover,
.page-about .about-cycle__detail summary:focus-visible {
  color: var(--color-orange);
}

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

.page-about .about-cycle__detail p {
  margin-top: .55rem;
  font-size: .87rem;
}

/* ========== 页面内链接条 ========== */
.page-about .about-links {
  padding: 1.5rem 0 2.5rem;
  border-top: 1px solid var(--color-gray-light);
}

.page-about .about-links__bar {
  display: flex;
  flex-wrap: wrap;
  gap: .65rem;
  align-items: center;
}

.page-about .about-links__label {
  flex-basis: 100%;
  font-size: .85rem;
  letter-spacing: .08em;
  color: var(--color-gray-mid);
}

/* ========== 桌面端 ========== */
@media (min-width: 768px) {
  .page-about .about-head {
    padding: 3.25rem 0 4rem;
  }

  .page-about .about-head::before {
    right: 8%;
    top: -40%;
  }

  .page-about .about-head .page-title {
    font-size: 2.35rem;
  }

  .page-about .about-head .page-description {
    font-size: 1.02rem;
  }

  .page-about .about-origin,
  .page-about .about-evolution,
  .page-about .about-devices,
  .page-about .about-commit {
    padding: 4.5rem 0;
  }

  .page-about .about-origin__grid {
    grid-template-columns: 1.05fr .95fr;
    gap: 3rem;
  }

  .page-about .about-origin__content h2,
  .page-about .about-evolution__head h2,
  .page-about .about-devices__content h2,
  .page-about .about-commit__main h2 {
    font-size: 1.75rem;
  }

  .page-about .about-evolution__head {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
    align-items: end;
    max-width: none;
    margin-bottom: 3rem;
  }

  .page-about .about-evolution__lede {
    font-size: 1rem;
  }

  /* 交错时间线 */
  .page-about .about-timeline {
    padding-left: 0;
    max-width: 960px;
    margin: 0 auto;
  }

  .page-about .about-timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }

  .page-about .about-timeline__item {
    width: calc(50% - 2rem);
    padding-bottom: 2.5rem;
  }

  .page-about .about-timeline__item:nth-child(odd) {
    margin-right: auto;
    padding-right: 3.5rem;
    text-align: right;
  }

  .page-about .about-timeline__item:nth-child(even) {
    margin-left: auto;
    padding-left: 3.5rem;
  }

  .page-about .about-timeline__item:nth-child(odd)::before {
    left: auto;
    right: -2.75rem;
  }

  .page-about .about-timeline__item:nth-child(even)::before {
    left: -2.75rem;
  }

  .page-about .about-timeline__item:nth-child(odd) .about-timeline__body,
  .page-about .about-timeline__item:nth-child(odd) .about-timeline__marker {
    text-align: left;
  }

  .page-about .about-devices__grid {
    grid-template-columns: .95fr 1.05fr;
    gap: 3rem;
  }

  .page-about .about-devices__content h2 {
    font-size: 1.7rem;
  }

  .page-about .about-devices__features {
    margin-top: 1.5rem;
  }

  .page-about .about-commit__grid {
    grid-template-columns: 1.05fr .95fr;
    gap: 3.5rem;
  }

  .page-about .about-commit__stats {
    margin-top: 2rem;
    padding-top: 1.5rem;
  }

  .page-about .about-commit__stats .stat__value {
    font-size: 1.7rem;
  }

  .page-about .about-commit__stats .stat__label {
    font-size: .8rem;
  }

  .page-about .about-cycle {
    padding: 1.25rem;
  }

  .page-about .about-links {
    padding-top: 2rem;
    padding-bottom: 3.25rem;
  }

  .page-about .about-links__bar {
    justify-content: flex-end;
  }

  .page-about .about-links__label {
    flex-basis: auto;
    margin-right: auto;
  }
}

@media (min-width: 1024px) {
  .page-about .about-head .page-title {
    font-size: 2.8rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-devices__media::after,
  .page-about .about-cycle__detail summary {
    transition: none;
  }
}