.page-about {
  --about-hero-bg: #0D1B2A;
  --about-card-bg-front: #1A2D42;
  --about-card-bg-back: #00A878;
  --about-timeline-line: #0066CC;
  --about-timeline-dot-size: 40px;
  --about-border-radius: 12px;
  --about-card-min-height: 220px;
  color: var(--text-dark);
  background: var(--bg-light);
}

/* ===== 面包屑 ===== */
.about-breadcrumb {
  max-width: var(--site-width);
  margin: 0 auto;
  padding: 1rem 1.5rem 0;
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 0.8rem;
  color: var(--neutral-gray);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.about-breadcrumb a {
  color: var(--info-blue);
  text-decoration: none;
  transition: color var(--transition);
}
.about-breadcrumb a:hover,
.about-breadcrumb a:focus-visible {
  color: var(--secondary-blue);
  text-decoration: underline;
}
.about-breadcrumb__sep {
  color: var(--neutral-gray);
  user-select: none;
}
.about-breadcrumb [aria-current="page"] {
  color: var(--text-dark);
  font-weight: 600;
}

/* ===== 首屏 Hero ===== */
.about-hero {
  background: var(--about-hero-bg);
  position: relative;
  overflow: hidden;
  padding: 2rem 0 3rem;
}
.about-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, rgba(0,168,120,0.15) 0%, rgba(0,102,204,0.10) 50%, transparent 80%);
  pointer-events: none;
}
.about-hero__inner {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  position: relative;
  z-index: 1;
}
.about-hero__left {
  flex: 0 0 auto;
}
.about-hero__title {
  font-family: 'Impact', 'Arial Black', sans-serif;
  font-weight: 900;
  font-size: 3.2rem;
  line-height: 1.05;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  color: #fff;
  margin: 0 0 1.2rem;
}
.about-hero__desc {
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-light);
  max-width: 560px;
  margin: 0 0 1.8rem;
}
.about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}
.about-hero__actions .btn {
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.7rem 1.6rem;
  border-radius: 6px;
  text-decoration: none;
  transition: all var(--transition);
  display: inline-block;
}
.about-hero__actions .btn-outline {
  background: transparent;
  border: 2px solid var(--accent-gold);
  color: var(--accent-gold);
}
.about-hero__actions .btn-outline:hover,
.about-hero__actions .btn-outline:focus-visible {
  background: var(--accent-gold);
  color: var(--text-dark);
}
.about-hero__actions .btn-gold {
  background: var(--accent-gold);
  border: 2px solid var(--accent-gold);
  color: var(--text-dark);
}
.about-hero__actions .btn-gold:hover,
.about-hero__actions .btn-gold:focus-visible {
  background: #e6c200;
  border-color: #e6c200;
}
.about-hero__right {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1.2rem;
}
.about-hero__visual-img {
  width: 100%;
  max-width: 600px;
  height: auto;
  border-radius: var(--about-border-radius);
  object-fit: cover;
  box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}
.about-hero__preview {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}
.about-hero__preview-tag {
  display: inline-block;
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.35rem 0.9rem;
  border-radius: 20px;
  background: rgba(0,168,120,0.20);
  color: var(--accent-gold);
  border: 1px solid rgba(255,215,0,0.30);
}

/* ===== 服务清单概述 ===== */
.about-services {
  padding: 3.5rem 0 3rem;
  background: var(--bg-light);
}
.about-services__header {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}
.about-services__header-img {
  width: 100%;
  max-width: 300px;
  height: auto;
  border-radius: var(--about-border-radius);
  object-fit: cover;
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}
.about-services__header-text {
  flex: 1;
}
.about-services__heading {
  font-family: 'Impact', 'Arial Black', sans-serif;
  font-weight: 900;
  font-size: 2.2rem;
  letter-spacing: -0.01em;
  text-transform: uppercase;
  color: var(--text-dark);
  margin: 0 0 0.8rem;
}
.about-services__intro {
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-dark);
  max-width: 640px;
  margin: 0;
}
.about-services__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

/* 卡片翻转 */
.about-services__card {
  perspective: 1000px;
  min-height: var(--about-card-min-height);
  cursor: pointer;
  outline: none;
}
.about-services__card:focus-visible {
  outline: 2px solid var(--accent-gold);
  outline-offset: 4px;
  border-radius: var(--about-border-radius);
}
.about-services__card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  min-height: var(--about-card-min-height);
  transition: transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
  transform-style: preserve-3d;
}
.about-services__card:hover .about-services__card-inner,
.about-services__card:focus-within .about-services__card-inner {
  transform: rotateY(180deg);
}
.about-services__card-front,
.about-services__card-back {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  min-height: var(--about-card-min-height);
  backface-visibility: hidden;
  border-radius: var(--about-border-radius);
  padding: 1.8rem 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-sizing: border-box;
}
.about-services__card-front {
  background: var(--about-card-bg-front);
  color: #fff;
  align-items: center;
  text-align: center;
}
.about-services__card-back {
  background: var(--about-card-bg-back);
  color: #fff;
  transform: rotateY(180deg);
  align-items: center;
  text-align: center;
}
.about-services__card-back p {
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 0.95rem;
  line-height: 1.6;
  margin: 0;
  max-width: 260px;
}
.about-services__card-icon {
  font-family: 'Impact', 'Arial Black', sans-serif;
  font-size: 2.8rem;
  font-weight: 900;
  color: var(--accent-gold);
  display: block;
  margin-bottom: 0.4rem;
  line-height: 1;
}
.about-services__card-title {
  font-family: 'Impact', 'Arial Black', sans-serif;
  font-size: 1.4rem;
  font-weight: 900;
  letter-spacing: -0.01em;
  text-transform: uppercase;
  margin: 0;
  color: #fff;
}

/* ===== 版本更新历程 ===== */
.about-timeline {
  padding: 3.5rem 0 3rem;
  background: var(--bg-dark);
  color: var(--text-light);
}
.about-timeline__heading {
  font-family: 'Impact', 'Arial Black', sans-serif;
  font-weight: 900;
  font-size: 2.2rem;
  letter-spacing: -0.01em;
  text-transform: uppercase;
  color: #fff;
  margin: 0 0 0.6rem;
}
.about-timeline__intro {
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  color: var(--neutral-gray);
  max-width: 560px;
  margin: 0 0 2.5rem;
}
.about-timeline__items {
  display: flex;
  flex-direction: column;
  gap: 0;
  position: relative;
  padding-left: 2rem;
}
.about-timeline__items::before {
  content: '';
  position: absolute;
  left: 20px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--about-timeline-line), var(--primary-green));
  border-radius: 2px;
}
.about-timeline__item {
  display: block;
  border: none;
  margin: 0;
  position: relative;
}
.about-timeline__item + .about-timeline__item {
  margin-top: 0.5rem;
}
.about-timeline__summary {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 1rem 1.2rem;
  background: rgba(255,255,255,0.04);
  border-radius: 10px;
  cursor: pointer;
  list-style: none;
  transition: background var(--transition);
  position: relative;
  z-index: 1;
}
.about-timeline__summary::-webkit-details-marker {
  display: none;
}
.about-timeline__summary:hover {
  background: rgba(255,255,255,0.08);
}
.about-timeline__summary:focus-visible {
  outline: 2px solid var(--accent-gold);
  outline-offset: 2px;
}
.about-timeline__dot {
  width: var(--about-timeline-dot-size);
  height: var(--about-timeline-dot-size);
  border-radius: 50%;
  flex-shrink: 0;
  object-fit: cover;
  border: 3px solid var(--accent-gold);
  box-shadow: 0 0 0 3px var(--bg-dark);
  background: var(--bg-dark);
  position: relative;
  z-index: 2;
}
.about-timeline__year {
  font-family: 'Impact', 'Arial Black', sans-serif;
  font-weight: 900;
  font-size: 1.1rem;
  color: var(--accent-gold);
  flex-shrink: 0;
  min-width: 5em;
}
.about-timeline__title {
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  color: #fff;
  flex: 1;
}
.about-timeline__toggle {
  font-family: 'Geometria', sans-serif;
  font-weight: 700;
  font-size: 1.4rem;
  color: var(--accent-gold);
  transition: transform var(--transition);
  flex-shrink: 0;
}
.about-timeline__item[open] .about-timeline__toggle {
  transform: rotate(45deg);
}
.about-timeline__detail {
  padding: 0.8rem 1.2rem 1.4rem 4.8rem;
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--neutral-gray);
}
.about-timeline__detail p {
  margin: 0;
}
.about-timeline__cta {
  margin-top: 2.5rem;
  padding: 1.2rem 1.5rem;
  background: rgba(255,255,255,0.05);
  border-radius: 10px;
  text-align: center;
  font-family: 'Geometria', 'Montserrat', 'Segoe UI', sans-serif;
  font-size: 0.95rem;
  color: var(--text-light);
}
.about-timeline__cta p {
  margin: 0;
}
.about-timeline__link {
  color: var(--accent-gold);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--transition);
}
.about-timeline__link:hover,
.about-timeline__link:focus-visible {
  color: #fff;
}

/* ===== 响应式：平板及以上 ===== */
@media (min-width: 640px) {
  .about-breadcrumb {
    padding: 1.2rem 2rem 0;
  }
  .about-hero {
    padding: 3rem 0 4rem;
  }
  .about-hero__title {
    font-size: 4rem;
  }
  .about-hero__desc {
    font-size: 1.05rem;
  }
  .about-services__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .about-timeline__items {
    padding-left: 3rem;
  }
  .about-timeline__items::before {
    left: 28px;
  }
  .about-timeline__year {
    font-size: 1.2rem;
    min-width: 6em;
  }
  .about-timeline__title {
    font-size: 1rem;
  }
}

/* ===== 响应式：桌面 ===== */
@media (min-width: 960px) {
  .about-breadcrumb {
    padding: 1.5rem 2rem 0;
  }
  .about-hero {
    padding: 4rem 0 5rem;
  }
  .about-hero__inner {
    flex-direction: row;
    align-items: center;
    gap: 3rem;
  }
  .about-hero__left {
    flex: 1 1 45%;
  }
  .about-hero__right {
    flex: 1 1 55%;
    align-items: flex-end;
    position: relative;
  }
  .about-hero__right::before {
    content: '';
    position: absolute;
    top: -20%;
    right: -10%;
    width: 70%;
    height: 140%;
    background: linear-gradient(135deg, rgba(0,168,120,0.25) 0%, rgba(0,102,204,0.15) 60%, transparent 100%);
    transform: skewX(-10deg);
    pointer-events: none;
    z-index: 0;
    border-radius: 20px;
  }
  .about-hero__visual-img {
    position: relative;
    z-index: 1;
  }
  .about-hero__preview {
    position: relative;
    z-index: 1;
  }
  .about-hero__title {
    font-size: 5.5rem;
  }
  .about-hero__desc {
    font-size: 1.1rem;
  }
  .about-services__header {
    flex-direction: row;
    align-items: flex-start;
    gap: 2.5rem;
  }
  .about-services__header-img {
    flex-shrink: 0;
  }
  .about-services__heading {
    font-size: 2.6rem;
  }
  .about-services__grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .about-timeline__heading {
    font-size: 2.6rem;
  }
  .about-timeline__items {
    padding-left: 4rem;
  }
  .about-timeline__items::before {
    left: 34px;
  }
  .about-timeline__year {
    font-size: 1.3rem;
    min-width: 7em;
  }
  .about-timeline__title {
    font-size: 1.05rem;
  }
  .about-timeline__detail {
    padding-left: 6rem;
  }
  .about-timeline__cta {
    padding: 1.5rem 2rem;
  }
}

/* ===== 超大桌面 ===== */
@media (min-width: 1280px) {
  .about-hero__title {
    font-size: 6.5rem;
  }
  .about-hero__desc {
    font-size: 1.15rem;
  }
}