/* ===== 页面专属：about ===== */
.page-about {
  display: flex;
  min-height: 100vh;
  background: var(--color-bg-dark);
  color: var(--color-white);
  font-family: var(--font-body);
  --about-track-w: 280px;
  --about-border-gold: 2px solid var(--color-gold);
  --about-border-crimson: 4px solid var(--color-crimson);
  --about-shadow-layer: 0 6px 24px rgba(0,0,0,0.5);
  --about-shadow-stack: 0 12px 36px rgba(0,0,0,0.6);
}

/* ===== 左侧轨道 ===== */
.about-track {
  position: sticky;
  top: 0;
  width: var(--about-track-w);
  min-width: var(--about-track-w);
  height: 100vh;
  background: var(--color-bg-darker);
  border-right: var(--about-border-crimson);
  box-shadow: inset -2px 0 0 var(--color-gold), 4px 0 20px rgba(0,0,0,0.6);
  display: flex;
  flex-direction: column;
  z-index: 10;
  /* 印刷边框装饰 */
  outline: 1px solid var(--color-gold-dark);
  outline-offset: -8px;
}

.about-track__inner {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 40px 20px 24px;
  position: relative;
}

/* 印刷边框角标 */
.about-track__inner::before,
.about-track__inner::after {
  content: "✦";
  position: absolute;
  font-size: 14px;
  color: var(--color-gold);
  opacity: 0.7;
}
.about-track__inner::before {
  top: 12px;
  left: 12px;
}
.about-track__inner::after {
  bottom: 12px;
  right: 12px;
}

.about-track__header {
  text-align: center;
  padding-bottom: 20px;
}

.about-track__logo {
  display: block;
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 900;
  color: var(--color-gold);
  letter-spacing: 2px;
  text-transform: uppercase;
}

.about-track__tagline {
  display: block;
  font-family: var(--font-body);
  font-size: 0.85rem;
  color: var(--color-gray-light);
  margin-top: 6px;
  letter-spacing: 1px;
}

.about-track__divider {
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-gold), transparent);
  margin: 0 10px 28px;
  opacity: 0.6;
}

.about-track__nav {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 32px;
}

.about-track__link {
  display: block;
  position: relative;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  color: var(--color-white);
  text-decoration: none;
  padding: 10px 16px;
  border-left: 3px solid transparent;
  transition: all var(--transition);
  overflow: hidden;
}

.about-track__link::before {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
  background: var(--color-crimson);
  transform: skewX(-15deg) translateX(-110%);
  transform-origin: left bottom;
  transition: transform 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  z-index: 0;
}

.about-track__link:hover::before {
  transform: skewX(-15deg) translateX(0);
}

.about-track__link:hover {
  color: var(--color-gold);
  border-left-color: var(--color-gold);
  padding-left: 22px;
}

/* 确保链接文字在伪元素上方 */
.about-track__link {
  position: relative;
  z-index: 1;
}

.about-track__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-top: auto;
  padding-top: 16px;
}

/* 标签 hover 斜向扩展 */
.about-track__tags .tag {
  transition: all var(--transition);
  cursor: default;
}

.about-track__tags .tag:hover {
  transform: skewX(-6deg) scale(1.05);
  box-shadow: 0 2px 12px rgba(255, 215, 0, 0.3);
}

.about-track__footer {
  text-align: center;
  padding-top: 18px;
  margin-top: 16px;
  border-top: 1px solid rgba(255, 215, 0, 0.2);
}

.about-track__footer-label {
  font-size: 0.75rem;
  color: var(--color-gray-mid);
  letter-spacing: 2px;
  text-transform: uppercase;
}

.about-track__footer-deco {
  display: block;
  color: var(--color-gold);
  font-size: 12px;
  margin-top: 4px;
  opacity: 0.5;
}

/* ===== 右侧内容 ===== */
.about-content {
  flex: 1;
  padding: 48px 56px 64px;
  max-width: 960px;
  margin: 0 auto;
  width: 100%;
}

/* 面包屑 */
.about-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--color-gray-light);
  margin-bottom: 48px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(255, 215, 0, 0.15);
}

.about-breadcrumb a {
  color: var(--color-gold);
  text-decoration: none;
  transition: color var(--transition);
}

.about-breadcrumb a:hover {
  color: var(--color-white);
  text-decoration: underline;
}

.about-breadcrumb__sep {
  color: var(--color-gray-mid);
  font-family: var(--font-numeric);
}

/* ===== 层级一：使命 ===== */
.about-mission {
  display: flex;
  flex-wrap: wrap;
  gap: 40px;
  align-items: center;
  margin-bottom: 72px;
  padding: 40px 32px;
  background: rgba(31, 31, 31, 0.7);
  box-shadow: var(--about-shadow-layer), 0 0 0 1px rgba(255, 215, 0, 0.08);
  position: relative;
}

.about-mission::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 120px;
  height: 4px;
  background: linear-gradient(90deg, transparent, var(--color-gold));
}

.about-mission__body {
  flex: 1;
  min-width: 260px;
}

.about-mission__title {
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 900;
  color: var(--color-gold);
  line-height: 1.1;
  margin: 0 0 20px;
  letter-spacing: -0.5px;
}

.about-mission__desc {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-white);
  margin-bottom: 28px;
  max-width: 520px;
}

.about-mission__actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.about-mission__visual {
  flex-shrink: 0;
  width: 500px;
  max-width: 100%;
}

.about-mission__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 500px;
  border: 1px solid var(--color-gold-dark);
  box-shadow: 0 4px 20px rgba(0,0,0,0.5);
  object-fit: cover;
}

/* ===== 层级二：平台覆盖 ===== */
.about-coverage {
  margin-bottom: 72px;
  padding: 32px 32px 40px;
  background: rgba(31, 31, 31, 0.5);
  box-shadow: var(--about-shadow-layer), 0 0 0 1px rgba(0, 77, 77, 0.2);
  position: relative;
}

.about-coverage::before {
  content: "";
  position: absolute;
  top: -12px;
  left: 32px;
  right: 32px;
  height: 1px;
  background: linear-gradient(90deg, var(--color-gold), transparent);
  opacity: 0.3;
}

.about-coverage .section-title {
  margin-bottom: 28px;
}

.about-coverage__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  align-items: flex-start;
}

.about-coverage__info {
  flex: 1;
  min-width: 240px;
}

.about-coverage__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.about-coverage__item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  padding: 8px 0;
  border-bottom: 1px dashed rgba(255, 215, 0, 0.12);
}

.about-coverage__icon {
  color: var(--color-gold);
  font-size: 1.2rem;
  flex-shrink: 0;
}

.about-coverage__label {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--color-white);
  min-width: 120px;
}

.about-coverage__note {
  font-size: 0.85rem;
  color: var(--color-gray-light);
  margin-left: auto;
}

.about-coverage__img {
  flex-shrink: 0;
  width: 300px;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--color-teal);
  box-shadow: 0 4px 16px rgba(0, 77, 77, 0.3);
  object-fit: cover;
  transition: box-shadow var(--transition);
}

.about-coverage__img:hover {
  box-shadow: 0 6px 24px rgba(0, 77, 77, 0.5);
}

/* ===== 层级三：核心功能 ===== */
.about-features {
  margin-bottom: 72px;
  padding: 32px 0;
}

.about-features .section-title {
  margin-bottom: 32px;
  padding-left: 32px;
}

.about-features__cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

/* 卡片叠层效果 */
.about-feature-card {
  position: relative;
  background: var(--color-bg-darker);
  border: 1px solid rgba(255, 215, 0, 0.12);
  padding: 32px 24px 28px;
  text-align: center;
  transition: all var(--transition);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.4), 8px 8px 0 rgba(0, 0, 0, 0.2);
  z-index: 1;
}

.about-feature-card:nth-child(2) {
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.4), 8px 8px 0 rgba(0, 0, 0, 0.2);
  top: 8px;
}

.about-feature-card:nth-child(3) {
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.4), 8px 8px 0 rgba(0, 0, 0, 0.2);
  top: 16px;
}

.about-feature-card:hover {
  background: var(--color-crimson);
  border-color: var(--color-gold);
  box-shadow: 4px 4px 0 var(--color-gold-dark), 8px 8px 0 rgba(0, 0, 0, 0.3);
  transform: translateY(-4px);
}

.about-feature-card__icon {
  display: block;
  width: 80px;
  height: 80px;
  margin: 0 auto 16px;
  object-fit: contain;
  border-radius: var(--radius);
  transition: transform var(--transition);
}

.about-feature-card:hover .about-feature-card__icon {
  transform: scale(1.06);
}

.about-feature-card__title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-gold);
  margin: 0 0 12px;
}

.about-feature-card__desc {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--color-white);
  margin: 0;
}

/* 卡片hover时文字微调 */
.about-feature-card:hover .about-feature-card__title {
  color: var(--color-white);
}

.about-feature-card:hover .about-feature-card__desc {
  color: rgba(255, 255, 255, 0.9);
}

/* ===== 收尾：用户承诺 ===== */
.about-promise {
  padding: 40px 32px;
  background: rgba(31, 31, 31, 0.6);
  box-shadow: var(--about-shadow-stack), 0 0 0 1px rgba(75, 0, 130, 0.15);
  position: relative;
}

.about-promise::before {
  content: "";
  position: absolute;
  bottom: 0;
  right: 0;
  width: 200px;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-indigo));
}

.about-promise .section-title {
  margin-bottom: 32px;
}

.about-promise__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-bottom: 36px;
}

.about-promise__item {
  padding: 20px 16px;
  border-left: 3px solid var(--color-gold-dark);
  transition: border-color var(--transition), background var(--transition);
}

.about-promise__item:hover {
  border-left-color: var(--color-gold);
  background: rgba(139, 0, 0, 0.15);
}

.about-promise__num {
  display: block;
  font-family: var(--font-numeric);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-gold);
  line-height: 1;
  margin-bottom: 8px;
}

.about-promise__title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-white);
  margin: 0 0 8px;
}

.about-promise__desc {
  font-size: 0.88rem;
  line-height: 1.6;
  color: var(--color-gray-light);
  margin: 0;
}

.about-promise__action {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 215, 0, 0.1);
}

/* ===== 响应式 - 移动端优先 ===== */
@media (max-width: 767px) {
  .page-about {
    flex-direction: column;
  }

  .about-track {
    position: relative;
    width: 100%;
    min-width: unset;
    height: auto;
    border-right: none;
    border-bottom: var(--about-border-crimson);
    box-shadow: inset 0 -2px 0 var(--color-gold), 0 4px 20px rgba(0,0,0,0.5);
    outline-offset: -4px;
  }

  .about-track__inner {
    padding: 24px 16px 16px;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
  }

  .about-track__inner::before,
  .about-track__inner::after {
    display: none;
  }

  .about-track__header {
    padding-bottom: 0;
    text-align: left;
    flex: 1;
    min-width: 140px;
  }

  .about-track__logo {
    font-size: 1.2rem;
  }

  .about-track__tagline {
    font-size: 0.75rem;
    margin-top: 2px;
  }

  .about-track__divider {
    display: none;
  }

  .about-track__nav {
    flex-direction: row;
    gap: 6px;
    margin-bottom: 0;
    order: 3;
    width: 100%;
    justify-content: center;
  }

  .about-track__link {
    font-size: 0.8rem;
    padding: 6px 12px;
    border-left: none;
    border-bottom: 2px solid transparent;
  }

  .about-track__link::before {
    display: none;
  }

  .about-track__link:hover {
    border-left-color: transparent;
    border-bottom-color: var(--color-gold);
    padding-left: 12px;
  }

  .about-track__tags {
    margin-top: 0;
    padding-top: 0;
    order: 2;
    flex-shrink: 0;
  }

  .about-track__tags .tag {
    font-size: 0.7rem;
    padding: 4px 8px;
  }

  .about-track__footer {
    display: none;
  }

  .about-content {
    padding: 32px 16px 48px;
  }

  .about-breadcrumb {
    margin-bottom: 32px;
  }

  .about-mission {
    padding: 28px 16px;
    margin-bottom: 48px;
  }

  .about-mission__title {
    font-size: 2rem;
  }

  .about-mission__visual {
    width: 100%;
  }

  .about-mission__img {
    max-width: 100%;
  }

  .about-coverage {
    padding: 24px 16px;
    margin-bottom: 48px;
  }

  .about-coverage__inner {
    flex-direction: column;
  }

  .about-coverage__img {
    width: 100%;
    max-width: 300px;
    margin: 0 auto;
  }

  .about-coverage__item {
    flex-direction: column;
    gap: 4px;
  }

  .about-coverage__note {
    margin-left: 0;
    padding-left: 24px;
  }

  .about-features {
    padding: 24px 0;
    margin-bottom: 48px;
  }

  .about-features .section-title {
    padding-left: 16px;
  }

  .about-features__cards {
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 0 16px;
  }

  .about-feature-card {
    padding: 24px 16px;
  }

  .about-feature-card:nth-child(2),
  .about-feature-card:nth-child(3) {
    top: 0;
  }

  .about-promise {
    padding: 28px 16px;
  }

  .about-promise__grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .about-promise__action {
    flex-direction: column;
    align-items: stretch;
  }

  .about-promise__action .btn {
    text-align: center;
  }
}

/* ===== 桌面端微调 ===== */
@media (min-width: 768px) and (max-width: 1023px) {
  .about-track {
    --about-track-w: 220px;
    min-width: 220px;
  }

  .about-content {
    padding: 40px 32px 56px;
  }

  .about-mission__title {
    font-size: 2.4rem;
  }

  .about-mission__visual {
    width: 100%;
  }

  .about-features__cards {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-promise__grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1280px) {
  .about-content {
    padding: 56px 72px 80px;
    max-width: 1040px;
  }

  .about-mission {
    padding: 48px 40px;
  }

  .about-mission__title {
    font-size: 3.4rem;
  }
}