:root {
  --bg: #f4f7fb;
  --card: #ffffff;
  --text: #162234;
  --text-soft: #4d5f77;
  --line: #dbe3ef;
  --brand: #0b63ff;
  --brand-deep: #0643af;
  --brand-soft: #e9f1ff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif;
  background: radial-gradient(circle at top right, #dbe8ff 0%, var(--bg) 42%, #eef2f8 100%);
  color: var(--text);
  line-height: 1.6;
}

a {
  color: inherit;
  text-decoration: none;
}

/* 样式块分组：布局容器 */
.container {
  width: min(1120px, 92vw);
  margin: 0 auto;
}

/* 样式块分组：顶部导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.78);
  border-bottom: 1px solid rgba(20, 50, 90, 0.08);
}

.nav-wrap {
  display: flex; /* 关键布局属性：品牌与导航左右分布 */
  align-items: center;
  justify-content: space-between;
  min-height: 70px;
}

.brand {
  font-weight: 800;
  letter-spacing: 0.4px;
  font-size: 1.1rem;
}

.brand span {
  color: var(--text-soft);
  font-weight: 600;
}

.nav-links {
  display: flex; /* 关键布局属性：导航项水平排列 */
  gap: 22px;
  font-size: 0.95rem;
  color: var(--text-soft);
}

.nav-links a:hover {
  color: var(--brand);
}

/* 样式块分组：代练场景轮播 */
.carousel-section {
  padding: 28px 0 0;
}

.carousel {
  position: relative; /* 关键布局属性：承载绝对定位的按钮/指示点 */
  overflow: hidden;
  border-radius: 18px;
  border: 1px solid rgba(20, 50, 90, 0.08);
  box-shadow: 0 18px 34px rgba(8, 32, 76, 0.12);
}

.carousel-track {
  position: relative;
  min-height: 240px; /* 魔法数字来源：按 1200x420 轮播图在主容器缩放后的最小显示高度 */
}

.carousel-slide {
  display: none;
  width: 100%;
}

.carousel-slide.is-active {
  display: block;
  animation: fade-in 300ms ease;
}

.carousel-slide img {
  width: 100%;
  display: block;
  aspect-ratio: 20 / 7;
  object-fit: cover;
  background: #12254f;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 38px;
  height: 38px;
  border: 0;
  border-radius: 50%;
  cursor: pointer;
  font-size: 30px;
  line-height: 38px;
  color: #fff;
  background: rgba(9, 28, 70, 0.48);
}

.carousel-btn.prev {
  left: 12px;
}

.carousel-btn.next {
  right: 12px;
}

.carousel-dots {
  position: absolute;
  left: 50%;
  bottom: 12px;
  transform: translateX(-50%);
  display: flex; /* 关键布局属性：指示点横向排列 */
  gap: 8px;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  border: 0;
  cursor: pointer;
  background: rgba(255, 255, 255, 0.6);
}

.dot.is-active {
  width: 22px; /* 魔法数字来源：当前激活点拉伸为普通点约 2.2 倍，增强可识别性 */
  background: #ffffff;
}

/* 样式块分组：首页首屏 */
.hero {
  padding: 34px 0 46px;
}

.hero-grid {
  display: grid; /* 关键布局属性：首屏双列布局 */
  grid-template-columns: 1.35fr 1fr;
  gap: 24px;
}

.hero-main h1 {
  margin: 0 0 12px;
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.18;
}

.hero-kicker {
  margin: 0 0 6px;
  color: var(--brand-deep);
  font-weight: 700;
  letter-spacing: 1px;
}

.hero-desc {
  margin: 0 0 22px;
  color: var(--text-soft);
  max-width: 54ch;
}

.hero-actions {
  display: flex; /* 关键布局属性：按钮横排 */
  gap: 12px;
}

.hero-card {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(140deg, #fdfefe 0%, #f2f7ff 100%);
  box-shadow: 0 20px 36px rgba(8, 32, 76, 0.08);
}

.hero-card h2 {
  margin-top: 0;
  font-size: 1.1rem;
}

.hero-card ul {
  margin: 0;
  padding-left: 20px;
  color: var(--text-soft);
}

/* 样式块分组：通用 section */
.section {
  padding: 58px 0;
}

.section h2 {
  margin: 0 0 18px;
  font-size: 1.72rem;
}

.section.muted {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.56) 0%, rgba(231, 239, 252, 0.66) 100%);
  border-top: 1px solid rgba(20, 50, 90, 0.06);
  border-bottom: 1px solid rgba(20, 50, 90, 0.06);
}

.lead {
  margin: 0;
  color: var(--text-soft);
  max-width: 72ch;
}

.cards.three {
  display: grid; /* 关键布局属性：三栏能力卡片 */
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
}

.card h3 {
  margin: 0 0 10px;
}

.card p {
  margin: 0;
  color: var(--text-soft);
}

/* 样式块分组：推广专题 */
.promo {
  background: linear-gradient(180deg, rgba(233, 241, 255, 0.52) 0%, rgba(255, 255, 255, 0.86) 100%);
  border-top: 1px solid rgba(20, 50, 90, 0.06);
  border-bottom: 1px solid rgba(20, 50, 90, 0.06);
}

.promo-cards {
  margin-top: 18px;
}

.promo-card {
  background: linear-gradient(160deg, #ffffff 0%, #f3f8ff 100%);
}

.promo-actions {
  margin-top: 16px;
  display: flex; /* 关键布局属性：专题行动按钮横向排列 */
  gap: 10px;
}

/* 样式块分组：FAQ */
.faq-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.faq-item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px;
}

.faq-item h3 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.faq-item p {
  margin: 0;
  color: var(--text-soft);
}

/* 样式块分组：商务合作 */
.business-card {
  margin-top: 16px;
  padding: 18px;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: linear-gradient(145deg, #ffffff 0%, #eef5ff 100%);
  box-shadow: 0 10px 20px rgba(8, 32, 76, 0.06);
}

.business-card h3 {
  margin: 0 0 8px;
}

.business-card p {
  margin: 0 0 8px;
  color: var(--text-soft);
}

.qq-link {
  color: var(--brand-deep);
  font-weight: 700;
  border-bottom: 1px dashed rgba(6, 67, 175, 0.45);
}

.business-note {
  font-size: 0.9rem;
}

/* 样式块分组：公告轮播 */
.news-list {
  position: relative;
  min-height: 152px; /* 魔法数字来源：按三段公告内容最大高度预留 */
}

.news-item {
  display: none;
  padding: 20px;
  border-radius: 14px;
  background: var(--card);
  border: 1px solid var(--line);
}

.news-item.is-active {
  display: block;
  animation: fade-in 260ms ease;
}

.news-item time {
  color: var(--brand-deep);
  font-weight: 700;
}

.news-item h3 {
  margin: 6px 0 8px;
}

.news-item p {
  margin: 0;
  color: var(--text-soft);
}

.news-actions {
  margin-top: 14px;
  display: flex;
  gap: 10px;
}

/* 样式块分组：系统更新进度时间线 */
.progress-timeline {
  display: grid; /* 关键布局属性：时间线卡片纵向栅格排列 */
  gap: 12px;
  margin-top: 18px;
}

.progress-item {
  position: relative; /* 关键布局属性：用于承载左侧强调线与节点 */
  padding: 16px 18px 16px 22px;
  border-radius: 14px;
  background: var(--card);
  border: 1px solid var(--line);
  box-shadow: 0 10px 20px rgba(8, 32, 76, 0.05);
}

.progress-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 14px;
  bottom: 14px;
  width: 4px; /* 魔法数字来源：与卡片圆角比例匹配的视觉强调线宽 */
  border-radius: 999px;
  background: linear-gradient(180deg, #1c74ff 0%, #0f47b8 100%);
}

.progress-item time {
  color: var(--brand-deep);
  font-weight: 700;
}

.progress-item h3 {
  margin: 6px 0 8px;
  font-size: 1.06rem;
}

.progress-item p {
  margin: 0;
  color: var(--text-soft);
}

/* 样式块分组：按钮 */
.btn {
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 9px 16px;
  font-size: 0.92rem;
  cursor: pointer;
  transition: transform 0.16s ease, box-shadow 0.16s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--brand) 0%, #2f7fff 100%);
  color: #fff;
  box-shadow: 0 10px 18px rgba(11, 99, 255, 0.25);
}

.btn-ghost {
  background: var(--brand-soft);
  border-color: #c8dafd;
  color: var(--brand-deep);
}

/* 样式块分组：页脚 */
.site-footer {
  padding: 26px 0;
  border-top: 1px solid rgba(20, 50, 90, 0.08);
}

.footer-inner {
  display: flex; /* 关键布局属性：左右对齐 */
  justify-content: space-between;
  align-items: center;
  color: var(--text-soft);
}

/* 响应式断点用途：平板/手机单列布局 */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .cards.three {
    grid-template-columns: 1fr;
  }

  .faq-list {
    grid-template-columns: 1fr;
  }

  .promo-actions {
    flex-wrap: wrap;
  }
}

/* 响应式断点用途：小屏导航折行与按钮压缩 */
@media (max-width: 640px) {
  .nav-wrap {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding: 10px 0;
  }

  .nav-links {
    flex-wrap: wrap;
    gap: 10px 16px;
    font-size: 0.9rem;
  }

  .hero {
    padding-top: 42px;
  }

  .hero-actions {
    flex-wrap: wrap;
  }

  .promo-actions {
    width: 100%;
  }

  .carousel-track {
    min-height: 170px; /* 魔法数字来源：移动端保留轮播文案可读性的最小高度 */
  }

  .carousel-btn {
    width: 32px;
    height: 32px;
    font-size: 24px;
    line-height: 32px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

@keyframes fade-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}