/* ==========================================================
   数企云 AI 应用在线培训官网  -  全局样式
   视觉：科技蓝 + 紫渐变 / 专业简洁 / 响应式
   ========================================================== */

:root {
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --accent: #7c3aed;
  --gradient: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  --dark: #0f172a;
  --text: #1e293b;
  --text-light: #64748b;
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --border: #e2e8f0;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 20px 50px rgba(37, 99, 235, 0.15);
  --max-w: 1200px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}

img {
  max-width: 100%;
  display: block;
}

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

ul {
  list-style: none;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============ 通用组件 ============ */
.section {
  padding: 84px 0;
}

.section--soft {
  background: var(--bg-soft);
}

.section-head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px;
}

.section-head .tag {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.1);
  color: var(--primary);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 1px;
  margin-bottom: 16px;
}

.section-head h2 {
  font-size: 34px;
  font-weight: 800;
  color: var(--dark);
  margin-bottom: 14px;
  line-height: 1.3;
}

.section-head p {
  color: var(--text-light);
  font-size: 17px;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 32px;
  border-radius: 999px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.3s ease;
  white-space: nowrap;
}

.btn--primary {
  background: var(--gradient);
  color: #fff;
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.35);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(37, 99, 235, 0.45);
}

.btn--ghost {
  background: transparent;
  color: var(--primary);
  border: 2px solid rgba(37, 99, 235, 0.5);
}

.btn--ghost:hover {
  background: rgba(37, 99, 235, 0.08);
  border-color: var(--primary);
}

.btn--light {
  background: #fff;
  color: var(--primary);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

.btn--light:hover {
  transform: translateY(-2px);
}

/* ============ 顶部导航 ============ */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 20px;
  font-weight: 800;
  color: var(--dark);
}

.logo__mark {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: var(--gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 20px;
  font-weight: 900;
  flex-shrink: 0;
}

.logo span {
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav__links a {
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  transition: all 0.2s;
}

.nav__links a:hover,
.nav__links a.active {
  color: var(--primary);
  background: rgba(37, 99, 235, 0.08);
}

.nav__cta {
  margin-left: 12px;
  padding: 9px 22px;
  font-size: 14px;
}

/* 汉堡菜单 */
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav__toggle span {
  width: 24px;
  height: 2px;
  background: var(--dark);
  border-radius: 2px;
  transition: all 0.3s;
}

/* ============ Hero ============ */
.hero {
  position: relative;
  background: var(--gradient);
  color: #fff;
  overflow: hidden;
  padding: 110px 0;
}

.hero::before {
  content: "";
  position: absolute;
  top: -120px;
  right: -120px;
  width: 480px;
  height: 480px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
}

.hero::after {
  content: "";
  position: absolute;
  bottom: -160px;
  left: -100px;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.06);
}

.hero__inner {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 860px;
  margin: 0 auto;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 20px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.3);
  font-size: 14px;
  font-weight: 500;
  margin-bottom: 28px;
  backdrop-filter: blur(4px);
}

.hero h1 {
  font-size: 52px;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 22px;
  letter-spacing: 1px;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(135deg, #fde68a, #fca5a5);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 18px;
  opacity: 0.9;
  max-width: 640px;
  margin: 0 auto 40px;
}

.hero__btns {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* Hero 数据条 */
.hero__stats {
  margin-top: 64px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius);
  padding: 28px 32px;
  backdrop-filter: blur(6px);
}

.hero__stats-item {
  text-align: center;
}

.hero__stats-item strong {
  display: block;
  font-size: 30px;
  font-weight: 800;
  margin-bottom: 4px;
}

.hero__stats-item span {
  font-size: 14px;
  opacity: 0.85;
}

/* ============ 课程方向卡片 ============ */
.course-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.course-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.course-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--gradient);
  opacity: 0;
  transition: opacity 0.3s;
}

.course-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.course-card:hover::before {
  opacity: 1;
}

.course-card__icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: rgba(37, 99, 235, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  margin-bottom: 20px;
}

.course-card h3 {
  font-size: 20px;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 10px;
}

.course-card p {
  color: var(--text-light);
  font-size: 15px;
  margin-bottom: 18px;
}

.course-card__meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
  color: var(--text-light);
  font-size: 14px;
}

.course-card__meta .count {
  color: var(--primary);
  font-weight: 700;
}

.course-card__link {
  color: var(--primary);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap 0.2s;
}

.course-card__link:hover {
  gap: 8px;
}

/* ============ 热门课程 ============ */
.hot-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.hot-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all 0.3s;
  display: flex;
  flex-direction: column;
}

.hot-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
}

.hot-card__body {
  padding: 24px 26px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.hot-card__tag {
  align-self: flex-start;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(124, 58, 237, 0.1);
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 12px;
}

.hot-card h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.5;
}

.hot-card p {
  color: var(--text-light);
  font-size: 14px;
  flex: 1;
  margin-bottom: 16px;
}

.hot-card__foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 14px;
  color: var(--text-light);
}

.hot-card__price {
  color: var(--primary);
  font-weight: 700;
  font-size: 16px;
}

/* ============ 学习方式 ============ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature {
  text-align: center;
  padding: 36px 24px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all 0.3s;
}

.feature:hover {
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}

.feature__icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 18px;
  border-radius: 50%;
  background: var(--gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
}

.feature h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
}

.feature p {
  color: var(--text-light);
  font-size: 14px;
}

/* ============ 平台资质 / 优势 ============ */
.advantage-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.advantage {
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 28px;
  display: flex;
  gap: 18px;
  align-items: flex-start;
}

.advantage__num {
  font-size: 28px;
  font-weight: 800;
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
  flex-shrink: 0;
}

.advantage h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 6px;
}

.advantage p {
  color: var(--text-light);
  font-size: 14px;
}

/* ============ CTA 区域 ============ */
.cta {
  background: var(--gradient);
  color: #fff;
  text-align: center;
  padding: 80px 0;
  position: relative;
  overflow: hidden;
}

.cta h2 {
  font-size: 34px;
  font-weight: 800;
  margin-bottom: 14px;
}

.cta p {
  opacity: 0.9;
  font-size: 17px;
  margin-bottom: 34px;
}

/* ============ 页脚 ============ */
.footer {
  background: var(--dark);
  color: #94a3b8;
  padding: 64px 0 0;
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 48px;
}

.footer__brand .logo {
  color: #fff;
  margin-bottom: 16px;
}

.footer__brand p {
  font-size: 14px;
  line-height: 1.8;
  max-width: 320px;
}

.footer h4 {
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 18px;
}

.footer__links li {
  margin-bottom: 12px;
}

.footer__links a {
  font-size: 14px;
  transition: color 0.2s;
}

.footer__links a:hover {
  color: #fff;
}

.footer__contact li {
  font-size: 14px;
  margin-bottom: 12px;
  display: flex;
  gap: 10px;
  align-items: center;
}

.footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 22px 0;
  text-align: center;
  font-size: 13px;
}

/* ============ 页面头 Banner（子页） ============ */
.page-hero {
  background: var(--gradient);
  color: #fff;
  padding: 76px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-hero h1 {
  font-size: 40px;
  font-weight: 800;
  margin-bottom: 12px;
}

.page-hero p {
  font-size: 17px;
  opacity: 0.9;
  max-width: 640px;
  margin: 0 auto;
}

.breadcrumb {
  margin-top: 18px;
  font-size: 14px;
  opacity: 0.85;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

/* ============ 课程筛选 ============ */
.filter-bar {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 48px;
}

.filter-bar button {
  padding: 10px 24px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.25s;
}

.filter-bar button:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.filter-bar button.active {
  background: var(--gradient);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.3);
}

/* 课程目录列表 */
.catalog {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.catalog-group {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow 0.3s;
}

.catalog-group:hover {
  box-shadow: var(--shadow);
}

.catalog-group__head {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 22px 28px;
  background: linear-gradient(90deg, rgba(37, 99, 235, 0.06), rgba(124, 58, 237, 0.06));
  border-bottom: 1px solid var(--border);
}

.catalog-group__head .icon {
  width: 46px;
  height: 46px;
  border-radius: 12px;
  background: var(--gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  flex-shrink: 0;
}

.catalog-group__head h3 {
  font-size: 19px;
  font-weight: 700;
  color: var(--dark);
}

.catalog-group__head p {
  font-size: 13px;
  color: var(--text-light);
}

.catalog-group__head .num {
  margin-left: auto;
  font-size: 13px;
  font-weight: 600;
  color: var(--primary);
  background: rgba(37, 99, 235, 0.1);
  padding: 5px 14px;
  border-radius: 999px;
  white-space: nowrap;
}

.catalog-list li {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 28px;
  border-bottom: 1px dashed var(--border);
  font-size: 15px;
  transition: background 0.2s;
}

.catalog-list li:last-child {
  border-bottom: none;
}

.catalog-list li:hover {
  background: rgba(37, 99, 235, 0.03);
}

.catalog-list .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--primary);
  flex-shrink: 0;
}

.catalog-list .name {
  font-weight: 500;
  flex: 1;
}

.catalog-list .hours {
  color: var(--text-light);
  font-size: 13px;
  white-space: nowrap;
}

.catalog-list .level {
  font-size: 12px;
  color: var(--accent);
  background: rgba(124, 58, 237, 0.1);
  padding: 2px 10px;
  border-radius: 999px;
  white-space: nowrap;
}

/* ============ 关于我们 ============ */
.about-intro {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}

.about-intro h2 {
  font-size: 28px;
  font-weight: 800;
  color: var(--dark);
  margin-bottom: 18px;
  line-height: 1.4;
}

.about-intro p {
  color: var(--text-light);
  margin-bottom: 14px;
  font-size: 15.5px;
}

.about-card {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}

.about-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--dark);
}

.about-card ul li {
  padding: 10px 0;
  border-bottom: 1px dashed var(--border);
  font-size: 15px;
  display: flex;
  gap: 10px;
  align-items: baseline;
}

.about-card ul li:last-child {
  border-bottom: none;
}

.about-card ul li::before {
  content: "·";
  color: var(--primary);
  font-weight: 800;
}

/* 联系信息 */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.contact-item {
  text-align: center;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 24px;
  transition: all 0.3s;
}

.contact-item:hover {
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}

.contact-item .icon {
  font-size: 34px;
  margin-bottom: 14px;
}

.contact-item h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}

.contact-item p {
  color: var(--text-light);
  font-size: 14px;
}

/* ============ 滚动显现动画 ============ */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
  .course-grid,
  .hot-list {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .footer__grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 60px 0;
  }

  .nav__links {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    padding: 16px 24px 24px;
    gap: 4px;
    box-shadow: 0 16px 32px rgba(15, 23, 42, 0.12);
    transform: translateY(-130%);
    transition: transform 0.3s ease;
    border-bottom: 1px solid var(--border);
  }

  .nav__links.open {
    transform: translateY(0);
  }

  .nav__links a {
    padding: 12px 16px;
    font-size: 16px;
  }

  .nav__cta {
    margin-left: 0;
    margin-top: 8px;
    text-align: center;
  }

  .nav__toggle {
    display: flex;
  }

  .hero {
    padding: 76px 0;
  }

  .hero h1 {
    font-size: 34px;
  }

  .hero p {
    font-size: 16px;
  }

  .hero__stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    padding: 22px;
  }

  .course-grid,
  .hot-list,
  .feature-grid,
  .advantage-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .about-intro {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .section-head h2,
  .cta h2 {
    font-size: 26px;
  }

  .page-hero h1 {
    font-size: 30px;
  }

  .footer__grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .catalog-group__head {
    flex-wrap: wrap;
  }

  .catalog-group__head .num {
    margin-left: 0;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 28px;
  }

  .hero__btns {
    flex-direction: column;
    width: 100%;
  }

  .hero__btns .btn {
    width: 100%;
  }
}