/* ===== 基础重置 ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #333;
  line-height: 1.6;
  background: #fff;
}

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

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

ul {
  list-style: none;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== 通用按钮 ===== */
.btn {
  display: inline-block;
  padding: 12px 32px;
  border: none;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

.btn-primary {
  background: #2980b9;
  color: #fff;
}

.btn-primary:hover {
  background: #1f6da0;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(41, 128, 185, 0.4);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border: 2px solid #fff;
}

.btn-outline:hover {
  background: #fff;
  color: #2980b9;
}

.btn-lg {
  padding: 16px 48px;
  font-size: 17px;
  border-radius: 10px;
}

.btn-sm {
  padding: 8px 20px;
  font-size: 13px;
  background: #2980b9;
  color: #fff;
  border-radius: 6px;
}

/* ===== 通用文本 ===== */
.text-center {
  text-align: center;
}

/* ===== 导航栏 ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #fff;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
}

.header-inner {
  display: flex;
  align-items: center;
  height: 68px;
  gap: 24px;
}

.logo {
  font-size: 20px;
  font-weight: 800;
  color: #1a5276;
  white-space: nowrap;
}

.nav {
  display: flex;
  gap: 20px;
  flex-shrink: 0;
}

.nav a {
  font-size: 14px;
  font-weight: 500;
  color: #555;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
  white-space: nowrap;
}

.nav a:hover,
.nav a.active {
  color: #2980b9;
  border-bottom-color: #2980b9;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-left: auto;
}

.search-box {
  display: flex;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  overflow: hidden;
}

.search-box input {
  border: none;
  outline: none;
  padding: 8px 14px;
  font-size: 14px;
  width: 180px;
  background: #f8f9fa;
}

.search-box button {
  background: #2980b9;
  color: #fff;
  border: none;
  padding: 8px 16px;
  cursor: pointer;
  font-size: 14px;
  transition: background 0.2s;
}

.search-box button:hover {
  background: #1f6da0;
}

.cart-icon {
  font-size: 14px;
  font-weight: 600;
  color: #555;
  position: relative;
  white-space: nowrap;
}

.cart-badge {
  position: absolute;
  top: -8px;
  right: -14px;
  background: #e74c3c;
  color: #fff;
  font-size: 11px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  margin-left: auto;
}

/* ===== Hero 轮播 ===== */
.hero {
  position: relative;
  overflow: hidden;
}

.hero-slider {
  position: relative;
  height: 520px;
}

.hero-slide {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.8s ease;
}

.hero-slide.active {
  opacity: 1;
}

.hero-content {
  text-align: center;
  color: #fff;
  max-width: 700px;
  padding: 0 20px;
}

.hero-content h1 {
  font-size: 48px;
  font-weight: 800;
  margin-bottom: 12px;
  text-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
}

.hero-slogan {
  font-size: 24px;
  margin-bottom: 16px;
  font-weight: 600;
}

.hero-content p {
  font-size: 17px;
  margin-bottom: 28px;
  opacity: 0.9;
  line-height: 1.7;
}

.hero-btns {
  display: flex;
  gap: 16px;
  justify-content: center;
}

.hero-dots {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
}

.dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.5);
  cursor: pointer;
  transition: all 0.3s;
}

.dot.active {
  background: #fff;
  transform: scale(1.2);
}

/* ===== 通用区块 ===== */
.section-block {
  padding: 72px 0;
}

.section-block.bg-light {
  background: #f8f9fa;
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-tag {
  display: inline-block;
  background: #eaf2f8;
  color: #2980b9;
  font-size: 13px;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: 20px;
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.section-title {
  font-size: 30px;
  font-weight: 700;
  color: #222;
}

.section-title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background: #2980b9;
  margin: 12px auto 0;
  border-radius: 2px;
}

.sub-title {
  font-size: 22px;
  font-weight: 700;
  color: #333;
  margin: 48px 0 28px;
  padding-left: 14px;
  border-left: 4px solid #2980b9;
}

/* ===== PART ONE: 平台发展背景 ===== */
.bg-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.bg-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 28px 24px;
  transition: all 0.3s;
}

.bg-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
  border-color: #2980b9;
}

.bg-num {
  font-size: 32px;
  font-weight: 800;
  color: #2980b9;
  margin-bottom: 12px;
  opacity: 0.3;
}

.bg-card h3 {
  font-size: 16px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.bg-card p {
  font-size: 13px;
  color: #777;
  line-height: 1.8;
}

.policy-banner {
  margin-top: 40px;
  background: linear-gradient(135deg, #1a5276 0%, #2980b9 100%);
  border-radius: 16px;
  padding: 40px;
}

.policy-text {
  color: #fff;
}

.policy-text h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
}

.policy-text p {
  font-size: 14px;
  line-height: 1.8;
  margin-bottom: 12px;
  opacity: 0.9;
}

/* ===== PART TWO: 平台核心优势 ===== */
.adv-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.adv-card {
  background: #fff;
  border-radius: 12px;
  padding: 32px 24px;
  text-align: center;
  border: 1px solid #f0f0f0;
  transition: all 0.3s;
}

.adv-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.1);
  border-color: #2980b9;
}

.adv-icon {
  font-size: 44px;
  margin-bottom: 16px;
}

.adv-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.adv-card p {
  font-size: 13px;
  color: #777;
  line-height: 1.8;
}

/* 品推体系 */
.promo-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.promo-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 10px;
  padding: 24px 20px;
  transition: all 0.3s;
}

.promo-card:hover {
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.06);
}

.promo-num {
  font-size: 28px;
  font-weight: 800;
  color: #2980b9;
  opacity: 0.4;
  margin-bottom: 8px;
}

.promo-card p {
  font-size: 14px;
  color: #555;
  line-height: 1.7;
}

/* 推广方式 */
.channel-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 8px;
}

.channel-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 28px;
  transition: all 0.3s;
}

.channel-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.channel-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.channel-card p {
  font-size: 14px;
  color: #777;
  line-height: 1.8;
}

/* 龙福的特点 */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-item {
  text-align: center;
  padding: 28px 16px;
  background: #fff;
  border-radius: 12px;
  border: 1px solid #f0f0f0;
  transition: all 0.3s;
}

.feature-item:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.feature-icon {
  font-size: 36px;
  margin-bottom: 12px;
}

.feature-item h4 {
  font-size: 16px;
  font-weight: 700;
  color: #333;
  margin-bottom: 8px;
}

.feature-item p {
  font-size: 13px;
  color: #777;
  line-height: 1.7;
}

/* 用户运营 */
.user-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.user-stat-card {
  background: linear-gradient(135deg, #1a5276 0%, #2980b9 100%);
  border-radius: 16px;
  padding: 32px;
  text-align: center;
  color: #fff;
}

.stat-number {
  font-size: 48px;
  font-weight: 800;
  display: inline;
}

.stat-unit {
  font-size: 20px;
  font-weight: 600;
  display: inline;
  margin-left: 4px;
}

.user-stat-card p {
  font-size: 16px;
  font-weight: 600;
  margin-top: 8px;
  margin-bottom: 8px;
}

.stat-desc {
  font-size: 13px;
  opacity: 0.8;
  line-height: 1.6;
}

/* 合作高校 */
.uni-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.uni-tag {
  display: inline-block;
  padding: 8px 18px;
  background: #fff;
  border: 1px solid #e0e0e0;
  border-radius: 20px;
  font-size: 14px;
  color: #555;
  transition: all 0.2s;
}

.uni-tag:hover {
  border-color: #2980b9;
  color: #2980b9;
}

.uni-tag.highlight {
  background: #eaf2f8;
  border-color: #2980b9;
  color: #2980b9;
  font-weight: 600;
}

/* ===== 校园经济规模 ===== */
.economy-section {
  background: linear-gradient(180deg, #f8f9fa 0%, #fff 100%);
}

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

.economy-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 32px 28px;
  transition: all 0.3s;
}

.economy-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.economy-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #2980b9;
  margin-bottom: 12px;
}

.economy-card p {
  font-size: 14px;
  color: #666;
  line-height: 1.8;
}

/* ===== PART THREE: 商家合作 ===== */
.platform-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 16px;
}

.platform-stat {
  text-align: center;
  padding: 32px 20px;
  background: #fff;
  border-radius: 12px;
  border: 1px solid #f0f0f0;
}

.platform-stat strong {
  display: block;
  font-size: 36px;
  font-weight: 800;
  color: #2980b9;
  margin-bottom: 8px;
}

.platform-stat span {
  font-size: 15px;
  color: #666;
}

/* 商家交易保障 */
.merch-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.merch-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 28px;
}

.merch-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 16px;
}

.merch-card ul {
  padding-left: 0;
}

.merch-card li {
  font-size: 14px;
  color: #555;
  line-height: 1.8;
  margin-bottom: 8px;
  padding-left: 20px;
  position: relative;
}

.merch-card li::before {
  content: "•";
  position: absolute;
  left: 4px;
  color: #2980b9;
  font-weight: bold;
}

.merch-card li strong {
  color: #333;
}

/* 商家权益 */
.merch-rights {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.right-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 28px;
  text-align: center;
  transition: all 0.3s;
}

.right-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.right-icon {
  font-size: 40px;
  margin-bottom: 14px;
}

.right-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.right-card p {
  font-size: 13px;
  color: #777;
  line-height: 1.8;
}

/* 行业趋势 */
.trend-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-left: 4px solid #2980b9;
  border-radius: 0 12px 12px 0;
  padding: 24px 28px;
}

.trend-card p {
  font-size: 14px;
  color: #555;
  line-height: 1.8;
}

.trend-card strong {
  color: #2980b9;
}

/* 技术赋能 */
.tech-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.tech-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 28px;
  transition: all 0.3s;
}

.tech-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.tech-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.tech-card p {
  font-size: 14px;
  color: #777;
  line-height: 1.8;
}

/* ===== PART FOUR: 未来规划 ===== */
.goal-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.goal-card {
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 28px;
  transition: all 0.3s;
}

.goal-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.goal-num {
  font-size: 28px;
  font-weight: 800;
  color: #2980b9;
  opacity: 0.3;
  margin-bottom: 12px;
}

.goal-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.goal-card p {
  font-size: 14px;
  color: #777;
  line-height: 1.8;
}

/* 企业愿景 */
.vision-section {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 48px;
}

.vision-card {
  background: linear-gradient(135deg, #1a5276 0%, #2980b9 100%);
  border-radius: 16px;
  padding: 36px 28px;
  text-align: center;
  color: #fff;
}

.vision-icon {
  font-size: 40px;
  margin-bottom: 14px;
}

.vision-card h4 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}

.vision-card p {
  font-size: 14px;
  opacity: 0.9;
  line-height: 1.7;
}

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

.contact-info h3 {
  font-size: 24px;
  font-weight: 700;
  color: #1a5276;
  margin-bottom: 8px;
}

.contact-info > p {
  font-size: 15px;
  color: #666;
  margin-bottom: 24px;
}

.contact-items {
  margin-bottom: 24px;
}

.contact-item {
  font-size: 14px;
  color: #555;
  margin-bottom: 8px;
}

.contact-slogan {
  font-size: 16px;
  font-weight: 600;
  color: #2980b9;
}

.contact-cta {
  background: linear-gradient(135deg, #1a5276 0%, #2980b9 100%);
  border-radius: 16px;
  padding: 40px;
  text-align: center;
  color: #fff;
}

.contact-cta h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 12px;
}

.contact-cta > p {
  font-size: 14px;
  opacity: 0.9;
  margin-bottom: 24px;
  line-height: 1.7;
}

.cta-note {
  font-size: 13px;
  opacity: 0.7;
  margin-top: 12px;
}

/* ===== 页脚 ===== */
.footer {
  background: #1a2332;
  color: #ccc;
  padding: 60px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 32px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-col h3 {
  font-size: 20px;
  color: #fff;
  margin-bottom: 16px;
}

.footer-col h4 {
  font-size: 15px;
  color: #fff;
  margin-bottom: 16px;
}

.footer-col p {
  font-size: 13px;
  line-height: 1.8;
  color: #999;
}

.footer-col a {
  display: block;
  font-size: 13px;
  color: #999;
  margin-bottom: 10px;
  transition: color 0.2s;
}

.footer-col a:hover {
  color: #2980b9;
}

.footer-bottom {
  text-align: center;
  padding: 20px 0;
  font-size: 12px;
  color: #666;
}

.footer-bottom a {
  color: #999;
  transition: color 0.2s;
}

.footer-bottom a:hover {
  color: #2980b9;
}

/* ===== 首页概览卡片 ===== */
.overview-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 24px;
}

.overview-card {
  display: block;
  background: #fff;
  border: 1px solid #f0f0f0;
  border-radius: 12px;
  padding: 32px 20px;
  text-align: center;
  transition: all 0.3s;
  cursor: pointer;
}

.overview-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.1);
  border-color: #2980b9;
}

.overview-icon {
  font-size: 44px;
  margin-bottom: 16px;
}

.overview-card h4 {
  font-size: 17px;
  font-weight: 700;
  color: #333;
  margin-bottom: 10px;
}

.overview-card p {
  font-size: 13px;
  color: #777;
  line-height: 1.8;
}

/* ===== 回到顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: #2980b9;
  color: #fff;
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
  box-shadow: 0 4px 12px rgba(41, 128, 185, 0.4);
  z-index: 99;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #1f6da0;
  transform: translateY(-3px);
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .bg-grid,
  .adv-grid,
  .promo-grid,
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .overview-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .footer-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .nav,
  .search-box {
    display: none;
  }

  .mobile-menu-btn {
    display: block;
  }

  .header-inner {
    justify-content: space-between;
  }

  .hero-slider {
    height: 440px;
  }

  .hero-content h1 {
    font-size: 32px;
  }

  .hero-slogan {
    font-size: 18px;
  }

  .hero-content p {
    font-size: 15px;
  }

  .hero-btns {
    flex-direction: column;
    align-items: center;
  }

  .section-block {
    padding: 48px 0;
  }

  .section-title {
    font-size: 24px;
  }

  .bg-grid,
  .adv-grid,
  .promo-grid,
  .feature-grid,
  .user-stats,
  .platform-stats,
  .merch-rights,
  .economy-grid,
  .goal-grid,
  .vision-section,
  .overview-grid {
    grid-template-columns: 1fr;
  }

  .merch-grid,
  .channel-grid,
  .tech-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

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

  .uni-grid {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .bg-grid,
  .adv-grid,
  .promo-grid,
  .feature-grid,
  .overview-grid {
    grid-template-columns: 1fr;
  }

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

  .platform-stats {
    grid-template-columns: 1fr;
  }
}