/* 全局重置与基础样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
  --telegram-blue: #0088cc;
  --sky-blue: #87ceeb;
  --dark-bg: #1a1a1a;
  --light-bg: #f5f5f5;
  --text-white: #ffffff;
  --text-gray: #666666;
  --card-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

body {
  line-height: 1.6;
  color: #333;
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
}

/* 导航栏样式 */
.navbar {
  background: white;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 1000;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.logo img {
  width: 40px;
  height: 40px;
}

.logo-text {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--telegram-blue);
}

.nav-btn {
  background: var(--telegram-blue);
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 50px;
  cursor: pointer;
  font-weight: bold;
  transition: all 0.3s ease;
}

.nav-btn:hover {
  transform: scale(1.05);
  background: #0077b3;
}

/* 主要内容区域 */
.main {
  margin-top: 80px;
  padding: 2rem 0;
}

/* 首页英雄区域 */
.hero {
  text-align: center;
  padding: 4rem 0;
  background: linear-gradient(135deg, #f0f9ff 0%, #e6f7ff 100%);
  border-radius: 20px;
  margin-bottom: 3rem;
}

.hero h1 {
  font-size: 2.5rem;
  color: var(--telegram-blue);
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  color: var(--text-gray);
  max-width: 700px;
  margin: 0 auto 2rem;
}

/* 下载卡片区域 */
.download-section {
  margin: 3rem 0;
}

.section-title {
  text-align: center;
  font-size: 2rem;
  color: var(--telegram-blue);
  margin-bottom: 2rem;
  position: relative;
}

.section-title::after {
  content: '';
  width: 80px;
  height: 4px;
  background: var(--sky-blue);
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  border-radius: 2px;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.download-card {
  background: white;
  border-radius: 15px;
  padding: 2rem;
  text-align: center;
  box-shadow: var(--card-shadow);
  transition: transform 0.3s ease;
}

.download-card:hover {
  transform: translateY(-5px);
}

.download-card img {
  width: 60px;
  height: 60px;
  margin-bottom: 1rem;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  color: var(--sky-blue);
  border: 2px solid var(--sky-blue);
  padding: 10px 18px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: bold;
  margin-top: 1rem;
  transition: all 0.3s ease;
}

.download-btn:hover {
  background: var(--sky-blue);
  color: white;
}

/* 文章网格样式 */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin: 2rem 0;
}

.article-card {
  background: white;
  border-radius: 15px;
  overflow: hidden;
  box-shadow: var(--card-shadow);
  transition: transform 0.3s ease;
}

.article-card:hover {
  transform: translateY(-5px);
}

.article-img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.article-content {
  padding: 1.5rem;
}

.article-title {
  font-size: 1.2rem;
  color: var(--telegram-blue);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.article-desc {
  color: var(--text-gray);
  font-size: 0.95rem;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* 用户评价样式 */
.testimonials {
  background: var(--light-bg);
  padding: 3rem 0;
  border-radius: 20px;
  margin: 3rem 0;
}

.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.testimonial-card {
  background: white;
  padding: 2rem;
  border-radius: 15px;
  box-shadow: var(--card-shadow);
  text-align: center;
}

.user-avatar {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  margin: 0 auto 1rem;
  object-fit: cover;
}

.user-name {
  font-weight: bold;
  color: var(--telegram-blue);
  margin-bottom: 0.5rem;
}

.user-review {
  color: var(--text-gray);
  font-style: italic;
  line-height: 1.5;
}

/* 页脚样式 */
.footer {
  background: var(--dark-bg);
  color: var(--text-white);
  text-align: center;
  padding: 2rem 0;
  margin-top: 3rem;
}

/* 404页面样式 */
.page-404 {
  text-align: center;
  padding: 12rem 0;
}

.page-404 h1 {
  font-size: 6rem;
  color: var(--telegram-blue);
  margin-bottom: 1rem;
}

.page-404 p {
  font-size: 1.5rem;
  color: var(--text-gray);
  margin-bottom: 2rem;
}

.back-btn {
  background: var(--telegram-blue);
  color: white;
  padding: 12px 30px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: bold;
  transition: all 0.3s ease;
}

.back-btn:hover {
  background: #0077b3;
}

/* 响应式适配 */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }
  
  .section-title {
    font-size: 1.6rem;
  }
  
  .nav-container {
    padding: 0.8rem 0;
  }
}