/* 柠萌学官网样式 */
:root {
  --primary: #FF6B35;
  --primary-light: #FF8C5A;
  --secondary: #4ECDC4;
  --dark: #2C3E50;
  --light: #F7F9FC;
  --text: #333;
  --text-light: #666;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--light);
}

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

nav .container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav .logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--primary);
  text-decoration: none;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

nav a {
  color: var(--dark);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

nav a:hover {
  color: var(--primary);
}

/* 主要内容 */
main {
  margin-top: 70px;
}

section {
  padding: 4rem 2rem;
}

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

/* Hero 区域 */
.hero {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
  text-align: center;
  padding: 6rem 2rem;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

/* 卡片 */
.cards {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2rem;
  margin-top: 2rem;
}

.cards .card {
  flex: 0 1 calc(20% - 1.6rem);
  min-width: 220px;
  max-width: 280px;
}

.card {
  background: white;
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card h3 {
  color: var(--primary);
  margin-bottom: 1rem;
}

/* 内容区块 */
.content-section {
  background: white;
}

.content-section:nth-child(even) {
  background: var(--light);
}

.content-section h2 {
  color: var(--dark);
  font-size: 2rem;
  margin-bottom: 1.5rem;
  text-align: center;
}

.content-section h3 {
  color: var(--primary);
  margin: 1.5rem 0 1rem;
}

/* FAQ 手风琴 */
.faq-item {
  background: white;
  border-radius: 8px;
  margin-bottom: 1rem;
  overflow: hidden;
}

.faq-item details {
  padding: 1.5rem;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--dark);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--primary);
}

.faq-item[open] summary::after {
  content: '−';
}

.faq-item p {
  margin-top: 1rem;
  color: var(--text-light);
  padding-left: 0;
}

/* 联系信息 */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

@media (max-width: 768px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

.contact-info {
  background: white;
  padding: 2rem;
  border-radius: 12px;
}

.contact-info h3 {
  color: var(--primary);
  margin-bottom: 1rem;
}

.contact-info p {
  margin-bottom: 0.5rem;
}

/* 页脚 */
footer {
  background: var(--dark);
  color: white;
  padding: 3rem 2rem;
  text-align: center;
}

footer a {
  color: var(--secondary);
}

/* CTA 按钮 */
.btn {
  display: inline-block;
  background: var(--primary);
  color: white;
  padding: 1rem 2rem;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  transition: background 0.3s, transform 0.3s;
}

.btn:hover {
  background: var(--primary-light);
  transform: scale(1.05);
}

/* 特色列表 */
.features {
  list-style: none;
}

.features li {
  padding: 0.5rem 0;
  padding-left: 1.5rem;
  position: relative;
}

.features li::before {
  content: '✓';
  color: var(--secondary);
  position: absolute;
  left: 0;
  font-weight: bold;
}

/* 汉堡菜单按钮 */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.8rem;
  cursor: pointer;
  color: var(--primary);
  padding: 0.25rem;
  line-height: 1;
}

/* 响应式 */
@media (max-width: 1200px) {
  .cards .card {
    flex: 0 1 calc(33.333% - 1.4rem);
  }
}

@media (max-width: 900px) {
  .cards .card {
    flex: 0 1 calc(50% - 1rem);
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  nav ul {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: white;
    flex-direction: column;
    gap: 0;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    padding: 0;
  }

  nav ul.open {
    display: flex;
  }

  nav ul li {
    border-bottom: 1px solid #f0f0f0;
  }

  nav ul li a {
    display: block;
    padding: 1rem 2rem;
  }

  .hero h1 {
    font-size: 2rem;
  }

  section {
    padding: 2rem 1rem;
  }

  .cards .card {
    flex: 0 1 100%;
    max-width: 400px;
  }
}