/* 现代化科技运动风格 - 学习路径 */
:root {
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --secondary-gradient: linear-gradient(135deg, #4e5fc1 0%, #5a6fd8 100%);
  --accent-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --dark-bg: #0f172a;
  --card-bg: rgba(255, 255, 255, 0.05);
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --border-radius: 16px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  --glow: 0 0 20px rgba(102, 126, 234, 0.3);
}

.learning-path {
    margin: 2rem 0;
}

.path-level {
    margin-bottom: 3rem;
    padding: 2rem;
    border-radius: var(--border-radius);
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    scroll-margin-top: 80px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.path-level::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--primary-gradient);
    opacity: 0;
    transition: var(--transition);
    z-index: -1;
}

.path-level:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow), var(--glow);
    border-color: rgba(102, 126, 234, 0.3);
}

.path-level:hover::before {
    opacity: 0.05;
}

.path-level h3 {
    color: #667eea;
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    text-align: center;
    position: relative;
}

.path-level h3::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background: var(--primary-gradient);
    border-radius: 2px;
}

.modules {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.module-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.module-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--primary-gradient);
    opacity: 0;
    transition: var(--transition);
    z-index: -1;
}

.module-card:hover {
    transform: translateY(-10px) scale(1.02);
    box-shadow: var(--shadow), var(--glow);
    border-color: rgba(102, 126, 234, 0.3);
}

.module-card:hover::before {
    opacity: 0.05;
}

.module-card h4 {
    color: #667eea;
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.module-card h4 a {
    color: #667eea;
    text-decoration: none;
    transition: var(--transition);
    position: relative;
}

.module-card h4 a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-gradient);
    transition: var(--transition);
}

.module-card h4 a:hover {
    color: #f093fb;
}

.module-card h4 a:hover::after {
    width: 100%;
}

.module-card p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.7;
}

.level-1 {
    border-left: 5px solid #667eea;
}

.level-2 {
    border-left: 5px solid #764ba2;
}

.level-3 {
    border-left: 5px solid #4e5fc1;
}

.level-4 {
    border-left: 5px solid #5a6fd8;
}

.level-5 {
    border-left: 5px solid #6f42c1;
}

.level-6 {
    border-left: 5px solid #e83e8c;
}

.intro-text {
    text-align: center;
    font-size: 1.25rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    color: var(--text-secondary);
}

/* 章节导航样式 */
.chapter-navigation {
    text-align: center;
    margin: 2rem 0;
    padding: 2rem;
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition);
}

.chapter-navigation:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow), var(--glow);
    border-color: rgba(102, 126, 234, 0.3);
}

.chapter-navigation h3 {
    margin-bottom: 1.5rem;
    color: #667eea;
    font-size: 1.5rem;
}

.chapter-navigation h3::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background: var(--primary-gradient);
    border-radius: 2px;
}

.nav-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
}

.nav-link {
    padding: 0.75rem 1.5rem;
    background: var(--primary-gradient);
    color: white;
    text-decoration: none;
    border-radius: 50px;
    margin: 0.25rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    font-weight: 500;
    box-shadow: var(--glow);
}

.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--accent-gradient);
    opacity: 0;
    transition: var(--transition);
    z-index: -1;
}

.nav-link:hover {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 20px 40px rgba(102, 126, 234, 0.4);
}

.nav-link:hover::before {
    opacity: 0.2;
}

/* 章节完整列表样式 */
.chapter-list {
    margin-top: 3rem;
    padding: 2rem;
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition);
}

.chapter-list:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow), var(--glow);
    border-color: rgba(102, 126, 234, 0.3);
}

.chapter-list h3 {
    text-align: center;
    color: #667eea;
    margin-bottom: 2rem;
    font-size: 1.8rem;
    position: relative;
}

.chapter-list h3::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--primary-gradient);
    border-radius: 2px;
}

.chapter-columns {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.chapter-column h4 {
    color: #667eea;
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.chapter-list ul {
    list-style-type: none;
    padding-left: 0;
}

.chapter-list li {
    margin-bottom: 0.75rem;
    padding: 0.5rem;
    border-radius: 8px;
    transition: var(--transition);
}

.chapter-list li:hover {
    background: rgba(102, 126, 234, 0.1);
    transform: translateX(5px);
}

.chapter-list a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
    display: block;
    padding: 0.5rem;
}

.chapter-list a:hover {
    color: #f093fb;
}

/* 回到顶部按钮样式 */
#backToTop {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 30px;
    z-index: 99;
    border: none;
    outline: none;
    background: var(--primary-gradient);
    color: white;
    cursor: pointer;
    padding: 15px;
    border-radius: 50%;
    font-size: 18px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.3);
    transition: var(--transition);
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

#backToTop:hover {
    transform: translateY(-5px) scale(1.1);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .modules {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .path-level {
        padding: 1.5rem;
    }
    
    .nav-links {
        flex-direction: column;
        align-items: center;
        gap: 0.75rem;
    }
    
    .nav-link {
        width: 80%;
        text-align: center;
    }
    
    .chapter-columns {
        grid-template-columns: 1fr;
    }
    
    .chapter-list {
        padding: 1.5rem;
    }
}