/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #e0e0e0;
    background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);
    min-height: 100vh;
}

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

/* 头部样式 */
.header {
    background: linear-gradient(135deg, #007AFF 0%, #5856D6 100%);
    color: white;
    padding: 60px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.header-content {
    position: relative;
    z-index: 1;
}

.header h1 {
    font-size: 3rem;
    margin-bottom: 10px;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.header h1 i {
    margin-right: 15px;
    color: #ffffff;
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    font-weight: 300;
}

/* 导航样式 */
.nav {
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(10px);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.search-box {
    position: relative;
    flex: 1;
    max-width: 400px;
}

.search-box i {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: #888;
}

.search-box input {
    width: 100%;
    padding: 12px 15px 12px 45px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 25px;
    background: rgba(255, 255, 255, 0.1);
    color: #e0e0e0;
    font-size: 14px;
    transition: all 0.3s ease;
}

.search-box input:focus {
    outline: none;
    border-color: #007AFF;
    background: rgba(255, 255, 255, 0.15);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.2);
}

.progress-indicator {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #e0e0e0;
    font-size: 14px;
}

.progress-bar {
    width: 120px;
    height: 8px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #007AFF, #5856D6);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 4px;
}

/* 主要内容样式 */
.main {
    padding: 40px 0;
}

.intro-section {
    margin-bottom: 60px;
}

.intro-card {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
}

.intro-card h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: #007AFF;
}

.intro-card h2 i {
    margin-right: 15px;
}

.intro-card p {
    font-size: 1.1rem;
    margin-bottom: 30px;
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.feature {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px;
    background: rgba(0, 122, 255, 0.1);
    border-radius: 10px;
    border: 1px solid rgba(0, 122, 255, 0.2);
}

.feature i {
    color: #007AFF;
    font-size: 1.2rem;
}

/* 章节样式 */
.chapters-section {
    margin-bottom: 60px;
}

.chapters-section h2 {
    font-size: 2.2rem;
    margin-bottom: 40px;
    text-align: center;
    color: #e0e0e0;
}

.chapters-section h2 i {
    margin-right: 15px;
    color: #007AFF;
}

.chapters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.chapter-card {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 30px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.chapter-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #007AFF, #5856D6);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.chapter-card:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(0, 122, 255, 0.3);
    box-shadow: 0 10px 30px rgba(0, 122, 255, 0.2);
}

.chapter-card:hover::before {
    transform: scaleX(1);
}

.chapter-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #007AFF, #5856D6);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.chapter-icon i {
    font-size: 1.8rem;
    color: white;
}

.chapter-content h3 {
    font-size: 1.4rem;
    margin-bottom: 15px;
    color: #e0e0e0;
}

.chapter-content p {
    margin-bottom: 20px;
    opacity: 0.8;
    line-height: 1.6;
}

.chapter-points {
    list-style: none;
    margin-bottom: 25px;
}

.chapter-points li {
    padding: 8px 0;
    padding-left: 25px;
    position: relative;
    opacity: 0.8;
    font-size: 0.9rem;
}

.chapter-points li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #007AFF;
    font-weight: bold;
}

.chapter-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: linear-gradient(135deg, #007AFF, #5856D6);
    color: white;
    text-decoration: none;
    border-radius: 25px;
    font-weight: 500;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.chapter-link:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(0, 122, 255, 0.4);
}

/* 提示部分样式 */
.tips-section {
    margin-bottom: 60px;
}

.tips-card {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 40px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.tips-card h3 {
    font-size: 1.8rem;
    margin-bottom: 30px;
    text-align: center;
    color: #e0e0e0;
}

.tips-card h3 i {
    margin-right: 10px;
    color: #FFD60A;
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
}

.tip {
    display: flex;
    gap: 15px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 15px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.tip i {
    font-size: 1.5rem;
    color: #FFD60A;
    margin-top: 5px;
}

.tip h4 {
    margin-bottom: 8px;
    color: #e0e0e0;
    font-size: 1.1rem;
}

.tip p {
    opacity: 0.8;
    font-size: 0.9rem;
    line-height: 1.5;
}

/* 系统要求样式 */
.system-requirements {
    margin-bottom: 60px;
}

.requirements-card {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 40px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.requirements-card h3 {
    font-size: 1.8rem;
    margin-bottom: 30px;
    text-align: center;
    color: #e0e0e0;
}

.requirements-card h3 i {
    margin-right: 10px;
    color: #007AFF;
}

.requirements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 25px;
}

.requirement {
    text-align: center;
    padding: 25px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 15px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.requirement h4 {
    margin-bottom: 10px;
    color: #007AFF;
    font-size: 1.1rem;
}

.requirement p {
    opacity: 0.8;
    font-size: 0.9rem;
}

/* 页脚样式 */
.footer {
    background: rgba(0, 0, 0, 0.3);
    padding: 40px 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: 60px;
}

.footer-content {
    text-align: center;
}

.footer-content p {
    margin-bottom: 20px;
    opacity: 0.7;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 30px;
}

.footer-links a {
    color: #007AFF;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #5856D6;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #007AFF, #5856D6);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    z-index: 1000;
    box-shadow: 0 4px 15px rgba(0, 122, 255, 0.3);
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0, 122, 255, 0.4);
}

.back-to-top.show {
    display: flex;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .nav-content {
        flex-direction: column;
        gap: 15px;
    }
    
    .search-box {
        max-width: 100%;
    }
    
    .intro-card {
        padding: 30px 20px;
    }
    
    .intro-card h2 {
        font-size: 2rem;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .chapters-grid {
        grid-template-columns: 1fr;
    }
    
    .tips-grid {
        grid-template-columns: 1fr;
    }
    
    .requirements-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-links {
        flex-direction: column;
        gap: 15px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .header {
        padding: 40px 0;
    }
    
    .intro-card {
        padding: 25px 15px;
    }
    
    .chapter-card {
        padding: 25px 20px;
    }
    
    .tips-card,
    .requirements-card {
        padding: 30px 20px;
    }
    
    .requirements-grid {
        grid-template-columns: 1fr;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.chapter-card,
.intro-card,
.tips-card,
.requirements-card {
    animation: fadeInUp 0.6s ease-out;
}

.chapter-card:nth-child(1) { animation-delay: 0.1s; }
.chapter-card:nth-child(2) { animation-delay: 0.2s; }
.chapter-card:nth-child(3) { animation-delay: 0.3s; }
.chapter-card:nth-child(4) { animation-delay: 0.4s; }