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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

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

/* 导航栏 */
.navbar {
    background-color: #2c3e50;
    color: white;
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: #3498db;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: #3498db;
}

/* 英雄区域 */
.hero {
    background: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
    color: white;
    padding: 8rem 0 4rem;
    margin-top: 56px;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.main-title {
    font-size: 3rem;
    font-weight: bold;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.subtitle {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.value-proposition {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    line-height: 1.8;
}

.download-stats {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
}

.stat {
    font-size: 1.1rem;
    font-weight: 500;
}

/* 表单卡片 */
.form-card {
    background-color: white;
    color: #333;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.form-card h3 {
    margin-bottom: 0.5rem;
    color: #2c3e50;
}

.form-subtitle {
    margin-bottom: 1.5rem;
    color: #7f8c8d;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #555;
}

.form-group input {
    width: 100%;
    padding: 0.8rem;
    border: 2px solid #e1e8ed;
    border-radius: 5px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.download-btn {
    width: 100%;
    padding: 1rem;
    background-color: #e74c3c;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
}

.download-btn:hover {
    background-color: #c0392b;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(231, 76, 60, 0.3);
}

.privacy-policy {
    margin-top: 1rem;
    font-size: 0.8rem;
    color: #95a5a6;
    text-align: center;
}

/* 通用按钮样式 */
.cta-btn {
    display: inline-block;
    padding: 1rem 2rem;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 1.1rem;
    font-weight: bold;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.cta-btn:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.3);
}

/* 章节标题 */
.section-title {
    text-align: center;
    font-size: 2.5rem;
    color: #2c3e50;
    margin-bottom: 3rem;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background-color: #3498db;
    border-radius: 2px;
}

/* 教程特色 */
.features {
    padding: 5rem 0;
    background-color: white;
}

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

.feature-card {
    background-color: #f8f9fa;
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border-color: #3498db;
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

.feature-card p {
    color: #7f8c8d;
    line-height: 1.6;
}

/* 内容预览 */
.preview {
    padding: 5rem 0;
    background-color: #ecf0f1;
}

.preview-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.preview-list h3 {
    margin-bottom: 1.5rem;
    color: #2c3e50;
}

.preview-list ul {
    list-style: none;
}

.preview-list li {
    padding: 0.8rem 0;
    border-bottom: 1px solid #bdc3c7;
    color: #555;
    position: relative;
    padding-left: 2rem;
}

.preview-list li::before {
    content: '▶';
    position: absolute;
    left: 0;
    color: #3498db;
    font-weight: bold;
}

.preview-image img {
    width: 100%;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

/* 客户见证 */
.testimonials {
    padding: 5rem 0;
    background-color: white;
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.testimonial-card {
    background-color: #f8f9fa;
    padding: 2rem;
    border-radius: 10px;
    transition: all 0.3s ease;
}

.testimonial-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.testimonial-rating {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.testimonial-text {
    margin-bottom: 1.5rem;
    font-style: italic;
    color: #555;
    line-height: 1.8;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.testimonial-author img {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    object-fit: cover;
}

.testimonial-author h4 {
    color: #2c3e50;
    margin-bottom: 0.2rem;
}

.testimonial-author p {
    color: #7f8c8d;
    font-size: 0.9rem;
}

/* FAQ */
.faq {
    padding: 5rem 0;
    background-color: #ecf0f1;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 1rem;
    border-radius: 5px;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 1.5rem;
    background-color: white;
    color: #2c3e50;
    border: none;
    text-align: left;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.3s ease;
}

.faq-question:hover {
    background-color: #f8f9fa;
}

.faq-icon {
    font-size: 1.5rem;
    transition: transform 0.3s ease;
}

.faq-question.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    background-color: white;
}

.faq-answer p {
    padding: 0 1.5rem 1.5rem;
    color: #555;
    line-height: 1.8;
}

/* 再次行动召唤 */
.cta {
    background: linear-gradient(135deg, #3498db 0%, #2c3e50 100%);
    color: white;
    padding: 5rem 0;
    text-align: center;
}

.cta-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.cta-subtitle {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* 页脚 */
.footer {
    background-color: #2c3e50;
    color: white;
    padding: 3rem 0 1.5rem;
}

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

.footer-info h3 {
    margin-bottom: 1rem;
    color: #3498db;
}

.footer-info p {
    color: #bdc3c7;
    line-height: 1.8;
}

.footer-links h4,
.footer-contact h4 {
    margin-bottom: 1rem;
    color: #3498db;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #bdc3c7;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #3498db;
}

.footer-contact p {
    color: #bdc3c7;
    margin-bottom: 0.5rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #34495e;
    color: #95a5a6;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
    background-color: white;
    margin: 10% auto;
    padding: 2rem;
    border-radius: 10px;
    width: 90%;
    max-width: 500px;
    text-align: center;
    position: relative;
}

.close-modal {
    position: absolute;
    right: 1rem;
    top: 0.5rem;
    font-size: 2rem;
    cursor: pointer;
    color: #95a5a6;
}

.modal-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.modal h3 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

.modal p {
    margin-bottom: 1.5rem;
    color: #555;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .main-title {
        font-size: 2.5rem;
    }

    .download-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .preview-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .features-grid,
    .testimonials-grid {
        grid-template-columns: 1fr;
    }

    .cta-title {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .main-title {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1.2rem;
    }

    .form-card {
        padding: 1.5rem;
    }

    .feature-card,
    .testimonial-card {
        padding: 1.5rem;
    }

    .section-title {
        font-size: 1.8rem;
    }
}