/* 全局样式重置和基础设置 */
:root {
    /* 颜色变量 */
    --primary-color: #0071e3;
    --secondary-color: #1d1d1f;
    --background-light: #fbfbfd;
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --white: #ffffff;
}

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

body {
    font-family: "SF Pro Display", -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--background-light);
}

/* 页头导航样式 */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    z-index: 1000;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 600;
}

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

.nav-menu a {
    color: var(--text-primary);
    text-decoration: none;
    font-size: 1rem;
    transition: color 0.3s ease;
}

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

/* 主视觉区域样式 */
.hero {
    padding: 120px 20px 60px;
    text-align: center;
    background: linear-gradient(to bottom, #fbfbfd, #f5f5f7);
}

.hero-content {
    max-width: 1000px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, #1d1d1f 0%, #434343 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    line-height: 1.6;
}

.video-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    background: var(--white);
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    position: relative;
    padding-top: 177.78%; /* 16:9的视频比例 */
    overflow: hidden;
}

/* 小尺寸版本 - 适合窄屏幕 */
.video-container.small {
    max-width: 400px;
}

/* 大尺寸版本 - 适合宽屏幕 */
.video-container.large {
    max-width: 600px;
}

.video-container video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        display: none; /* 移动端菜单将通过JavaScript控制显示 */
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }

    .video-container {
        padding-top: 177.78%; /* 保持9:16的比例 */
        max-width: 450px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 1s ease-out;
}

/* Features区域样式 */
.features {
    padding: 100px 20px;
    background: var(--white);
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    padding: 2rem;
    background: var(--background-light);
    border-radius: 20px;
    transition: transform 0.3s ease;
}

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

/* How it works 区域样式 */
.how-it-works {
    padding: 100px 20px;
    background: linear-gradient(to bottom, #f5f5f7, #ffffff);
}

.steps-container {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.step {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.step-number {
    font-size: 4rem;
    color: var(--primary-color);
    font-weight: 700;
    opacity: 0.2;
}

/* Testimonials区域样式 */
.testimonials {
    padding: 100px 20px;
    background: var(--white);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.testimonial-card {
    padding: 2rem;
    background: var(--background-light);
    border-radius: 20px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.05);
}

/* FAQ区域样式 */
.faq {
    padding: 100px 20px;
    background: var(--background-light);
}

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

.faq-item {
    margin-bottom: 1rem;
    border-bottom: 1px solid rgba(0,0,0,0.1);
}

.faq-question {
    padding: 1.5rem 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
}

.faq-answer {
    padding: 0 0 1.5rem;
    color: var(--text-secondary);
    display: none;
}

.faq-answer.active {
    display: block;
}

/* Pricing区域样式 */
.pricing {
    padding: 100px 20px;
    background: var(--white);
}

.pricing-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.price-card {
    padding: 3rem 2rem;
    background: var(--background-light);
    border-radius: 20px;
    text-align: center;
    transition: transform 0.3s ease;
}

.price-card:hover {
    transform: scale(1.02);
}

/* Footer样式 */
.footer {
    padding: 60px 20px;
    background: var(--secondary-color);
    color: var(--white);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.footer-info p {
    margin: 0.5rem 0;
    color: var(--text-secondary);
}

/* 通用按钮样式 */
.btn {
    display: inline-block;
    padding: 1rem 2rem;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 30px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
}

.btn:hover {
    background: #0077ed;
    transform: translateY(-2px);
}

/* 响应式调整 */
@media (max-width: 768px) {
    .features-grid,
    .testimonials-grid,
    .pricing-cards {
        grid-template-columns: 1fr;
    }

    .step {
        flex-direction: column;
        text-align: center;
    }

    .faq-container {
        padding: 0 1rem;
    }
}

/* 移动端菜单按钮样式 */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
}

.hamburger-line {
    display: block;
    width: 25px;
    height: 2px;
    background: var(--text-primary);
    margin: 5px 0;
    transition: 0.3s;
}

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--white);
        padding: 20px;
        flex-direction: column;
        align-items: center;
        transform: translateY(-100%);
        transition: transform 0.3s ease;
    }
    
    .nav-menu.active {
        transform: translateY(0);
    }
}

/* 视频错误提示样式 */
.video-error {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f5f5f7;
    color: var(--text-secondary);
}