/* 基础样式重置 */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --white: #ffffff;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    --gray-300: #dee2e6;
    --gray-400: #ced4da;
    --gray-500: #adb5bd;
    --gray-600: #6c757d;
    --gray-700: #495057;
    --gray-800: #343a40;
    --gray-900: #212529;
}

* {
    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: var(--gray-800);
    background-color: var(--gray-100);
}

/* 容器 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* 头部导航 */
.header {
    background-color: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.header nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

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

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

.nav-links a {
    color: var(--gray-700);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

/* 移动菜单 */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--gray-700);
}

.mobile-menu {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background-color: var(--white);
    padding: 1rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.mobile-menu.active {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.mobile-menu a {
    color: var(--gray-700);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
}

.mobile-menu a:hover {
    background-color: var(--gray-100);
    color: var(--primary-color);
}

/* 英雄区域 */
.hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, var(--primary-color), #0056b3);
    color: var(--white);
    text-align: center;
}

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

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.hero-features span {
    background-color: rgba(255,255,255,0.1);
    padding: 0.5rem 1rem;
    border-radius: 20px;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
}

.btn.primary {
    background-color: var(--primary-color);
    color: var(--white);
}

.btn.primary:hover {
    background-color: #0056b3;
}

.btn.secondary {
    background-color: var(--white);
    color: var(--primary-color);
}

.btn.secondary:hover {
    background-color: var(--gray-100);
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* 功能特点 */
.features {
    padding: 4rem 0;
    background-color: var(--white);
}

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

.feature-card {
    padding: 2rem;
    background-color: var(--white);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

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

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    color: var(--gray-800);
    margin-bottom: 1rem;
}

/* 使用步骤 */
.how-it-works {
    padding: 4rem 0;
    background-color: var(--gray-100);
}

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

.step {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: relative;
}

.step-number {
    position: absolute;
    top: -15px;
    left: -15px;
    width: 40px;
    height: 40px;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
}

/* 价格套餐 */
.pricing {
    padding: 4rem 0;
    background-color: var(--white);
}

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

.pricing-card {
    background-color: var(--white);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 2rem;
    text-align: center;
    position: relative;
}

.pricing-card.popular {
    border: 2px solid var(--primary-color);
}

.popular-tag {
    position: absolute;
    top: -12px;
    right: 20px;
    background-color: var(--primary-color);
    color: var(--white);
    padding: 0.25rem 1rem;
    border-radius: 20px;
    font-size: 0.875rem;
}

.price {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
    margin: 1rem 0;
}

.price span {
    font-size: 1rem;
    color: var(--gray-500);
}

.pricing-features ul {
    list-style: none;
    margin: 2rem 0;
}

.pricing-features li {
    margin-bottom: 0.5rem;
    color: var(--gray-700);
}

/* FAQ部分 */
.faq {
    padding: 4rem 0;
    background-color: var(--gray-100);
}

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

.faq-item {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.faq-item h3 {
    color: var(--gray-800);
    margin-bottom: 1rem;
}

/* 页面标题 */
h2 {
    text-align: center;
    font-size: 2.5rem;
    color: var(--gray-800);
    margin-bottom: 1rem;
}

.section-subtitle {
    text-align: center;
    color: var(--gray-600);
    margin-bottom: 2rem;
}

/* 页脚 */
.footer {
    background-color: var(--gray-800);
    color: var(--white);
    padding: 4rem 0 2rem;
}

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

.footer-col h4 {
    color: var(--white);
    margin-bottom: 1rem;
}

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

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

.footer-col a {
    color: var(--gray-400);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-col a:hover {
    color: var(--white);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--gray-700);
}

.footer-bottom a {
    color: var(--white);
    text-decoration: none;
}

/* 下载页面样式 */
.page-content {
    padding: 8rem 0 4rem;
}

.download-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 2rem;
}

.download-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-align: center;
}

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

.download-features {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.download-features h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.download-features ul {
    list-style: none;
}

.download-features li {
    margin-bottom: 1rem;
    color: var(--gray-600);
}

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

    .mobile-menu-btn {
        display: block;
    }

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

    .hero-features {
        flex-direction: column;
        gap: 1rem;
    }

    .cta-buttons {
        flex-direction: column;
    }

    .download-section {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.5rem;
    }

    .hero {
        padding: 6rem 0 3rem;
    }

    .feature-grid,
    .pricing-grid,
    .faq-grid {
        grid-template-columns: 1fr;
    }
}