/* styles.css */

/* --- 全局样式 --- */
:root {
    --google-blue: #4285f4;
    --google-red: #ea4335;
    --google-yellow: #fbbc05;
    --google-green: #34a853;
    --google-gray: #5f6368;
    --google-light-gray: #f8f9fa;
    --google-dark: #202124;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Google Sans', 'Segoe UI', Arial, sans-serif;
}

body {
    background-color: white;
    color: var(--google-dark);
    line-height: 1.5;
}

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

/* --- 头部样式 --- */
header {
    background-color: white;
    border-bottom: 1px solid #e8eaed;
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo-img {
    width: 100px;
    height: auto;
    vertical-align: middle;
}

.nav-links a {
    color: var(--google-gray);
    text-decoration: none;
    margin-left: 24px;
    font-size: 14px;
    transition: color 0.2s;
}

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

/* --- 主内容区样式 --- */
.hero {
    padding: 80px 0 60px;
    text-align: center;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 400;
    margin-bottom: 16px;
    color: var(--google-dark);
}

.hero p {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 40px;
    color: var(--google-gray);
}

/* 下载按钮样式 */
.download-btn {
    display: inline-flex;
    align-items: center;
    background-color: var(--google-blue);
    color: white;
    padding: 12px 24px;
    font-size: 1rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.2s, box-shadow 0.2s;
    box-shadow: 0 1px 2px rgba(0,0,0,0.1);
    margin: 12px 0;
}

.download-btn:hover {
    background-color: #2b68d3;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

.download-btn svg {
    margin-right: 8px;
}

/* 两段文字样式 */
.download-info, .version-info {
    font-size: 0.875rem;
    color: var(--google-gray);
    margin: 0;
    line-height: 1.2;
}

.hero-img {
    max-width: 100%;
    height: auto;
    margin: 20px auto 0;
    display: block;
    max-width: 800px;
}

/* --- 特性区域样式 --- */
.features {
    padding: 80px 0;
    background-color: var(--google-light-gray);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 400;
    margin-bottom: 60px;
    color: var(--google-dark);
}

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

.feature-card {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--google-light-gray);
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 16px;
    color: var(--google-dark);
}

.feature-card p {
    color: var(--google-gray);
}

/* --- 常见问题板块样式 --- */
.faq {
    padding: 80px 0;
    background-color: white;
}

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

.faq-item {
    margin-bottom: 16px;
    border: 1px solid #e8eaed;
    border-radius: 8px;
    overflow: hidden;
    transition: box-shadow 0.2s;
}

.faq-item:hover {
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.faq-question {
    padding: 20px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: white;
    transition: background-color 0.2s;
}

.faq-question:hover {
    background-color: var(--google-light-gray);
}

.faq-question::after {
    content: "+";
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--google-blue);
    transition: transform 0.2s;
}

.faq-question.active::after {
    content: "-";
    transform: rotate(180deg);
}

.faq-answer {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    background-color: white;
    color: var(--google-gray);
}

.faq-answer.active {
    padding: 20px;
    max-height: 500px;
}

/* --- 页脚样式 --- */
footer {
    background-color: #f1f3f4;
    padding: 40px 0 30px;
    color: var(--google-gray);
    font-size: 0.875rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--google-gray);
    text-decoration: none;
    margin-right: 24px;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--google-blue);
}

.copyright {
    margin-top: 20px;
}

/* --- 返回顶部按钮样式 --- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--google-blue);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 1.2rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
    transition: opacity 0.3s, visibility 0.3s, transform 0.3s;
    opacity: 0;
    visibility: hidden;
    z-index: 99;
}

.back-to-top:hover {
    background-color: #2b68d3;
    transform: translateY(-3px);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

/* --- 响应式设计 --- */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .header-content {
        flex-direction: column;
    }
    
    .nav-links {
        margin-top: 16px;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
        margin-bottom: 20px;
    }
    
    .hero-img {
        max-width: 90%;
    }
    
    .faq-question {
        font-size: 1rem;
        padding: 16px;
    }
    
    .faq-answer {
        font-size: 0.9rem;
    }
}