* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

:root {
    --google-blue: #1a73e8;
    --google-blue-hover: #1557b0;
    
    --bg-surface: #ffffff;
    --bg-container: #f8f9fa;
    --bg-tonal: #e8f0fe;
    
    --text-primary: #202124;
    --text-secondary: #5f6368;
    
    --radius-large: 28px;
    --radius-medium: 16px;
    --radius-pill: 100px;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: "Product Sans", "Roboto", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-surface);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; transition: var(--transition); }

header {
    background-color: var(--bg-surface);
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-container {
    max-width: 1140px;
    height: 64px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
}
.logo img { 
    height: 32px; 
    width: 32px; 
    display: block; 
}
.logo-text {
    font-size: 22px;
    font-weight: 500;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.nav-links { display: flex; gap: 32px; }
.nav-links a {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
}
.nav-links a:hover { color: var(--google-blue); }

.notice-banner {
    background-color: var(--bg-surface);
    color: var(--text-secondary);
    font-size: 13px;
    padding: 12px 24px;
    text-align: center;
    border-top: 1px solid #f1f3f4;
    border-bottom: 1px solid #e8eaed;
    letter-spacing: 0.2px;
}
.notice-banner a {
    color: var(--google-blue);
    text-decoration: none;
    margin-left: 6px;
    font-weight: 500;
    border-bottom: 1px solid transparent;
}
.notice-banner a:hover { 
    color: var(--google-blue-hover);
    border-bottom-color: var(--google-blue-hover);
}

.hero {
    max-width: 840px;
    margin: 0 auto;
    padding: 64px 24px 40px 24px;
    text-align: center;
}
.hero h1 {
    font-size: 44px;
    font-weight: 400;
    color: var(--text-primary);
    letter-spacing: -0.5px;
    margin-bottom: 16px;
    line-height: 1.2;
}
.hero .tagline {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 32px;
    font-weight: 400;
}

.cta-group {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    border-radius: var(--radius-pill);
    font-size: 14px;
    font-weight: 500;
    letter-spacing: 0.25px;
    cursor: pointer;
}
.btn-primary {
    background-color: var(--google-blue);
    color: #ffffff;
}
.btn-primary:hover {
    background-color: var(--google-blue-hover);
    box-shadow: 0 1px 3px rgba(60,64,67,0.3), 0 4px 8px rgba(60,64,67,0.15);
}
.btn-secondary {
    background-color: #f1f3f4;
    color: var(--google-blue);
    border: 1px solid transparent;
}
.btn-secondary:hover {
    background-color: var(--bg-tonal);
    box-shadow: 0 1px 2px rgba(60,64,67,0.3);
}

.hero .tip {
    font-size: 13px;
    color: var(--text-secondary);
}

.main-content {
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 24px 64px 24px;
}

/* 1. 软件截图画廊区 */
.section-preview {
    background-color: var(--bg-container);
    padding: 48px 32px 36px 32px;
    border-radius: var(--radius-large);
    text-align: center;
    margin-bottom: 48px;
}
.section-preview h2, .section-features h2, .section-versions h2, .section-privacy h2 {
    font-size: 24px;
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-primary);
}
.section-sub {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 28px;
}
.preview-scroll {
    display: flex;
    gap: 20px;
    overflow-x: auto;
    padding: 4px 4px 16px 4px;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
}
.preview-scroll::-webkit-scrollbar {
    height: 6px;
}
.preview-scroll::-webkit-scrollbar-track {
    background: transparent;
}
.preview-scroll::-webkit-scrollbar-thumb {
    background: #dadce0;
    border-radius: 10px;
}
.preview-scroll::-webkit-scrollbar-thumb:hover {
    background: #bdc1c6;
}
.preview-item {
    flex: 0 0 240px;
    scroll-snap-align: start;
    display: flex;
    flex-direction: column;
    align-items: center;
}
.preview-img {
    border-radius: var(--radius-medium);
    border: 1px solid #e8eaed;
    box-shadow: 0 1px 3px rgba(60,64,67,0.15);
    display: block;
    width: 240px;
    height: auto;
    aspect-ratio: 9 / 19.5;
    object-fit: cover;
    background-color: #ffffff;
    transition: var(--transition);
}
.preview-img:hover {
    transform: translateY(-2px);
    box-shadow: 0 1px 3px rgba(60,64,67,0.3), 0 4px 8px rgba(60,64,67,0.15);
}
.preview-caption {
    margin-top: 10px;
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* 2. 核心功能网格 */
.section-features {
    margin-top: 0;
    margin-bottom: 48px;
}
.section-features h2 {
    text-align: center;
    margin-bottom: 24px;
}
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}
.card {
    background-color: var(--bg-container);
    padding: 32px;
    border-radius: var(--radius-large);
    border: 1px solid transparent;
    transition: var(--transition);
}
.card:hover {
    background-color: #f1f3f4;
}
.card h3 {
    font-size: 20px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 12px;
}
.card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* 3. 支持版本 & 4. 隐私声明 */
.section-versions, .section-privacy {
    margin-top: 48px;
    background-color: var(--bg-container);
    padding: 48px 32px;
    border-radius: var(--radius-large);
    text-align: center;
}
.section-versions h2, .section-privacy h2 {
    margin-bottom: 28px;
}
.tags-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    max-width: 880px;
    margin: 0 auto;
}
.tag {
    background-color: #ffffff;
    color: var(--text-primary);
    padding: 10px 20px;
    border-radius: var(--radius-medium);
    font-size: 14px;
    font-weight: 500;
    border: 1px solid #e8eaed;
    transition: var(--transition);
}
.tag:hover {
    background-color: var(--bg-tonal);
    color: var(--google-blue);
    border-color: transparent;
}

.privacy-desc {
    font-size: 15px;
    line-height: 1.8;
    color: var(--text-secondary);
    max-width: 720px;
    margin: 0 auto;
}

footer {
    margin-top: 64px;
    background-color: var(--bg-container);
    border-top: 1px solid #e8eaed;
    padding: 48px 24px;
}
.footer-content {
    max-width: 1140px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    font-size: 13px;
    color: var(--text-secondary);
}
.footer-links {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
    justify-content: center;
}
.footer-links a:hover { color: var(--text-primary); }

.icp-row {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    color: #9aa0a6;
}
.icp-row a:hover { color: var(--text-secondary); }
.icp-row img { width: 16px; height: 16px; vertical-align: middle; margin-right: 4px; display: inline-block; }

@media (max-width: 768px) {
    .nav-links { display: none; }
    
    .hero { padding: 40px 16px 24px 16px; }
    .hero h1 { font-size: 32px; }
    .hero .tagline { font-size: 16px; margin-bottom: 24px; }
    
    .cta-group { flex-direction: column; width: 100%; gap: 12px; }
    .btn { width: 100%; max-width: 260px; margin: 0 auto; padding: 12px 24px; }
    
    .main-content { padding: 0 16px 40px 16px; }
    
    .section-preview, .section-features, .section-versions, .section-privacy { 
        margin-top: 32px; 
        margin-bottom: 32px; 
        padding: 32px 16px; 
        border-radius: var(--radius-medium); 
    }
    .section-preview h2, .section-features h2, .section-versions h2, .section-privacy h2 { font-size: 20px; margin-bottom: 16px; }
    .section-sub { margin-bottom: 20px; font-size: 13px; }
    
    .preview-item { flex: 0 0 180px; }
    .preview-img { width: 180px; border-radius: 12px; }
    
    .grid { gap: 16px; }
    .card { padding: 24px; border-radius: var(--radius-medium); }
    
    .privacy-desc { font-size: 14px; }
    
    .tags-container {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 8px;
        width: 100%;
    }
    .tag { 
        padding: 8px 14px; 
        font-size: 13px; 
    }
    
    footer { padding: 32px 16px; margin-top: 48px; }
    .footer-content { gap: 16px; }
}