/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* CSS变量定义 - 白天主题 */
:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --background-color: #ffffff;
    --surface-color: #f8fafc;
    --text-color: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --gradient-start: #667eea;
    --gradient-end: #764ba2;
}

/* 夜晚主题 */
[data-theme="dark"] {
    --primary-color: #818cf8;
    --secondary-color: #c084fc;
    --background-color: #0f172a;
    --surface-color: #1e293b;
    --text-color: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --gradient-start: #818cf8;
    --gradient-end: #c084fc;
}

/* 基础样式 */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

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

/* 头部样式 */
.header {
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo svg {
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 主题切换按钮 */
.theme-toggle {
    position: relative;
}

.theme-btn {
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: 50px;
    padding: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    position: relative;
    width: 48px;
    height: 48px;
}

.theme-btn:hover {
    border-color: var(--primary-color);
    transform: scale(1.05);
}

.theme-btn svg {
    position: absolute;
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.sun-icon {
    opacity: 1;
    transform: rotate(0deg);
}

.moon-icon {
    opacity: 0;
    transform: rotate(180deg);
}

[data-theme="dark"] .sun-icon {
    opacity: 0;
    transform: rotate(180deg);
}

[data-theme="dark"] .moon-icon {
    opacity: 1;
    transform: rotate(0deg);
}

/* 主要内容区域 */
.main {
    min-height: calc(100vh - 200px);
}

/* 英雄区域 */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--surface-color) 0%, var(--background-color) 100%);
}

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

.app-icon {
    display: flex;
    justify-content: center;
}

.app-info {
    max-width: 600px;
}

.app-name {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.app-version {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.app-description {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
}

/* 下载按钮 */
.download-section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    text-decoration: none;
    padding: 1rem 2rem;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--shadow-color);
    max-width: 250px;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--shadow-color);
}

.download-btn svg {
    stroke: white;
}

.download-size {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* 功能特性区域 */
.features {
    padding: 4rem 0;
    background-color: var(--surface-color);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background-color: var(--background-color);
    padding: 2rem;
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 10px var(--shadow-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px var(--shadow-color);
    border-color: var(--primary-color);
}

.feature-icon {
    display: flex;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.feature-icon svg {
    color: var(--primary-color);
    stroke-width: 2.5;
}

.feature-card h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* 页脚样式 */
.footer {
    background-color: var(--surface-color);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

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

.footer-section h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

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

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

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: var(--primary-color);
}

.footer-section p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}
/* 页脚底部 */
.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer-bottom a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-bottom a:hover {
    color: var(--primary-color);
    text-decoration: underline;
} 响应式设计 */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }
    
    .app-name {
        font-size: 2.5rem;
    }
    
    .app-description {
        font-size: 1rem;
    }
    
    .download-btn {
        max-width: 100%;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .features {
        padding: 2rem 0;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .app-name {
        font-size: 2rem;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-content > * {
    animation: fadeInUp 0.6s ease-out;
}

.feature-card {
    animation: fadeInUp 0.6s ease-out;
    animation-fill-mode: both;
}

.feature-card:nth-child(1) { animation-delay: 0.1s; }
.feature-card:nth-child(2) { animation-delay: 0.2s; }
.feature-card:nth-child(3) { animation-delay: 0.3s; }
.feature-card:nth-child(4) { animation-delay: 0.4s; }