/* 基础变量 */
:root {
    --primary: #3498db;
    --primary-hover: #2980b9;
    --gradient-start: #3498db;
    --gradient-end: #2ecc71;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition-speed: 0.3s;
}

/* 暗色模式变量 */
@media (prefers-color-scheme: dark) {
    :root {
        --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    }
}

/* 全局样式 */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
}

/* 英雄区域样式 */
.hero {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    padding: 6rem 2rem;
    margin: -2rem -2rem 2rem -2rem;
    position: relative;
    overflow: hidden;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: rgba(255, 255, 255, 0.1);
    transform: rotate(30deg);
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    animation: fadeInUp 0.8s ease-out;
}

.hero p {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 2rem auto;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

/* 特性卡片样式 */
.feature-card {
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
    animation: fadeInUp 0.8s ease-out;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

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

.feature-icon {
    display: inline-block;
    padding: 1rem;
    background: rgba(52, 152, 219, 0.1);
    border-radius: 50%;
    margin-bottom: 1.5rem;
}

/* 按钮样式 */
.cta-button {
    background: white;
    color: var(--primary);
    font-weight: 600;
    padding: 1rem 2.5rem;
    border-radius: 50px;
    box-shadow: var(--card-shadow);
    animation: fadeInUp 0.8s ease-out 0.4s backwards;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
    background: white;
    color: var(--primary-hover);
}

/* 快捷键部分样式 */
.keyboard-shortcuts {
    background: rgba(52, 152, 219, 0.05);
    padding: 2rem;
    border-radius: 12px;
    margin: 3rem 0;
}

kbd {
    background: white;
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 0.2rem 0.5rem;
    font-size: 0.9rem;
    box-shadow: 0 2px 0 #ddd;
}

/* 隐私安全部分样式 */
.privacy {
    border-left: 4px solid var(--primary);
    padding-left: 2rem;
    margin: 3rem 0;
}

/* 页脚样式 */
footer {
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
    border-top: 1px solid rgba(0, 0, 0, 0.1);
}

footer a {
    color: var(--primary);
    text-decoration: none;
    margin: 0 1rem;
}

footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* 动画关键帧 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 响应式调整 */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .keyboard-shortcuts, .privacy {
        padding: 1.5rem;
    }
}