/* 页面过渡动画 */
.active-section {
    opacity: 0;
    animation: fadeIn 0.4s ease forwards;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 页面加载动画 */
body {
    opacity: 0;
    transition: opacity 0.5s ease;
}

body.page-loaded {
    opacity: 1;
}

/* 容器初始动画 */
.container.animate-in {
    animation: containerFadeIn 0.8s ease-out forwards;
}

@keyframes containerFadeIn {
    from { 
        opacity: 0;
        transform: translateY(20px);
    }
    to { 
        opacity: 1;
        transform: translateY(0);
    }
}

/* 头部元素动画 */
.container.animate-in header {
    opacity: 0;
    animation: headerSlideDown 0.8s ease forwards 0.2s;
}

@keyframes headerSlideDown {
    from { 
        opacity: 0;
        transform: translateY(-20px);
    }
    to { 
        opacity: 1;
        transform: translateY(0);
    }
}

/* 页面切换动画 */
#browse-section.active-section {
    animation: slideInFromLeft 0.4s ease forwards;
}

#upload-section.active-section {
    animation: slideInFromRight 0.4s ease forwards;
}

@keyframes slideInFromLeft {
    from { opacity: 0; transform: translateX(-20px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInFromRight {
    from { opacity: 0; transform: translateX(20px); }
    to { opacity: 1; transform: translateX(0); }
}

/* 卡片加载动画 */
.prompt-card {
    opacity: 0;
    transform: translateY(20px);
    animation: cardFadeIn 0.4s ease forwards;
}

@keyframes cardFadeIn {
    to { opacity: 1; transform: translateY(0); }
}

/* 卡片的交错加载效果 */
.prompt-card:nth-child(3n+1) { animation-delay: 0.1s; }
.prompt-card:nth-child(3n+2) { animation-delay: 0.2s; }
.prompt-card:nth-child(3n+3) { animation-delay: 0.3s; }