css body 低耗粒子颜色波动变换动画

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, 
        #686869 0%, 
        #764ba2 15%, 
        #7f7380 30%, 
        #afa7a9 45%, 
        #4facfe 60%, 
        #454848 75%, 
        #aae7be 90%, 
        #6b6161 100%);
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
    color: var(--text-color);
    min-height: 100vh;
    overflow-x: hidden;
    transition: background-color 0.3s, color 0.3s;
    position: relative;
}

@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}