.gradient-background {
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: -1;
    background: linear-gradient(-45deg, #1e3c72, #2a5298, #23a6d5, #1f8ef1);
    background-size: 400% 400%;
    animation: gradient 15s ease infinite;
}

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

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}