body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
}

.centered-image {
    text-align: center;
}

.centered-image img {
    width: 90px;
    height: auto;
}

.background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: linear-gradient(45deg, #CCCCFF, #000000, #000000, #CCCCFF);
    /* background: linear-gradient(45deg, #FFFFFF, #CC00CC, #FF5733, #CCCCFF, #FDCCA4); */
    /* background: linear-gradient(45deg, #4e54c8, #8f94fb, #4e54c8, #8f94fb); */
    background-size: 400% 400%;
    animation: gradient 45s ease infinite;
}

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