html {
    height: 100%;
}

body {
    position: relative;
    margin: 0;
    height: 100%;
    display: flex;
}

.pre-login-background {
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: 0;
    position: fixed;
    left: 0;
    overflow: hidden;
    top: 0;
}

.pre-login-loader {
    position: absolute;
    z-index: 1;
    border: 12px solid #f3f3f3;
    border-top: 12px solid #3498db;
    border-radius: 50%;
    width: 120px;
    height: 120px;
    box-sizing: content-box;
    animation: spin 2s linear infinite;
    top: calc(50% - 72px);
    left: calc(50% - 72px);
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

.app {
    z-index: 99;
}