wait.css

body {
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    overflow: hidden;
    position: relative;
}

.background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, #303030 30%, #000000);
    z-index: -1;
}

.content {
    text-align: center;
    color: white;
}

h1 {
    font-weight: bold;
}

input[type="radio"] {
    margin: 10px;
    display: inline-block;
}

.bubble {
    position: absolute;
    width: 100px;
    height: 100px;
    background: cover;
    animation: float 14s infinite;
    margin-left: 12%;
}
.bubble1 {
    position: absolute;
    width: 100px;
    height: 100px;
    background: cover;
    animation: float 10s infinite;
    margin-left: 48%;
}
.bubble2 {
    position: absolute;
    width: 100px;
    height: 100px;
    background: cover;
    animation: float 16s infinite;
    margin-left: 73%;
}
.bubble3 {
    position: absolute;
    width: 100px;
    height: 100px;
    background: cover;
    animation: float 18s infinite;
    margin-left: 90%;
}
.emoji {
    position: absolute;
    width: 100px;
    height: 100px;
    background: cover;
    animation: float 12s infinite;
}
@keyframes float {
    0% {
        transform: translateY(3000%);
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    100% {
        transform: translateY(-100%);
        opacity: 0;
    }
}