* {
    background: #000;
}

.block {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 600px;
}

.block__quad {
    background: #382828;
    width: 200px;
    height: 200px;
    line-height: 120px;
    text-align: center;
    border-radius: 50px;
}

p {
    background: none;
    font-size: 40px;
    color: #382828;
    transition: 500ms 500ms;
}

.block__quad:hover p {
    color: green;
}

.block__loading {
    background: white;
    width: 0px;
    height: 25px;
    position: absolute;
    top: 100px;
    left: 50%;
    margin-left: -300px;
    transition-duration: 500ms;
}

.block__quad:hover .block__loading {
    width: 600px;
}