*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body{
    background-color: gray;
    min-height: 100vh;
    display: grid;
    place-items: center;
}

.center-div{
    width: 10rem;
    height: 10rem;
    background-color: crimson;
    position: relative;
    transform: rotate(45deg);
    animation: pulse 0.5s linear infinite;
    
}
.center-div::before{
    content: "";
    width: 100%;
    height: 100%;
    background-color: crimson;
    position: absolute;
    border-radius: 50%;
    transform: translateY(-50%);
}
.center-div::after {
    content: "";
    width: 100%;
    height: 100%;
    background-color:crimson;
    position: absolute;
    border-radius: 50%;
    transform: translatex(-50%);
    transform-style: flat;
}
@keyframes pulse {
    from{
        transform: scale(1) rotate(45deg);
    }
    to{
        transform: scale(1.1) rotate(45deg);
    }
}