style.css

*
{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body
{
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #0b1522;
}
.heart
{
    height: 150px;
    width: 150px;
    background-color: red;
    position: relative;
    transform: rotate(45deg);
    box-shadow: -20px 20px 150px #f20044;
    animation: palpitar 0.5s linear infinite alternate;
}
.content
{
    position: fixed;
    margin-bottom: 50px;
    text-align: center;
}
h1,h2
{
    color: white;
}
@keyframes palpitar
{
    0%
    {
        transform: rotate(45deg) scale(1.10);
    }
    80%
    {
        transform: rotate(45deg) scale(1.0);
    }
    100%
    {
        transform: rotate(45deg) scale(0.80);
    }
}
.heart::before
{
    content: "";
    position: absolute;
    height: 150px;
    width: 150px;
    background: red;
    right: 50%;
    border-radius: 50%;
    box-shadow: 20px 20px 150px #f20044;
}
.heart::after
{
    content: "";
    position: absolute;
    height: 150px;
    width: 150px;
    background: red;
    top: -50%;
    border-radius: 50%;
    box-shadow: 20px 20px 150px #f20044;
}