.theme-toggle-header{
    width:45px;
    height:45px;
    border:none;
    border-radius:50%;
    background:#d50000;
    color:#fff;
    font-size:20px;
    cursor:pointer;
    display:flex;
    align-items:center;
    justify-content:center;
    transition:.3s;
}

.theme-toggle-header:hover{
    transform:scale(1.08);
}