menu.css

#menu{
    width: 35px;
    height: 30px;
    margin: 30px 0 20px 20px;
    cursor: pointer;
}

.bar{
    height: 5px;
    width: 100%;
    background-color: #b81568;
    display: block;
    border-radius: 5px;
    transition: 0.3s ease;
}

#bar1{
    transform: translateY(-4px);
}

#bar3{
    transform: translateY(4px);
}

.change .bar{
    background-color: white;
}

.change #bar1{
    transform: translateY(4px) rotateZ(-45deg);
}

.change #bar3{
    transform: translateY(-6px) rotate(45deg);
}

.change #bar2{
    opacity: 0;
}

.nav-menu li a{
    color: white;
    text-decoration: none;
}

.nav-menu li{
    list-style: none;
    padding: 16px 0;
}

.nav-menu{
    padding: 0;
    margin: 0 20px;
    transition: 0.3s ease;
    display: none;
}

.nav-menu li a:hover{
    font-weight: bold;
}

.change{
    display: block;
}

.menu-bg{
    z-index: 1;
    width: 0;
    height: 0;
    margin: 30px 0 20px 20px;
    background: radial-gradient(circle,#e94498,#b81568);
    transition: 0.3s ease;
    border-radius: 50%;

}

.change-bg{
    width: 550px;
    height: 540px;
    transform: translate(-50%, -20%);
}

.menu-bg, #menu-bar{
    top: 0;
    left: 0;
    position: absolute;
}

#menu-bar{
    z-index: 2;
}