* {
    padding:  0;
    margin: 0;
    box-sizing: border-box;
}


#hamburger-icon {
    margin: auto 0;
    display: none;
    cursor: pointer;
}

#hamburger-icon div {
    width: 35px;
    height: 3px;
    background-color:blue;
    margin: 6px 0;
    transition: 0.4s;
    
}
.open .bar1 {
    -webkit-transform: rotate( -45deg) translate(-6px, 6px);
    transform: rotate( -45deg) translate(-6px, 6px);
}
.open .bar2 {
    opacity: 0;
}
.open .bar3 {
    -webkit-transform: rotate( 45deg) translate(-6px, -8px);
    transform: rotate( 45deg) translate(-6px, -8px);
}
.open .mobile-menu {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    list-style: none;
}
.mobile-menu {
    display: none;
    position: absolute;
    top: 50px;
    left: 0;
    height: calc(100vh - 50px);
    width: 100%;
    list-style: none;
}
.mobile-menu a {
    text-decoration: none;
    color:black;
}
@media only screen and (max-width: 750px) {
    header nav {
        display: none;
    }
    #hamburger-icon {
        display: block;
    }
}