Thank you Nithy,
i have amended the color_scheme-2.scss file because thats the color scheme i have selected for the theme. i added the code below and it worked successfully:
.navbar-collapse .custom-menu ul.mr-auto{
display: flex;
flex-direction: row;
display: -webkit-flex; /* Safari */
-webkit-flex-direction: row;
}
i think i will also add your suggested css code above to the eguru.scss so that these changes apply to all the color schemes.