main.css
/* Media Queries */
/* Mobile Devices - Phones/Tablets */
@media only screen and (max-width: 991px) {
/* MOBILE NAVIGATION */
.navbar ul.nav {
display: flex;
flex-direction: column;
position: fixed;
justify-content: start;
top: 15vh;
+ left: 0;
background-color: #999;
width: 100%;
height: 100vh;
transform: translate(100%);
-webkit-transform: translate(100%);
text-align: center;
overflow: hidden;
padding: 15px 30px;
}