Please add this code in custom.css file of parent theme or in style.css file of child theme:
.et-mobile-menu li > a {
line-height: 40px;
}
.et-mobile-menu .side-block .close-block{
line-height:1.2;
}
How to create custom.css you can watch in this tutorial – https://www.youtube.com/watch?v=Qok2zRedRMY.
Regards