How to decrease the gap between underlines and text on mobile menu

Hello experts,

How to increase the the gap between underline and text, while reducing the line hight?
My mobile menu on phone and tablet looks ugly.
I would like the line hight smaller and the underlines further away from the text.
I guess it’s not possible to have a different color instead of an underline…?
Also, a hover effect would be fantastic but I think I read it's not possible on mobile…?

Here are the codes I am using to get a smaller font size

/* Customizing mobile menu */
.header-menu-nav-item a {
  line-height: 1.6rem;
}
@media only screen and (max-width: 640px) {

/* font size for mobile menu */
  .header-menu-nav-item a {
      font-size: 1.4rem;
  }
}

/* Customizing tablet menu */
.header-menu-nav-item a {
  line-height: 1.2rem;
}
@media only screen and (max-width: 1024px) {

/* font size for tablet menu */
  .header-menu-nav-item a {
      font-size: 1.4rem;
  }
}

Thank you very much in advance.

best,

D*

Thank you. very much