Hamburger menu on Wexley Mobile/Tablet

#mobileNav.menu-open {
    height: 100vh !important;
}
#mobileNav .wrapper {
    position: relative;
    width: 100%;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
}
.site-title #mobileMenuLink a {
    color: transparent;
    width: 100%;
    height: 15px;
    user-select: none
}
#mobileMenuLink {
    position: fixed;
    text-align: right;
    right: 20px;
    top: 60px;
    background-color: transparent;
    z-index: 9999;
}

#mobileMenuLink:before,
#mobileMenuLink:after {
  content: '';
  position:absolute;
  width: 40px;
  height: 1px;
  background:#000;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  transition:0.5s;
  left: 0;
}

#mobileNav.menu-open + #mobileMenuLink {
  background:rgba(0,0,0,0);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0);
}

#mobileNav.menu-open + #mobileMenuLink:before {
  top: 0;
  transform:rotate(45deg);
}

#mobileNav.menu-open + #mobileMenuLink:after {
  top: 0;
  transform:rotate(135deg);
  box-shadow: 0 -2px 5px rgba(0, 0, 0, 0.2);
}

Copy this to Settings->Design->Custom Css

Thank you so much! It works, but is there a way to make the menu a full page without scroll down (image attached)?

Secondly, can I ask how to reduce the space between the header – post and font size of the title on mobile/tablet only (image attached)? Because the space looks right for the desktop ver. Thank you!