You can use the following starting code for your Moodle customlti.css


/* Moodle*/

body {

       font-family: "Open Sans","Helvetica Neue",Arial,sans-serif; !important;

       color: #262626;

}


.buttonContent{


       color: #373a3c;

   background-color: #fff;

   border-color: #ccc;

       border-radius: .25rem;

}


.buttonContent:hover {

       background-color: #E6E6E6;

       

}


.light-theme a {

       text-decoration: none;

       background: #F2F3F5;

}


.light-theme a:hover {

       text-decoration: none;

       background: #E6EAF0;

}


.light-theme .current {

   background: #E6E6E6;

       border-color:#ccc;        

       color:#262626;

}