.btn,
.nav a {
    position: relative;
    overflow: hidden;
    outline: none !important; /* remove dotted border */
}
.btn:after,
.nav a:after {
    content: "";
    background: rgba(255,255,255,0.3);
    display: block;
    position: absolute;
    border-radius: 50%;
    padding-top: 240%;
    padding-left: 240%;
    margin-top: -120%;
    margin-left: -120%;
    opacity: 0;
    transition: all 1s;
	pointer-events:none;
}
.btn:active:after,
.nav a:active:after {
    padding-top: 0;
    padding-left: 0;
    margin-top: 0;
    margin-left: 0;
    opacity: 1;
    transition: 0s;
}