@keyframes logo-blink {
    from { opacity:0.0; }
    to { opacity:1.0; }
}

@-webkit-keyframes logo-blink {
    from { opacity:0.0; }
    to { opacity:1.0; }
}

header .menu-bar .hmdev-logo .underscore {
    width:100%;
    height:100%;
    background-size:75%;
    background-repeat:no-repeat;
    background-position:center center;
    animation:logo-blink 1s infinite alternate;
    -webkit-animation:logo-blink 1s infinite alternate ease-in-out;
}