.btn { width:40px; height:40px; border:none; background:none; background-position:center; background-repeat:no-repeat; background-size:contain; color:transparent; cursor:pointer; border-radius:5px; }

.btn[disabled]		{ opacity:0.5; }
.btn-menu		{ background-image:url('/img/menuicons-dark-80/menuicon-071.png'); }
.btn-back		{ background-image:url('/img/menuicons-dark-80/menuicon-103.png'); }
.btn-loading		{ background-image:url('/img/menuicons-dark-80/menuicon-119.png'); }
.btn-install		{ background-image:url('/img/menuicons-dark-80/menuicon-091.png'); }
.btn-orientation	{ background-image:url('/img/menuicons-dark-80/menuicon-382.png'); opacity:0.4; }
.btn-orientation[data-locked=true]	{ opacity:1.0; }

.btn-install.light	{ background-image:url('/img/menuicons-light-80/menuicon-091.png'); }