a.sm2_button {
 position:relative;
 display:inline-block; /* If you worry about old browser bugs, Firefox 2 might not like this and may need -moz-inline-box instead. :D */
 width:17px;
 height:17px;
 text-indent:-9999px; /* don't show link text */
 overflow:hidden; /* don't draw inner link text */
 vertical-align:middle;
 /* and, a bit of round-ness for the cool browsers. */
 border-radius:0;
 margin-top:-1px; /* vertical align tweak */
 transition: all 0.2s ease-in-out;
 /* weird IE 6/7 display fixes, and/or I'm doing it wrong */
 *text-indent:0px;
 *line-height:99em;
 *vertical-align: top;
}

a.sm2_button:focus {
 outline:none; /* maybe evil, but don't show the slight border outline on focus. */
}

a.sm2_button,
a.sm2_button.sm2_paused:hover {
 background-image:url(../images/play.png);
 background-image: none, url(../images/play-2x.png);
 background-repeat:no-repeat;
 background-size: 9px 10px;
 background-position:5px 50%;
 margin-left: 8px;
}

a.sm2_button:hover,
a.sm2_button.sm2_playing,
a.sm2_button.sm2_playing:hover {
}

a.sm2_button.sm2_playing,
a.sm2_button.sm2_playing:hover {
 background-image:url(../images/pause.png);
 background-image: none, url(../images/pause-2x.png);
}

a.sm2_button.sm2_paused,
a.sm2_button.sm2_paused:hover {
}