How about…
input[type=submit] {
color: #e6e3e6;
padding: 10px 20px;
background: -moz-linear-gradient(
top,
#7a7a7a 0%,
#242424);
background: -webkit-gradient(
linear, left top, left bottom,
from(#7a7a7a),
to(#242424));
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
border-radius: 5px;
border: 0px solid #000000;
-moz-box-shadow:
0px 1px 3px rgba(000,000,000,0.5),
inset 0px 0px 1px rgba(255,255,255,0.7);
-webkit-box-shadow:
0px 1px 3px rgba(000,000,000,0.5),
inset 0px 0px 1px rgba(255,255,255,0.7);
box-shadow:
0px 1px 3px rgba(000,000,000,0.5),
inset 0px 0px 1px rgba(255,255,255,0.7);
text-shadow:
0px -1px 0px rgba(000,000,000,0.4),
0px 1px 0px rgba(255,255,255,0.3);
width: 100%;
background: #7a7a7a; /* Old browsers */
/* IE9 SVG, needs conditional override of 'filter' to 'none' */
background: url(data:image/svg+xml;base64,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);
background: -moz-linear-gradient(top, #7a7a7a 0%, #0f0f0f 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#7a7a7a), color-stop(100%,#0f0f0f)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, #7a7a7a 0%,#0f0f0f 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, #7a7a7a 0%,#0f0f0f 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top, #7a7a7a 0%,#0f0f0f 100%); /* IE10+ */
background: linear-gradient(to bottom, #7a7a7a 0%,#0f0f0f 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#7a7a7a', endColorstr='#0f0f0f',GradientType=0 ); /* IE6-8 */
cursor: pointer;
}