The code you first posted seems to have some properties missing. To see what I mean, open the Blaskan original stylesheet:
https://s-ssl.wordpress.com/wp-content/themes/pub/blaskan/style.css?m=1333592456g&minify=false
And look for the "input[type=submit]" rule.
Here it is for reference:
input[type=submit] {
background: #2e6eb0;
background: -moz-linear-gradient(top, #76aee8, #2e6eb0);
background: -o-linear-gradient(top, #76aee8, #2e6eb0);
background: -webkit-gradient(linear, left top, left bottom, from(#76aee8), to(#2e6eb0));
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#76aee8', endColorstr='#2e6eb0' );
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#76aee8, endColorstr=#2e6eb0)";
border: solid 1px #2e6eb0;
-webkit-border-radius: 6px;
-moz-border-radius: 6px;
border-radius: 6px;
-webkit-box-shadow: 0 1px 2px rgba(0,0,0,.3);
-moz-box-shadow: 0 1px 2px rgba(0,0,0,.3);
box-shadow: 0 1px 2px #000;
box-shadow: 0 1px 2px rgba(0,0,0,.3);
color: #fff;
cursor: hand;
cursor: pointer;
display: inline-block;
font-weight: bold;
margin: 0 2px;
padding: 5px;
text-align: center;
text-shadow: 0 1px 1px #000;
text-shadow: 0 1px 1px rgba(0,0,0,.3);
vertical-align: baseline;
}
There are some vendor specific rules in there that will affect different browsers in different ways. You should also note that gradients are new in CSS and not all browsers support them—some older browsers don't support them at all in fact. In that case, the fall back solid color is used and so you should set that as well.
To change the gradients for the submit button (not including the hover, focus, or active states), you could start with the CSS from the original stylesheet and just topye the color values and update those. Here is an example:
input[type=submit] {
background: #808080;
background: -moz-linear-gradient(top, #F2F2F2, #808080);
background: -o-linear-gradient(top, #F2F2F2, #808080);
background: -webkit-gradient(linear, left top, left bottom, from(#F2F2F2), to(#808080));
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#F2F2F2', endColorstr='#808080' );
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#F2F2F2, endColorstr=#808080)";
border: solid 1px #808080;
}
To also change out the hover, focus, and active states, you would need to repeat the code with different colors you pick out for each of those states just like you can see in the original stylesheet. Here is an example to get you started:
input[type=submit]:hover,
input[type=submit]:focus {
background: #f43059;
background: -moz-linear-gradient(top, #fba2b5, #f43059);
background: -o-linear-gradient(top, #fba2b5, #fba2b5);
background: -webkit-gradient(linear, left top, left bottom, from(#fba2b5), to(#f43059));
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#fba2b5', endColorstr='#f43059');
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#fba2b5, endColorstr=#f43059)";
border-color: #f43059;
}
input[type=submit]:active {
background: #fba2b5;
background: -moz-linear-gradient(top, #f43059, #fba2b5);
background: -o-linear-gradient(top, #f43059, #fba2b5);
background: -webkit-gradient(linear, left top, left bottom, from(#f43059), to(#fba2b5));
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#f43059', endColorstr='#fba2b5');
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#f43059, endColorstr=#fba2b5)";
border-color: #f43059;
color: #fba2b5;
}
Adjust the color codes as necessary.