Product Page CSS

I'm looking for the css section that allows customising of the Product Page colours - specifically the Add to Cart button background colour which I'd like to be red. Can someone point me towards the correct CSS file.

css/vm_ecommerce.css

Best use chromes "Inspect element" to see what to change.

Yes, I did that and it seems that it's all specified in the five default styles. I can't change the button colours without changing other elements too.

I'd have to define a Custom style in the template settings, which is a possibility, but I don't really want to go through each individual setting as I'm happy with almost all the colours in Style 4 except the buy button.

Where are the Custom Style settings saved to? Maybe I could copy the Style 4 that I use and call it a Custom Style, then I'd be able to adjust just what I need, not everything.

css generated code for button is in template_css.php (using template parameters):

#product-tabs li a.current,#product-tabs li a.current:hover,
#product-tabs .nav li a:hover, #product-tabs .nav li a:focus,
span.addtocart-button input.addtocart-button, span.addtocart-button input.notify-button,
span.addtocart-button input.addtocart-button:hover, span.addtocart-button input.notify-button:hover {
background: -webkit-gradient(linear, 0 0, 0 bottom, from(<?php echo $vmTabActiveBgStart; ?>), to(<?php echo $vmTabActiveBgEnd; ?>));
background: -moz-linear-gradient(<?php echo $vmTabActiveBgStart; ?>, <?php echo $vmTabActiveBgEnd; ?>);
color: <?php echo $vmTabActiveColor; ?> !important;
background: linear-gradient(<?php echo $vmTabActiveBgStart; ?>, <?php echo $vmTabActiveBgEnd; ?>);
-pie-background: linear-gradient(<?php echo $vmTabActiveBgStart; ?>, <?php echo $vmTabActiveBgEnd; ?>);
filter: progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr='<?php echo $vmTabActiveBgStart; ?>', endColorstr='<?php echo $vmTabActiveBgEnd; ?>');
position:relative;
}

also see htis file:

components/com_virtuemart/assets/css/vmsite-ltr.css

Thanks for the quick reply. The actual fill colours for the button appear to be defined in the five standard template styles PHP files and affect other elements too. None of the CSS that I can see defines the colours and Chrome Inspect Element points towards the actual page URL rather than a CSS file.

background comes form template_css.php definition