Font-weight not consistent between browsers

I recently changed Helvetica to Roboto in my custom child theme. I kept the font-weight the same 300 here:
@import url(http://fonts.googleapis.com/css?family=Roboto:300|Sorts+Mill+Goudy:300,400,500);

and here:
body,
input,
#title {
font-weight: 300;
}

It looks good everywhere except in Safari on my laptop. There it comes across as bold. Interestingly, it looks good in Safari on my desktop. And it looks good on my laptop in Firefox and Chrome.

Any thoughts? Do I need to adjust settings on my laptop? In Safari?

Here’s my site.