Fix CSS value error for "font-style: bold"

<errormsg>
Error in parsing value for 'font-style'.  Declaration dropped.
<file>
style.css
<line>
24 and 39
<browser>
firefox 32.03
<action>
changed 'font-style: bold' to 'font-weight: bold' in lines 24 and 39
<ref>
http://www.w3schools.com/cssref/pr_font_weight.asp
<tested>
firefox 32.03, ie 10.0.21, chrome 38.0.2125