How to change font size and style ?

May I know how to change font size and style (like bold) of the theme ?

Those are the fonts for :

(1) homepage slider
(2) categories Page Slider
(3) widget
(4) menu

Many thanks.

 

Hello,

Paste this code in Custom CSS
Appearance > Theme Option > Styling Option > Custom CSS

Code:

.slider-item section {
font-weight: bold;
}
 
.sidebar {
font-weight: bold;
}
 
#menu {
font-weight: bold;
}