How can I change the size of font in articles in both desktop view and mobile phone view?

Dear aojan,
Please send us your URL link to check your site then we will send code for you.

Thanks.

www.kutaknet.com/

Thanks.

Dear aojan,
Please change this code in file: /templates/sj_lifemag/css/template-red.css line 6378
#k2Container.itemView .itemBody div.itemFullText {
margin-bottom: 30px;
color: #333;
font-size: 13px;
}

Thanks.