Article page number button problem

Hi, I am a new member here and I need a little bit help with my theme. I have bought a theme from cms masters and they give me the permission to modify it . They already helped me with many thing but with this, they said that it will be included in an update for this theme, but the releasing date is unknow or they don’t know if they will release it. So, this is why I need your help. I am the administrator of , and many of my tutorials are very very very long. One of them have over 500 images and I want to split the post in several pages but the page number are not very clear. Here you have an example <---- the page numbers ar .1 .2 .3 .4 .5

What I want to do is to change those buttons. To make some bigger and clear buttons , easy to see by my readers. I will appreciate very much if somebody will help me with this.

PS : as you can see , I am a 3D modeler and article writer. Coding is not one of my best friends so please be patient. Just ask any file you need and I will provide it .

Thank you