How to make post box transparent

user css proporty opacity
example

.classname{
  opacity:0.5 /*Will set opacity to 50%*/
 }

opacity accepts value from 0 to 1.

Hello Fransie
please use following code in CSS

article.post {
 opacity:0.7 /*Will set opacity to 50%*/
}

This will solve your issue.

Thank you

You can set the background color of the box with an opacity using rgba;

article.post {
    background-color: rgba(200, 54, 54, 0.7);
}

You can get rgb values from a tool like Photoshop or an online convertor like this one http://hex2rgba.devoth.com/

This works in all current browsers. Internet explorer 8 will show a solid color.

Hello Fransie,

You can try this in your Custom CSS to make the box transparent:

article.page, .hentry {
    background: transparent none repeat scroll 0 0 !important;
}
.hentry, .hentry p, article p {
    color: #fff;
}

If the above code is not helping you please provide a screenshot of the page or provide direct link to the page where you face the problem.

Hope that helps you, feel free to ask if there is any other problem.

Thank you.