Add text to top of Index Pages

Site URL: https://christopherswan.co.uk

Hi, 
I would like to add a short page description to the top of the index pages on my site to describe what is shown in the index below. This would be used on the following pages.

https://christopherswan.co.uk/portfolio

https://christopherswan.co.uk/projects

https://christopherswan.co.uk/places

Is there code that can do this? 

Thank you! 

Add to Design > Custom CSS

body#collection-5eca63ae29359c0004f2a323 div#projectThumbs:before {
    content: "This is porfolio page";
    display: block;
    text-align: center;
}
body#collection-5eca76a8e3d0ce7bf2dbf117 div#projectThumbs:before {
    content: "This is project page";
    display: block;
    text-align: center;
}
body#collection-5eca921dbb99ad6e8659fb1d div#projectThumbs:before {
    content: "This is place page";
    display: block;
    text-align: center;
}

Thank you so much Tuanphan. Would it be possible to add one line space below the text so that it doesn't sit directly above the index images?

Thank you - that's perfect!