The text selection is the highlight color. The default is a light blue but if you don't like it you can change it with the tutorials below.
Step 1: Find A Color
Before we can change the color, we need to find a color. You can very easily find a color on color-hex.com. Once you find the color you like, copy the color code. For this tutorial we are going to be using #0cde70.
Step 2: Install The Code
Click the "Edit HTML/CSS" button under the themes tab and scroll down in the sidebar until you find: "_page-type.less". Then copy the code below:
background: #0cde70; /* WebKit/Blink Browsers */
background: #0cde70; /* Gecko Browsers */
Paste the code into the tab and press save.
You Are Done! Enjoy Your New Highlight Color!