For example in the post World's Longest Blog Comments, thereafter the contents of a very long comment I hide a Spoiler, so it can be opened and closed. It is conceivable if the text is displayed as is without spoilers then it will take some space and the entire post will be very long and damage the look of the blog.
How to Make Spoiler:
1. How to make a Spoiler without background color.
2.SPOILER WITH BORDER AND BACKGROUND COLORS
<Div style = "color: # 000000; = This is to change the text color background: # EBF3FB; = This is to change the background color border: 1px solid # AACCEE; = This is for size and border color