Works well and simply.

Thank you ??

I had tried another plugin, BBS Spoilers, but I prefered Inline Spoilers for two simple reasons:
– the absence of a “collapse” button eating away vertical pixels without any need for it
– the spoiler zone’s width is slightly smaller and doesn’t take additional pixels on the right and the left

Additional note, just in case it may help other people who don’t have a white background or unusual theme appearances, if you want to customize the body of the spoiler area, you can make it with:

.spoiler-body {
whatever you need;
}