Antoine looking for a nice, light, easily configurable ide
I started coding websites about 20 years ago, and I've likely tried everything since. For me personally, my #1 favorite is NotePad++ (one of the few reasons why I keep a Windows box alive). I use NP++ for a lot of different projects too, including formating text layouts for word processors, spreadsheets, file lists, macros, music playlists, etc..
On Linux, I like Geany, but the 'end' key goes to the end of the line instead of going to the right edge of the screen like what's done in word processors, and since I use word processors more often than most anything else, 28 years of muscle memory insists that I don't use Geany. 😉 I've seen that there is supposed to be a fix for the 'end of line' command, but it hasn't ever worked for me.
BlueFish has become my #1 choice on Linux. It doesn't have many of the features like NP++, but for basic HTML/CSS, it's very agreeable.
Notepadqq is also good. I like it for it being a little more utilitarian.
Gedit seems to be even more utilitarian, but when the mood hits, I enjoy using it.
On autosave, I learned something super important during the Windows ME days, and the habit is just as strong today: I frequently press ctrl/s in all word processors, spreadsheets, and editors. 😉