Holy fuck...I didn't expect this.
simple terminal from suckless.org
(aka. st) After appiled path "alpha" -> It did transperent in the way that if you have 2 terminal overlaps -> It'll draw a transperent surface with the underline terminal. so, It's not an idea for open vim with i3 tab or stack mode. I kinda gave up on using it until I realize -> what if underline terminal is "mpv" which is video player. This is a result (Holy fuck is awesome). by set "hi Normal ctermbg=NONE" in vimrc to make transperent background with vim.
Now, I have "mps-youtube" which allow me to watch youtube with mpv, basicly (vim + youtube) as the same time.
ps. If gif is not play -> tell me, I'll upload video. (seriously, is awesome)