Hide Firefox min, max and close buttons.

hide_buttons.css

/*
You can add this block to your userChrome.css or you can 
save the file and import it to your userChrome.css
@import "css/userChrome-files/hide_buttons.css";
Just change the path to the file.
*/

/************************************************
Hide min max and close Buttons in Private Mode
************************************************/

:root[privatebrowsingmode]

.titlebar-min,
.titlebar-max,
.titlebar-close
{
    display: none !important;
}

/********************************
Hide min max and close buttons
*********************************/

.titlebar-min,
.titlebar-max,
.titlebar-close
{
    display: none !important;
}

/*************************************************
Hide min max and close Buttons in F11 FullScreen
*************************************************/

:root[sizemode=fullscreen]

#minimize-button,
#restore-button,
#close-button
{
    display: none !important;
}


/*EOF*/