gmail.user.css

/* ==UserStyle==
@name        gmail - Hide unused buttons, shrink sidebars
@namespace   StylishThemes
@version     1.0.6
@homepageURL https://github.com/quiddity-wp/style-tweaks
@updateURL   https://raw.githubusercontent.com/quiddity-wp/style-tweaks/master/gmail.user.css
@license     CC-0
@author      quiddity-wp
==/UserStyle== */

@-moz-document domain("mail.google.com") {
  
  /* Hide unused button to shorten top-bar */
  div[aria-label="Add to Tasks"], div[title="Add to Tasks"] {
    display: none !important;
  }
  
  /* Hide the useless formatting-toolbar options */
  div[aria-label="Undo ‪(Ctrl-Z)‬"] {
    display: none;
  }
  div[aria-label="Redo ‪(Ctrl-Y)‬"] {
    display: none;
  }
  div[aria-label="Font ‪(Ctrl-Shift-5, Ctrl-Shift-6)‬"] {
    display: none;
  }
  div[aria-label="Underline ‪(Ctrl-U)‬"] {
    display: none;
  }
  div[aria-label="Text color"] {
    display: none;
  }
  div[aria-label="Align"] {
    display: none;
  }
    
/* Bigger Labels popup */
 .J-M-Jz {
  max-height: 430px !important;
}
  
}