hideSlackSidebar.css

/* hide the sidebar */

#team_menu {display: none;}
#col_channels_bg {display: none;}
#col_channels {display: none;}
#messages_container {margin-left: 0;}
#messages-input-container {left: -160px;}

/* move the favouites star over */
#channel_header .star {
  right: 50px;
  left: auto;
}