A mod for the Discord web app - to give extra shortcut keys for hiding sidebars, plus more layout stuff...

mog86uk-Discord-Layout-Mod.user.js

// ==UserScript==
// @name         Discord Layout Mod
// @namespace    mog86uk-discord-layout-mod
// @version      1.0
// @description  A mod for the Discord web app - to give extra shortcut keys for hiding sidebars, plus more layout stuff...
// @author       mog86uk
// @match        https://discordapp.com/channels/*
// @require      http://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js
// @grant        none
// ==/UserScript==

jQuery.noConflict();
jQuery(document).ready(function($) {
    /*jshint multistr: true */

    var TheStyleSheet="\
.channel-members-wrap {min-width: 220px !important;} /* default = min-width: 240px; */\n\
.channel-members {padding: 0 0 20px !important;} /* default = padding: 20px 0; */\n\
.channel-members h2 {margin: 9px 0 0 !important;} /* default = margin: 9px 0; margin-top: 30px; */\n\
.member-status {padding: 5px 16px 5px 10px !important;} /* default = padding: 5px 16px 5px 30px; */\n\
.title-wrap {min-height: 10px !important;} /* default = min-height: 57px; */\n\
.message-group {padding: 10px 0 !important;} /* default = padding: 20px 0; */\n\
.channel-textarea {margin: 10px 0 30px !important;} /* default = margin: 20px 0 30px; */";

    addGlobalStyle(TheStyleSheet);

    $(document).on('keydown', function(evt) {

        if (evt.ctrlKey) {
            switch(evt.which) {
                case 71: // Ctrl + G
                    evt.preventDefault();
                    $('.title-wrap').toggle();
                    break;
                case 72: // Ctrl + H
                    evt.preventDefault();
                    $('.guilds-wrapper').toggle();
                    break;
                case 74: // Ctrl + J
                    evt.preventDefault();
                    $('.channels-wrap').toggle();
            }
        }
    });

    function addGlobalStyle(css) {
        var head, style;
        head = document.getElementsByTagName('head')[0];
        if (!head) { return; }
        style = document.createElement('style');
        style.type = 'text/css';
        style.innerHTML = css;
        head.appendChild(style);
    }
});

Ctrl + G = show/hide title bar
Ctrl + H = show/hide server list
Ctrl + J = show/hide channel list
(Ctrl + U = show/hide channel member list)