userscript.js

// override the growl and use notification center
// wait 10 seconds for everything to load, then do this
setTimeout(function() {
 window.fluid.showUserNotification({
  title: "Loaded user script",
  description: "Yep, loaded",
  priority: 0,
  sticky: true,
  identifier: "slack-message",
 });

 TS.ui.growls.show = function(incomingTitle, text, a, b, c) {
  window.fluid.showUserNotification({
   title: incomingTitle,
   description: text,
   priority: 0,
   sticky: false,
   identifier: "slack-message",
  });
 }
}, 10000);


// With pattern: "*voxmedia.slack.com*" for the userscript

var path = window.fluid.resourcePath + "js/";
var underscore = path + "underscore.js";
var dzslack = path + "dzslack.js";

window.fluid.include(underscore);
window.fluid.include(dzslack);

userstyle.css

.light_theme .message {
  padding-left:0;
  color: #fff;
  font-size: 16px;
}
 
.message .mention {
  font-weight: bold;
}
 
.member_preview_link,
.channel-list-more,
#channel-list .channel,
#im-list .member,
#group-list .group {
    display: none;
}

#channel-list .channel.unread,
#channel-list .channel.active,
#im-list .member.unread,
#im-list .member.active,
#group-list .group.unread,
#group-list .group.active {
    display: block;
}
#channel-list .channel.mention a {
    color: yellow !important;
}


/* Added with "*voxmedia.slack.com*" as the pattern */

.dz_theme .member_preview_link, .dz_theme .member_image {
    display: none !important;
}

.dz_theme #starred_section_header {
    display: none !important;
}

.dz_theme #channels_header,
.dz_theme #groups_header,
.dz_theme #direct_messages_header {
    display: none !important;
}

.dz_theme #team_menu {
    visibility: hidden !important;
}

.dz_theme #user_menu {
    display: none !important;
}

.dz_theme #col_channels {
    z-index: 100000 !important;
    margin-top: -53px !important;
}

.dz_theme #help_icon {
    display: none !important;
}

.dz_theme .modal-backdrop {
    z-index: 10000000 !important;
}
.dz_theme #lightbox_dialog, .dz_theme .modal {
    z-index: 100000000 !important;    
}