Just a quick dark slack theme, work in progress

slack.css

/* 
Sidebar Theme:
#140E1D,#140E1D,#65375B,#FFABED,#65375B,#F9B98C,#FFABED,#FFABED 
*/

* {
  box-shadow: unset !important;
}

.client_main_container,
.channel_header,
#channel_topic_text, 
#footer, #msg_input, #msg_form, #footer_msgs,
.search_input, .search_form,
.reply_bar,
#flex_contents, #flex_contents .heading,
.message_input,
.reply_count {
	background-color: #140E1D !important;
	color: #494452 !important;
  border-color: #234A66 !important;
}

ts-message {
  background-color: #140E1D !important;
}

.message_body {
	color: #F9B98C;
}

.light_theme ts-message .message_content a.message_sender {
	background-color: #65375B !important;
  color: #FFABED !important;
}

.client_main_container .bot_message .message_sender, .bot_message .message_sender a {
  background-color: #234A66 !important;
  color: #8ECDFF !important;
} 

.day_divider_label {
	background-color: #65375B !important;
	color: #FFABED;
}

.day_msgs, .convo_flexpane_divider {
  border-top: none !important;
}

#client_body:not(.onboarding)::before {
  display: none !important;
}

.app_preview_link_slug, .internal_member_link, .internal_user_group_link, ts-mention {
  background-color: #005156 !important;
  color: #8ECDFF !important;
}

.client_main_container a, 
.client_main_container a:link, 
.client_main_container a:visited {
   color: #8ECDFF !important;
}

a.mention, a:link.mention, a:visited.mention, .mention {
  background-color: #2E4F21 !important;
  color: #9AD685 !important;
}

a.timestamp, a:link.timestamp, a:visited.timestamp,
.file_preview_link,
ts-message .meta.msg_inline_file_preview_toggler .msg_inline_media_toggler, 
ts-message .meta.msg_inline_file_preview_toggler .ts_icon_dropbox, 
ts-message .meta.msg_inline_file_preview_toggler a, 
ts-message .meta.msg_inline_img_toggler .msg_inline_media_toggler, 
ts-message .meta.msg_inline_img_toggler .ts_icon_dropbox, 
ts-message .meta.msg_inline_img_toggler a,
ts-message .reply_bar .last_reply_at, 
ts-message .reply_bar .view_conv_hover {
  color: #494452 !important;
}

.btn_msg_action, .action_hover_container, .btn_unstyle {
  background-color: #140E1D !important;
  border-color: #234A66 !important;
  color: #8ECDFF !important; 
}

.bot_label {
  display: none !important;
}

*::-webkit-scrollbar { width: 4px; }
*::-webkit-scrollbar-track-piece,
*::-webkit-scrollbar-track,
*::-webkit-scrollbar-corner,
*::-webkit-scrollbar-button { display: none; }
*::-webkit-scrollbar-thumb {
  background-color: #494452 !important;
}