add descriptions and modify css

mattermost.md

@@ -6,9 +6,9 @@ description: "A list of communities and a NixNet-styled theme for Mattermost"
 cover: /assets/pages/mattermost.png 
 ---
 ## Communities
-- [NixNet](https://matter.nixnet.xyz/signup_user_complete/?id=n5qbfgiuaidmtmppetgj45zxuh)
-- [LenoirLUG](https://matter.nixnet.xyz/signup_user_complete/?id=rrko34wdzjfo5ykc49d1kkikeo)
-- [Linux Audio](https://matter.nixnet.xyz/signup_user_complete/?id=5ob84if1w3bx3n5phhsbjm3ohh)
+- [NixNet](https://matter.nixnet.xyz/signup_user_complete/?id=n5qbfgiuaidmtmppetgj45zxuh) - General chat, randomness, shiptosting, getting support, etc.
+- [Linux Audio](https://matter.nixnet.xyz/signup_user_complete/?id=5ob84if1w3bx3n5phhsbjm3ohh) - Open to anyone with an interest in audio recording, production, etc. on Linux
+- [LenoirLUG](https://matter.nixnet.xyz/signup_user_complete/?id=rrko34wdzjfo5ykc49d1kkikeo) - A chat room for the Lenoir Linux User Group
 
 ## Theme
 I've created a theme for Mattermost that uses the same colour scheme as the NixNet website. Copy and paste the code below into the application's theme settings under `Account Settings > Display > Theme > Custom Theme`.
@@ -34,9 +34,9 @@ I've created a theme for Mattermost that uses the same colour scheme as the NixN
   "buttonBg":"#5a76c7",
   "buttonColor":"#ffffff",
   "errorTextColor":"#654040",
-   "mentionHighlightBg":"#426350",
-   "mentionHighlightLink":"#2b6863",
+  "mentionHighlightBg":"#949494",
+  "mentionHighlightLink":"#66aaa5",
   "codeTheme":"monokai",
   "mentionBg":"#573c3c"
-}
+}```
 ```