Modularized modal styling's

* Also fixed white on white text that I missed in join-form's text field

freechat-client/sass/join-modal.scss

@@ -0,0 +1,16 @@
+@import 'general';
+
+.join-style {
+    color: $text;
+    background: $top-grey;
+}
+
+.join-form-label {
+    color: $text;
+}
+
+// override 'general's whitesmoke color fo thie dialog
+.form-text {
+    color: black;
+}
+

freechat-client/sass/style.scss

@@ -1,5 +1,6 @@
 @import 'general';
 @import 'scroll';
+@import 'join-modal';
 
 body {
     color: $text;
@@ -42,16 +43,6 @@ input {
     margin-right: 1em;
 }
 
-// Join modal meme
-.join-style {
-    color: $text;
-    background: $top-grey;
-}
-
-.join-form-label {
-    color: $text;
-}
-
 // mostly used to let the sidebar be of a correct height
 .wrapper {
     display: flex;