fix(auth): mas breaks security modal styling

The move to the Matrix Auth Service means the app no longer uses the light theme after login. Due to this, custom styling has now been set.

Author: hazzuk

res/css/views/auth/_CompleteSecurityBody.pcss

@@ -9,12 +9,17 @@ Please see LICENSE files in the repository root for full details.
 
 .mx_CompleteSecurityBody {
     width: 600px;
-    color: $authpage-primary-color;
-    background-color: $background;
+    /* color: $authpage-primary-color; */
+    /* background-color: $background; */
     border-radius: 8px;
     padding: 20px;
     box-sizing: border-box;
 
+    /* elecord, custom colours */
+    color: #ebeef2;
+    background-color: #000000d9;
+    outline: solid #7d7d7d5c;
+
     h2 {
         font-size: $font-24px;
         font-weight: var(--cpd-font-weight-semibold);