Revamp the app members table

- remove some of the custom styles in the page-specific style sheet.
Instead, try to rely on default USWDS styles as much as possible.
- tweak a few values in the tables stylesheet
- move some markup around in the members template

styles/elements/_tables.scss

@@ -66,7 +66,7 @@ table.atat-table {
 
         display: table-cell;
         white-space: nowrap;
-        border-bottom-style: dashed;
+        border-bottom-style: solid;
         border-top: none;
 
         &:last-child {
@@ -88,18 +88,14 @@ table.atat-table {
       th,
       td {
         @include block-list-header;
-
         display: table-cell;
         white-space: nowrap;
+        color: black;
       }
     }
   }
 
   @at-root .panel #{&} {
-    tr:last-child td {
-      border-bottom: 0;
-    }
-
     &:last-child {
       margin-bottom: 0;
     }
@@ -138,10 +134,6 @@ table.atat-table {
   }
 
   @at-root .panel #{&} {
-    tr:last-child td {
-      border-bottom: 0;
-    }
-
     &:last-child {
       margin-bottom: 0;
     }