style: Refactor simple table styles for better structure

- Added a new class for handling "no data" rows.
- Moved all `td` and `th` styling inside the `tr` block for clarity.
- Kept existing text alignment rules but organized them better.
- Improved padding and color settings for empty states.

app/assets/stylesheets/_simple-tables.scss

@@ -5,28 +5,38 @@
   width: 100%;
   background-color: white;
 
-  td {
-    text-align: right;
-  }
-
-  td:first-child {
-    text-align: left;
-  }
-
-  th {
-    text-align: center;
-  }
-
-  th.u-left {
-    text-align: left;
-  }
-
-  th.u-right {
-    text-align: right;
-  }
-
-  .u-row-odd {
-    background-color: $grey-3;
+  tr {
+    &.no-data {
+      td:first-child {
+        text-align: center;
+        padding: 0.5em;
+        color: $grey-2;
+      }
+    }
+
+    td {
+      text-align: right;
+    }
+
+    td:first-child {
+      text-align: left;
+    }
+
+    th {
+      text-align: center;
+    }
+
+    th.u-left {
+      text-align: left;
+    }
+
+    th.u-right {
+      text-align: right;
+    }
+
+    .u-row-odd {
+      background-color: $grey-3;
+    }
   }
 }
 
@@ -46,4 +56,4 @@
     padding: 0.25em 0.25em 0.25em 0;
     border-bottom: 1px solid $grey-3;
   }
-}
+}