Refactor CSS styles across multiple components for improved consistency and maintainability

- Removed redundant styles and consolidated common styles in styles.scss
- Updated layout and spacing variables for better responsiveness
- Simplified component-specific styles in apartment, lease, tenant, and dashboard components
- Enhanced readability and organization of CSS by utilizing CSS layers
- Ensured consistent use of design tokens for colors, spacing, and borders

frontend/src/app/components/tenant-card/tenant-card.css

@@ -3,10 +3,6 @@
 }
 .tenant-card {
   min-width: 0;
-  padding: 20px;
-  border: 1px solid var(--border);
-  border-radius: 22px;
-  background: var(--surface);
 }
 .tenant-identity {
   display: flex;
@@ -146,8 +142,7 @@
   color: var(--text-muted);
   font-size: 0.82rem;
 }
-.attachment-row mat-spinner,
-.card-actions mat-spinner {
+.attachment-row mat-spinner {
   display: inline-block;
   margin-right: 6px;
   vertical-align: middle;
@@ -158,13 +153,5 @@
   font-size: 0.78rem;
 }
 .card-actions {
-  display: flex;
-  justify-content: flex-end;
   margin-top: 12px;
 }
-.card-actions .mat-mdc-button {
-  --mdc-text-button-label-text-color: var(--accent);
-}
-.card-actions .danger-action.mat-mdc-button {
-  --mdc-text-button-label-text-color: var(--danger);
-}