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/guarantor-form/guarantor-form.css

@@ -1,26 +1,10 @@
 :host {
   display: block;
 }
-.form-grid {
-  display: grid;
-  gap: 2px;
-}
-.form-grid mat-form-field {
-  width: 100%;
-}
 .add-guarantor.mat-mdc-outlined-button {
-  --mdc-outlined-button-label-text-color: var(--accent);
-  --mdc-outlined-button-outline-color: var(--border-strong);
   width: 100%;
 }
 @media (min-width: 700px) {
-  .form-grid {
-    grid-template-columns: repeat(2, minmax(0, 1fr));
-    gap: 18px;
-  }
-  .full-field {
-    grid-column: span 2;
-  }
   .add-guarantor.mat-mdc-outlined-button {
     width: auto;
   }