style: update border-radius and padding values across components

- standardize border-radius from 8px to 6px for consistent styling
- adjust padding values from 1rem to 0.75rem for better visual hierarchy
- remove redundant overflow-y properties for cleaner code

docs/.vitepress/theme/components/appendix/tracking-design/ToolSelectionDemo.vue

@@ -314,7 +314,7 @@ const getRecommendation = () => {
   background: var(--vp-c-brand);
   color: white;
   border: none;
-  border-radius: 8px;
+  border-radius: 6px;
   font-size: 1rem;
   font-weight: 600;
   cursor: pointer;
@@ -373,9 +373,9 @@ const getRecommendation = () => {
   grid-template-columns: repeat(3, 1fr);
   gap: 1rem;
   margin-bottom: 1rem;
-  padding: 1rem;
+  padding: 0.75rem;
   background: var(--vp-c-bg-soft);
-  border-radius: 8px;
+  border-radius: 6px;
 }
 
 .detail-item {