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/backend-evolution/MonolithVsMicroserviceDemo.vue

@@ -79,10 +79,10 @@ const reset = () => {
 <style scoped>
 .monolith-microservice-demo {
   border: 1px solid var(--vp-c-divider);
-  border-radius: 8px;
+  border-radius: 6px;
   background: var(--vp-c-bg-soft);
   padding: 1.5rem;
-  margin: 1rem 0;
+  margin: 0.5rem 0;
 }
 
 .controls {
@@ -129,8 +129,8 @@ const reset = () => {
 .architecture-block {
   background: var(--vp-c-bg);
   border: 1px solid var(--vp-c-divider);
-  border-radius: 8px;
-  padding: 1rem;
+  border-radius: 6px;
+  padding: 0.75rem;
   display: flex;
   flex-direction: column;
   align-items: center;
@@ -146,8 +146,8 @@ const reset = () => {
 .server-container {
   border: 2px solid #3b82f6;
   background: #eff6ff;
-  padding: 1rem;
-  border-radius: 8px;
+  padding: 0.75rem;
+  border-radius: 6px;
   width: 100%;
   text-align: center;
   transition: all 0.3s;