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-languages/BackendLanguagesDemo.vue

@@ -230,12 +230,12 @@ const getCurrentLang = () => {
 <style scoped>
 .backend-languages-demo {
   border: 1px solid var(--vp-c-divider);
-  border-radius: 8px;
+  border-radius: 6px;
   background: var(--vp-c-bg-soft);
-  padding: 1rem;
-  margin: 1rem 0;
-  max-height: 600px;
-  overflow-y: auto;
+  padding: 0.75rem;
+  margin: 0.5rem 0;
+  
+  
 }
 
 .demo-header {
@@ -286,10 +286,10 @@ const getCurrentLang = () => {
 }
 
 .language-card {
-  padding: 1rem;
+  padding: 0.75rem;
   background: var(--vp-c-bg-soft);
   border: 2px solid transparent;
-  border-radius: 8px;
+  border-radius: 6px;
   cursor: pointer;
   transition: all 0.2s ease;
   text-align: center;
@@ -338,8 +338,8 @@ const getCurrentLang = () => {
 
 .lang-detail {
   background: var(--vp-c-bg);
-  border-radius: 8px;
-  padding: 1rem;
+  border-radius: 6px;
+  padding: 0.75rem;
   margin-top: 0.75rem;
   border: 1px solid var(--vp-c-divider);
 }