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/auth-design/AuthNvsAuthZDemo.vue

@@ -149,9 +149,9 @@ const decisionLog = computed(() => {
 .authn-authz-demo {
   border: 1px solid var(--vp-c-divider);
   background: var(--vp-c-bg-soft);
-  border-radius: 8px;
+  border-radius: 6px;
   padding: 1.5rem;
-  margin: 1rem 0;
+  margin: 0.5rem 0;
 }
 
 .header {
@@ -179,8 +179,8 @@ const decisionLog = computed(() => {
 .card {
   background: var(--vp-c-bg);
   border: 1px solid var(--vp-c-divider);
-  border-radius: 8px;
-  padding: 1rem;
+  border-radius: 6px;
+  padding: 0.75rem;
 }
 
 .card-title {
@@ -229,7 +229,7 @@ const decisionLog = computed(() => {
 .result {
   border: 1px solid var(--vp-c-divider);
   background: var(--vp-c-bg-alt);
-  border-radius: 8px;
+  border-radius: 6px;
   padding: 0.75rem;
   margin-bottom: 0.75rem;
 }