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/frontend-engineering/SourceMapDemo.vue

@@ -37,7 +37,7 @@ console.log('总和:', sum);</code></pre>
         <div class="code-panel minified">
           <div class="panel-title">🔧 压缩后 (Minified)</div>
           <pre class="code-block"><code>function n(n,r){var t=n+r;return console.log("结果:",t),t}var r=n(10,20);console.log("总和:",r);
-//# sourceMappingURL=app.js.map</code></pre>
+// sourceMappingURL=app.js.map (指向映射文件)</code></pre>
         </div>
       </div>
 
@@ -104,10 +104,10 @@ console.log('总和:', sum);</code></pre>
 <style scoped>
 .source-map-demo {
   border: 1px solid var(--vp-c-divider);
-  border-radius: 8px;
+  border-radius: 6px;
   background-color: var(--vp-c-bg-soft);
-  padding: 1rem;
-  margin: 1rem 0;
+  padding: 0.75rem;
+  margin: 0.5rem 0;
   font-family: var(--vp-font-family-mono);
 }