fix: 修复侧边栏布局——sidebar与main-content并排显示

renderer/index.html

@@ -91,6 +91,8 @@
       <button id="btn-dismiss" class="banner-btn">忽略</button>
     </div>
 
+    <!-- Workspace: Sidebar + Main Content -->
+    <div id="workspace">
       <!-- Sidebar -->
       <div id="sidebar">
         <div id="sidebar-header">
@@ -143,6 +145,7 @@
         <div id="preview" class="markdown-body"></div>
       </div>
     </div>
+    </div>
 
     <!-- Status bar -->
     <div id="statusbar">

renderer/style.css

@@ -66,6 +66,7 @@ html, body {
   display: flex;
   flex-direction: column;
   height: 100vh;
+  position: relative;
 }
 
 /* ===== Toolbar ===== */
@@ -297,6 +298,14 @@ html, body {
 }
 
 /* ===== Main Content ===== */
+#workspace {
+  flex: 1;
+  display: flex;
+  flex-direction: row;
+  overflow: hidden;
+  min-height: 0;
+}
+
 #main-content {
   flex: 1;
   display: flex;