Fix in-modal PDF preview rendering

js/main.js

@@ -550,18 +550,14 @@ class App {
           throw new Error(`PDF preview failed: ${response.status}`);
         }
 
-        const pdfBlob = await response.blob();
-        this.currentPreviewObjectUrl = URL.createObjectURL(pdfBlob);
+        clearPreviewObjectUrl();
         body.innerHTML = `
           <div class="preview-pdf-wrap" style="width:100%; height:100%; display:flex; flex-direction:column;">
-            <embed
-              src="${this.currentPreviewObjectUrl}"
-              type="application/pdf"
-              width="100%"
-              height="100%"
-              style="flex:1; border:0;"
+            <iframe
+              src="${url}"
+              class="preview-pdf-frame"
               title="${file.name} preview"
-            />
+            ></iframe>
           </div>`;
       } catch (err) {
         body.innerHTML = this.previewFallback(

styles.css

@@ -1315,8 +1315,8 @@ body {
   overflow: auto;
   background: #f8fafc;
   display: flex;
-  align-items: center;
-  justify-content: center;
+  align-items: stretch;
+  justify-content: stretch;
   position: relative;
 }
 
@@ -1327,6 +1327,19 @@ body {
   display: block;
 }
 
+.preview-pdf-wrap {
+  flex: 1;
+  min-height: 0;
+}
+
+.preview-pdf-frame {
+  width: 100%;
+  height: 100%;
+  border: 0;
+  display: block;
+  flex: 1;
+}
+
 .preview-image {
   max-width: 100%;
   max-height: 100%;