diff --git a/platform/frontend/topics.html b/platform/frontend/topics.html
index 9974cdb..22dd034 100644
--- a/platform/frontend/topics.html
+++ b/platform/frontend/topics.html
@@ -9,7 +9,7 @@
     <style>
         .selected-count { color: var(--color-text-secondary); font-size: var(--font-size-body); margin-left: auto; }
         .preview-dialog-custom .el-dialog__body { overflow-y: auto; max-height: calc(90vh - 120px); padding: 16px 20px; }
-        .preview-dialog-custom .preview-body { max-height: none !important; min-height: 300px; overflow: visible; }
+        .preview-dialog-custom .preview-body { max-height: calc(90vh - 200px); min-height: 300px; overflow-y: auto; }
         .preview-dialog-custom .preview-body img { max-width: 100%; }
         .topic-card-list { display: none; }
         @media (max-width: 768px) {
@@ -426,12 +426,23 @@ const TopicsApp = {
             if (!this.previewTopic || !this.editContent) { this.$message.warning('没有内容可保存'); return; }
             this.savingContent = true;
             try {
+                const original = this.platformContents[this.previewPlatform] || '';
+                let headHtml = '';
+                if (original) {
+                    try {
+                        const parser = new DOMParser();
+                        const doc = parser.parseFromString(original, 'text/html');
+                        const head = doc.querySelector('head');
+                        if (head) headHtml = head.innerHTML;
+                    } catch (e) {}
+                }
+                const fullHtml = '<!DOCTYPE html><html><head>' + headHtml + '</head><body>' + this.editContent + '</body></html>';
                 await this.api(`/api/articles/${this.previewTopic.id}/content`, {
                     method: 'PUT',
-                    body: JSON.stringify({ platform: this.previewPlatform, html_content: this.editContent })
+                    body: JSON.stringify({ platform: this.previewPlatform, html_content: fullHtml })
                 });
                 this.$message.success('保存成功');
-                this.platformContents[this.previewPlatform] = this.editContent;
+                this.platformContents[this.previewPlatform] = fullHtml;
                 this.editing = false;
             } catch (e) { this.$message.error('保存失败: ' + e.message); }
             finally { this.savingContent = false; }
