2026-04-18-19-08-43 - 六项UI优化：基础字段无下划线、field-value联动高亮、视频按钮整合、视频间距紧凑、签名空行、图片占位符自适应高度

src/pages/TemplateManage.tsx

@@ -145,11 +145,14 @@ export default function TemplateManage() {
   const fillPlaceholderSrc = (placeholder: HTMLElement, src: string) => {
     placeholder.innerHTML = `
       <span class="delete-btn" contenteditable="false">×</span>
-      <img src="${src}" style="max-width:100%;max-height:100%;object-fit:contain;display:block;margin:0 auto;" draggable="false">
+      <img src="${src}" style="max-width:100%;height:auto;display:block;margin:0 auto;" draggable="false">
     `;
     placeholder.classList.add('has-image');
     placeholder.style.border = 'none';
     placeholder.style.background = 'transparent';
+    placeholder.style.height = 'auto';
+    placeholder.style.width = 'auto';
+    placeholder.style.lineHeight = 'normal';
     saveTemplateContent();
   };