fix: 上传题卡预览问题

src/modules/card/views/CardPreview.vue

@@ -165,7 +165,7 @@ export default {
       const iframeDom = document.createElement("iframe");
       document.getElementById("preview-frame").appendChild(iframeDom);
       const wwidth = window.innerWidth;
-      const wheight = window.innerHeight - 10;
+      const wheight = window.innerHeight - 60;
       iframeDom.style.cssText = `width: ${wwidth}px;height: ${wheight}px;border:none;outline:none;`;
       const iframeDoc = iframeDom.contentDocument;
       iframeDoc.open();