fix: preview css (#2664)

* fix: when error copyHtml

* fix: add preview css

Author: Chasen-Zhang

src/css/custom.scss

@@ -372,6 +372,25 @@ textarea {
   display: flex;
   width: 100%;
 }
+.ant-btn {
+  font-size: 14px;
+  height: 32px;
+  padding: 0px 15px;
+  border-radius: 6px;
+  outline: none;
+  position: relative;
+  display: inline-flex;
+  gap: 8px;
+  align-items: center;
+  justify-content: center;
+  white-space: nowrap;
+  text-align: center;
+  background-image: none;
+  cursor: pointer;
+  transition: all 0.2s cubic-bezier(0.645, 0.045, 0.355, 1);
+  user-select: none;
+  touch-action: manipulation;
+}
 
 .ant-dropdown .ant-dropdown-menu {
   background-color: var(--color-bg-1);