nongxiaohe/admin/static/lib/simditor/plugins/html/simditor-html.css

.simditor.simditor-html .simditor-wrapper > textarea {
  display: block !important;
}
.simditor.simditor-html .simditor-body,
.simditor.simditor-html .simditor-placeholder {
  display: none;
}