refactor: 删除不使用的样式

Author: ArgoZhang

src/components/BootstrapBlazor.PdfReader/wwwroot/css/pdf_viewer.css

@@ -141,30 +141,6 @@
     margin-inline: 5px;
 }
 
-.pdfViewer .page.loadingIcon::after {
-    position: absolute;
-    top: 0;
-    left: 0;
-    content: "";
-    width: 100%;
-    height: 100%;
-    background: url("images/loading-icon.gif") center no-repeat;
-    display: none;
-    transition-property: display;
-    transition-delay: var(--loading-icon-delay);
-    z-index: 5;
-    contain: strict;
-}
-
-.pdfViewer .page.loading::after {
-    display: block;
-}
-
-.pdfViewer .page:not(.loading)::after {
-    transition-property: none;
-    display: none;
-}
-
 .pdfPresentationMode .pdfViewer {
     padding-bottom: 0;
 }