doc: 更新样式

Author: ArgoZhang

src/BootstrapBlazor.Server/Components/Pages/Index.razor

@@ -6,7 +6,7 @@
 
 <section class="bd-masthead">
     <div class="container-xxl bd-gutter">
-        <div class="col-md-8 mx-auto text-center">
+        <div class="text-center d-flex align-items-center flex-column">
             <a class="d-inline-flex text-dark text-decoration-none" href="https://github.com/dotnetcore/BootstrapBlazor?wt.mc_id=DT-MVP-5004174" rel="noopener" target="_blank">
                 <span class="py-2 px-3 rounded-5 masthead-notice">
                     @Localizer["Support"]