feat: 怎加 is-page 样式

Author: ArgoZhang

src/BootstrapBlazor/Components/Watermark/Watermark.razor.cs

@@ -54,6 +54,7 @@ public partial class Watermark
     public int? Gap { get; set; }
 
     private string? ClassString => CssBuilder.Default("bb-watermark")
+        .AddClass("is-page", ChildContent is null)
         .AddClassFromAttributes(AdditionalAttributes)
         .Build();
 

src/BootstrapBlazor/Components/Watermark/Watermark.razor.scss

@@ -1,10 +1,10 @@
 .bb-watermark {
     position: relative;
-    pointer-events: none;
-}
 
-body > .bb-watermark {
-    position: fixed;
-    inset: 0;
-    z-index: 9999;
+    &.is-page {
+        position: fixed;
+        inset: 0;
+        z-index: 9999;
+        pointer-events: none;
+    }
 }