Better move error visibility

Shogi.UI/Shared/TemporaryModal.razor

@@ -0,0 +1,39 @@
+@using System.Timers
+<div class="TemporaryModal PrimaryTheme ThemeVariant--Contrast">
+	<div class="content">
+		@ChildContent
+	</div>
+	<button class="close" @onclick="OnClickClose">X</button>
+	<div class="countdown" style="--timeToClose: @TimeToClose">
+		<div class="time-background">
+			<div class="time"></div>
+		</div>
+		<div class="time-helper-text">This message will close soon.</div>
+	</div>
+</div>
+
+@code {
+	[Parameter][EditorRequired] public RenderFragment? ChildContent { get; set; }
+	[Parameter][EditorRequired] public EventCallback OnClickClose { get; set; }
+
+	[Parameter] public int SecondsUntilClose { get; set; } = 3;
+
+	private string TimeToClose => $"{SecondsUntilClose}s";
+	private System.Timers.Timer closingTimer = new System.Timers.Timer();
+
+	protected override void OnParametersSet()
+	{
+		closingTimer = new System.Timers.Timer(TimeSpan.FromSeconds(SecondsUntilClose).TotalMilliseconds)
+			{
+				AutoReset = false
+			};
+		closingTimer.Elapsed += new System.Timers.ElapsedEventHandler(OnTimerElapsed);
+
+		closingTimer.Start();
+	}
+
+	private void OnTimerElapsed(object? source, ElapsedEventArgs elapsedEventArgs)
+	{
+		OnClickClose.InvokeAsync();
+	}
+}