Refresh header and footer with signet, gradient, nav pills and three-column footer; fix box-sizing of design boxes

Elternbeirat.Web.Tests/FooterYearTests.cs

@@ -0,0 +1,27 @@
+using Elternbeirat.Web.Features.Layout;
+
+namespace Elternbeirat.Web.Tests;
+
+/// <summary>
+/// Unit tests for the footer's copyright year. Pure logic, no PocketBase needed.
+/// </summary>
+public class FooterYearTests
+{
+    [Fact]
+    public void New_year_in_Berlin_wins_over_the_UTC_year()
+    {
+        // 23:30 UTC on New Year's Eve is already 00:30 in Berlin (winter time, +1),
+        // so the footer must show the new year although the server clock says the old.
+        var now = new DateTimeOffset(2026, 12, 31, 23, 30, 0, TimeSpan.Zero);
+
+        FooterYear.For(now).ShouldBe(2027);
+    }
+
+    [Fact]
+    public void Ordinary_day_keeps_its_year()
+    {
+        var now = new DateTimeOffset(2026, 10, 1, 12, 0, 0, TimeSpan.Zero);
+
+        FooterYear.For(now).ShouldBe(2026);
+    }
+}