Add runtime hints for CSS resource

web/src/main/java/org/springframework/security/web/aot/hint/WebMvcSecurityRuntimeHints.java

@@ -20,6 +20,7 @@ import org.springframework.aot.hint.MemberCategory;
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
 import org.springframework.aot.hint.TypeReference;
+import org.springframework.core.io.ClassPathResource;
 import org.springframework.security.web.access.expression.WebSecurityExpressionRoot;
 
 /**
@@ -40,6 +41,12 @@ class WebMvcSecurityRuntimeHints implements RuntimeHintsRegistrar {
 					TypeReference
 						.of("org.springframework.security.web.csrf.CsrfTokenRequestAttributeHandler$SupplierCsrfToken"),
 					MemberCategory.INVOKE_DECLARED_METHODS);
+
+		ClassPathResource css = new ClassPathResource("org/springframework/security/default-ui.css");
+		if (css.exists()) {
+			hints.resources().registerResource(css);
+		}
+
 	}
 
 }

web/src/test/java/org/springframework/security/web/aot/hint/WebMvcSecurityRuntimeHintsTests.java

@@ -62,4 +62,10 @@ class WebMvcSecurityRuntimeHintsTests {
 			.withMemberCategories(MemberCategory.INVOKE_DECLARED_METHODS)).accepts(this.hints);
 	}
 
+	@Test
+	void cssHasHints() {
+		assertThat(RuntimeHintsPredicates.resource().forResource("org/springframework/security/default-ui.css"))
+			.accepts(this.hints);
+	}
+
 }