because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

response 결과가 '302'로 나옴

css 파일이 존재하지만, Spring boot Security에서 로그인 예외처리를 하지 않아서 접근이 안되는 문제

환경설정에서 예외 처리를 해줘야 함

@Configuration
@EnableWebSecurity
public class WebSecurityConfig {
	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http.authorizeHttpRequests((requests) -> requests
				.requestMatchers("/", "{css 디렉토리}/*.css").permitAll()
				.anyRequest().authenticated())
			.formLogin((form) -> form
				.loginPage("/login")
				.permitAll())
			.logout((logout) -> logout.permitAll());
		return http.build();
	}

하위 디렉토리 전체를 예외처리해야 하는 경우

@Configuration
@EnableWebSecurity
public class WebSecurityConfig {
	@Bean
	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
		http.authorizeHttpRequests((requests) -> requests
				.requestMatchers("/", "{css 디렉토리}/**").permitAll()
				.anyRequest().authenticated())
			.formLogin((form) -> form
				.loginPage("/login")
				.permitAll())
			.logout((logout) -> logout.permitAll());
		return http.build();
	}