style: fix some style issued

src/main/resources/templates/login.html

@@ -9,6 +9,7 @@
     <div th:replace="~{fragments.html :: nav}"></div>
     <main>
         <div class="login-form">
+            <img th:src="@{/user.svg}" alt="user-logo" />
             <h2 class="centered">Anmelden</h2>
             <div class="centered notification error" th:if="${param.error}">Anmeldung nicht erfolgreich</div>
             <div class="centered notification notice" th:if="${param.expired}">Sitzung abgelaufen oder von einem Administrator beendet.</div>
@@ -16,7 +17,7 @@
             <form method="post" th:action="@{/login}">
                 <input type="text" id="username" name="username" class="form-control" placeholder="Username" required="" autofocus="" />
                 <input type="password" id="password" name="password" class="form-control" placeholder="Password" required="" />
-                <button type="submit">Anmelden</button>
+                <button class="btn" type="submit">Anmelden</button>
                 <hr th:if="${not oidcLogins.isEmpty()}" />
                 <a th:each="oidcLogin : ${oidcLogins}" class="btn" th:href="@{/oauth2/authorization/{provider}(provider=${oidcLogin.component1()})}">OIDC Login - [[ ${oidcLogin.component2()} ]]</a>
             </form>