<div class="login-container">
  <section class="login" id="login">
    <header>
      <h2>Application Name</h2>
      <h4>Login</h4>
    </header>
    <form class="login-form" action="#" method="post">
      <input type="text" class="login-input" placeholder="User" required autofocus/>
      <input type="password" class="login-input" placeholder="Password" required/>
      <div class="submit-container">
        <button type="submit" class="login-button">SIGN IN</button>
      </div>
    </form>
  </section>
  <p>2016 - <a href="https://www.twitter.com/isacfadoni">Isac Fadoni</a></p>
</div>
<button id="e1">Login error!</button>
html {
  height: 100%;
}

body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: relative;
  min-height: 100%;
  background: #F1F1F1;
}

/* Animation Keyframes */
@keyframes scale_header {
  0%   {max-height: 0px; margin-bottom: 0px; opacity: 0;}
  100% {max-height: 117px; margin-bottom: 25px; opacity: 1;}
}

@keyframes input_opacity {
  0%   {transform: translateY(-10px); opacity: 0}
  100% {transform: translateY(0px); opacity: 1}
}

@keyframes text_opacity {
  0% {color: transparent;}
}

@keyframes error_before {
  0%   {height: 5px; background: rgba(0, 0, 0, 0.156); color: transparent;}
  10%  {height: 117px; background: #FFFFFF; color: #C62828}
  90%  {height: 117px; background: #FFFFFF; color: #C62828}
  100% {height: 5px; background: rgba(0, 0, 0, 0.156); color: transparent;}
}


/* Login Form */
.login-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
  width: 340px;
  height: auto;
  padding: 5px;
  box-sizing: border-box;
}

.login-container img {
  width: 200px;
  margin: 0 0 20px 0;
}

.login-container p {
  align-self: flex-start;
  font-family: 'Roboto', sans-serif;
  font-size: 0.8rem;
  color: rgba(0, 0, 0, 0.5);
}

.login-container p a {
  color: rgba(0, 0, 0, 0.4);
}

.login {
  position: relative;
  width: 100%;
  padding: 10px;
  margin: 0 0 10px 0;
  box-sizing: border-box;
  border-radius: 3px;
  background: #FAFAFA;
  overflow: hidden;
  animation: input_opacity 0.2s cubic-bezier(.55, 0, .1, 1);
  box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.14),
              0 1px 5px 0 rgba(0, 0, 0, 0.12),
              0 3px 1px -2px rgba(0, 0, 0, 0.2);
}

.login > header {
  position: relative;
  width: 100%;
  padding: 10px;
  margin: -10px -10px 25px -10px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.1);
  background: #009688;
  font-family: 'Roboto', sans-serif;
  font-size: 1.3rem;
  color: #FAFAFA;
  animation: scale_header 0.6s cubic-bezier(.55, 0, .1, 1), text_opacity 1s cubic-bezier(.55, 0, .1, 1);
  box-shadow: 0px 2px 2px 0px rgba(0, 0, 0, 0.14),
              0px 1px 5px 0px rgba(0, 0, 0, 0.12),
              0px 3px 1px -2px rgba(0, 0, 0, 0.2);
}

.login > header:before {
  content: '';
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  width: 100%;
  height: 5px;
  padding: 10px;
  margin: -10px 0 0 -10px;
  box-sizing: border-box;
  background: rgba(0, 0, 0, 0.156);
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  color: transparent;
  z-index: 5;
}

.login.error_1 > header:before,
.login.error_2 > header:before {
  animation: error_before 3s cubic-bezier(.55, 0, .1, 1);
}

.login.error_1 > header:before {
  content: 'Invalid username or password!';
}

.login.error_2 > header:before {
  content: 'Invalid or expired Token!';
}

.login > header h2 {
  margin: 50px 0 10px 0;
}

.login > header h4 {
  font-size: 0.7em;
  animation: text_opacity 1.5s cubic-bezier(.55, 0, .1, 1);
  color: rgba(255, 255, 255, 0.4);
}

/* Form */
.login-form {
  padding: 15px;
  box-sizing: border-box;
}


/* Inputs */
.login-input {
  position: relative;
  width: 100%;
  padding: 10px 5px;
  margin: 0 0 25px 0;
  border: none;
  border-bottom: 2px solid rgba(0, 0, 0, 0.2);
  box-sizing: border-box;
  background: transparent;
  font-size: 1rem;
  font-family: 'Roboto', sans-serif;
  font-weight: 500;
  opacity: 1;
  animation: input_opacity 0.8s cubic-bezier(.55, 0, .1, 1);
  transition: border-bottom 0.2s cubic-bezier(.55, 0, .1, 1);
}

.login-input:focus {
  outline: none;
  border-bottom: 2px solid #E37F00;
}


/* Submit Button */
.submit-container {
  display: flex;
  flex-direction: row;
  justify-content: flex-end;
  position: relative;
  padding: 10px;
  margin: 35px -25px -25px -25px;
  border-top: 1px solid rgba(0, 0, 0, 0.1);
}

.login-button {
  padding: 10px;
  border: none;
  border-radius: 3px;
  background: transparent;
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  font-weight: 500;
  color: #E37F00;
  cursor: pointer;
  opacity: 1;
  animation: input_opacity 0.8s cubic-bezier(.55, 0, .1, 1);
  transition: background 0.2s ease-in-out;
}

.login-button.raised {
  padding: 5px 10px;
  color: #FAFAFA;
  background: #E37F00;
  box-shadow: 0px 2px 2px 0px rgba(0, 0, 0, 0.137255),
              0px 1px 5px 0px rgba(0, 0, 0, 0.117647),
              0px 3px 1px -2px rgba(0, 0, 0, 0.2);
}

.login-button:hover {
  background: rgba(0, 0, 0, 0.05);
}

.login-button.raised:hover {
  background: #FDAB43;
}
var form = document.getElementById('login');
var buttonE1 = document.getElementById('e1');

buttonE1.addEventListener('click', function () {
  form.classList.add('error_1');
  setTimeout(function () {
    form.classList.remove('error_1');
  }, 3000);
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.