* {
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

body {
  background: #333;
  font: 100%/1 "Helvetica Neue", Arial, sans-serif;
}

.login {
  position: absolute;
  top: 50%;
  left: 50%;
  margin: -10rem 0 0 -10rem;
  width: 20rem;
  height: 20rem;
  padding: 20px;
  background: #fff;
  border-radius: 5px;
  overflow: hidden;
}
.login:hover > .login-header, .login.focused > .login-header {
  width: 2rem;
}
.login:hover > .login-header > .text, .login.focused > .login-header > .text {
  font-size: 1rem;
  transform: rotate(-90deg);
}
.login.loading > .login-header {
  width: 20rem;
}
.login.loading > .login-header > .text {
  display: none;
}
.login.loading > .login-header > .loader {
  display: block;
}

.login-header {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 1;
  width: 20rem;
  height: 20rem;
  background: orange;
  transition: width 0.5s ease-in-out;
}
.login-header > .text {
  display: block;
  width: 100%;
  height: 100%;
  font-size: 5rem;
  text-align: center;
  line-height: 20rem;
  color: #fff;
  transition: all 0.5s ease-in-out;
}
.login-header > .loader {
  display: none;
  position: absolute;
  left: 5rem;
  top: 5rem;
  width: 10rem;
  height: 10rem;
  border: 2px solid #fff;
  border-radius: 50%;
  animation: loading 2s linear infinite;
}
.login-header > .loader:after {
  content: "";
  position: absolute;
  left: 4.5rem;
  top: -0.5rem;
  width: 1rem;
  height: 1rem;
  background: #fff;
  border-radius: 50%;
  border-right: 2px solid orange;
}
.login-header > .loader:before {
  content: "";
  position: absolute;
  left: 4rem;
  top: -0.5rem;
  width: 0;
  height: 0;
  border-right: 1rem solid #fff;
  border-top: 0.5rem solid transparent;
  border-bottom: 0.5rem solid transparent;
}

@keyframes loading {
  50% {
    opacity: 0.5;
  }
  100% {
    transform: rotate(360deg);
  }
}
.login-form {
  margin: 0 0 0 2rem;
  padding: 0.5rem;
}

.login-input {
  display: block;
  width: 100%;
  font-size: 2rem;
  padding: 0.5rem 1rem;
  box-shadow: none;
  border-color: #ccc;
  border-width: 0 0 2px 0;
}
.login-input + .login-input {
  margin: 10px 0 0;
}
.login-input:focus {
  outline: none;
  border-bottom-color: orange;
}

.login-btn {
  position: absolute;
  right: 1rem;
  bottom: 1rem;
  width: 5rem;
  height: 5rem;
  border: none;
  background: orange;
  border-radius: 50%;
  font-size: 0;
  border: 0.6rem solid transparent;
  transition: all 0.3s ease-in-out;
}
.login-btn:after {
  content: "";
  position: absolute;
  left: 1rem;
  top: 0.8rem;
  width: 0;
  height: 0;
  border-left: 2.4rem solid #fff;
  border-top: 1.2rem solid transparent;
  border-bottom: 1.2rem solid transparent;
  transition: border 0.3s ease-in-out 0s;
}
.login-btn:hover, .login-btn:focus, .login-btn:active {
  background: #fff;
  border-color: orange;
  outline: none;
}
.login-btn:hover:after, .login-btn:focus:after, .login-btn:active:after {
  border-left-color: orange;
}