App.css

*, *:before, *:after {
  box-sizing: inherit;
}

html {
  box-sizing: border-box;
  height: 100%;
  overflow: hidden;
}

body {
  background: #f2f2f2;
  height: 100%;
}

h1 {
  font-size: 1.5em;
  font-weight: 100;
}

#card-form {
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.panel {
  background: #FFF;
  width: 80%;
  box-shadow: 0 2px 2px 0 rgba(0, 0, 0, .16), 0 0 2px 0 rgba(0, 0, 0, .12);
}

.panel-header {
  background: #93A2FA;
  color: #FFF;
  font-family: 'Roboto', verdana, sans-serif;
}

.panel-header, .panel-footer {
  padding: 1em 2em;
}

.panel-footer {
  background: #f3f3f3;
}

.panel-content {
  padding: 1em 2em;
  overflow: hidden;
}

.textfield-float-label {
  width: 49%;
  display: inline-block;
}

.paysafe-js-label {
  font-family: 'Roboto', verdana, sans-serif;
  transform: translateY(0.4em);
  font-size: 1.125em;
  line-height: 32px;
  transition: all .15s ease-out;
  display: block;
  width: 100%;
  font-weight: 400;
  overflow: hidden;
  margin-bottom: 0.5em;
}

.paysafe-js {
  height: 32px;
  margin-bottom: 1em;
  display: block;
  background-color: transparent;
  color: rgba(0, 0, 0, .87);
  border: none;
  border-bottom: 1px solid rgba(0, 0, 0, .26);
  outline: 0;
  width: 100%;
  font-size: 16px;
  padding: 0;
  box-shadow: none;
  border-radius: 0;
  position: relative;
}

.pay-button {
  background: #93A2FA;
  color: #fff;
  margin: 0 auto;
  border: 0;
  border-radius: 5px;
  padding: 1em 3em;
  font-size: 1em;

  box-shadow: 0 0 2px rgba(0, 0, 0, .12), 0 2px 2px rgba(0, 0, 0, .2);
}

@media (max-width: 600px) {
  html {
    overflow: auto;
  }
  #card-form {
    height: auto;
    margin: 2em;
    font-size: 13px;
  }
  .panel {
    width: 100%;
  }
  .textfield-float-label {
    width: 100%;
    display: inline-block;
  }
  .pay-button {
    width: 100%;
  }
}