html, body {
  background-color: #171640;
  color: #eee;
}
body {
  visibility: hidden;
}
hr {
  border-top-color: rgba(255, 255, 255, .3);
}
img.img-full {
  max-width: 100%;
}

/* loading spinner */
.lds-ring {
  display: inline-block;
  position: relative;
  width: 20px;
  height: 20px;
}
.lds-ring div {
  box-sizing: border-box;
  display: block;
  position: absolute;
  width: 16px;
  height: 16px;
  margin: 2px;
  border: 2px solid #fff;
  border-radius: 50%;
  animation: lds-ring 1.2s cubic-bezier(0.5, 0, 0.5, 1) infinite;
  border-color: #fff transparent transparent transparent;
}
.lds-ring div:nth-child(1) {
  animation-delay: -0.45s;
}
.lds-ring div:nth-child(2) {
  animation-delay: -0.3s;
}
.lds-ring div:nth-child(3) {
  animation-delay: -0.15s;
}
@keyframes lds-ring {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

/* footer */
footer p {
  margin-top: 3rem;
  color: #5e32ec;
  font-size: .9rem;
  text-align: center;
}

/* #serial-container */
#serial-container {
  margin-top: 3rem;
}
#serial-container h1 {
  margin-bottom: 2rem;
  font-size: 1rem;
  text-align: center;
}
#serial-container h1 img {
  max-width: 85%;
}
#serial-container button[type=submit].btn {
  line-height: 1em;
}
#serial-container button[type=submit].btn span {
  display: block;
  font-size: 16px;
  margin: 2px 0;
}
#serial-container fieldset {
  margin-top: 3rem;
}
#serial-container fieldset legend {
  margin-bottom: 1rem;
  padding-bottom: .5rem;
  font-size: 1.4rem;
  line-height: 1em;
  border-bottom: rgba(255, 255, 255, .15) 1px solid;
}
#serial-container fieldset ul {
  list-style-type: '※';
  padding-left: 1rem;
  font-size: .9em;
}
#serial-container fieldset ul li {
  padding-left: .5em;
}
#serial-container .result-section .text-center {
  min-height: 10rem;
}
#serial-container .result-section .items {
  margin: 2rem auto 0 auto;
  padding-bottom: 4rem;
  max-width: 54rem;
  font-size: .95em;
  text-align: justify;
  line-height: 1.5em;
}