*,
*::after,
*::before {
  margin: 0;
  padding: 0;
  box-sizing: inherit; }

html {
  font-size: 62.5%; }
  @media (max-width: 75em) {
    html {
      font-size: 56.25%; } }
  @media (max-width: 56.25em) {
    html {
      font-size: 50%; } }

body {
  box-sizing: border-box; }

body {
  min-height: calc(var(--vh, 1vh) * 100);
  background-color: #307de2;
  position: relative; }

.audio-img {
  background-image: url(https://media.giphy.com/media/qWLNlDMfimhXtM5g0M/source.gif);
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center center; }

.btn-container {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%); }

.btn {
  font-family: sans-serif;
  font-size: 3rem;
  cursor: pointer;
  padding: 1rem 2rem;
  border: none;
  outline: none;
  border-radius: 1rem;
  font-weight: bold;
  box-shadow: 0.4rem 0.4rem 1rem rgba(0, 0, 0, 0.5);
  transition: all .1s; }
  .btn:disabled {
    cursor: not-allowed;
    background-color: #929292;
    color: #707070; }
    .btn:disabled:hover {
      background-color: #929292;
      color: #707070; }
  .btn:hover {
    color: #fff;
    background: #dd9700; }
  .btn:active {
    transform: translateY(0.5rem);
    box-shadow: none; }