html {
  margin: 0 auto;
  font-size: 100%;
  -webkit-text-size-adjust: none;
  font-family: sans-serif;
  box-sizing: border-box;
}
*,
*:before,
*:after {
  box-sizing: inherit;
}
body {
  margin: 0 auto;
  display: -webkit-flex;
  display: -moz-flex;
  display: -ms-flexbox;
  display: -ms-flex;
  display: flex;
  -webkit-align-items: center;
  -moz-align-items: center;
  -ms-align-items: center;
  align-items: center;
  background: url('../gfx/bg.jpg') no-repeat center center;
  background-size: cover;
}
body .modal {
  margin: auto;
  background: rgba(255, 255, 255, 0.95);
  -webkit-backdrop-filter: blur(10px);
  border-radius: 5px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.8);
  padding: 20px;
  width: 80%;
  max-width: 600px;
  min-width: 600px;
}
@media screen and (max-width: 640px) {
  body .modal {
    min-width: 0;
  }
}