body {
  font-family: Arial, sans-serif;
  text-align: center;
  margin: 20px;
  color: #fff;
}

h1 {
  margin-bottom: 20px;
}

button {
  padding: 10px 20px;
  font-size: 16px;
  margin: 5px;
}

#loading {
  display: none;
  font-size: 18px;
  font-weight: bold;
  margin-top: 20px;
}

.hidden {
  display: none;
}

.download-by-date {
  margin-top: 30px;
}

.pattern {
  background-image: url(back.png);
}

/* Mobile-friendly styles */
@media screen and (max-width: 480px) {

  h1 {
    font-size: 24px;
  }

  button {
    padding: 8px 16px;
    font-size: 14px;
  }

  #loading {
    font-size: 16px;
  }

  .download-by-date {
    margin-top: 20px;
  }
}