html {
  font-size: 62.5%;
  font-family: "Chewy", sans-serif;
  box-sizing: border-box;
}

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

body {
  background: #06beb6; /* fallback for old browsers */
  background: -webkit-linear-gradient(
    to right,
    #48b1bf,
    #06beb6
  ); /* Chrome 10-25, Safari 5.1-6 */
  background: linear-gradient(
    to right,
    #48b1bf,
    #06beb6
  ); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
}

img {
  max-width: 100%;
}

h1 {
  font-size: 3.5rem;
}

div.contenedor-general {
  width: 1240px;
  max-width: 100%;
  margin: 0 auto;
  height: 100vh;
  /*border: 2px dotted black;*/
}

h1.titulo {
  text-align: center;
  margin: 2rem 0;
  display: block;
}

div.contenedor-tarjetas {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
}

div.tarjeta {
  background-image: url(../img/cover.jpg);
  width: 12rem;
  height: 14rem;
  display: flex;
  justify-content: center;
  align-items: center;
  -webkit-box-shadow: 4px 6px 17px -4px rgba(0, 0, 0, 0.75);
  -moz-box-shadow: 4px 6px 17px -4px rgba(0, 0, 0, 0.75);
  box-shadow: 4px 6px 17px -4px rgba(0, 0, 0, 0.75);
  margin: 2rem 2rem;
  border-radius: 1rem;
  padding: 0.5rem;
  position: relative;
}

img.tarjeta-img {
  display: none;
  border-radius: 1rem;
}

/* Adicionales */

.acertada {
  display: block;
}

div.pantalla-bloqueada {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: rgba(0, 0, 0, 0.75);
  z-index: 5;
  display: none;
}

h2.mensaje {
  font-size: 5rem;
  color: white;
  z-index: 10;
  text-align: center;
  margin: 32rem 0;
}

div.error {
  position: fixed;
  bottom: 5rem;
  font-size: 3rem;
}

div.nivel-dificultad {
  position: fixed;
  bottom: 5rem;
  font-size: 3rem;
  right: 21rem;
}

/* Ajustes para celulares */
@media (max-width: 768px) {
  div.error {
    left: 1rem;
    bottom: 8rem;
    font-size: 2rem;
  }

  div.nivel-dificultad {
    bottom: 3rem;
    right: auto;
    left: 1rem;
    transform: none;
    font-size: 2rem;
    white-space: nowrap;
  }
}