html {
  box-sizing: border-box;
  font-size: 16px;
}
*, *:before, *:after {
  box-sizing: inherit;
}

body {
  background: #f0f2f6;
  font-family: Arial, sans-serif;
  text-align: center;
  color: #222;
  margin: 0;
  min-height: 100vh;
}

h1 {
  margin-top: 2.2rem;
  color: #3d5a80;
  font-size: clamp(1.6rem, 4vw, 2.7rem);
}

#hud {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.2rem;
  margin: 0.5rem auto;
  font-size: clamp(1em, 2vw, 1.15em);
  color: #223757;
  width: 100%;
  max-width: 650px;
  padding: 0 1vw;
}

/* ==== Tablero responsive ==== */
#game-board {
  margin: 2.1rem auto 1rem auto;
  display: grid;
  grid-template-columns: repeat(6, minmax(45px, 1fr));
  gap: 1rem;
  justify-content: center;
  max-width: 98vw;
  padding: 0 1vw;
}

.card {
  aspect-ratio: 1 / 1;
  width: 100%;
  background: #98c1d9;
  color: #293241;
  font-size: clamp(1.2rem, 4vw, 2.3rem);
  border-radius: 0.8rem;
  box-shadow: 0 2px 8px #bbb;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  user-select: none;
  transition: background 0.2s, opacity 0.4s;
}

.card.flipped {
  background: #e0fbfc;
  cursor: default;
}

.card.matched {
  background: #3d5a80;
  color: #fff;
  opacity: 0.7;
  cursor: default;
}

.card.hide {
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.45s;
}

#status {
  font-size: clamp(1em, 2vw, 1.2em);
  min-height: 2em;
  margin-bottom: 1em;
  color: #3d5a80;
}

#restart-btn {
  background: #3d5a80;
  color: #fff;
  font-size: clamp(1em, 2vw, 1.16em);
  border: none;
  border-radius: 0.6rem;
  padding: 0.5em 2em;
  cursor: pointer;
  transition: background 0.2s;
  margin-bottom: 1.3em;
}
#restart-btn:hover {
  background: #223757;
}

/* ==== Pantallas móviles ==== */
@media (max-width: 600px) {
  h1 {
    margin-top: 5vw;
    font-size: clamp(1.3rem, 7vw, 2.1rem);
  }
  #hud {
    font-size: clamp(1em, 5vw, 1.25em);
    gap: 4vw;
    max-width: 98vw;
    padding: 0 2vw;
  }
  #game-board {
    grid-template-columns: repeat(2, 1fr);
    gap: 5vw;
    padding: 2vw;
    margin-top: 5vw;
    margin-bottom: 5vw;
    max-width: 98vw;
  }
  .card {
    border-radius: 5vw;
    font-size: clamp(1.2rem, 11vw, 3rem);
  }
  #restart-btn {
    font-size: clamp(1em, 6vw, 1.3em);
    border-radius: 5vw;
    padding: 3vw 10vw;
    margin-bottom: 5vw;
  }
  #status {
    font-size: clamp(1em, 7vw, 1.3em);
    margin-bottom: 4vw;
  }
}

/* ==== Tablets o pantallas intermedias ==== */
@media (min-width: 601px) and (max-width: 900px) {
  #game-board {
    grid-template-columns: repeat(4, 1fr);
    gap: 2vw;
  }
  .card {
    font-size: clamp(1.3em, 6vw, 2.6rem);
  }
}

/* ==== Pantallas muy grandes ==== */
@media (min-width: 1200px) {
  #hud {
    font-size: clamp(1.1em, 1vw, 1.3em);
    max-width: 800px;
  }
  #game-board {
    max-width: 700px;
    grid-template-columns: repeat(6, 1fr);
    gap: 1.5rem;
  }
  .card {
    font-size: clamp(2rem, 2vw, 3rem);
  }
}

/* ==== Extra pequeñas ==== */
@media (max-width: 350px) {
  #game-board {
    grid-template-columns: repeat(1, 1fr);
    gap: 2vw;
    padding: 1vw;
  }
  .card { font-size: clamp(1rem, 23vw, 1.8rem); }
  #hud {
    font-size: clamp(1em, 9vw, 1.1em);
    gap: 2vw;
  }
}