body {
  background-image: url('../img/bg.jpg');
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center;
  min-height: 100vh;
}

.header {
  margin: 20px;
  text-align: center;
  color: #fff;
}

.sets-container {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  margin-top: 20px;
  width: 100%;
  height: 100%;
}

.sets {
  width: 200px;
  height: 295px;
  margin: 10px;
  -webkit-box-shadow: 0px 9px 22px 14px rgba(255,255,255,0.7); 
  box-shadow: 0px 9px 22px 14px rgba(255,255,255,0.7);
}

.img {
  position: absolute;
  transition: all 0.8s ease;
}

.caption {
  position: relative;
  text-align: center;
  top: 295px;
}

@media (max-width: 768px) {
  .header {
    margin: 16px 12px;
  }

  .header h1 {
    font-size: 1.5rem;
    line-height: 1.3;
  }

  .header h2 {
    font-size: 1rem;
    margin-top: 8px;
  }

  .sets-container {
    flex-direction: column;
    margin-top: 10px;
    gap: 38px;
    padding-bottom: 20px;
  }

  .sets {
    width: 170px;
    height: 251px;
    margin: 0;
    box-shadow: 0px 6px 16px 8px rgba(255,255,255,0.45);
  }

  .caption {
    top: 251px;
    font-size: 0.9rem;
  }
}