html {
  box-sizing: border-box;
}
body {
  background-image: url();
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  margin: 0;
  min-height: 100vh;
}
.button-container {
  display: grid;
  gap: 30px;

  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
button {
  padding: 10px 30px;
  font-size: 1.8rem;
  font-family: "Lucida Sans", "Lucida Sans Regular", "Lucida Grande",
    "Lucida Sans Unicode", Geneva, Verdana, sans-serif;
  border-radius: 10px;
  cursor: pointer;
  color: #ffffff;
  background-color: #333;
  outline: none;
  box-shadow: 0 0.3rem rgba(121, 121, 121, 0.65);
}

button:hover {
  filter: brightness(150%);
}

button:active {
  transform: translate(0, 0.3rem);
  box-shadow: 0 0.1rem rgba(255, 255, 255, 0.65);
}