* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  width: 100%;
}

body {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 1rem;
  background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
}

#box {
  height: 250px;
  width: 250px;
  background-color: white;
  border: 5px solid black;
  border-radius: 0.7rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color:white;
  font-weight: 600;
  font-family: Arial, Helvetica, sans-serif;
}

#btn1 {
  padding: 0.8rem 1.6rem;
  font-size: 1rem;
  background-color: #0f2027;
  color: white;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: transform 0.2s;
}

#btn1:hover {
  transform: scale(1.1);
}

@media (min-width: 900px) {
  #box {
    height: 400px;
    width: 400px;
    font-size: 2rem;
  }
  #btn1 {
    padding: 0.8rem 1.8rem;
    font-size: 1rem;
  }
}