* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}
body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100dvh;
  background-color:rgba(128, 128, 128, 0.188);
  /* background-image: url(blackboard.jpg);
  background-size: contain; */
}
.container {
  text-align: center;
  width: 300px;
  background-color: white;
  border-radius: 15px;
  height: fit-content;
  padding: 10px;
  box-shadow:
    0 0 2px 0 rgba(0, 0, 0, 0.5),
    0 0 4px 0 rgba(0, 0, 0, 0.8);
}
.container h3 {
  color: bla;
}
.display {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 50px;
  margin: 10px 0;
}
.display input {
  width: 100%;
  height: 50px;
  font-size: 20px;
  font-weight: 700;
  background-color: rgba(128, 128, 128, 0.1);
  color: black;
  outline: none;
  border: none;
  border-radius: 5px;
  padding: 0 10px;
  box-shadow:
    inset 0 0px 2px rgba(0, 0, 0, 0.5),
    inset 0 0 4px rgba(0, 0, 0, 0.5);
}
.buttonbox {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
  gap: 0.4rem;
}
.btn {
  height: 40px;
  cursor: pointer;
  border-radius: 0.5rem;
  font-weight: 600;
  color: white;
  background-color: black;
  border: none;
  /* box-shadow: 0 2px 2px rgba(0, 0, 0, 0.5); */
}
.btn:active {
  transform: scale(0.95);
}
#equalto {
  grid-column: span 4;
}
.imp {
  background-color: rgba(255, 68, 0, 0.954);
}