* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Montserrat", sans-serif;
  font-weight: bold;
}
body {
  background: url(pattern.jpg) no-repeat;
  height: 100vh;
}
.calculator {
  margin-top: 20px;
}
.output {
  background-color: rgb(88, 212, 115);
  padding: 10px 20px;
  min-height: 50px;
}

.btn {
  margin: 1px;
}

.output {
  height: 150px;
  grid-column: 1 / -1;
  background-color: rgba(0, 0, 0, 0.75);
  display: flex;
  align-items: flex-end;
  justify-content: space-around;
  flex-direction: column;
  padding: 10px;
  word-wrap: break-word;
  word-break: break-all;
}

.output .previous-operand {
  color: rgba(255, 255, 255, 0.479);
  font-size: 1.5rem;
}

.output .current-operand {
  color: white;
  font-size: 2rem;
}
.operator {
  font-size: 1.1rem !important;
}
@media (max-width: 600px) {
  .output .previous-operand {
    color: rgba(255, 255, 255, 0.479);
    font-size: 0.9rem;
  }
  .output {
    padding: 0;
    height: 100px;
  }
  .output .current-operand {
    font-size: 1rem !important;
  }
}
@media (max-height: 600px) {
  .output {
    padding: 0;
    height: 100px;
  }

  .calculator button {
    height: 30px;
    font-size: 0.7rem !important;
  }
}