* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-family: "Roboto Mono", monospace;
  }
  body {
    height: 100vh;
    background: linear-gradient(to bottom, rgb(13, 17, 17) 50%,  rgb(187, 184, 184) 50%);
  }
  .calculator {
    width: 400px;
    background-color: #000000;
    padding: 50px 30px;
    position: absolute;
    transform: translate(-50%, -50%);
    top: 50%;
    left: 50%;
    border-radius: 8px;
    box-shadow: 0 20px 50px rgba(100, 101, 102, 0.4);
  }
  .display {
    width: 100%;
  }
  .display input {
    width: 100%;
    padding: 15px 10px;
    text-align: right;
    border: none;
    background-color: transparent;
    color: #ffffff;
    font-size: 35px;
  }
  .display input::placeholder {
    color: #f0faf3;
  }
  .buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 20px;
    margin-top: 40px;
  }
  .buttons input[type="button"] {
    font-size: 20px;
    padding: 17px;
    border: none;
    background-color: transparent;
    color: #ffffff;
    cursor: pointer;
    border-radius: 5px;
  }
  .buttons input[type="button"]:hover {
    box-shadow: 0 8px 25px #fdfbfb;
  }
  input[type="button"]#equal {
    grid-row: span 2;
    background-color: #0e0d0d;
  }