style.css

* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-family: "Roboto Mono", monospace;
  }
   
body {
    background-color: black;
    font-family: cursive;
  }
   /* TO CREATE GLOWING HEADING TEXT  */
  .glow {
    font-size: 60px;
    color: #fff;
    text-align: center;
    animation: glow 1s ease-in-out infinite alternate;
  }
  @-webkit-keyframes glow {
    from {
      text-shadow: 0 0 10px #0e0e0e, 0 0 20px #1c1919, 0 0 30px #000000, 0 0 40px #494647, 0 0 50px #090809, 0 0 60px #151314, 0 0 70px #cdc2c7;
    }
    
    to {
      text-shadow: 0 0 20px #4e4d4d, 0 0 30px #000000, 0 0 40px #0d0007, 0 0 50px #020202, 0 0 60px #242122, 0 0 70px #181517, 0 0 80px #6c5d65;
    }
  }
  
  header{
    display: flex;
    justify-content: center;
    padding-top: 10px;
    font-size: x-large;
    color:black;
    font-style:initial;
}
  body {
    height: 100vh;
    /* background: radial-gradient(to bottom, #f0f0f0 50%, #898991 50%); */
    background: rgb(202,206,227);
background: radial-gradient(circle, rgba(202,206,227,1) 6%, rgba(37,37,37,1) 85%);
    
  }
  .calculator {
    width: 400px;
    background-color: #1b1b1d;
    padding: 50px 30px;
    position: absolute;
    transform: translate(-50%, -50%);
    top: 58%;
    left: 50%;
    border-radius: 8px;
    box-shadow: 0 20px 50px rgba(142, 146, 162, 0.4);
  }
  .display {
    width: 100%;
  }
  .display input {
    width: 100%;
    padding: 15px 10px;
    text-align: right;
    border: none;
    background-color: transparent;
    color: #cfb72d;
    font-size: 35px;
  }
  .display input::placeholder {
    color: #d6d6d6;
    text-shadow: #fff;
  }
  .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 #d5d6d9;
  }
  input[type="button"]#equal {
    grid-row: span 2;
    background-color: #168345;
    color:#000000
  }
  input[type="button"][value="0"] {
    grid-column: span 2;
  }

  input[type="button"][value="DEL"] {
    background-color: #f9544c;
  }

 
  input[type="button"][value="AC"] {
    background-color: #f6f658;
    color:#000000;
  }