* {
    margin: 0;
    padding: 0;
    font-family: Tahoma;
    box-sizing: border-box;
  }
  
  body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #23242a;
  }
  
  .box {
    position: relative;
    width: 380px;
    height: 420px;
    background: #1c1c1c;
    border-radius: 8px;
    overflow: hidden;
  }
  .box::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 380px;
    height: 420px;
    background: linear-gradient(0deg, transparent, crimson, crimson);
    transform-origin: bottom right;
    -webkit-animation: animate 6s linear infinite;
            animation: animate 6s linear infinite;
  }
  .box::after {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 380px;
    height: 420px;
    background: linear-gradient(0deg, transparent, crimson, crimson);
    transform-origin: bottom right;
    -webkit-animation: animate 6s linear infinite;
            animation: animate 6s linear infinite;
    -webkit-animation-delay: -3s;
            animation-delay: -3s;
  }
  @-webkit-keyframes animate {
    0% {
      transform: rotate(0deg);
    }
    100% {
      transform: rotate(360deg);
    }
  }
  @keyframes animate {
    0% {
      transform: rotate(0deg);
    }
    100% {
      transform: rotate(360deg);
    }
  }
  .box .form {
    position: absolute;
    inset: 2px;
    border-radius: 8px;
    background: #28292d;
    z-index: 10;
    padding: 4rem 3rem;
    display: flex;
    flex-direction: column;
  }
  #display{
    text-align: right;
    height: 40px;
    line-height: 40px;
    padding: 1px 8px;
    font-size: 25px;
    
  }

 .buttons{
    display: grid;
    border-bottom: 1px solid #999;
    border-left: 1px solid #999;
   
    grid-template-columns: 1fr 1fr 1fr 1fr;
  }

  .buttons > div {
    border-top: 1px solid #999;
    border-right: 1px solid #999;
  }

  .button{
    border: 0.5px solid #999;
    line-height: 60px;
    color: crimson;
    text-align: center;
    font-size: 20px;
    transition: ease-in-out .5s;
    cursor: pointer;
  }

  .button:hover{
    background-color: white;
  }
  #equal{
    background-color: crimson;
    color: white;
  }