*{
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: Arial, Helvetica, sans-serif;
            letter-spacing: 1px;
        }

        body{
            min-height: 100vh;
            max-width: 100%;
            display: flex;
            justify-content: center;
            align-items: center;
            /* display: grid;
            place-items: center; */
            background: linear-gradient(45deg, #0a0a0a, #3a4452);
        }

        .calculator{
            padding: 15px;
            box-shadow: 0 0 15px #000;
            border: 2px solid rgb(116,114,114);
            border-radius: 15px;
        }

        .display input{
            width: 360px;
            border: none;
            outline: none;
            padding: 20px;
            margin: 10px;
            background: transparent;
            color: #fff;
            font-size: 40px;
            text-align: right;
            cursor: pointer;
        }

        input::placeholder{
            color: #fff;
        }

        button{
            width: 70px;
            height: 70px;
            margin: 10px;
            background: transparent;
            color: #fff;
            font-size: 22px;
            font-weight: 600;
            border: 0;
            border-radius: 50%;
            box-shadow: -5px -6px 15px #000;
            outline: 1px solid #313131;
            outline-offset: 3px;
            cursor: pointer;
        }

        button:active{
            background: #000;
            transform: translate(2px, 2px);
        }

        .opr{
            color: #fbff00;
            background: #1e1919;
            font-weight: 700;
        }

        #eqBtn{
            background: orangered;
            font-weight: 900;
        }