* {
    margin: 0;
    padding: 0;
}

body {
    background-image: url("../images/background-theme.jpg");
    background-size: auto;
    background-repeat: no-repeat;
}

.img img {
    width: 100%;
    border-top-left-radius: 15px;
    border-top-right-radius: 15px;
}

.calc {
    position: relative;
    margin-top: 40px;
    margin-left: 100px;
    width: 400px;
    height: 680px;
    background: url("../images/hulk2.png") bottom 70px right 20px;
    background-size: 90%;
    background-repeat: no-repeat;
    box-sizing: border-box;
    border-radius: 15px;
    box-shadow: 0 0 20px 10px #4b9819;
}

.calc-header {
    position: relative;
}

.screen {
    position: absolute;
    right: 15px;
    top: 145px;
    width: 350px;
    height: 50px;
    color: white;
    text-align: right;
    font-size: 36px;
    padding-top: 13px;
    padding-right: 20px;
    background: rgb(44, 50, 50);
    border: 2px solid orange;
    border-radius: 30px;
    outline: none;
}

.calculator-keyboard {
    width: 400px;
    margin-top: 15px;
    margin-left: 13px;
}

.btn {
    list-style: none;
    float: left;
    padding: 15px;
    margin: 5px;
    width: 82px;
    height: 70px;
    border: 2px solid orange;
    box-sizing: border-box;
    background: rgba(44, 50, 50, 0.73);
    border-radius: 10px;
    color: white;
    font-size: 32px;
    text-align: center;
    box-shadow: 0 0 5px 0 #ffff00;
    cursor: pointer;
}

.operator:disabled {
    background-color: gray;
    opacity: 65%;
    cursor: not-allowed;
}

.operator:not(:disabled):hover {
    box-shadow: 0 0 5px 2px #62a506;
    border: none;
}

.selected-operator {
    background-color: #4b9819;
    color: black;
    border: none;
}

.clear {
    margin: 5px;
    width: 174px;
    border: 2px solid orange;
    box-sizing: border-box;
    background: rgba(44, 50, 50, 0.73);
    border-radius: 10px;
    color: white;
    font-size: 32px;
    text-align: center;
    box-shadow: 0 0 5px 0 #ffff00;
    cursor: pointer;
}

.backspace svg {
    position: absolute;
    width: 40px;
    height: 40px;
    fill: white;
    right: 135px;
}

.null {
    margin: 5px;
    width: 174px;
    height: 70px;
    border: 2px solid orange;
    box-sizing: border-box;
    background: rgba(44, 50, 50, 0.73);
    border-radius: 10px;
    color: white;
    font-size: 32px;
    text-align: center;
    box-shadow: 0 0 5px 0 #ffff00;
    cursor: pointer;
}

.copyright {
    width: 340px;
    color: rgba(255, 255, 255, 0.56);
    font-size: 13px;
    margin-left: 20px;
}

.calculator-keyboard li:hover {
    box-shadow: 0 0 5px 2px #62a506;
    border: none;
}

.copyright {
    width: 340px;
    color: rgba(255, 255, 255, 0.56);
    font-size: 20px;
    margin-left: 20px;
}