*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body{
    min-height: 100vh;
    background-color: #efeff2;
    display: flex;
    justify-content: center;
    align-items: center;
}

.calculator {
    width: 300px;
    height: 500px;
    box-shadow: 4px 4px 30px rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    background-color: #22252d;
    overflow: hidden;

}

form input{
    width: 100%;
    height: 75px;
    border: none;
    border-radius: 12px;
    font-size: 2.5rem;
    padding: 1rem;
    color: #fff;
    background-color: #000;
    text-align: right;
    pointer-events: none;
}


.btns {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    justify-content: center;
    margin: 15px 8px;
} 

.btns > .btn:nth-child(17) {
    grid-column: 1 / 5;
    width: 96%;
}

.btn {
    border: 1px solid #000;
    margin: 5px 6px;
    width: 60px;
    height: 52px;
    font-size: 22px;
    font-weight: 600;
    border-radius: 5px;
    cursor: pointer;
}

.btn-yellow{
    color: #fff;
    background-color: rgb(224, 146, 62);
}
.btn-gray{
    background-color: rgb(224, 146, 224);
}
.btn-green{
    color: #fff;
    background: green;
}
.btn-red{
    color: #fff;
    background: red;
}