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

body{
    width: 100%;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: sans-serif;
}

.calculator{
    width: 420px;
    height: 600px;
    background-color: black;
    padding: 20px 20px 10px;
    display: flex;
    flex-direction: column;
    border-radius: 2%;
    
}

.calculator__display{
    width: 100%;
    outline: none;
    font-size: 50px;
    padding: 5px 10px;
    background-color: gray;
    border-radius: 5%;
    color: white;
}

.calculator__keys{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(5, 1fr);
    margin: 20px 0 0;
    gap: 5px;

}

.calculator__key{
    background-color: lightblue;
    cursor: pointer;
    font-size: 40px;
    padding: 20px;
    border-radius: 50%;
    transition: .5s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.calculator__key:hover{
    background-color: rgb(141, 227, 255);
}

.action_btn{
    background-color: aliceblue;
}

.action_btn:hover{
    background-color: rgb(239, 114, 255);
}

.clear_btn{
    grid-row-start: 5;
    grid-column-start: 1;
    background-color: rgb(255, 230, 3);
}

.clear_btn:hover{
    background-color: orange;
}

#equal{
    grid-row-start: 5;
    grid-column-start: 4;
}

#equal + .action_btn{
    grid-row-start: 4;
    grid-column-start: 4;
}