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

:root {
    --super-light-gray: #d9dddc;
    --light-gray:#808588;
    --dark-gray: #222021;
    --mild-gray: #484945;
    --orange: #e27a53;
}

body {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-content: center;
    margin: 1%;
    padding: 1%;
}

header {
    text-align: center;
    font-family: Arial, Helvetica, sans-serif;
    width: 100%;
    margin-bottom: 20px;
}

h1 {
    color: var(--light-gray);
    font-size: 25px;
}

.container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-content: center;
    padding: 1%;
    width: 40%;
    background-color: var(--dark-gray);
    border-radius: 10px;
    color: var(--super-light-gray);
    box-shadow: 20px 20px 20px rgba(0, 0, 0, 0.15);
}

.output {
    display: flex;
    justify-content: center;
    align-content: center;
    width: 100%;
    padding: 1%;
}

p {
    display: flex;
    justify-content: end;
    align-content: center;
    width: 100%;
    padding: 2%;
    font-family: Arial, Helvetica, sans-serif;
    font-size: 40px;
    box-shadow: inset 0px 0px 20px rgba(0, 0, 0, 0.5);
}

.button-container {
    display: flex;
    flex-wrap: wrap;
    width: 100%;
    gap: 3.5px;
}

.column {
    display: flex;
    justify-content: center;
    align-content: center;
    width: 100%;
    gap: 4px;
}

button {
    border: none;
    border-radius: 10px;
    font-size: 25px;
    width: 100%;
    height: 95px;
    color: var(--super-light-gray);
    cursor: pointer;

    transition: 0.1s ease;
}

button:hover {
    opacity: 0.7;
}

button:active {
    transform: scale(0.90);
}

.num-0 {
    width: 202%;
}

.dark-gray {
    background-color: var(--mild-gray);
}

.light-gray {
    background-color: var(--light-gray);
}

.orange {
    background-color: var(--orange);
}

@media screen and (max-width: 768px) {
    .container {
        width: 80%;
    }

    .output {
        padding: 2%;
    }

    p {
        font-size: 30px;
    }

    button {
        font-size: 25px;
        height: 120px;
    }
}

@media screen and (max-width: 480px) {
    .container {
        width: 80%;
    }

    button {
        font-size: 15px;
        height: 65px;
    }

    .num-0 {
        width: 207%;
    }

    .output {
        padding: 2%;
    }

    p {
        font-size: 20px;
    }
}