/* hsb colors and gridmax */
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    display: grid;
    padding: 20px;
    background: #767676;
    color: #676767;
    font-family: sans-serif;
}

.calculator {
    width: min(100%, 367px);
    padding: 20px;
    border: 1px solid red;
    border-radius: 24px;
    background: #171e2d;
}

.display {
    min-height: 167px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    align-items: flex-end;
    overflow: hidden;
    padding: 12px 4px 22px;
    text-align: right;
    font-size: 2rem;
}

.keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

button {
    min-height: 67px;
    border: 0;
    border-radius: 16px;
    background: #252e40;
    color: #f6f7fb;
    font-size: 1.25rem;
    transition: filter 0.15s, transform 0.1s;
    touch-action: manipulation;
}

button:hover {
    filter: brightness(1.2);
}

button.utility, button.operator, button.equals {
    background: #3985f7;
}

button.zero {
    grid-column: span 2;
}