/* style.css */
body {
    background-color: #f0f0f0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

.calculator {
    background: #000;
    border-radius: 20px;
    padding: 20px;
    width: 320px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
}

.display {
    color: white;
    font-size: 72px;
    text-align: right;
    padding: 20px;
    min-height: 120px;
    overflow: hidden;
}

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

button {
    border: none;
    border-radius: 50%;
    width: 65px;
    height: 65px;
    font-size: 28px;
    cursor: pointer;
    transition: 0.2s;
}

button:active {
    filter: brightness(130%);
}

.number {
    background: #333;
    color: white;
}

.function {
    background: #a5a5a5;
    color: black;
}

.operator {
    background: #ff9f0a;
    color: white;
}

.zero {
    grid-column: span 2;
    width: 140px;
    border-radius: 35px;
    text-align: left;
    padding-left: 28px;
}