/* Reset básico */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(135deg, #74ebd5, #ACB6E5);
}

.calculator {
    background: #ffffffdd;
    padding: 20px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    max-width: 400px;
    width: 90%;
}

.display {
    background: #f0f0f0;
    border-radius: 15px;
    padding: 20px;
    font-size: 2em;
    text-align: right;
    margin-bottom: 20px;
    min-height: 60px;
    word-wrap: break-word;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
}

button {
    padding: 20px;
    font-size: 1.2em;
    border: none;
    border-radius: 15px;
    cursor: pointer;
    transition: 0.2s;
    background: #e0e0e0;
    color: #333;
}

button:hover {
    background: #d4d4d4;
}

button.operator {
    background: #4e54c8;
    color: #fff;
}

button.operator:hover {
    background: #3b40a1;
}

button.equal {
    background: #ff6b6b;
    color: #fff;
    grid-column: span 2;
}

button.equal:hover {
    background: #e45555;
}

@media (max-width: 500px) {
    .display {
        font-size: 1.5em;
        padding: 15px;
    }

    button {
        padding: 15px;
        font-size: 1em;
    }
}