body {
    background: linear-gradient(135deg, #2c3e50, #3498db);
    font-family: Arial, Helvetica, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

/* Calculadora */
#calculadora {
    background-color: #1e272e;
    padding: 15px;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.5);
}

/* Pantalla */
.caja_valor {
    width: 100%;
    height: 60px;
    font-size: 26px;
    text-align: right;
    padding: 10px;
    border-radius: 10px;
    border: none;
    background-color: #dfe6e9;
    color: #2d3436;
}

/* Botones */
.boton,
.boton_largo {
    width: 60px;
    height: 50px;
    font-size: 18px;
    border-radius: 10px;
    border: none;
    margin: 4px;
    cursor: pointer;
    background-color: #636e72;
    color: white;
    transition: 0.2s;
}

.boton_largo {
    width: 130px;
}

/* Botones de función */
.funcion {
    background-color: #e17055;
}

/* Hover */
.boton:hover,
.boton_largo:hover {
    background-color: #b2bec3;
    color: #2d3436;
}

/* Igual */
#esIgual {
    background-color: #00b894;
    font-weight: bold;
}

#esIgual:hover {
    background-color: #55efc4;
}