body{
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f0f0f5;
    font-family: Arial, sans-serif;
}
.titulo {
    text-align: center;     
    margin-bottom: 20px;       
    font-size: 2em;            
    color: #222;              
}
.Caltor{
    background-color: #222;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.3);
}
#mostrar{
    width: 100%;
    height: 50px;
    text-align: right;
    font-size: 2em;
    margin-bottom: 15px;
    border-radius: 5px;
    border: none;
    padding: 5px;
    background-color: #eee;
}
.botones{
    display: grid;
    grid-template-columns: repeat(4, 60px);
    gap: 10px;
}

button{
    padding: 20px;
    font-size: 1.2em;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    background-color: #444;
    color: #fff;
    transition: all 0.2s;
}
button:hover{
    background-color: #666;
}
button.operador{
    background-color: #ff9500;
}
button.operador:hover{
    background-color: #ffa733;
}
button.igual{
    background-color: #00c851;
    grid-column: span 2;
}
button.igual:hover{
    background-color: #33d07f;
}
button.borrar{
    background-color: #ff4444;
}
button.borrar:hover{
    background-color: #ff6666;
}