body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background-color: #f7f9fa;
    text-align: center;
}

table {
    margin: 40px auto 0 auto;
    border-collapse: separate;
    border-spacing: 8px;
    background: #fff;
    border-radius: 14px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.07);
    padding: 16px;
}

input#txtPantalla {
    width: 100%;
    font-size: 1.5rem;
    text-align: right;
    padding: 12px 10px;
    background-color: #f2f4f6;
    border: 1px solid #d1d9e0;
    border-radius: 8px;
    color: #222;
    margin-bottom: 6px;
}

button {
    width: 56px;
    height: 56px;
    font-size: 1.15rem;
    border: 1px solid #d1d9e0;
    margin: 4px;
    border-radius: 6px;
    cursor: pointer;
    background: #f8fafc;
    color: #333;
    transition: background 0.15s, border 0.15s;
}
button:hover {
    background: #e9ecef;
    border-color: #bfc9d1;
} 

#btn0, #btn1, #btn2, #btn3, #btn4, #btn5, #btn6, #btn7, #btn8, #btn9, #btnPunto {
    background: #f8fafc;
    color: #222;
}
#btn0:hover, #btn1:hover, #btn2:hover, #btn3:hover, #btn4:hover,
#btn5:hover, #btn6:hover, #btn7:hover, #btn8:hover, #btn9:hover, #btnPunto:hover {
    background: #e9ecef;
    color: #111;
}

#btnSumar, #btnRestar, #btnMultiplicar, #btnDividir {
    background: #f4f5f7;
    color: #444;
    border: 1px solid #d1d9e0;
}
#btnSumar:hover, #btnRestar:hover, #btnMultiplicar:hover, #btnDividir:hover {
    background: #e9ecef;
    color: #111;
} 

#btnIgual {
    background: #e1e7ef;
    color: #1a3a5a;
    border: 1px solid #bfc9d1;

#btnIgual:hover {
    background: #d0dae7;
    color: #0d223a;
}
}

#btnLimpiar {
    background: #f4f5f7;
    color: #444;
    border: 1px solid #d1d9e0;
}
#btnLimpiar:hover {
    background: #e9ecef;
    color: #111;
}