@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;600;700&display=swap');

* {
    box-sizing: border-box;
}

body {
    font-family: 'Poppins', Arial, sans-serif;
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    background: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
    display: flex;
    justify-content: center;
    align-items: center;
}

.calculadora-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.calculadora {
    background-color: white;
    padding: 25px;
    border-radius: 20px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.25);
    width: 300px;
}

#pantalla {
    width: 100%;
    height: 60px;
    background-color: #f4f4f9;
    font-size: 26px;
    font-weight: 600;
    text-align: right;
    padding: 10px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    margin-bottom: 20px;
    color: #2c3e50;
}

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

button {
    padding: 15px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    border-radius: 10px;
    background-color: #f0f2f5;
    color: #333;
    transition: background-color 0.2s, transform 0.1s;
}

button:hover {
    background-color: #e4e6eb;
}

button:active {
    transform: scale(0.95);
}

.operador {
    background: linear-gradient(135deg, #6a11cb, #2575fc);
    color: white;
}

.operador:hover {
    opacity: 0.9;
}

#igual {
    background-color: #27ae60;
    color: white;
}

#igual:hover {
    background-color: #219653;
}

#borrar {
    background-color: #c0392b;
    color: white;
}

#borrar:hover {
    background-color: #a93226;
}

.punto {
    background-color: #7f8c8d;
    color: white;
}

.punto:hover {
    background-color: #707b7c;
}

.btn-volver {
    background: white;
    color: #2575fc;
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 20px;
    font-weight: 600;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
    transition: background 0.2s, color 0.2s;
}

.btn-volver:hover {
    background: #6a11cb;
    color: white;
}