body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: #0f172a; 
            color: #ffffff;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
        }

        .imc-contenedor {
            background-color: #1e293b; 
            padding: 30px;
            border-radius: 20px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
            text-align: center;
            width: 360px;
            border-top: 4px solid #a855f7; 
        }

        h1 {
            font-size: 1.6rem;
            margin-bottom: 20px;
            color: #f1f5f9;
        }

        .grupo-entrada {
            text-align: left;
            margin-bottom: 15px;
        }

        .grupo-entrada label {
            display: block;
            margin-bottom: 5px;
            font-size: 0.9rem;
            color: #94a3b8;
        }

        .grupo-entrada input {
            width: 100%;
            padding: 10px;
            border-radius: 8px;
            border: 1px solid #334155;
            background-color: #020617;
            color: #ffffff;
            font-size: 1rem;
            box-sizing: border-box;
        }

        .btn-calcular {
            width: 100%;
            padding: 12px;
            font-size: 1rem;
            font-weight: bold;
            background-color: #a855f7; 
            color: white;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            margin-top: 10px;
            transition: background 0.2s, transform 0.1s;
        }

        .btn-calcular:active {
            transform: scale(0.98);
        }

        .pantalla-resultado {
            background-color: #020617;
            padding: 15px;
            border-radius: 10px;
            margin-top: 20px;
            display: none; 
            text-align: center;
        }

        .numero-imc {
            font-size: 2.5rem;
            font-weight: bold;
            font-family: monospace;
            color: #38bdf8; 
            margin-bottom: 5px;
        }

        .estado-imc {
            font-size: 1.1rem;
            font-weight: 600;
        }