body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: url('https://images.pexels.com/photos/1552242/pexels-photo-1552242.jpeg') no-repeat center center fixed;
    background-size: cover;
}
.overlay {
    background-color: rgba(255, 255, 255, 0.85);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}
.container {
    max-width: 500px;
    background: #ffffff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}
h1 {
    text-align: center;
    color: #00796b;
}
label {
    display: block;
    margin-top: 15px;
    font-weight: bold;
    color: #004d40;
}
input {
    width: 100%;
    padding: 10px;
    margin-top: 5px;
    border: 1px solid #b2dfdb;
    border-radius: 6px;
}
button {
    width: 100%;
    padding: 12px;
    margin-top: 20px;
    background-color: #00796b;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    cursor: pointer;
}
button:hover {
    background-color: #004d40;
}
#resultado {
    margin-top: 25px;
    padding: 15px;
    border-radius: 8px;
    font-weight: bold;
    white-space: pre-line;
    text-align: center;
}
.abaixo { background: #bbdefb; color: #0d47a1; }
.normal { background: #c8e6c9; color: #1b5e20; }
.sobrepeso { background: #fff9c4; color: #f57f17; }
.obesidade { background: #ffcdd2; color: #b71c1c; }