body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 0;
    padding: 20px;
}
.container {
    max-width: 400px;
    margin: 0 auto;
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
h1 {
    text-align: center;
    color: #333;
}
input[type="date"] {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    border: 1px solid #ddd;
    border-radius: 4px;
}
button {
    width: 100%;
    padding: 10px;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}
button:hover {
    background: #0056b3;
}
#result {
    margin-top: 20px;
    font-size: 18px;
    font-weight: bold;
    text-align: center;
    color: #28a745;
}