body {
    font-family: Arial, sans-serif;
    padding: 20px;
    background-color: #f4f4f4;
    margin: 0;
}
.header {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}
.header img {
    height: 50px;
}
.header a.button-link {
    padding: 10px 15px;
    background-color: #007BFF;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    font-size: 16px;
    font-weight: bold;
}
h2 {
    margin-top: 20px;
}
input, button {
    font-size: 16px;
    padding: 10px;
    margin-top: 10px;
    margin-bottom: 10px;
    width: 100%;
    max-width: 300px;
    box-sizing: border-box;
}
.warning {
    color: red;
    font-weight: bold;
    margin-top: 10px;
}
.result {
    font-size: 18px;
    font-weight: bold;
    margin-top: 20px;
}
footer {
    text-align: center;
    margin-top: 60px;
    font-size: 14px;
    color: #888;
}