* { box-sizing: border-box; }
body {
    font-family: Tahoma, sans-serif;
    background: #f4f6f9;
    margin: 0;
    padding: 20px;
    text-align: center;
}
.container {
    max-width: 500px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}
h1 { color: #333; margin: 0 0 10px; }
p { color: #666; margin: 5px 0; }
input, button {
    width: 100%;
    padding: 12px;
    margin: 10px 0;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
}
button {
    background: #007bff;
    color: white;
    border: none;
    cursor: pointer;
}
button:hover { background: #0056b3; }
.alert { padding: 10px; margin: 10px 0; background: #fff3cd; color: #856404; border-radius: 8px; }
.result { margin: 20px 0; }
footer { margin-top: 40px; font-size: 14px; color: #999; }
footer a { color: #007bff; }