body {
            background: #f0f2f5;
            font-family: Arial, sans-serif;
            display: flex;
            height: 100vh;
            justify-content: center;
            align-items: center;
            margin: 0;
        }
        .container {
            background: white;
            padding: 2rem 3rem;
            border-radius: 8px;
            box-shadow: 0 4px 15px rgba(0,0,0,0.1);
            width: 320px;
            text-align: center;
        }
        h1 {
            margin-bottom: 1.5rem;
            color: #333;
        }
        input {
            width: 100%;
            padding: 10px 12px;
            margin-bottom: 1rem;
            border: 1px solid #ccc;
            border-radius: 4px;
            font-size: 1rem;
            box-sizing: border-box;
        }
        button {
            width: 100%;
            padding: 10px 12px;
            background-color: #4a90e2;
            border: none;
            border-radius: 4px;
            color: white;
            font-weight: bold;
            font-size: 1rem;
            cursor: pointer;
            transition: background-color 0.3s ease;
        }
        button:hover {
            background-color: #357ABD;
        }
        #error {
            margin-top: 1rem;
            font-weight: bold;
        }