* {
            box-sizing: border-box;
        }

        body {
            margin: 0;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
            font-family: Arial, sans-serif;
            background: #f4f6fb;
        }

        .container {
            width: 100%;
            max-width: 420px;
            padding: 35px;
            background: white;
            border-radius: 14px;
            box-shadow: 0 8px 30px rgba(0,0,0,.07);
        }

        h2 {
            margin: 0 0 10px;
            color: #172033;
        }

        p {
            color: #64748b;
            line-height: 1.6;
        }

        input {
            width: 100%;
            padding: 13px;
            margin: 15px 0;
            border: 1px solid #cbd5e1;
            border-radius: 7px;
            font-size: 15px;
        }

        button {
            width: 100%;
            padding: 13px;
            border: none;
            border-radius: 7px;
            background: #2563eb;
            color: white;
            font-size: 15px;
            font-weight: bold;
            cursor: pointer;
        }

        button:disabled {
            opacity: .6;
            cursor: not-allowed;
        }

        #message {
            margin-top: 15px;
            font-size: 14px;
        }

        a {
            display: block;
            margin-top: 20px;
            text-align: center;
            color: #2563eb;
            text-decoration: none;
        }