body {
            margin: 0;
            min-height: 100vh;
            background: #0f172a;
            color: white;
            font-family: Arial, sans-serif;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .box {
            width: min(400px, calc(100% - 30px));
            background: #1e293b;
            padding: 25px;
            border-radius: 18px;
            box-sizing: border-box;
        }
        h2 {
            margin-top: 0;
        }
        input {
            width: 100%;
            box-sizing: border-box;
            padding: 12px;
            margin: 10px 0 15px;
            border: 0;
            border-radius: 9px;
            background: #334155;
            color: white;
        }
        button,
        a {
            display: block;
            width: 100%;
            box-sizing: border-box;
            padding: 12px;
            border: 0;
            border-radius: 9px;
            text-align: center;
            text-decoration: none;
            cursor: pointer;
        }
        button {
            background: #3b82f6;
            color: white;
        }
        .back {
            margin-top: 10px;
            background: #334155;
            color: white;
        }
        .message {
            margin-bottom: 15px;
            padding: 10px;
            border-radius: 8px;
            background: #14532d;
        }
        .error {
            margin-bottom: 15px;
            padding: 10px;
            border-radius: 8px;
            background: #7f1d1d;
        }