* {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            font-family: 'Arial', sans-serif;
        }
        body {
            background-color: #f5f5f5;
            color: #333;
            line-height: 1.6;
        }
        .container {
            max-width: 100%;
            margin: 0 auto;
            padding: 20px;
        }
        header {
            background-color: #2c3e50;
            color: white;
            padding: 20px 0;
            margin-bottom: 20px;
        }
        header h1 {
            text-align: center;
            font-size: 24px;
            font-weight: normal;
        }
        .card {
            background-color:rgb(250,250,250);
            border:none;
            margin-bottom: 20px;
            padding: 20px;
            border-radius: 0;
        }
        .card-title {
            font-size: 18px;
            margin-bottom: 15px;
            padding-bottom: 10px;
            border-bottom: 1px solid #eee;
            color: #2c3e50;
        }
        .form-group {
            margin-bottom: 20px;
        }
        label {
            display: block;
            margin-bottom: 5px;
            font-weight: bold;
        }
        input[type="text"],
        input[type="password"],
        input[type="tel"],
        select {
            width: 100%;
            padding: 10px;
            border:none;
            font-size: 16px;
            border-radius: 0;
            height: 50px;
            line-height: 50px;
        }
        button, .btn {
            background-color: #2c3e50;
            color: white;
            border: none;
            padding: 10px 15px;
            font-size: 16px;
            cursor: pointer;
            text-decoration: none;
            display: inline-block;
            width: 100%;
            border-radius: 0;
            height: 50px;
        }
        button:hover, .btn:hover {
            background-color: #1a252f;
        }
        .text-center {
            text-align: center;
        }
        .text-danger {
            color: #e74c3c;
        }
        .text-success {
            color: #27ae60;
        }
        table {
            width: 100%;
            border-collapse: collapse;
            margin-top: 20px;
            font-size: 14px;
        }
        table, th, td {
            border:none;
        }
        th, td {
            padding: 10px;
            text-align: left;
        }
        th {
            background-color: #2c3e50;
            color: white;
        }
        tr:nth-child(even) {
            background-color: #f2f2f2;
        }
        .admin-panel {
            margin-top: 20px;
        }
        .tab-container {
            margin-top: 20px;
        }
        .tab-buttons {
            display: flex;
            border-bottom: 1px solid #ddd;
            margin-bottom: 15px;
        }
        .tab-button {
            padding: 8px 15px;
            background-color: #f1f1f1;
            border: none;
            cursor: pointer;
            margin-right: 5px;
            font-size: 14px;
            flex: 1;
            text-align: center;
        }
        .tab-button.active {
            background-color: #2c3e50;
            color: white;
        }
        .tab-content {
            display: none;
        }
        .tab-content.active {
            display: block;
        }
        .qr-code {
            margin: 20px auto;
           width: 50%;
            display: block;
        }
        .source-other-group {
            display: none;
            margin-top: 10px;
        }
        
        @media (min-width: 768px) {
            .container {
                max-width: 100%;
            }
            header h1 {
                font-size: 28px;
            }
            .card-title {
                font-size: 20px;
            }
            table {
                font-size: 16px;
            }
        }