body {
            background-color: #007bff;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
            padding: 0 15px;
            box-sizing: border-box;
        }
        .container {
            max-width: 800px;
            width: 100%;
            background: white;
            padding: 30px;
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
            box-sizing: border-box;
        }
        h1 {
            text-align: center;
            color: #333;
            margin-bottom: 20px;
            font-weight: bold;
            text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
        }
        .form-control {
            width: 100%;
            padding: 10px;
            border-radius: 5px;
            margin-bottom: 20px;
            resize: none;
        }
        .form-control[contenteditable=true]:empty:before {
            content: attr(placeholder);
            color: #ccc;
        }
        .mini {
            height: 80px;
        }
        .medium {
            height: 150px;
        }
        .btn {
            width: 100%;
            padding: 15px;
            font-size: 1rem;
            color: #fff;
            background-color: #28a745;
            border: none;
            border-radius: 5px;
            cursor: pointer;
            transition: background-color 0.3s;
            margin-bottom: 10px;
        }
        .btn i {
            margin-right: 5px;
        }
        .btn:hover {
            background-color: #218838;
        }
        .btn-clear {
            background-color: #dc3545;
        }
        .btn-clear:hover {
            background-color: #c82333;
        }
        .alert {
            display: none;
            margin-top: 10px;
            padding: 10px;
            color: #721c24;
            background-color: #f8d7da;
            border-color: #f5c6cb;
            border-radius: 4px;
        }
        .highlighted {
            background-color: #fff3cd;
            color: #856404;
            padding: 5px;
        }
        .btn-group {
            display: flex;
            justify-content: space-between;
            gap: 15px;
        }
        @media (max-width: 576px) {
            .btn {
                padding: 10px;
                font-size: 0.9rem;
            }
            .medium {
                height: 120px;
            }
            .mini {
                height: 60px;
            }
            .btn-group {
                flex-direction: column;
                gap: 10px;
            }
        }