body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.4;
            color: #333;
            max-width: 800px;
            margin: 0 auto;
            padding: 15px;
            background-color: #f8f9fa;
        }
        .container {
            background-color: white;
            border-radius: 8px;
            padding: 20px;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
        }
        h1 {
            color: #2c3e50;
            text-align: center;
            margin-bottom: 20px;
            font-size: 24px;
        }
        .controls {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 15px;
            gap: 10px;
        }
        .lesson-selector {
            padding: 8px;
            border-radius: 5px;
            border: 1px solid #ddd;
            background-color: white;
            flex: 1;
        }
        .status {
            padding: 8px 12px;
            border-radius: 5px;
            font-weight: 500;
            text-align: center;
            background-color: #e9ecef;
            color: #495057;
            flex: 2;
        }
        .matching-container {
            display: flex;
            gap: 15px;
            margin: 15px 0;
        }
        .column {
            flex: 1;
            display: flex;
            flex-direction: column;
            gap: 8px;
        }
        .item {
            padding: 12px;
            border: 1px solid #dee2e6;
            border-radius: 5px;
            cursor: pointer;
            transition: all 0.15s;
            background-color: white;
            min-height: 30px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 16px;
        }
        .item:hover {
            background-color: #f8f9fa;
            border-color: #adb5bd;
        }
        .item.selected {
            border-color: #007bff;
            background-color: #e8f4ff;
        }
        .item.matched {
            border-color: #28a745;
            background-color: #f0fff4;
            cursor: default;
        }
        .character {
            font-size: 28px;
            text-align: center;
        }
        .pinyin {
            font-size: 16px;
            color: #6c757d;
            text-align: center;
        }
        .meaning {
            font-size: 14px;
            color: #495057;
            text-align: center;
        }
        .progress {
            margin: 15px 0;
            height: 8px;
            background-color: #e9ecef;
            border-radius: 4px;
            overflow: hidden;
        }
        .progress-bar {
            height: 100%;
            background-color: #007bff;
            width: 0%;
            transition: width 0.3s ease;
        }
        .btn {
            padding: 10px 15px;
            border: none;
            border-radius: 5px;
            cursor: pointer;
            font-size: 14px;
            transition: all 0.2s;
            background-color: #6c757d;
            color: white;
            width: 100%;
        }
        .btn:hover {
            background-color: #5a6268;
        }
        .feedback {
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            padding: 20px 30px;
            border-radius: 8px;
            font-weight: bold;
            z-index: 1000;
            opacity: 0;
            transition: opacity 0.3s;
            pointer-events: none;
        }
        .correct-feedback {
            background-color: #d4edda;
            color: #155724;
            border: 1px solid #c3e6cb;
        }
        .incorrect-feedback {
            background-color: #f8d7da;
            color: #721c24;
            border: 1px solid #f5c6cb;
        }
/* Стиль для активной кнопки */
.btn:not(:disabled) {
    background-color: #A8E6A1 !important; /* Мягкий пастельно-зелёный */
    color: #000 !important;
}

.btn:not(:disabled):hover {
    background-color: #8FDAA0 !important; /* Немного насыщеннее при наведении */
    transform: translateY(-1px);
}

/* Стиль для disabled кнопки */
.btn:disabled {
    background-color: #cccccc !important;
    color: #666666 !important;
    cursor: not-allowed !important;
    transform: none !important;
}