/* ===== 口算练习专用样式 ===== */

        /* 年级标签 */
        .grade-tabs {
            display: flex;
            flex-wrap: wrap;
            gap: 0.6rem;
            margin-bottom: 1.8rem;
            justify-content: center;
        }

        .grade-tab {
            padding: 0.5rem 1.8rem;
            border-radius: 60px;
            border: 2px solid #f3dcc6;
            background: white;
            font-family: 'Quicksand', 'Microsoft YaHei', sans-serif;
            font-weight: 700;
            font-size: 1rem;
            color: #7a5a3e;
            cursor: pointer;
            transition: all 0.2s;
            user-select: none;
            -webkit-tap-highlight-color: transparent;
        }

        .grade-tab:hover {
            border-color: #dba272;
            background: #fdf6ed;
        }

        .grade-tab.active {
            background: #dba87a;
            border-color: #b88256;
            color: white;
            box-shadow: 0 4px 0 #b88256;
        }

        .grade-tab .grade-icon {
            margin-right: 6px;
        }

        /* 练习区域 */
        #practiceArea {
            margin-top: 1.5rem;
        }

        .problem-display {
            text-align: center;
            padding: 2rem 0 1.5rem 0;
        }

        .problem-display .question-text {
            font-size: 3.5rem;
            font-weight: 700;
            color: #3f2a19;
            letter-spacing: 4px;
            background: #fffbf5;
            padding: 1rem 2rem;
            border-radius: 60px;
            display: inline-block;
            border: 3px solid #f7e3cf;
            box-shadow: 0 4px 0 #dba87a;
            min-width: 200px;
        }

        .problem-display .question-number-hint {
            font-size: 1rem;
            color: #a87a5a;
            margin-top: 0.5rem;
        }

        .input-area {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.8rem;
            margin: 1.5rem auto;
            max-width: 320px;
            width: 100%;
        }

        .input-area input[type="number"] {
            font-size: 1.8rem;
            width: 100%;
            padding: 0.7rem 1.2rem;
            border-radius: 60px;
            border: 3px solid #f3dcc6;
            background: white;
            font-family: 'Quicksand', 'Microsoft YaHei', sans-serif;
            font-weight: 700;
            color: #3f2a19;
            text-align: center;
            outline: none;
            transition: 0.15s;
            box-sizing: border-box;
        }

        .input-area input[type="number"]:focus {
            border-color: #dba272;
            box-shadow: 0 0 0 4px #fae1c6;
        }

        .input-area .btn {
            font-size: 1.1rem;
            padding: 0.7rem 2.2rem;
            width: 100%;
            justify-content: center;
        }

        .feedback-text {
            text-align: center;
            font-size: 1.4rem;
            font-weight: 700;
            min-height: 3rem;
            padding: 0.5rem;
            border-radius: 40px;
            margin-top: 0.2rem;
        }

        .feedback-text.correct {
            color: #4caf50;
        }

        .feedback-text.wrong {
            color: #e74c3c;
        }

        .progress-wrapper {
            margin: 1.8rem 0 1.2rem;
        }

        .progress-track {
            height: 14px;
            background: #f0e4d4;
            border-radius: 40px;
            overflow: hidden;
            border: 2px solid #f7e3cf;
            box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.06);
        }

        .progress-fill {
            height: 100%;
            background: linear-gradient(90deg, #dba87a, #c2824b);
            width: 0%;
            border-radius: 40px;
            transition: width 0.3s ease;
        }

        .stats-row {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1.5rem 2.5rem;
            background: #fffbf5;
            padding: 0.8rem 1.8rem;
            border-radius: 60px;
            border: 2px solid #f7e3cf;
            font-weight: 600;
            color: #5a3a24;
            font-size: 1rem;
        }

        .stats-row .stat-item i {
            color: #d98c4a;
            margin-right: 6px;
        }

        .stats-row .stat-item .stat-value {
            color: #4e2f1b;
            font-weight: 700;
        }

        /* 结果区域 */
        .result-card {
            text-align: center;
            padding: 2rem 1rem;
        }

        .result-card .big-icon {
            font-size: 5rem;
            margin-bottom: 1rem;
            display: block;
        }

        .result-card h2 {
            font-size: 2.2rem;
            color: #4e2f1b;
            margin-bottom: 1.2rem;
        }

        .result-card .result-stats {
            background: #fcf0e2;
            padding: 1.5rem 2rem;
            border-radius: 40px;
            display: inline-block;
            text-align: left;
            font-size: 1.1rem;
            line-height: 2;
            border: 2px solid #fae2cb;
            margin-bottom: 1.5rem;
        }

        .result-card .result-stats .stat-label {
            font-weight: 600;
            color: #7a5a3e;
        }

        .result-card .result-stats .stat-value {
            font-weight: 700;
            color: #4e2f1b;
        }

        .wrong-list {
            margin-top: 2rem;
            text-align: left;
        }

        .wrong-list h3 {
            font-size: 1.3rem;
            color: #c45a32;
            margin-bottom: 0.8rem;
            text-align: center;
        }

        .wrong-list table {
            width: 100%;
            border-collapse: collapse;
            background: white;
            border-radius: 20px;
            overflow: hidden;
            box-shadow: 0 4px 12px rgba(190, 120, 60, 0.1);
        }

        .wrong-list th {
            background: #fcf0e2;
            padding: 0.7rem 1rem;
            font-weight: 700;
            color: #5a3a24;
            text-align: left;
            border-bottom: 2px solid #fae2cb;
        }

        .wrong-list td {
            padding: 0.6rem 1rem;
            border-bottom: 1px solid #f7e3cf;
            color: #3f2a19;
        }

        .wrong-list tr:last-child td {
            border-bottom: none;
        }

        .wrong-list .wrong-answer {
            color: #e74c3c;
            font-weight: 700;
        }

        .wrong-list .correct-answer {
            color: #4caf50;
            font-weight: 700;
        }

        .hidden {
            display: none !important;
        }

        /* 移动端适配 */
        @media (max-width: 768px) {
            .grade-tabs {
                gap: 0.4rem;
            }

            .grade-tab {
                padding: 0.4rem 1rem;
                font-size: 0.85rem;
                flex: 1 1 auto;
                text-align: center;
                min-width: 60px;
            }

            .problem-display .question-text {
                font-size: 2.2rem;
                padding: 0.8rem 1.2rem;
                min-width: 100px;
            }

            .input-area {
                max-width: 100%;
                padding: 0 0.5rem;
            }

            .input-area input[type="number"] {
                font-size: 1.5rem;
                padding: 0.6rem 1rem;
            }

            .input-area .btn {
                font-size: 1rem;
                padding: 0.6rem 1.5rem;
            }

            .feedback-text {
                font-size: 1.1rem;
                min-height: 2.5rem;
            }

            .stats-row {
                gap: 0.6rem 1.2rem;
                font-size: 0.8rem;
                padding: 0.6rem 1rem;
                border-radius: 40px;
                flex-wrap: wrap;
            }

            .stats-row .stat-item {
                white-space: nowrap;
            }

            .result-card .result-stats {
                font-size: 0.95rem;
                padding: 1rem 1.2rem;
            }

            .result-card h2 {
                font-size: 1.6rem;
            }

            .result-card .big-icon {
                font-size: 3.5rem;
            }
        }

        @media (max-width: 400px) {
            .grade-tab {
                font-size: 0.75rem;
                padding: 0.3rem 0.6rem;
                min-width: 50px;
            }

            .problem-display .question-text {
                font-size: 1.8rem;
                padding: 0.6rem 0.8rem;
                min-width: 60px;
                letter-spacing: 2px;
            }

            .input-area input[type="number"] {
                font-size: 1.3rem;
                padding: 0.5rem 0.8rem;
            }

            .stats-row .stat-item {
                font-size: 0.7rem;
            }
        }

        /* 打印样式 */
        @media print {
            .header,
            .config-panel,
            .grade-tabs,
            .footer,
            .tip,
            .input-area,
            .feedback-text,
            .breadcrumb,
            .tool-nav {
                display: none !important;
            }

            .main-card {
                box-shadow: none;
                border: none;
                padding: 0;
            }

            .problem-display .question-text {
                font-size: 2rem;
                border: 1px solid #ddd;
                box-shadow: none;
            }

            .stats-row {
                border: 1px solid #ddd;
                background: #f9f9f9;
            }
        }