body {
        margin: 0;
        font-family: var(--font-stack);
        background-color: var(--dark-bg);
        background-image: linear-gradient(rgba(0, 229, 255, 0.05) 1px, transparent 1px),
                          linear-gradient(90deg, rgba(0, 229, 255, 0.05) 1px, transparent 1px);
        background-size: 40px 40px;
        color: var(--text);
        display: flex;
        flex-direction: column;
        align-items: center;
        min-height: 100vh;
        padding-bottom: 100px;
        -webkit-tap-highlight-color: transparent;
        touch-action: manipulation;
    }

    h1 {
        margin-top: 40px;
        font-size: clamp(1.2rem, 5vw, 2.2rem);
        color: var(--primary);
        text-shadow: 0 0 10px var(--primary);
        text-align: center;
        text-transform: uppercase;
        white-space: nowrap;
        width: 100%;
        overflow: hidden;
        text-overflow: ellipsis;
        padding: 0 10px;
        box-sizing: border-box;
        user-select: none;
        -webkit-user-select: none;
    }

    /* --- 高亮样式 --- */
    .active-highlight {
        background-color: rgba(0, 229, 255, 0.2) !important;
        border-left: 5px solid #FFD700 !important;
        color: #fff !important;
        transition: background-color 0.2s;
    }

    /* 启动屏幕 */
    #start-screen {
        display: flex; flex-direction: column; gap: 15px;
        width: 90%; max-width: 450px; margin-top: 20px;
    }

    .mode-btn {
        padding: 20px; font-size: 1.2rem;
        border: 2px solid var(--secondary);
        background: rgba(124, 77, 255, 0.1); color: var(--text);
        border-radius: 12px; cursor: pointer;
        display: flex; align-items: center; justify-content: space-between;
        transition: transform 0.1s;
        user-select: none; -webkit-user-select: none;
    }
    .mode-btn:active { transform: scale(0.98); background: var(--secondary); color: #fff; }
    
    .mode-btn.list-mode { border-color: var(--primary); background: rgba(0, 229, 255, 0.1); }
    .mode-btn.list-mode:active { background: var(--primary); color: #000; }

    .mode-btn.text-mode { border-color: var(--accent); background: rgba(255, 64, 129, 0.1); }
    .mode-btn.text-mode:active { background: var(--accent); color: #fff; }

    /* 新增：拼写模式样式 */
    .mode-btn.spelling-mode { border-color: #00E676; background: rgba(0, 230, 118, 0.1); }
    .mode-btn.spelling-mode:active { background: #00E676; color: #000; }

    .mode-icon { font-size: 1.5rem; }

    /* 舞台样式 */
    .stage {
        display: none; 
        width: 95%; flex-direction: column;
        align-items: center; 
    }
    
    #game-stage { max-width: 600px; }
    #list-stage { max-width: 900px; }
    #text-stage { max-width: 800px; }

    /* 底部固定控制栏 */
    .bottom-bar {
        position: fixed; bottom: 0; left: 0; width: 100%;
        background: rgba(13, 17, 23, 0.95);
        border-top: 1px solid var(--secondary);
        padding: 15px;
        display: flex; justify-content: center; gap: 20px;
        box-shadow: 0 -5px 20px rgba(0,0,0,0.5);
        z-index: 100;
        backdrop-filter: blur(10px);
        padding-bottom: env(safe-area-inset-bottom, 20px);
    }

    .play-btn {
        padding: 12px 30px; border-radius: 50px; font-size: 1.1rem; border: none; font-weight: bold; cursor: pointer;
        box-shadow: 0 4px 10px rgba(0,0,0,0.3); transition: all 0.2s; min-width: 160px;
        user-select: none; -webkit-user-select: none;
    }
    .play-btn.start { background: var(--primary); color: #000; }
    .play-btn.stop { background: #ff4444; color: #fff; }
    .return-btn {
        padding: 12px 20px; border-radius: 50px; border: 1px solid #555; background: transparent; color: #aaa; cursor: pointer;
        user-select: none; -webkit-user-select: none;
    }

    /* --- 表格样式 --- */
    .table-wrapper {
        width: 100%; overflow-x: auto;
        background: rgba(22, 27, 34, 0.8);
        border-radius: 12px; border: 1px solid var(--secondary);
    }
    table { width: 100%; border-collapse: collapse; min-width: 350px; } 
    
    th { padding: 12px 15px; text-align: left; background: rgba(124, 77, 255, 0.25); color: var(--primary); position: sticky; top: 0; z-index: 10; }
    
    td { padding: 8px 15px; text-align: left; border-left: 5px solid transparent; }
    
    /*单词列表中的column宽度调整 col-id主要靠调整padding-left和padding-right;*/
    .col-id { width: 40px; color: #8b949e; text-align: center; vertical-align: middle; border-bottom: 1px solid rgba(124, 77, 255, 0.2);  padding-left: 5px; padding-right: 5px; padding-top: 10px;}
    .col-word { width: 45%; color: var(--primary); font-weight: bold; font-size: 1.0rem; padding-top: 10px; padding-left: 3px;} /*use padding-left to move the 'English' column all the way left to save space*/
    .col-cn { width: 55%; color: #ccc; padding-top: 10px; font-size: 1.0rem;}
    
    .row-main td { border-bottom: none; }
    .row-sent td { border-bottom: 1px solid rgba(124, 77, 255, 0.2); padding-bottom: 3px; padding-top: 0; }
    
    .sent-block {
        display: block; font-style: italic; color: #8b949e; 
        background: rgba(0,0,0,0.3); padding: 8px 12px; border-radius: 6px;
        /*margin-top: 5px; line-height: 1.5; font-size: 0.95rem;*/
        margin-top: 0px; line-height: 0.8; font-size: 0.95rem;
        cursor: pointer; transition: all 0.2s;
    }
    .sent-block:hover { background-color: rgba(0, 229, 255, 0.2); color: #FFD700; }

    .mini-btn {
        background: none; border: 1px solid var(--secondary); color: var(--secondary);
        border-radius: 50%; width: 28px; height: 28px; cursor: pointer;
        display: inline-flex; align-items: center; justify-content: center; 
        margin-right: 8px; margin-left: 0;
        flex-shrink: 0;
        user-select: none; -webkit-user-select: none;
    }
    .cell-flex { display: flex; align-items: center; }

    /* 单词链接样式 */
    .word-link {
        color: var(--primary);
        text-decoration: underline;
        text-decoration-color: rgba(0, 229, 255, 0.3);
        text-underline-offset: 3px;
        cursor: pointer;
        transition: all 0.2s;
    }
    .word-link:hover { color: #fff; text-decoration-color: #fff; }

    /* 课文样式 */
    .text-container {
        width: 100%; background: rgba(22, 27, 34, 0.6);
        border-radius: 15px; padding: 20px; box-sizing: border-box; border: 1px solid var(--accent);
        margin-bottom: 80px;
    }
    .paragraph-box { margin-bottom: 30px; padding-bottom: 20px; border-bottom: 1px dashed rgba(255, 255, 255, 0.1); }
    .para-en-container { font-size: 1.3rem; line-height: 1.8; margin-bottom: 15px; }
    .clickable-sentence {
        cursor: pointer; padding: 4px 6px; border-radius: 4px;
        border-bottom: 1px solid transparent; border-left: 5px solid transparent;
        display: inline-block; transition: background-color 0.2s;
    }
    .clickable-sentence:hover { background-color: rgba(0, 229, 255, 0.2); color: #FFD700; }
    .para-cn { font-size: 1rem; color: #8b949e; background: rgba(0,0,0,0.2); padding: 10px; border-radius: 8px; }

    /* --- 闪卡样式 --- */
    .flashcard-container { perspective: 1000px; width: 100%; height: 500px; margin-bottom: 30px; }
    .flashcard { position: relative; width: 100%; height: 100%; text-align: center; transition: transform 0.6s; transform-style: preserve-3d; }
    .flashcard.flipped { transform: rotateY(180deg); }
    
    .card-face {
        position: absolute; width: 100%; height: 100%; backface-visibility: hidden;
        display: flex; 
        flex-direction: column; 
        align-items: center; 
        justify-content: center; /* 垂直居中 */
        gap: 15px;
        border-radius: 20px; border: 2px solid var(--primary);
        background: linear-gradient(145deg, #1c232b, #161b22); 
        padding: 20px; box-sizing: border-box;
        overflow-y: auto;
    }
    .card-back { background: linear-gradient(145deg, #2d1b2e, #221324); transform: rotateY(180deg); border-color: var(--accent); }
    
    .content-wrapper {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center; /* 垂直居中 */
        width: 100%;
        flex: 1;
    }

    .main-text { font-size: 2.2rem; font-weight: bold; color: var(--primary); line-height: 1.2; width: 90%; border-bottom: 1px solid rgba(255,255,255,0.1); }
    
    /* 闪卡中文释义样式 (含词性) */
    .sub-text { 
        font-size: 1.6rem; 
        color: var(--accent); 
        font-weight: bold; 
        margin-bottom: 0px; 
        margin-top: 10px; 
        width: 90%;
        border-bottom: 1px solid rgba(255,255,255,0.1);
        padding-bottom: 3px;
    }
    .pos-tag {
        font-size: 0.8em; color: #8b949e; font-weight: normal; margin-right: 8px;
        background: rgba(255,255,255,0.1); padding: 2px 6px; border-radius: 4px;
        margin-top: 10px;
    }
    
    .sentence-box { 
        font-size: 1.1rem; color: #b0b0b0; 
        background: rgba(255,255,255,0.05); 
        padding: 12px; border-radius: 8px; 
        width: 95%; text-align: left; 
        margin-top: 5px; 
        border-left: 3px solid var(--primary);
    }
    
    /* 考点扩展框 */
    .expansion-box {
        width: 95%;
        text-align: left;
        background: rgba(124, 77, 255, 0.1);
        border: 1px dashed var(--secondary);
        border-radius: 8px;
        padding: 12px;
        margin-top: 10px;
        font-size: 0.95rem;
        color: #E6EDF3;
        line-height: 1.5;
    }
    .expansion-title {
        color: var(--secondary);
        font-weight: bold;
        display: block;
        margin-bottom: 5px;
        font-size: 0.9rem;
    }

    .clickable-box {
        cursor: pointer;
        transition: all 0.2s;
        border: 1px solid transparent;
    }
    .clickable-box:hover {
        background-color: rgba(255, 215, 0, 0.15);
        border-color: rgba(255, 215, 0, 0.3);
        color: #fff;
    }
    
    .hint-controls {
        margin-top: 20px;
        display: flex;
        gap: 15px;
        justify-content: center;
    }
    .hint-btn {
        background: transparent;
        border: 1px solid rgba(0, 229, 255, 0.5);
        color: rgba(0, 229, 255, 0.8);
        padding: 6px 12px;
        border-radius: 20px;
        font-size: 0.9rem;
        cursor: pointer;
        transition: all 0.2s;
    }
    .hint-btn:hover { background: rgba(0, 229, 255, 0.15); color: #fff; }
    .front-hint-text {
        margin-top: 15px; font-size: 1rem; color: #aaa; font-style: italic;
        background: rgba(0, 0, 0, 0.3); padding: 10px; border-radius: 6px;
        width: 90%; text-align: center; display: none;
    }

    /* 大喇叭按钮 */
    .btn-speak-lg { 
        background: rgba(0, 229, 255, 0.15); border: 2px solid var(--primary); color: var(--primary); 
        border-radius: 50%; width: 60px; height: 60px; cursor: pointer; font-size: 1.8rem; 
        flex-shrink: 0; user-select: none; -webkit-user-select: none; margin-top: 15px;
        display: flex; align-items: center; justify-content: center;
    }
    
    .controls { display: flex; gap: 20px; width: 100%; justify-content: center; }
    .nav-btn { padding: 12px 25px; border: 1px solid var(--text); background: rgba(255,255,255,0.05); color: var(--text); border-radius: 8px; cursor: pointer; user-select: none; -webkit-user-select: none;}

    /* --- 弹窗 (Modal) 样式 --- */
    .modal-overlay {
        position: fixed; top: 0; left: 0; width: 100%; height: 100%;
        background: rgba(0, 0, 0, 0.85);
        z-index: 2000;
        display: none;
        justify-content: center;
        align-items: center;
        backdrop-filter: blur(5px);
    }
    .modal-card {
        background: linear-gradient(145deg, #1c232b, #161b22);
        width: 90%; max-width: 500px; max-height: 85vh;
        border-radius: 20px;
        border: 2px solid var(--primary);
        padding: 25px;
        box-shadow: 0 10px 30px rgba(0,0,0,0.5);
        position: relative;
        overflow-y: auto;
        text-align: center;
        animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
        display: flex; flex-direction: column; align-items: center; justify-content: center;
    }
    @keyframes popIn { from { transform: scale(0.8); opacity: 0; } to { transform: scale(1); opacity: 1; } }
    
    .modal-close-btn {
        position: absolute; top: 10px; right: 15px;
        background: none; border: none; color: #888; font-size: 2rem; cursor: pointer;
        line-height: 1; z-index: 10;
    }
    .modal-close-btn:hover { color: #fff; }