/* 摺疊面板 (Accordion) 樣式 */
.accordion {
    background-color: #f1f4f9;
    color: #002395;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    text-align: left;
    border: none;
    border-radius: 8px;
    outline: none;
    font-size: 1.1rem;
    font-weight: bold;
    transition: 0.4s;
    margin-bottom: 0.5rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

/* 滑鼠經過或展開時的樣式 */
.accordion.active, .accordion:hover {
    background-color: #002395;
    color: white;
}

/* 在按鈕右側加上 + 號與 - 號的視覺提示 */
.accordion:after {
    content: '\002B'; /* Unicode 的加號 */
    font-size: 1.5rem;
    float: right;
    margin-left: 5px;
}

.accordion.active:after {
    content: "\2212"; /* Unicode 的減號 */
}

/* 隱藏的內容面板 */
.panel {
    padding: 0 18px;
    background-color: white;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    border-radius: 0 0 8px 8px;
    margin-bottom: 1rem;
}

.panel p {
    margin-top: 1rem;
    line-height: 1.6;
}

/* 文法表格樣式 (補充原本在單字表格裡用到的共用樣式) */
.table-responsive {
    overflow-x: auto;
    margin-top: 1rem;
}

.vocab-table {
    width: 100%;
    border-collapse: collapse;
    background-color: white;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.vocab-table th, .vocab-table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #eee;
}

.vocab-table th {
    background-color: #f1f4f9;
    color: #002395;
    font-weight: 600;
}

.vocab-table tbody tr:hover {
    background-color: #f8f9fa;
    transition: background-color 0.2s ease;
}

.vocab-word {
    font-weight: bold;
    color: #ed2939;
}