/* ------------------------------------------------------ */
/* 文件： style.css                                        */
/* 功能： 前端样式表                                        */
/* ------------------------------------------------------ */

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    background-color: #f7f9fc;
    color: #333;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background-color: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    overflow: hidden;
}

.main-title {
    text-align: center;
    padding: 20px;
    border-bottom: 2px solid #007bff;
    margin: 0;
    color: #333;
}

/* 消息提示 */
.error-message {
    color: #d93025;
    text-align: center;
    padding: 20px;
    font-weight: bold;
}
.no-data-message {
    text-align: center;
    padding: 20px;
    color: #555;
}

/* 折叠菜单 */
summary {
    cursor: pointer;
    font-weight: bold;
    padding: 15px 20px;
    user-select: none;
    outline: none;
    transition: background-color 0.2s;
}
summary:hover {
    background-color: #f4f4f4;
}

/* 一级分类 */
.cat-l1 > summary {
    font-size: 1.8em;
    color: #0056b3;
    border-bottom: 2px solid #e0e0e0;
}

/* 二级分类 */
.cat-l2 {
    margin-left: 20px;
}
.cat-l2 > summary {
    font-size: 1.4em;
    color: #007bff;
    border-bottom: 1px solid #eee;
}

/* 三级分类 */
.cat-l3 {
    padding-left: 40px;
    border-bottom: 1px dashed #ccc;
}
.cat-l3-title {
    font-size: 1.2em;
    color: #555;
    font-weight: bold;
    padding: 10px 0;
}

/* 知识点 */
.knowledge-point {
    padding: 10px 0 15px 20px;
}
.kp-title {
    font-size: 1.1em;
    color: #1a1a1a;
    font-weight: 600;
}
.kp-notes {
    font-size: 0.95em;
    color: #4a4a4a;
    margin: 5px 0;
    background: #fdfdfd;
    border-left: 3px solid #007bff;
    padding: 8px 12px;
    border-radius: 0 4px 4px 0;
}

/* 试题 */
.questions-block {
    margin-top: 15px;
    padding-left: 10px;
}
.questions-title {
    font-weight: bold;
    color: #333;
}
.question-item {
    margin: 10px 0;
    padding: 10px;
    background: #f9f9f9;
    border: 1px solid #eee;
    border-radius: 5px;
}
.question-text {
    margin: 0 0 8px 0;
}
.toggle-answer {
    background: #007bff;
    color: white;
    border: none;
    padding: 5px 10px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9em;
    transition: background-color 0.2s;
}
.toggle-answer:hover {
    background: #0056b3;
}
.answer {
    display: none; /* 默认隐藏答案 */
    margin-top: 8px;
    padding: 8px;
    background: #e6f7ff;
    border: 1px solid #b3e0ff;
    border-radius: 4px;
    color: #0056b3;
    font-weight: 500;
}