/* 全局样式 */
:root {
    --primary-color: #44546A;
	<!-- --primary-color: #2c3e50;-->
    --secondary-color: #3498db;
    --text-color: #333;
    --bg-color: #DEEBF7;
	<!--   --bg-color: #fff; -->
    --border-color: #eee;  
}

body {
    <!--font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Trebuchet MS, sans-serif;-->
		font-family: -apple-system, BlinkMacSystemFont, "Trebuchet MS", Roboto, "Helvetica Neue", Trebuchet MS, sans-serif;
    line-height: 1.3;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
    padding: 0;
}

/* 布局 */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* 导航栏 */
.nav-main {
    background-color: var(--primary-color);
    padding: 1rem 0;
    text-align: center;
}

.nav-main a {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    margin: 0 0.5rem;
    transition: all 0.3s ease;
}

.nav-main a.active {
    border-bottom: 2px solid white;
}

.nav-main a:hover {
    background-color: #070F8F;
    border-radius: 4px;
}

/* 标题样式 */
h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 3px solid var(--secondary-color);
}

h2 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin: 2rem 0 1.5rem;
}

/* 课程列表样式 */
.course-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.course-item {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    position: relative;
    overflow: hidden;
}

.course-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background-color: var(--secondary-color);
}

.course-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.course-item h3 {
    font-size: 1.4rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.course-item p {
    color: #666;
    margin-bottom: 0.5rem;
}

.course-link {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    transition: background-color 0.3s;
}

.course-link:hover {
    background-color: var(--secondary-color);
}

/* 课程页面样式 */
.course-page section {
    margin-bottom: 1rem;
	<!--margin-bottom: 3rem;-->
}

.course-info ul {
    list-style: none;
    padding: 0;
}

.course-info li {
    margin: 0.5rem 0;
}

/* Excel风格表格样式 */
.assessment-table {
    width: 100%;
    border-collapse: collapse;
    border: 1px solid #ccc;
    font-family: Arial, sans-serif;
    margin: 1rem 0;
}

.assessment-table th,
.assessment-table td {
    border: 1px solid #ccc;
    padding: 8px 12px;
    text-align: left;
}

.assessment-table th {
    background-color: #f0f0f0;
    font-weight: bold;
    border-bottom: 2px solid #ccc;
}

.assessment-table tr:nth-child(even) {
    background-color: #f8f8f8;
}

.assessment-table tr:hover {
    background-color: #f5f5f5;
}

.assessment-table thead th {
    background: linear-gradient(to bottom, #f8f8f8, #e8e8e8);
    border-bottom: 2px solid #999;
}

.assessment-table td:nth-child(2) {
    text-align: center;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .course-list {
        grid-template-columns: 1fr;
    }
    
    main {
        padding: 1rem;
    }
}

/* 页脚样式 */
footer {
    text-align: center;
    padding: 2rem;
    background: var(--primary-color);
    color: white;
    margin-top: 4rem;
}