/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    color: #374151;
    background-color: #f9fafb;
}

/* 导航栏 */
.navbar {
    background-color: #3B82F6;
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar h1 {
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin-left: 2rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: #E0E7FF;
}

/* 个人信息卡片 */
.profile-section {
    padding: 3rem 0;
    background-color: white;
}

.profile-card {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    padding: 2rem;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.profile-avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background-color: #3B82F6;
    margin: 0 auto 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 3rem;
    font-weight: bold;
}

.profile-card h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: #1F2937;
}

.profile-card p {
    font-size: 1.1rem;
    color: #6B7280;
    margin-bottom: 0.5rem;
}

/* 课程部分 */
.courses-section {
    padding: 3rem 0;
}

.section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 2rem;
    color: #1F2937;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.course-card {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    padding: 1.5rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px rgba(0,0,0,0.1);
}

.course-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: #1F2937;
}

.course-card p {
    color: #6B7280;
    margin-bottom: 1.5rem;
}

.course-link {
    display: inline-block;
    background-color: #3B82F6;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.course-link:hover {
    background-color: #2563EB;
}

/* 课程详情页 */
.course-detail {
    padding: 3rem 0;
    background-color: white;
}

.course-header {
    text-align: center;
    margin-bottom: 3rem;
}

.course-header h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #1F2937;
}

.course-content {
    max-width: 800px;
    margin: 0 auto;
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    padding: 2rem;
}

.course-content h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #1F2937;
}

.course-content p {
    margin-bottom: 1.5rem;
    color: #6B7280;
}

.back-link {
    display: inline-block;
    margin-top: 2rem;
    color: #3B82F6;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.back-link:hover {
    color: #2563EB;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar .container {
        flex-direction: column;
        align-items: flex-start;
    }

    .nav-links {
        margin-top: 1rem;
    }

    .nav-links li {
        margin-left: 1rem;
        margin-right: 1rem;
    }

    .courses-grid {
        grid-template-columns: 1fr;
    }

    .profile-card h2 {
        font-size: 1.5rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .course-header h2 {
        font-size: 2rem;
    }
}

/* 页脚 */
.footer {
    background-color: #1F2937;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer p {
    margin: 0;
}