/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

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

/* 头部样式 */
header {
    text-align: center;
    padding: 40px 20px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

header h1 {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 10px;
}

header p {
    color: #666;
    font-size: 1.1rem;
}

/* 课程卡片样式 */
.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    padding: 20px 0;
}

.course-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 40px 30px;
    text-align: center;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
}

.course-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.course-card .icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.course-card h2 {
    font-size: 1.8rem;
    color: #333;
    margin-bottom: 10px;
}

.course-card .class-name {
    font-size: 1rem;
    color: #888;
    margin-bottom: 20px;
}

.course-card .description {
    color: #666;
    line-height: 1.6;
}

/* JavaScript课程卡片颜色 */
.course-card.javascript {
    border-left: 5px solid #f7df1e;
}

.course-card.javascript .icon {
    color: #f7df1e;
}

/* HTML+CSS课程卡片颜色 */
.course-card.html-css {
    border-left: 5px solid #e34c26;
}

.course-card.html-css .icon {
    color: #e34c26;
}

/* 返回按钮 */
.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 30px;
    text-decoration: none;
    color: #333;
    font-weight: 500;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    margin-bottom: 20px;
}

.back-btn:hover {
    background: #fff;
    transform: translateX(-5px);
}

/* 学生列表样式 */
.student-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
    padding: 20px 0;
}

.student-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 25px 20px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    cursor: pointer;
}

.student-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.student-card .avatar {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    margin: 0 auto 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.5rem;
    font-weight: bold;
}

.student-card .name {
    font-size: 1.1rem;
    color: #333;
    font-weight: 500;
}

.student-card .project-name {
    font-size: 0.85rem;
    color: #888;
    margin-top: 5px;
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    color: #666;
}

.empty-state .icon {
    font-size: 4rem;
    margin-bottom: 20px;
    opacity: 0.5;
}

/* 页面标题区域 */
.page-header {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

.page-header h1 {
    color: #333;
    font-size: 2rem;
    margin-bottom: 5px;
}

.page-header .subtitle {
    color: #888;
}

/* 响应式设计 */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .course-card {
        padding: 30px 20px;
    }

    .student-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 15px;
    }
}