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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f4f4f4;
}

.container {
    width: 100%;
    margin: 0 auto;
    padding: 20px;
}

/* 头部样式 */
header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background-color: #4CAF50;
    color: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

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

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* 专业选择器样式 */
.major-selector {
    margin-bottom: 30px;
    text-align: center;
}

.major-selector h2 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: #333;
}

#majorSelect {
    padding: 12px 20px;
    font-size: 1.1rem;
    border: 2px solid #ddd;
    border-radius: 5px;
    background-color: white;
    cursor: pointer;
    transition: border-color 0.3s ease;
}

#majorSelect:focus {
    outline: none;
    border-color: #4CAF50;
}

/* 内容区域样式 */
.content {
    background-color: white;
    border-radius: 8px;
    padding: 25px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.info-section {
    margin-bottom: 30px;
    text-align: center;
}

#majorTitle {
    font-size: 2rem;
    color: #333;
    margin-bottom: 20px;
}

.btn-export {
    background-color: #4CAF50;
    color: white;
    border: none;
    padding: 12px 25px;
    font-size: 1.1rem;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    font-weight: bold;
}

.btn-export:hover {
    background-color: #45a049;
}

/* 分类区域样式 */
.categories {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.category {
    background-color: #f9f9f9;
    border-radius: 8px;
    padding: 20px;
    border: 1px solid #eee;
}

.category-title {
    font-size: 1.4rem;
    color: #4CAF50;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #4CAF50;
}

/* 项目列表样式 */
.items-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.item-card {
    background-color: white;
    border-radius: 6px;
    padding: 15px;
    box-shadow: 0 1px 5px rgba(0, 0, 0, 0.1);
    border-left: 4px solid #4CAF50;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.item-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.15);
}

.item-card h4 {
    font-size: 1.2rem;
    color: #333;
    margin-bottom: 8px;
}

.item-card .item-details {
    font-size: 0.95rem;
    color: #666;
    margin-bottom: 5px;
}

.item-card .item-details a {
    color: #4CAF50;
    text-decoration: none;
    transition: color 0.3s ease;
}

.item-card .item-details a:hover {
    color: #45a049;
    text-decoration: underline;
}

.item-card .item-description {
    font-size: 0.9rem;
    color: #777;
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px solid #eee;
}

.item-card .item-categories {
    margin-top: 8px;
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
}

.category-tag {
    background-color: #4CAF50;
    color: white;
    padding: 3px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
}

/* 难度标签样式 */
.difficulty-tag {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: bold;
    margin-top: 5px;
}

.difficulty-tag.beginner {
    background-color: #4CAF50;
    color: white;
}

.difficulty-tag.intermediate {
    background-color: #ff9800;
    color: white;
}

.difficulty-tag.advanced {
    background-color: #f44336;
    color: white;
}

/* 页脚样式 */
footer {
    text-align: center;
    margin-top: 30px;
    padding: 20px;
    color: #666;
    font-size: 0.9rem;
}

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

    header h1 {
        font-size: 2rem;
    }

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

    .category {
        padding: 15px;
    }

    #majorSelect {
        width: 100%;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.7rem;
    }

    #majorTitle {
        font-size: 1.5rem;
    }

    .category-title {
        font-size: 1.2rem;
    }
}