body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f5f5f5;
    color: #333;
}
h1{
    font-size: 26px;
}
header {
    background-color: #1a5276;
    color: white;
    padding: 20px;
    text-align: center;
}

nav {
    background-color: #2874a6;
    padding: 10px 0;
}

nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: space-around;
    max-width: 1200px;
    margin: 0 auto;
}

nav a {
    color: white;
    text-decoration: none;
    padding: 10px 20px;
    transition: background-color 0.3s;
}

nav a:hover {
    background-color: #3498db;
    border-radius: 4px;
}

main {
    padding: 20px;
    max-width: 1200px;
    margin: 0 auto;
    min-height: calc(100vh - 220px);
}

footer {
    background-color: #1a5276;
    color: white;
    text-align: center;
    padding: 10px;
    position: relative;
    bottom: 0;
    width: 100%;
}

/* 卡片样式 */
.user-card, .material-card, .stat-card {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    margin: 15px 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.user-types, .learning-materials, .statistics-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

/* 表格样式 */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

th, td {
    border: 1px solid #ddd;
    padding: 12px;
    text-align: left;
}

th {
    background-color: #f2f2f2;
}

tr:nth-child(even) {
    background-color: #f9f9f9;
}

/* 表单样式 */
form {
    background-color: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

input[type="text"],
input[type="number"],
input[type="date"],
input[type="tel"],
input[type="datetime-local"],
select, textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-sizing: border-box;
}

button, input[type="submit"] {
    background-color: #2874a6;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover, input[type="submit"]:hover {
    background-color: #3498db;
}

/* 标签页样式 */
.tab-button {
    background-color: #ddd;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.tab-button.active {
    background-color: #2874a6;
    color: white;
}

.tab-content {
    display: none;
    padding: 20px 0;
}

.tab-content.active {
    display: block;
}

/* 图片占位符 */
.place-image img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
}