body {
    font-family: 'SimSun', 'Microsoft YaHei', Arial, sans-serif;
    font-size: 14px;
    background-color: #f0f2f5;
    margin: 0;
    padding: 20px;
}

.container {
    display: flex;
    width: 1200px;
    margin: 0 auto;
    background-color: #fff;
}

.sidebar {
    width: 280px;
    padding: 20px;
    border-right: 1px solid #e8e8e8;
    flex-shrink: 0;
}

.main-content {
    flex-grow: 1;
    padding: 20px;
}

.sidebar .header {
    background-color: #295ea3;
    color: white;
    padding: 15px;
    font-size: 16px;
    font-weight: bold;
}

.sidebar ul {
    list-style: none;
    padding: 0;
    margin: 20px 0;
}

.sidebar ul li {
    padding: 12px 15px;
    cursor: pointer;
}

.sidebar ul li:hover {
    background-color: #f5f5f5;
}

.query-section {
    border-top: 1px solid #e8e8e8;
    padding-top: 20px;
}

.query-section h3 {
    font-size: 16px;
    margin-top: 0;
}

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

.form-group label {
    display: block;
    margin-bottom: 5px;
}

.form-group input[type="text"] {
    width: calc(100% - 22px);
    padding: 8px 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
}

.btn-search {
    width: 100%;
    padding: 10px;
    background-color: #295ea3;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
}

.main-content h2 {
    font-size: 18px;
    border-bottom: 2px solid #295ea3;
    padding-bottom: 10px;
    margin-top: 0;
}

.letter-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

.letter-table th, .letter-table td {
    border: 1px solid #e8e8e8;
    padding: 12px;
    text-align: left;
}

.letter-table th {
    background-color: #f2f2f2;
    font-weight: bold;
}

.letter-table a {
    color: #333;
    text-decoration: none;
}

.letter-table a:hover {
    text-decoration: underline;
}