.sl-letters {
    max-width: 800px;
    margin: 0 auto;
}
.sl-filter-form {
    margin-bottom: 20px;
}
.sl-filter-form label {
    margin-right: 10px;
}
.sl-letters-table {
    width: 100%;
    border-collapse: collapse;
}
.sl-letters-table th,
.sl-letters-table td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}
.sl-letters-table th {
    background-color: #f2f2f2;
}
.sl-letters-table a {
    color: #0073aa;
    text-decoration: none;
}
.sl-letters-table a:hover {
    text-decoration: underline;
}