body {
                background-color: #e9ecef;
              }
              :root {
                --bs-primary: #dc3545; /* Bootstrap red */
                --bs-primary-rgb: 220, 53, 69;
              }
              .feature-icon {
                color: var(--bs-primary);
              }
              #username:focus,
              #password:focus {
                border-color: var(--bs-danger-border-subtle);
                box-shadow: 0 0 0 0.25rem rgba(var(--bs-danger-rgb), 0.25);
              }
              
              #username:focus,
#password:focus {
  border-color: #f5c2c7;
  box-shadow: 0 0 0 0.25rem rgba(220, 53, 69, 0.25);
}
                .search-input-group { max-width: 300px; }
                .th-original-url { min-width: 250px; }
                .td-original-url {
                    max-width: 300px;
                    overflow: hidden;
                    text-overflow: ellipsis;
                    white-space: nowrap;
                }
                .sidebar .nav-link {
                    color: #333;
                    margin-bottom: 0.1rem;
                    border-radius: 0.375rem;
                    transition: background-color 0.15s ease-in-out, color 0.15s ease-in-out;
                }
                .sidebar .nav-link:hover {
                    background-color: var(--bs-danger-bg-subtle);
                    color: var(--bs-emphasis-color);
                }
                .sidebar .nav-link.active,
                .sidebar .nav-link.active:hover {
                    background-color: var(--bs-danger);
                    color: var(--bs-white);
                }
                .sidebar .nav-link .bi {
                    margin-right: 0.5rem;
                    width: 1.2em;
                    text-align: center;
                }
                .sidebar .nav > .nav-link {
                    padding-left: 0.75rem;
                }
                 .sidebar .nav-item.dropdown > .nav-link.dropdown-toggle {
                     padding-left: 0.75rem;
                 }
                .sidebar .dropdown-menu {
                    position: static !important;
                    transform: none !important;
                    display: none;
                    float: none !important;
                    width: 100% !important;
                    margin-top: 0;
                    padding: 0;
                    border: none;
                    box-shadow: none;
                    background-color: transparent;
                }
                .sidebar .dropdown-menu.show {
                    display: block;
                }
                .sidebar .dropdown-item {
                    padding: .5rem 1rem;
                    color: #333;
                    transition: background-color 0.15s ease-in-out, color 0.15s ease-in-out;
                    border-radius: 0;
                    padding-left: 2rem; /* Indent dropdown items */
                }
                .sidebar .dropdown-item:hover {
                    background-color: var(--bs-danger-bg-subtle);
                    color: var(--bs-emphasis-color);
                }
                .sidebar .dropdown-item.active,
                .sidebar .dropdown-item:active {
                    background-color: var(--bs-danger);
                    color: var(--bs-white);
                }
                .sidebar .dropdown-divider {
                    margin: 0.5rem 0;
                    border-top-color: rgba(0,0,0,0.1);
                }
                .sidebar .dropdown-toggle::after {
                    margin-left: auto;
                    vertical-align: middle;
                }
                .sidebar .dropdown-toggle[aria-expanded="true"] {
                     background-color: var(--bs-danger-bg-subtle);
                     color: var(--bs-emphasis-color);
                }
                 .sidebar .nav-link.text-danger:hover {
                     background-color: var(--bs-danger-bg-subtle);
                     color: var(--bs-danger) !important;
                 }