help/_scss/_search.scss

.search-header {
    background: $primary;
    color: #fff;

    .input-group {
        .form-control {
            border-top-right-radius: 0;
            border-bottom-right-radius: 0;
        }

        .btn.btn-light {
            border-top-left-radius: 0;
            border-bottom-left-radius: 0;
        }
    }
}

.search-navbar {
    padding: 0;
}

.search-sidebar-toggle {
    align-items: center;
    font-weight: bold;
    text-align: center;
    width: 100%;

    &:hover {
        background: $gray-300;
        text-decoration: none;
    }

    &[aria-expanded="true"] {
        .fa-chevron-down {
            transform: rotate(180deg);
        }
    }
}