@media (max-width: 768px) {
    .background-image {
        width: 100%;
        height: 30%;
        opacity: 0.3;
    }

    .content {
        padding: 0px 5%;
    }

    h1 {
        font-size: 2em;
    }

    /* header */
    header {
        flex-direction: column; /* empilha logo e menu */
        align-items: center;
    }

        header > div {
            width: 100%;
            display: flex;
            justify-content: center; /* centraliza a logo */
            margin-bottom: 10px;
        }

        header nav {
            width: 100%;
        }

            header nav ul.menu {
                flex-direction: column; /* menu vertical */
                align-items: center; /* centraliza itens */
                gap: 10px;
            }

                header nav ul.menu li ul.submenu {
                    position: static; /* faz submenu aparecer dentro do fluxo */
                }


    /* botoes index */
    #txtTermo {
        border-radius: 10px;
    }

    .btn-index-buscar {
        border-top-left-radius: 10px !important;
        border-bottom-left-radius: 10px !important;
    }
    .btn-index-buscarAvancado {
        border-top-right-radius: 10px !important;
        border-bottom-right-radius: 10px !important;
    }

    .input-group {
        flex-direction: column; /* muda o layout para vertical */
        align-items: stretch; /* faz os itens ocuparem toda a largura */
    }

        .input-group .form-control {
            width: 100%;
            border-radius: 0.25rem 0.25rem 0 0; /* opcional, arredonda parte superior */
        }

    .input-group-append {
        width: 100%;
        display: flex;
        justify-content: space-between; /* ou 'center' se quiser centralizar */
        margin-top: 10px; /* espaço entre o input e os botões */
    }

        .input-group-append .btn {
            flex: 1; /* faz os botões ocuparem espaço igual */
            margin: 0 5px;
        }
}