Ayuda , Menus desplegables no funcionan en el template responsive de mi web

BUenas a todos soy nuevo en joomla y estoy trabajando con una pagina y todo va de maravilla hasta que decidi probar el modo
responsive de mi pagina en un par de moviles y la sorpresa fue que los menus desplegables no funcionan , sola me salen las primeras pestañas del menu pero las subpestañas no aparecen , espero alguien me pueda ayudar con esto adjunto el codigo css de la plantilla responsive .

GRACIAS !!!

[code type=php].responsive body
{
min-width: 240px;
}

.responsive .art-content-layout img,
.responsive .art-content-layout video
{
max-width: 100%;
height: auto !important;
}

.responsive.responsive-phone .art-content-layout img
{
float: none !important;
}

.responsive .art-content-layout .art-sidebar0,
.responsive .art-content-layout .art-sidebar1,
.responsive .art-content-layout .art-sidebar2
{
width: auto !important;
}

.responsive .art-content-layout,
.responsive .art-content-layout-row,
.responsive .art-layout-cell
{
display: block;
}

.responsive .art-slidenavigator
{
display: none !important;
}

.responsive .art-collage
{
display: none !important;
}

.responsive .image-caption-wrapper
{
width: auto !important;
}

.responsive .art-textblock
{
display: none;
}

.responsive.responsive-tablet .art-vmenublock,
.responsive.responsive-tablet .art-block
{
margin-left: 1%;
margin-right: 1%;
width: 48%;
float: left;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}

.responsive .art-responsive-embed
{
position: relative;
padding-bottom: 56.25%;
/* 16:9 */
height: 0;
}

.responsive .art-responsive-embed iframe,
.responsive .art-responsive-embed object,
.responsive .art-responsive-embed embed
{
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}

.responsive .art-header
{
width: auto;
height: auto;
min-height: 100px;
background-position: center center !important;
background-size: cover !important;
background-repeat: repeat !important;
}

.responsive .art-header .art-headline,
.responsive .art-header .art-slogan
{
display: block !important;
top: 0 !important;
left: 0 !important;
margin: 2% !important;
}

.responsive .art-header .art-headline a,
.responsive .art-header .art-slogan
{
white-space: normal !important;
}

.responsive .art-header .art-shapes .art-textblock
{
padding: 2% !important;
margin: 2% !important;
line-height: normal;
background-image: none;
background-color: rgba(127, 127, 127, 0.7);
color: #eee !important;
display: none;
top: auto;
left: auto;
width: auto;
height: auto;
}

.responsive .art-header .art-shapes .art-textblock *,
.responsive .art-header .art-shapes .art-textblock a:hover,
.responsive .art-header .art-shapes .art-textblock a:visited,
.responsive .art-header .art-shapes .art-textblock a:link
{
color: #eee !important;
}

.responsive .art-header .art-shapes .art-textblock>div
{
display: none;
top: auto;
left: auto;
width: auto;
height: auto;
padding: 0 !important;
}

.responsive .art-header .art-shapes,
.responsive .art-header .art-shapes *
{
position: relative;
text-align: center;
-webkit-transform: none !important;
-moz-transform: none !important;
-o-transform: none !important;
-ms-transform: none !important;
transform: none !important;
}

.responsive .art-header #art-flash-area,
.responsive .art-header .art-shapes>*
{
display: none;
}

.responsive #art-header-bg
{
background-position: center center !important;
background-size: cover !important;
background-repeat: repeat !important;
}

/* Search */
.responsive .art-shapes~.art-textblock
{
position: relative !important;
display: block !important;
margin: 1% auto !important;
width: 75% !important;
top: auto !important;
right: auto !important;
bottom: auto !important;
left: auto !important;
}

/* dynamic width nav */
.responsive nav.art-nav,
.responsive .art-nav-inner
{
width: auto !important;
position: relative !important;
top: auto !important;
left: auto !important;
right: auto !important;
bottom: auto !important;
margin-top: 0;
margin-bottom: 0;
}

.responsive .responsive-nav
{
padding-left: 0;
padding-right: 0;
margin-top: 20px;
}

/* full width hmenu, instead of inline-block */
.responsive .responsive-nav ul.art-hmenu
{
display: block;
float: none;
text-align: center;
}

/* elements on different lines */
.responsive .responsive-nav ul.art-hmenu li
{
float: none;
}

/* horizontal margins */
.responsive .responsive-nav ul.art-hmenu>li:first-child,
.responsive .responsive-nav ul.art-hmenu>li:last-child,
.responsive .responsive-nav ul.art-hmenu>li
{
margin-left: 0;
margin-right: 0;
}

/* separator */
.responsive .responsive-nav ul.art-hmenu>li:before
{
display: none;
}

/* vertical distance between items */
.responsive .responsive-nav ul.art-hmenu a
{
margin-top: 1px !important;
margin-bottom: 1px !important;
text-align: center;
height: auto;
white-space: normal;
}

.responsive .responsive-nav ul.art-hmenu>li:first-child>a
{
margin-top: 0 !important;
}

.responsive .responsive-nav ul.art-hmenu>li:last-child>a
{
margin-bottom: 0 !important;
}

/* fixes for extended menu */
.responsive .responsive-nav .ext,
.responsive .responsive-nav ul.art-hmenu>li>ul,
.responsive .responsive-nav ul.art-hmenu>li>ul>li
{
width: auto !important;
}

/* submenu position on hover */
.responsive .responsive-nav ul.art-hmenu ul
{
left: auto !important;
right: auto !important;
top: auto !important;
bottom: auto !important;
display: none !important;
position: relative !important;
visibility: visible !important;
}

.responsive .responsive-nav ul.art-hmenu>li>ul>li:first-child:after
{
display: none;
}
.responsive .responsive-nav ul.art-hmenu ul a
{
padding-left: 4% !important;
}
.responsive .responsive-nav ul.art-hmenu ul ul a
{
padding-left: 6% !important;
}
.responsive .responsive-nav ul.art-hmenu ul ul ul a
{
padding-left: 8% !important;
}
.responsive .responsive-nav ul.art-hmenu ul ul ul ul a
{
padding-left: 10% !important;
}
.responsive .responsive-nav ul.art-hmenu ul ul ul ul ul a
{
padding-left: 12% !important;
}

.responsive .responsive-nav ul.art-hmenu>li>ul
{
padding: 1px;
}

.responsive .responsive-nav ul.art-hmenu>li>ul:before
{
top: 0;
right: 0;
bottom: 0;
left: 0;
}

.responsive .art-sheet
{
width: auto !important;
min-width: 240px !important;
max-width: none;
margin-right: 1% !important;
margin-left: 1% !important;
margin-top: 1% !important;
}

#art-resp {
display: none;
}

@media all and (max-width: 899px)
{
#art-resp, #art-resp-t { display: block; }
#art-resp-m { display: none; }
}

@media all and (max-width: 480px)
{
#art-resp, #art-resp-m { display: block; }
#art-resp-t { display: none; }
}

.responsive .art-content-layout,
.responsive .art-content-layout-row,
.responsive .art-layout-cell
{
display: block;
}

.responsive .art-layout-cell
{
width: auto !important;
height: auto !important;
border-right-width: 0 !important;
border-left-width: 0 !important;
border-radius: 0 !important;
}

.responsive .art-content-layout:after,
.responsive .art-content-layout-row:after,
.responsive .art-layout-cell:after
{
content: “.”;
display: block;
height: 0;
clear: both;
visibility: hidden;
}

.responsive .art-post
{
border-radius: 0;
}

.responsive .art-footer-inner
{
width: auto;
padding: 2% !important;
}

.responsive .responsive-tablet-layout-cell
{
width: 50% !important;
float: left;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}[/code]