function despre(){
document.getElementById('menu1Container').style.visibility = 'visible';
document.getElementById('menu2Container').style.visibility = 'hidden';
document.getElementById('menu3Container').style.visibility = 'hidden';
document.getElementById('head2lin2col1').style.visibility = 'hidden';
document.getElementById('head2lin2col2').style.visibility = 'hidden';

}
function tarife(){
document.getElementById('menu2Container').style.visibility = 'visible';
document.getElementById('menu1Container').style.visibility = 'hidden';
document.getElementById('menu3Container').style.visibility = 'hidden';
document.getElementById('head2lin2col1').style.visibility = 'hidden';
document.getElementById('head2lin2col2').style.visibility = 'hidden';
}
function contact(){
document.getElementById('menu3Container').style.visibility = 'visible';
document.getElementById('menu1Container').style.visibility = 'hidden';
document.getElementById('menu2Container').style.visibility = 'hidden';
document.getElementById('head2lin2col1').style.visibility = 'hidden';
document.getElementById('head2lin2col2').style.visibility = 'hidden';
}
function oferta(){
document.getElementById('head2lin2col1').style.visibility = 'visible';
document.getElementById('head2lin2col2').style.visibility = 'visible';
document.getElementById('menu3Container').style.visibility = 'hidden';
document.getElementById('menu1Container').style.visibility = 'hidden';
document.getElementById('menu2Container').style.visibility = 'hidden';
}