and after doing that – try:

@media only screen and (max-width: 479px) {
  .html_header_transparency #top .avia-builder-el-0 .container, 
  .html_header_transparency #top .avia-builder-el-0 .slideshow_caption {
    padding-top: 25px;
  }
  @media only screen and (max-width: 476px) {
    #top .avia-caption-content {
      display: none!important
    }
  }
}

my solution – a little adjust of css from ismael – but easiest way is to remove it – and remove please the rule:

#header_main .widget {
  display: flex;
  align-items: center;
  margin-left: 85%;
  margin-top: 2%;
  position: absolute;
}

now try:

@media only screen and (min-width: 1430px) {
  #header #header_main {
    width: 1430px;
    margin: 0 auto;
  }
}

@media only screen and (min-width: 990px) {
  #header #header_main {
    display: flex;
    flex-flow: row wrap;
    justify-content: space-around;
  }
  #header #header_main > * {
    flex: 1 1 auto;
    align-self: center;
    width: unset;
  }
  #header #header_main .av-logo-container {
    flex-basis: calc(100% - 170px);
    flex-grow: 1;
    order: 1;
    max-width: unset;
  }
  #header #header_main .widget {
    margin-right: 50px;
    flex-grow: 0;
    flex-basis: 120px !important;
    order: 2;
    display: flex;
    justify-content: center;
  }
  #header #header_main #header_main_alternate {
    flex-basis: 100%;
    order: 3;
    border-top: none;
  }
}

@media only screen and (max-width: 989px) {
  #header #header_main {
    display: flex;
    flex-flow: wrap column-reverse;
  }
  #header #header_main .widget {
    margin-top: 0px;
    padding: 10px 0 !important;
  }
}

sadly we loose with this the border-top of #header_main_alternate – or you can live with it that the border-top does not have the full screen-width.
then remove that border-top: none line.

See solution here: https://kriesi.at/support/topic/double-tag-when-footer-is-a-page/#post-1486881

By the way, if you have two date pickers, one for the start date and one for the end date, you can restrict the second date picker so that it only allows dates that are later. For example, we can also remove weekends from the selection.

here in my example the minDate/maxDate are relative Values by +7 Days and +12 Month:

function my_datepicker_limits() {
?>
<script type="text/javascript">
window.addEventListener("DOMContentLoaded", function () { 
(function($) { 
    setTimeout(function() {
        var $allDatepickers = $('.avia_datepicker');

        // Let's assume that the first avia_datepicker found is the start date
        var $startDateField = $allDatepickers.eq(0);
        // and the second avia_datepicker found the end date
        var $endDateField = $allDatepickers.eq(1);

        // Check whether we have found at least two datepicker fields
        if ($startDateField.length === 0 || $endDateField.length === 0) {
            console.warn('Could not find both Start and End datepicker fields. Ensure they are the first two .avia_datepicker elements.');
            return; // Exit script if not enough fields are found
        }

        // Find the container of the end date field (the <p> element in your structure)
        // This is the parent tag of the input field that also contains the label.
        var $endDateFieldContainer = $endDateField.parent('p.form_element');

        // Fallback if the container is not the <p> tag or is not found
        if (!$endDateFieldContainer.length) {
            $endDateFieldContainer = $endDateField; // Then we only hide the input field itself
        }

        function updateEndDatepickerState() {
            var selectedStartDate = $startDateField.datepicker('getDate');
            

            if (selectedStartDate) {
                // Optional: Add one day to ensure that the end date is at least one day after the start date.
                // then remove the backslashes of the next line
                // selectedStartDate.setDate(selectedStartDate.getDate() + 1);
              
                // If a start date is selected, display the end date field
                $endDateFieldContainer.css('display', 'block'); // Verwendet 'block', da <p> ein Block-Element ist

                $endDateField.datepicker('option', 'minDate', selectedStartDate);

                // Optional: Make sure that the end date is not before the start date.
                var currentEndDate = $endDateField.datepicker('getDate');
                if (currentEndDate && currentEndDate < selectedStartDate) {
                    $endDateField.datepicker('setDate', selectedStartDate);
                }

            } else {
                // If no start date is selected, hide the end date field
                $endDateFieldContainer.css('display', 'none');

                // Reset minDate of the end date date picker (e.g. to “today”)
                $endDateField.datepicker('option', 'minDate', 0);
            }
        }

        if ($startDateField.data('datepicker')) {
            $startDateField.datepicker('option', {
                beforeShowDay: $.datepicker.noWeekends,
                minDate: "+7d", 
                maxDate: "+12m",
                onSelect: function(dateText, inst) {
                    // Update the state when a date is selected
                    updateEndDatepickerState();
                },
                onClose: function(dateText, inst) {
                    // Update the state even when closing the data picker (for robustness)
                    updateEndDatepickerState();
                }
            });
        }

        if ($endDateField.data('datepicker')) {
            $endDateField.datepicker('option', {
                // beforeShowDay: $.datepicker.noWeekends,
                minDate: 0,
                maxDate: "+12m"
            });
        }

        // Execute the function once when loading the page to set the initial state
        updateEndDatepickerState();

    }, 500);
}(jQuery));
});
</script>
<?php
}
add_action('wp_footer', 'my_datepicker_limits', 20);

see: https://webers-testseite.de/datepicker/

Edit here – because topic is closed:
This was also only intended as additional information. It is in case someone lands here via the search. They may have exactly this request.

this is the whole css for transparency fixed header on small screens ( if header_meta is present some height values had to be corrected ) from my testpage above:

@media only screen and (max-width:989px) {
  .responsive #top #wrap_all #header .container {
    width:95%;
    max-width:95%
  }
  #header {
    position:fixed !important;
    height:80px !important;
    max-height:80px !important
  }
  .responsive #top .av-logo-container ,
  .responsive #top .logo a,
  .responsive #top .logo img,
  .responsive #top .logo svg {
    height:80px !important;
    max-height:80px !important;
    line-height:80px !important
  }
  .responsive #top .av-main-nav .menu-item-avia-special a {
    height:80px !important;
    line-height:80px !important
  }
  #top .header_bg,
  .responsive.html_mobile_menu_tablet #top #wrap_all .av_header_transparency {
    background-color:transparent !important
  }
  .responsive.html_mobile_menu_tablet #top #wrap_all #header:not(.av_header_transparency) {
    background-color:#FFF !important
  }
  #top #header.header-scrolled .header_bg {
    background-color:#FFF !important
  }
  .responsive.html_mobile_menu_tablet #top .av_header_transparency .logo img.alternate,
  .responsive.html_mobile_menu_tablet #top .av_header_transparency .logo .subtext.avia-svg-logo-sub {
    display:block !important
  }
  .responsive.html_mobile_menu_tablet #top .av_header_transparency.av_alternate_logo_active .logo a > img,
  .responsive.html_mobile_menu_tablet #top .av_header_transparency.av_alternate_logo_active .logo a > svg {
    opacity:0
  }
  html:not(.html_header_transparency) #top .header_bg {
    background-color:#FFF !important
  }
  .responsive:not(.html_header_transparency).html_mobile_menu_tablet.html_header_top #top #main {
    padding-top:80px !important
  }
}

try:

@media only screen and (max-width:989px) {
  .responsive.html_mobile_menu_tablet #top .av_header_transparency .logo img.alternate,
  .responsive.html_mobile_menu_tablet #top .av_header_transparency .logo .subtext.avia-svg-logo-sub {
    display:block !important
  }
  .responsive.html_mobile_menu_tablet #top .av_header_transparency.av_alternate_logo_active .logo a > img,
  .responsive.html_mobile_menu_tablet #top .av_header_transparency.av_alternate_logo_active .logo a > svg {
    opacity:0
  }
}

_______________

in layout.css there is that rule – this has to be overwritten – if you set your header to fixed position:

@media only screen and (max-width: 989px) {
  .responsive.html_mobile_menu_tablet #top .av_header_transparency .logo .subtext.avia-svg-logo-sub, 
  .responsive.html_mobile_menu_tablet #top .av_header_transparency .logo img.alternate {
    display: none;
  }
}
@media only screen and (max-width: 767px) {
  .responsive #top .av_header_transparency .logo .subtext.avia-svg-logo-sub, 
  .responsive #top .av_header_transparency .logo img.alternate {
    display: none;
  }
}