Source code for https://victorfont.com/formidable-pro-css-grid-flex-box/

flex.css

.start-flex {
    display: flex;
    flex-direction: row;
    flex: 1;
    flex-wrap: nowrap
}

.monday,
.tuesday,
.wednesday,
.thursday,
.friday,
.saturday {
    margin-right: 3px;
}

monday.html

<div class="start-flex"><!-- start flex -->
<div id="frm_field_[id]_container" class="monday frm_form_field form-field [required_class][error_class]">
    <label for="field_[key]" class="frm_primary_label">[field_name]
        <span class="frm_required">[required_label]</span>
    </label>
    [input]
    [if description]<div class="frm_description" id="frm_desc_field_[key]">[description]</div>[/if description]
    [if error]<div class="frm_error">[error]</div>[/if error]
</div>

sunday.html

<div id="frm_field_[id]_container" class="sunday frm_form_field form-field [required_class][error_class]">
    <label for="field_[key]" class="frm_primary_label">[field_name]
        <span class="frm_required">[required_label]</span>
    </label>
    [input]
    [if description]<div class="frm_description" id="frm_desc_field_[key]">[description]</div>[/if description]
    [if error]<div class="frm_error">[error]</div>[/if error]
</div>
</div><!-- flex end -->