@media (max-width: 767px) {

    /* ================================
       MOBILNÁ HLAVIČKA – ČISTÁ VERZIA
       ================================ */

    #header {
        position: relative !important;
        height: auto !important;
        min-height: 0 !important;
        margin: 0 !important;
        padding: 0 !important;
        overflow: visible !important;
    }

    #header::after {
        display: none !important;
        content: none !important;
    }

    #header .navigation-wrapper {
        position: relative !important;
        height: auto !important;
        min-height: 0 !important;
        margin: 0 !important;
        padding: 0 15px !important;
        overflow: visible !important;
        box-sizing: border-box !important;
    }

    /* Horný riadok 74 px + vyhľadávanie 50 px */
    #header .header-top {
        position: relative !important;

        display: grid !important;
        grid-template-columns: 125px minmax(0, 1fr) !important;
        grid-template-rows: 74px 50px !important;
        grid-template-areas:
            "logo actions"
            "search search" !important;

        align-items: center !important;
        column-gap: 8px !important;

        width: 100% !important;
        height: 124px !important;
        min-height: 124px !important;

        margin: 0 !important;
        padding: 0 !important;

        overflow: visible !important;
        box-sizing: border-box !important;
    }

    /* ================================
       LOGO
       ================================ */

    #header .header-top > .site-name-wrapper {
        grid-area: logo !important;

        position: static !important;
        display: flex !important;
        align-items: center !important;
        align-self: center !important;

        width: 125px !important;
        height: 74px !important;
        min-width: 0 !important;

        margin: 0 !important;
        padding: 0 !important;

        transform: none !important;
    }

    #header .site-name,
    #header .site-name a {
        position: static !important;

        display: flex !important;
        align-items: center !important;

        width: 100% !important;
        height: auto !important;

        top: auto !important;
        right: auto !important;
        bottom: auto !important;
        left: auto !important;

        margin: 0 !important;
        padding: 0 !important;

        transform: none !important;
    }

    #header .site-name a {
        max-width: 120px !important;
    }

    #header .site-name img {
        display: block !important;

        width: 100% !important;
        max-width: 120px !important;
        height: auto !important;

        margin: 0 !important;
    }

    /* ================================
       PRIHLÁSENIE, VÝPREDAJ, KOŠÍK
       ================================ */

    #header .header-top > .navigation-buttons {
        grid-area: actions !important;

        position: static !important;

        display: flex !important;
        align-items: center !important;
        align-self: center !important;
        justify-content: flex-end !important;

        width: 100% !important;
        height: 74px !important;
        min-width: 0 !important;

        margin: 0 !important;
        padding: 0 !important;

        transform: none !important;
    }

    #header .navigation-buttons > a,
    #header .navigation-buttons > button {
        top: auto !important;
        right: auto !important;
        bottom: auto !important;
        left: auto !important;

        margin-top: 0 !important;
        margin-bottom: 0 !important;

        transform: none !important;
    }

    #header .navigation-buttons .top-nav-button {
        position: static !important;
        top: auto !important;

        margin-top: 0 !important;
        margin-bottom: 0 !important;
    }

    /* ================================
       VYHĽADÁVANIE
       ================================ */

    #header .header-top > .search {
        grid-area: search !important;

        position: relative !important;

        top: auto !important;
        right: auto !important;
        bottom: auto !important;
        left: auto !important;

        display: block !important;
        visibility: visible !important;
        opacity: 1 !important;

        width: calc(100% + 30px) !important;
        max-width: none !important;
        min-width: 0 !important;
        height: 50px !important;

        margin: 0 -15px !important;
        padding: 5px 15px 5px 68px !important;

        background-color: #FF6B83 !important;

        box-sizing: border-box !important;
        transform: none !important;
        z-index: 2 !important;
    }

    #header .header-top .search::before {
        display: none !important;
        content: none !important;
    }

    #header .search-form,
    #header .search form,
    #header .search fieldset,
    #header .search .compact-form {
        position: static !important;

        display: flex !important;
        flex-flow: row nowrap !important;
        align-items: stretch !important;

        width: 100% !important;
        min-width: 0 !important;
        height: 40px !important;

        margin: 0 !important;
        padding: 0 !important;
        border: 0 !important;
    }

    #header .search input {
        position: static !important;

        flex: 1 1 0 !important;
        width: 0 !important;
        min-width: 0 !important;
        height: 40px !important;

        margin: 0 !important;
        padding: 0 12px !important;

        background-color: #fff !important;
        border: 0 !important;
        border-radius: 8px 0 0 8px !important;

        font-size: 15px !important;
        box-sizing: border-box !important;
    }

    #header .search input::placeholder {
        color: #B4B4B4 !important;
        font-size: 15px !important;
    }

    #header .search button[type="submit"],
    #header .search .btn {
        position: static !important;

        flex: 0 0 90px !important;
        width: 90px !important;
        min-width: 90px !important;
        max-width: 90px !important;
        height: 40px !important;

        margin: 0 !important;
        padding: 0 8px !important;

        border: 1px solid #fff !important;
        border-radius: 0 8px 8px 0 !important;

        transform: none !important;
        white-space: nowrap !important;
        box-sizing: border-box !important;
    }

    /* ================================
       HAMBURGER
       ================================ */

    #header button[data-testid="hamburgerMenu"],
    #header button[data-target="navigation"],
    #header .navigation-buttons > .top-nav-button-menu,
    #header .navigation-buttons > .toggle-window[data-target="navigation"] {
        position: absolute !important;

        top: auto !important;
        right: auto !important;
        bottom: 10px !important;
        left: 17px !important;

        display: block !important;
        visibility: visible !important;
        opacity: 1 !important;

        width: 38px !important;
        min-width: 38px !important;
        height: 30px !important;

        margin: 0 !important;
        padding: 0 !important;

        background-color: transparent !important;
        background-image:
            linear-gradient(#fff, #fff),
            linear-gradient(#fff, #fff),
            linear-gradient(#fff, #fff) !important;

        background-size:
            27px 3px,
            27px 3px,
            27px 3px !important;

        background-position:
            center 5px,
            center 13px,
            center 21px !important;

        background-repeat: no-repeat !important;

        border: 0 !important;
        border-radius: 0 !important;
        box-shadow: none !important;

        color: transparent !important;
        font-size: 0 !important;
        line-height: 0 !important;

        transform: none !important;
        z-index: 20 !important;
    }

    #header button[data-testid="hamburgerMenu"] > *,
    #header button[data-target="navigation"] > *,
    #header .navigation-buttons > .top-nav-button-menu > *,
    #header .navigation-buttons > .toggle-window[data-target="navigation"] > * {
        display: none !important;
    }

    #header button[data-testid="hamburgerMenu"]::before,
    #header button[data-testid="hamburgerMenu"]::after,
    #header button[data-target="navigation"]::before,
    #header button[data-target="navigation"]::after {
        display: none !important;
        content: none !important;
    }

    /* ================================
       MEDZERA PRED BANNEROM
       ================================ */

    body.in-index #header + .content-wrapper,
    body.in-index #header + #content-wrapper {
        margin-top: 14px !important;
    }
}

Na koniec mobile-header-fix.css pridaj:

@media (max-width: 767px) {

    /* Skrytá horná navigácia nesmie zaberať miesto */
    #header .top-navigation-bar,
    .top-navigation-bar {
        display: none !important;
        visibility: hidden !important;

        width: 0 !important;
        height: 0 !important;
        min-height: 0 !important;
        max-height: 0 !important;

        margin: 0 !important;
        padding: 0 !important;
        border: 0 !important;

        overflow: hidden !important;
    }

    /* Odstránenie prípadnej rezervy nad hlavičkou */
    #header,
    #header .navigation-wrapper,
    #header .header-top {
        margin-top: 0 !important;
        padding-top: 0 !important;
    }
}