.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: var(--color-white);
    box-shadow: 0 2px 2px rgba(0, 0, 0, 0.1);
    height: var(--header-h);
    display: flex;
    justify-content: center;
    padding: 0;
}
.site-header__inner {
    width: 100%;
    max-width: 1670px;
    padding: 0 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
    height: 100%;
}
.site-header__logo {
    display: inline-flex;
    align-items: flex-start;
    flex-shrink: 0;
    width: 129px;
    height: 129px;
    position: relative;
    z-index: 2;
    align-self: flex-start;
    margin-top: 8px;
}
.site-header__logo img { width: 129px; height: 129px; object-fit: contain; display: block; }
.site-header__right {
    display: flex; align-items: center; gap: 24px; flex-grow: 1; justify-content: flex-end;
}
.site-nav { display: flex; align-items: center; }
.site-nav__list { display: flex; gap: 24px; align-items: stretch; }
.site-nav__item { position: relative; display: flex; align-items: center; }
/* Hidden from the desktop top bar but still read by main.js into the hamburger/mega-menu (Die Hochschule). */
.site-nav__item--hamburger-only { display: none; }
.site-nav__link {
    font-family: var(--font-body);
    font-weight: 600; font-size: 16px; line-height: 24px; color: var(--color-black);
    display: inline-flex;
    align-items: center;
    padding: calc((var(--header-h) - 24px) / 2) 0;
}
.site-nav__link:hover { color: var(--color-blue); }

.site-nav__submenu {
    position: absolute;
    top: 100%;
    left: -16px;
    min-width: 280px;
    padding: 8px 0;
    background: var(--color-grey-light-1);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
    visibility: hidden;
    opacity: 0;
    transform: translateY(8px);
    transition: opacity .18s ease, transform .18s ease, visibility .18s ease;
    z-index: 1;
}
.site-nav__sublink {
    display: block;
    padding: 14px 24px;
    font-family: var(--font-body);
    font-weight: 600;
    font-size: 13px;
    line-height: 1.4;
    letter-spacing: 0.5px;
    color: var(--color-black);
    text-transform: uppercase;
    white-space: nowrap;
    transition: background-color .15s ease, color .15s ease;
}
.site-nav__sublink:hover,
.site-nav__sublink:focus-visible {
    background: var(--color-white);
    color: var(--color-blue);
}
.site-nav__item.has-submenu:hover > .site-nav__submenu,
.site-nav__item.has-submenu:focus-within > .site-nav__submenu {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
}
.site-nav__item.has-submenu:hover > .site-nav__link,
.site-nav__item.has-submenu:focus-within > .site-nav__link {
    color: var(--color-blue);
}
.site-nav__item:nth-last-child(-n+2) > .site-nav__submenu {
    left: auto;
    right: -16px;
}
.site-header__actions { display: flex; align-items: center; gap: 12px; }
.site-header__actions .icon-btn,
.site-header__actions .lang-btn,
.site-header__actions .btn { flex-shrink: 0; }
.nav-toggle { display: inline-flex; }

.site-search { position: relative; display: inline-flex; align-items: center; }
.site-search__form { position: relative; display: inline-flex; align-items: center; }
.site-search__toggle { position: relative; z-index: 2; }
/* No square hover background on the lens while the search field is expanded. */
.site-search.is-open .site-search__toggle:hover { background: transparent; }
.site-search__input {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 0;
    height: 40px;
    padding: 0;
    margin: 0;
    border: 1px solid transparent;
    border-radius: var(--radius-pill);
    background: var(--color-grey-light-1);
    font: inherit;
    font-size: 14px;
    color: var(--color-black);
    opacity: 0;
    pointer-events: none;
    transition: width .35s ease, padding .35s ease, opacity .25s ease, border-color .25s ease;
}
.site-search__input::-webkit-search-cancel-button { -webkit-appearance: none; appearance: none; }
.site-search.is-open .site-search__input {
    width: 260px;
    padding: 0 48px 0 16px;
    opacity: 1;
    pointer-events: auto;
    border-color: var(--color-grey-light-2);
}

@media (max-width: 1439px) {
    .site-header__inner { padding: 0 24px; }
    .site-nav__list { gap: 18px; }
    /* Tablet: small logo like on smartphones (meeting 08.07.). */
    .site-header__logo { width: 60px; height: 60px; margin-top: 0; align-self: center; }
    .site-header__logo img { width: 60px; height: 60px; }
}

/* Mobile quick-CTA bar: hidden on desktop, shown under the top bar on phones */
.mobile-cta { display: none; }

@media (max-width: 1023px) {
    .site-header { height: auto; flex-direction: column; padding: 0; }
    .site-header__inner { height: 76px; padding: 8px 20px; gap: 8px; align-items: center; }
    .site-header__logo { width: 60px; height: 60px; margin-top: 0; align-self: center; }
    .site-header__logo img { width: 60px; height: 60px; }
    .site-nav { display: none; }
    .nav-toggle { display: inline-flex; }
    .site-search.is-open .site-search__input { width: 200px; }

    .mobile-cta {
        display: flex;
        gap: 10px;
        width: 100%;
        padding: 10px 16px 12px;
        background: var(--color-white);
        border-top: 1px solid var(--color-grey-light-2);
    }
    .mobile-cta__btn {
        flex: 1 1 0;
        min-width: 0;
        height: auto;
        min-height: 48px;
        padding: 8px 10px;
        font-size: 13px;
        line-height: 1.2;
        white-space: normal;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .site-search.is-open .site-search__input { width: 160px; }
}

/* ============================================================
   Mega menu (opens via .nav-toggle, built by JS from .site-nav)
   ============================================================ */
.mega-menu {
    position: fixed;
    inset: 0;
    z-index: 100;
    visibility: hidden;
    opacity: 0;
    transition: opacity .2s ease, visibility .2s ease;
}
.mega-menu.is-open {
    visibility: visible;
    opacity: 1;
}
.mega-menu__overlay {
    position: absolute;
    inset: 0;
    background: rgba(18, 18, 18, 0.6);
    cursor: pointer;
}
.mega-menu__panel {
    position: relative;
    z-index: 1;
    width: calc(100% - 80px);
    max-width: 1280px;
    margin: calc(var(--header-h) + 16px) auto 40px;
    padding: 40px 64px 40px 40px;
    background: var(--color-white);
    border-radius: 24px;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.18);
    display: grid;
    grid-template-columns: minmax(220px, 290px) 1fr;
    gap: 56px;
    max-height: calc(100vh - var(--header-h) - 56px);
    overflow-y: auto;
}
.mega-menu__close {
    position: absolute;
    top: 24px;
    right: 24px;
    width: 40px;
    height: 40px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--color-black);
    border-radius: 8px;
    cursor: pointer;
}
.mega-menu__close:hover { background: var(--color-grey-light-1); }

.mega-menu__categories {
    display: flex;
    flex-direction: column;
}
.mega-menu__category {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 16px 24px;
    border-radius: 8px;
    border-top: 1px solid var(--color-grey-light-2);
    font-family: var(--font-heading);
    font-size: 22px;
    line-height: 30px;
    font-weight: 700;
    color: var(--color-black);
    text-align: left;
    text-decoration: none;
    cursor: pointer;
    transition: background-color .15s ease, color .15s ease;
}
.mega-menu__category:first-child { border-top-color: transparent; }
.mega-menu__category:hover { color: var(--color-blue); }
.mega-menu__category--active,
.mega-menu__category--active:hover {
    background: var(--color-blue);
    color: var(--color-white);
    border-top-color: transparent;
}
.mega-menu__category--active + .mega-menu__category { border-top-color: transparent; }
.mega-menu__category-chev { flex-shrink: 0; width: 14px; height: 14px; color: currentColor; }

.mega-menu__columns {
    column-count: 2;
    column-gap: 64px;
    padding-top: 12px;
}
.mega-menu__columns--empty {
    column-count: 1;
    color: var(--color-grey-dark);
    font-size: 16px;
    line-height: 24px;
}
.mega-menu__sublink {
    display: block;
    padding: 8px 0;
    font-size: 16px;
    line-height: 28px;
    font-weight: 400;
    color: var(--color-black);
    break-inside: avoid;
    transition: color .15s ease;
}
.mega-menu__sublink:hover { color: var(--color-blue); }

body.mega-menu-open { overflow: hidden; }

@media (max-width: 1439px) {
    .mega-menu__panel { padding: 32px; gap: 32px; }
    .mega-menu__category { font-size: 18px; line-height: 26px; padding: 12px 16px; }
    .mega-menu__columns { column-gap: 40px; }
}

@media (max-width: 767px) {
    .mega-menu__panel {
        width: calc(100% - 24px);
        margin: calc(var(--header-h) + 12px) auto 24px;
        padding: 24px 16px;
        grid-template-columns: 1fr;
        gap: 12px;
        border-radius: 16px;
    }
    .mega-menu__close { top: 12px; right: 12px; }
    .mega-menu__category { font-size: 18px; padding: 14px 16px; }
    .mega-menu__columns { column-count: 1; padding: 4px 16px 8px; }
    /* Akkordeon: Unterpunkte haengen mobil direkt unter dem aktiven Punkt. */
    .mega-menu__categories .mega-menu__columns { padding: 8px 16px 12px; }
    .mega-menu__categories .mega-menu__columns + .mega-menu__category { border-top-color: var(--color-grey-light-2); }
}

/* Tablet-only CTA between logo and menu (preliminary until designer layout). */
.header-cta--tablet { display: none; }
@media (min-width: 1024px) and (max-width: 1365px) {
    .header-cta--tablet { display: inline-flex; margin-left: 16px; }
    .site-nav__link { white-space: nowrap; }
    .site-nav__list { gap: 14px; }
    .site-header__actions { gap: 8px; }
}

/* Ab 1366: Desktop-Buttons sichtbar; Nav einzeilig, Abstaende leicht kompakter. */
@media (min-width: 1366px) {
    .site-nav__link { white-space: nowrap; }
    .site-nav__list { gap: 16px; }
    .site-header__actions { gap: 10px; }
}

/* Meeting 15.07.: beim Scrollen Logo in die Leiste einpassen (kein Ueberlappen). */
.site-header--scrolled .site-header__logo { width: 60px; height: 60px; margin-top: 0; align-self: center; transition: width .15s ease, height .15s ease; }
.site-header--scrolled .site-header__logo img { width: 60px; height: 60px; }