/* ==========================================================================
   InduTech HK — Navbar
   Palette abgeleitet aus dem Logo: Slate-Navy Grund, Stahl-Blaugrau Typo,
   Cyan als technischer Akzent.
   ========================================================================== */

:root {
    --nav-ink:          #16232b;              /* Logo-Hintergrund */
    --nav-ink-2:        #1b2a33;
    --nav-glass:        rgba(22, 35, 43, .72);
    --nav-glass-solid:  rgba(18, 29, 36, .94);

    --steel:            #b5c4cc;              /* Logo-Typo */
    --steel-dim:        #8b9ea8;
    --steel-bright:     #eef4f7;

    --accent:           #4fb6c9;
    --accent-soft:      rgba(79, 182, 201, .38);

    --nav-hairline:     rgba(181, 196, 204, .12);

    --nav-h:            80px;
    --nav-h-sm:         64px;

    --ease:             cubic-bezier(.4, 0, .2, 1);
    --ease-out:         cubic-bezier(.16, 1, .3, 1);

    --font-nav:         "Barlow", ui-sans-serif, system-ui, -apple-system,
                        "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

*,
*::before,
*::after { box-sizing: border-box; }

body {
    margin: 0;
    font-family: var(--font-nav);
    background: #0f181e;
    color: var(--steel);
}

/* --------------------------------------------------------------------------
   Header shell
   -------------------------------------------------------------------------- */

#header {
    position: sticky;
    top: 0;
    z-index: 1000;
    isolation: isolate;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: clamp(1rem, 3vw, 3rem);
    padding-inline: max(1.25rem, calc((100% - 1280px) / 2));

    background: transparent;
    border-bottom: 1px solid var(--nav-hairline);
    transition: box-shadow .35s var(--ease);
}

/* Die Glas-Ebene liegt bewusst auf einem Pseudo-Element, NICHT auf #header:
   backdrop-filter erzeugt einen containing block für position:fixed —
   das Mobile-Panel würde dann am Header statt am Viewport hängen. */
#header::after {
    content: "";
    position: absolute;
    inset: 0;
    z-index: -1;
    background: var(--nav-glass);
    -webkit-backdrop-filter: blur(18px) saturate(160%);
    backdrop-filter: blur(18px) saturate(160%);
    transition: background .35s var(--ease);
}

/* Kein backdrop-filter (ältere Browser) -> deckender Fallback */
@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
    #header::after { background: var(--nav-glass-solid); }
}

/* Feine Akzent-Haarlinie an der Oberkante */
#header::before {
    content: "";
    position: absolute;
    inset: 0 0 auto 0;
    height: 1px;
    background: linear-gradient(
        90deg,
        transparent,
        var(--accent-soft) 20%,
        var(--accent-soft) 80%,
        transparent
    );
    opacity: .7;
    pointer-events: none;
}

/* Progressive Enhancement: Header wird beim Scrollen kompakter & dichter.
   Nur Browser mit scroll-driven animations, sonst schadlos ignoriert. */
@supports (animation-timeline: scroll()) {
    @media (min-width: 901px) and (prefers-reduced-motion: no-preference) {
        #header,
        #header::after,
        .header-top {
            animation: linear both;
            animation-timeline: scroll(root block);
            animation-range: 0 140px;
        }
        #header        { animation-name: nav-lift; }
        #header::after { animation-name: nav-densify; }
        .header-top    { animation-name: nav-shrink; }

        @keyframes nav-lift {
            to { box-shadow: 0 10px 30px -12px rgba(0, 0, 0, .65); }
        }
        @keyframes nav-densify {
            to { background: var(--nav-glass-solid); }
        }
        @keyframes nav-shrink {
            to { height: 62px; }
        }
    }
}

.header-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    flex: 0 0 auto;
    height: var(--nav-h);
    transition: height .35s var(--ease);
}

/* --------------------------------------------------------------------------
   Logo
   -------------------------------------------------------------------------- */

.header-top > a:first-child {
    display: inline-flex;
    align-items: center;
    flex: 0 0 auto;
    border-radius: 10px;
    transition: transform .35s var(--ease-out), filter .35s var(--ease);
}

.header-top > a:first-child img {
    display: block;
    height: clamp(34px, 4.4vw, 48px);
    width: auto;
    transition: height .35s var(--ease);
}

.header-top > a:first-child:hover {
    transform: translateY(-1px);
    filter: drop-shadow(0 6px 14px rgba(79, 182, 201, .28));
}

.header-top > a:first-child:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 6px;
}

/* --------------------------------------------------------------------------
   Navigation — Desktop
   -------------------------------------------------------------------------- */

#header nav ul {
    display: flex;
    align-items: center;
    gap: clamp(.25rem, 1.4vw, 1rem);
    margin: 0;
    padding: 0;
    list-style: none;
}

.nav-child > a {
    position: relative;
    display: block;
    padding: .7rem .95rem;
    font-size: .82rem;
    font-weight: 500;
    letter-spacing: .11em;
    text-transform: uppercase;
    color: var(--steel-dim);
    text-decoration: none;
    border-radius: 8px;
    transition: color .28s var(--ease);
    -webkit-tap-highlight-color: transparent;
}

/* Unterstrich, der von links einläuft */
.nav-child > a::after {
    content: "";
    position: absolute;
    left: .95rem;
    right: .95rem;
    bottom: .35rem;
    height: 2px;
    border-radius: 2px;
    background: linear-gradient(90deg, var(--accent), var(--steel));
    transform: scaleX(0);
    transform-origin: left center;
    transition: transform .4s var(--ease-out);
}

.nav-child > a:hover,
.nav-child > a:focus-visible { color: var(--steel-bright); }

.nav-child > a:hover::after,
.nav-child > a:focus-visible::after { transform: scaleX(1); }

.nav-child > a:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* Aktive Seite */
.nav-child.active > a { color: var(--steel-bright); }
.nav-child.active > a::after {
    transform: scaleX(1);
    background: var(--accent);
    box-shadow: 0 0 12px var(--accent-soft);
}

/* --------------------------------------------------------------------------
   Hamburger (CSS-only, ohne JS)
   -------------------------------------------------------------------------- */

.side-menu {
    position: absolute;
    opacity: 0;
    pointer-events: none;
    width: 1px;
    height: 1px;
}

#hamb {
    display: none;               /* erst ab Mobile-Breakpoint */
    position: relative;
    flex: 0 0 auto;
    width: 46px;
    height: 46px;
    margin-right: -8px;
    border-radius: 12px;
    cursor: pointer;
    border: 1px solid var(--nav-hairline);
    background: rgba(181, 196, 204, .05);
    transition: background .25s var(--ease), border-color .25s var(--ease);
    -webkit-tap-highlight-color: transparent;
}

#hamb:active { background: rgba(181, 196, 204, .12); }

.hamb-line,
.hamb-line::before,
.hamb-line::after {
    position: absolute;
    left: 50%;
    width: 22px;
    height: 2px;
    border-radius: 2px;
    background: var(--steel);
    transition: transform .4s var(--ease-out),
                background-color .25s var(--ease),
                opacity .2s var(--ease);
}

.hamb-line {
    top: 50%;
    transform: translate(-50%, -50%);
}

.hamb-line::before,
.hamb-line::after {
    content: "";
    left: 0;
}

.hamb-line::before { transform: translateY(-7px); }
.hamb-line::after  { transform: translateY(7px); }

/* -> X */
.side-menu:checked ~ .header-top .hamb-line {
    background: transparent;
}
.side-menu:checked ~ .header-top .hamb-line::before {
    transform: translateY(0) rotate(45deg);
    background: var(--accent);
}
.side-menu:checked ~ .header-top .hamb-line::after {
    transform: translateY(0) rotate(-45deg);
    background: var(--accent);
}

.side-menu:focus-visible ~ .header-top #hamb {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-soft);
}

/* --------------------------------------------------------------------------
   Mobile / Tablet
   -------------------------------------------------------------------------- */

@media (max-width: 900px) {
    :root { --nav-h: var(--nav-h-sm); }

    #hamb { display: block; }

    #header { padding-inline: clamp(1rem, 4vw, 1.5rem); }

    .header-top { flex: 1 1 auto; }

    #header nav {
        position: fixed;
        inset: var(--nav-h-sm) 0 0 0;
        padding: 1.75rem clamp(1.25rem, 5vw, 2.5rem) 3rem;
        background: var(--nav-glass-solid);
        -webkit-backdrop-filter: blur(22px) saturate(160%);
        backdrop-filter: blur(22px) saturate(160%);
        overflow-y: auto;
        overscroll-behavior: contain;

        opacity: 0;
        visibility: hidden;
        transform: translateY(-10px);
        transition: opacity .3s var(--ease),
                    transform .4s var(--ease-out),
                    visibility .3s linear .3s;
    }

    /* #header vorangestellt, damit die Regel die Specificity von
       "#header nav" oben schlägt. */
    #header .side-menu:checked ~ nav {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
        transition-delay: 0s, 0s, 0s;
    }

    #header nav ul {
        flex-direction: column;
        align-items: stretch;
        gap: .25rem;
    }

    .nav-child {
        border-bottom: 1px solid var(--nav-hairline);
    }
    .nav-child:last-child { border-bottom: 0; }

    .nav-child > a {
        padding: 1.15rem .25rem;
        font-size: 1.05rem;
        letter-spacing: .06em;
        color: var(--steel);
    }

    /* Unterstrich weicht einem linken Akzentbalken.
       Hier muessen ALLE Zustaende aufgezaehlt werden, die weiter oben eine
       eigene transform-Regel haben (:hover, :focus-visible, .active): die
       Desktop-Regeln dort haben zwei Klassen und damit die hoehere
       Specificity — Media Queries erhoehen die Specificity nicht. Fehlt ein
       Zustand, behaelt er "transform: scaleX(1)", verliert damit die
       vertikale Zentrierung und der Balken sitzt eine halbe Hoehe zu tief. */
    .nav-child > a::after,
    .nav-child > a:hover::after,
    .nav-child > a:focus-visible::after,
    .nav-child.active > a::after {
        left: -.75rem;
        right: auto;
        top: 50%;
        bottom: auto;
        width: 3px;
        height: 0;
        border-radius: 3px;
        background: var(--accent);
        transform: translateY(-50%);
        transition: height .35s var(--ease-out);
        box-shadow: none;
    }

    .nav-child > a:hover::after,
    .nav-child > a:focus-visible::after,
    .nav-child.active > a::after { height: 26px; }

    .nav-child.active > a { color: var(--steel-bright); }

    /* Gestaffeltes Einblenden der Links (--i kommt aus dem Template) */
    .nav-child {
        opacity: 0;
        transform: translateY(12px);
        transition: opacity .4s var(--ease), transform .5s var(--ease-out);
    }
    #header .side-menu:checked ~ nav .nav-child {
        opacity: 1;
        transform: translateY(0);
        transition-delay: calc(80ms + var(--i, 0) * 55ms);
    }
}

/* --------------------------------------------------------------------------
   Reduced motion
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
    #header,
    #header *,
    #header *::before,
    #header *::after {
        transition-duration: .01ms !important;
        animation-duration: .01ms !important;
        transition-delay: 0ms !important;
    }
}