/* ==========================================================================
   S-001 Global Header - Lum-Tech
   ==========================================================================
   Dark-envelope header with hairline bottom border. Logo left, primary nav
   centered-right, login CTA top-right. Sticky with subtle height collapse
   on scroll. Mobile drawer at < 900px.
   ========================================================================== */

/* --------------------------------------------------------------------------
   Site Header
   -------------------------------------------------------------------------- */

.site-header {
    position: relative;
    width: 100%;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    z-index: var(--z-sticky);
    transition: background-color var(--transition-base) var(--ease-out),
                border-color var(--transition-base) var(--ease-out),
                padding var(--transition-base) var(--ease-out);
}

.site-header--sticky {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
}

body.has-sticky-header {
    padding-top: 96px;
}

.site-header--scrolled {
    background-color: rgba(10, 22, 40, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom-color: rgba(232, 238, 245, 0.08);
}

.site-header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 96px;
    gap: var(--space-xl);
    transition: height var(--transition-base) var(--ease-out);
}

.site-header--scrolled .site-header__inner {
    height: 72px;
}

body.has-sticky-header.is-scrolled {
    padding-top: 72px;
}

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

.site-header__brand {
    flex-shrink: 0;
}

.site-header__logo-link {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
    transition: opacity var(--transition-fast) var(--ease-out);
}

.site-header__logo-link:hover {
    opacity: 0.8;
}

.site-header__logo-link:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 4px;
    border-radius: var(--radius-sm);
}

.site-header__logo {
    display: block;
    height: 48px;
    width: auto;
    max-width: 200px;
    /* Logo is now a native-white SVG — no filter hack needed. */
    transition: height var(--transition-base) var(--ease-out);
}

.site-header--scrolled .site-header__logo {
    height: 34px;
}

/* --------------------------------------------------------------------------
   Primary Navigation
   -------------------------------------------------------------------------- */

.site-header__nav {
    flex: 1;
    display: flex;
    justify-content: center;
}

.site-header__menu {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
    margin: 0;
    padding: 0;
    list-style: none;
}

.site-header__menu-item {
    margin: 0;
}

.site-header__menu-link {
    display: inline-block;
    padding: var(--space-sm) 0;
    font-family: var(--font-body);
    font-size: 14px;
    font-weight: 400;
    letter-spacing: 0.02em;
    color: var(--text-primary);
    text-decoration: none;
    position: relative;
    transition: color var(--transition-fast) var(--ease-out);
}

.site-header__menu-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--color-accent);
    transition: width var(--transition-base) var(--ease-out);
}

.site-header__menu-link:hover,
.site-header__menu-link:focus-visible {
    color: var(--color-accent);
    outline: none;
}

.site-header__menu-link:hover::after,
.site-header__menu-link:focus-visible::after {
    width: 100%;
}

.site-header__menu-item.current-menu-item .site-header__menu-link,
.site-header__menu-item.current-page-ancestor .site-header__menu-link {
    color: var(--color-accent);
}

.site-header__menu-item.current-menu-item .site-header__menu-link::after,
.site-header__menu-item.current-page-ancestor .site-header__menu-link::after {
    width: 100%;
}

/* --------------------------------------------------------------------------
   Utility Actions (login + hamburger)
   -------------------------------------------------------------------------- */

.site-header__actions {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-shrink: 0;
}

.site-header__login {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 22px;
    font-family: var(--font-body);
    font-size: 13px;
    font-weight: 400;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-primary);
    background-color: transparent;
    border: 1px solid rgba(232, 238, 245, 0.35);
    border-radius: var(--radius-sm);
    text-decoration: none;
    transition: border-color var(--transition-fast) var(--ease-out),
                color var(--transition-fast) var(--ease-out),
                background-color var(--transition-fast) var(--ease-out);
}

.site-header__login:hover,
.site-header__login:focus-visible {
    border-color: var(--color-accent);
    color: var(--color-accent);
    outline: none;
}

/* --------------------------------------------------------------------------
   Mobile Hamburger
   -------------------------------------------------------------------------- */

.site-header__menu-toggle {
    display: none;
    width: 44px;
    height: 44px;
    padding: 0;
    background: transparent;
    border: 1px solid rgba(232, 238, 245, 0.2);
    border-radius: var(--radius-sm);
    cursor: pointer;
    align-items: center;
    justify-content: center;
    position: relative;
    z-index: 2;
    transition: border-color var(--transition-fast) var(--ease-out);
}

.site-header__menu-toggle:hover,
.site-header__menu-toggle:focus-visible {
    border-color: var(--color-accent);
    outline: none;
}

.site-header__hamburger {
    display: inline-flex;
    flex-direction: column;
    gap: 4px;
    width: 18px;
}

.site-header__hamburger-line {
    display: block;
    width: 100%;
    height: 1px;
    background-color: var(--text-primary);
    transition: transform var(--transition-base) var(--ease-out),
                opacity var(--transition-fast) var(--ease-out);
}

.site-header__menu-toggle[aria-expanded="true"] .site-header__hamburger-line:nth-child(1) {
    transform: translateY(5px) rotate(45deg);
}

.site-header__menu-toggle[aria-expanded="true"] .site-header__hamburger-line:nth-child(2) {
    opacity: 0;
}

.site-header__menu-toggle[aria-expanded="true"] .site-header__hamburger-line:nth-child(3) {
    transform: translateY(-5px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   Mobile Drawer
   -------------------------------------------------------------------------- */

.mobile-menu {
    position: fixed;
    inset: 0;
    z-index: var(--z-modal);
    pointer-events: none;
    visibility: hidden;
    transition: visibility 0s linear var(--transition-base);
}

.mobile-menu[aria-hidden="false"] {
    visibility: visible;
    pointer-events: auto;
    transition-delay: 0s;
}

.mobile-menu__overlay {
    position: absolute;
    inset: 0;
    background-color: rgba(5, 11, 24, 0.7);
    opacity: 0;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    transition: opacity var(--transition-base) var(--ease-out);
}

.mobile-menu[aria-hidden="false"] .mobile-menu__overlay {
    opacity: 1;
}

.mobile-menu__panel {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(420px, 85vw);
    background-color: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    padding: 32px 28px;
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
    transform: translateX(100%);
    transition: transform var(--transition-base) var(--ease-out);
    overflow-y: auto;
}

.mobile-menu[aria-hidden="false"] .mobile-menu__panel {
    transform: translateX(0);
}

.mobile-menu__close {
    align-self: flex-end;
    width: 40px;
    height: 40px;
    padding: 0;
    background: transparent;
    border: 1px solid rgba(232, 238, 245, 0.2);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: border-color var(--transition-fast) var(--ease-out);
}

.mobile-menu__close:hover,
.mobile-menu__close:focus-visible {
    border-color: var(--color-accent);
    outline: none;
}

.mobile-menu__nav {
    flex: 1;
}

.mobile-menu__list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.mobile-menu__item {
    margin: 0;
}

.mobile-menu__link {
    display: block;
    padding: 16px 0;
    font-family: var(--font-heading);
    font-size: 22px;
    font-weight: 200;
    color: var(--text-primary);
    text-decoration: none;
    border-bottom: 1px solid var(--border-color);
    transition: color var(--transition-fast) var(--ease-out),
                padding-left var(--transition-fast) var(--ease-out);
}

.mobile-menu__link:hover,
.mobile-menu__link:focus-visible {
    color: var(--color-accent);
    padding-left: 4px;
    outline: none;
}

.mobile-menu__cta {
    margin-top: auto;
}

/* --------------------------------------------------------------------------
   Breakpoints
   -------------------------------------------------------------------------- */

@media (max-width: 900px) {
    .site-header__nav {
        display: none;
    }

    .site-header__login {
        display: none;
    }

    .site-header__menu-toggle {
        display: inline-flex;
    }

    .site-header__inner {
        height: 80px;
    }

    body.has-sticky-header {
        padding-top: 80px;
    }

    .site-header--scrolled .site-header__inner {
        height: 64px;
    }

    body.has-sticky-header.is-scrolled {
        padding-top: 64px;
    }
}

/* --------------------------------------------------------------------------
   Reduced Motion
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
    .site-header,
    .site-header__inner,
    .site-header__logo,
    .site-header__menu-link::after,
    .site-header__login,
    .site-header__hamburger-line,
    .mobile-menu__overlay,
    .mobile-menu__panel,
    .mobile-menu__link {
        transition-duration: 0s;
    }
}