/* ==========================================================================
   NAV — fixed 80px header, white background, dark dropdown on mobile.
   Markup: header.site-header > .container.site-header__inner >
     .site-header__logo, nav#nav-menu.site-nav, button.nav-toggle
   JS: js/main.js toggles `.is-open` on #site-header and `.is-scrolled` on
   scroll (see initNavToggle / initHeaderScroll).
   ========================================================================== */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-nav);
  height: var(--nav-height);
  background: var(--color-bg-primary);
  border-bottom: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition-base);
}

.site-header.is-scrolled {
  box-shadow: 0 2px 16px rgba(0, 0, 0, 0.07);
}

.site-header__inner {
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

/* ---- Logo --------------------------------------------------------------- */
.site-header__logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.site-header__logo img {
  height: 52px;
  width: auto;
}

/* ---- Desktop nav (links + CTA) ------------------------------------------ */
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.site-nav__links a {
  font-family: var(--font-body);
  font-weight: var(--fw-body-medium);
  font-size: var(--fs-nav-link);
  letter-spacing: var(--ls-nav);
  text-transform: uppercase;
  color: var(--color-text-primary);
  transition: opacity var(--transition-fast);
}

.site-nav__links a:hover,
.site-nav__links a:focus-visible {
  opacity: 0.5;
}

/* ---- Mobile hamburger toggle ---------------------------------------------*/
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

.nav-toggle__bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: 1px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle__bar + .nav-toggle__bar {
  margin-top: 5px;
}

.site-header.is-open .nav-toggle__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.site-header.is-open .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}
.site-header.is-open .nav-toggle__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---- Mobile layout -------------------------------------------------------*/
@media (max-width: 859px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--color-bg-dark);
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
  }

  .site-header.is-open .site-nav {
    max-height: calc(100vh - var(--nav-height));
    overflow-y: auto;
    padding: 1.25rem 1.5rem 2rem;
  }

  .site-nav__links {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__links a {
    display: block;
    font-family: var(--font-heading);
    font-weight: var(--fw-heading-xbold);
    font-size: 2rem;
    letter-spacing: 0.04em;
    color: var(--color-white);
    padding: 0.6rem 0;
    border-bottom: 1px solid var(--color-border-dark-soft);
  }

  .site-nav__cta {
    margin-top: var(--space-lg);
    align-self: flex-start;
    padding: var(--btn-padding-lg);
    font-size: var(--fs-btn);
  }
}