/* =====================================================================
   HEADER / NAWIGACJA
   Stan domyślny: przezroczysty nad ciemnym hero (logo + tekst jasne).
   Po scrollu (.scrolled): białe tło, cień, logo + tekst granatowe.
   ===================================================================== */

:root { --header-height: 72px; }

.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: transparent;
  border-bottom: var(--stroke-border) solid transparent;
  transition: background-color .3s ease, box-shadow .3s ease, border-color .3s ease;
}
.site-header.scrolled {
  background: var(--bg-default);
  border-bottom-color: var(--border-default);
  box-shadow: var(--shadow-200);
  backdrop-filter: saturate(1.4) blur(8px);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-800);
  width: 100%;
}

/* ---- LOGO (zamiana jasne ↔ granat) ---- */
.site-header__logo { display: inline-flex; align-items: center; }
.site-header__logo img { height: 30px; width: auto; }
.site-header__logo .logo-brand { display: none; }
.site-header.scrolled .logo-light { display: none; }
.site-header.scrolled .logo-brand { display: block; }

/* ---- NAWIGACJA DESKTOP ---- */
.site-nav { display: flex; align-items: center; gap: var(--space-800); }
.site-nav a {
  position: relative;
  font-size: var(--scale-02);
  font-weight: var(--weight-medium);
  color: var(--text-on-brand);
  padding-block: var(--space-200);
  transition: color .3s ease;
}
.site-header.scrolled .site-nav a { color: var(--text-default); }
.site-nav a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 2px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s ease;
}
.site-nav a:hover { text-decoration: none; }
.site-nav a:hover::after { transform: scaleX(1); }

/* ---- AKCJE ---- */
.site-header__actions { display: flex; align-items: center; gap: var(--space-300); }
.site-header__login { color: var(--text-on-brand); }
.site-header__login:hover { background: var(--white-200); color: var(--text-on-brand); }
.site-header.scrolled .site-header__login { color: var(--text-default); }
.site-header.scrolled .site-header__login:hover { background: var(--bg-secondary); }

/* nad ciemnym hero przycisk primary jest jasny (wysoki kontrast);
   po scrollu wraca do granatu na białym tle */
.site-header:not(.scrolled) .site-header__actions .btn-primary {
  background: var(--white-1000);
  color: var(--text-brand);
  border-color: var(--white-1000);
}
.site-header:not(.scrolled) .site-header__actions .btn-primary:hover {
  background: var(--brand-100);
  border-color: var(--brand-100);
}

/* ---- HAMBURGER ---- */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px; height: 44px;
  padding: 10px;
  background: transparent;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-200);
}
.hamburger span {
  display: block;
  width: 24px; height: 2px;
  background: var(--text-on-brand);
  border-radius: var(--radius-full);
  transition: transform .3s ease, opacity .2s ease, background-color .3s ease;
}
.site-header.scrolled .hamburger span { background: var(--text-default); }
.hamburger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.hamburger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---- MENU MOBILNE ---- */
.mobile-nav {
  position: fixed;
  inset: var(--header-height) 0 auto 0;
  z-index: 95;
  display: flex;
  flex-direction: column;
  gap: var(--space-200);
  padding: var(--space-600) clamp(var(--space-400), 5vw, var(--space-800)) var(--space-800);
  background: var(--bg-default);
  border-bottom: var(--stroke-border) solid var(--border-default);
  box-shadow: var(--shadow-400);
  transform: translateY(-110%);
  transition: transform .3s ease;
}
.mobile-nav.open { transform: translateY(0); }
.mobile-nav a:not(.btn) {
  font-size: var(--scale-04);
  font-weight: var(--weight-medium);
  color: var(--text-default);
  padding: var(--space-400) var(--space-200);
  border-bottom: var(--stroke-border) solid var(--border-default);
}
.mobile-nav a:not(.btn):hover { color: var(--text-brand); text-decoration: none; }
.mobile-nav .btn { margin-top: var(--space-400); width: 100%; }

.mobile-nav__scrim {
  position: fixed;
  inset: 0;
  z-index: 90;
  background: var(--black-400);
  opacity: 0;
  visibility: hidden;
  transition: opacity .3s ease, visibility .3s ease;
}
.mobile-nav__scrim.open { opacity: 1; visibility: visible; }

/* ---- RESPONSYWNOŚĆ ---- */
@media (max-width: 768px) {
  .site-nav { display: none; }
  .site-header__actions .btn { display: none; }
  .hamburger { display: flex; }
}
@media (min-width: 769px) {
  .mobile-nav, .mobile-nav__scrim { display: none; }
}