/* =============================================
   ХЕДЕР — навигация
   Тёмный поверх hero → белый при скролле
   ============================================= */

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-header);
  background: rgba(28, 58, 43, 0.4);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  transition: all var(--transition-base);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

/* При скролле — белый/светлый */
.header.scrolled {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.header__logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  flex-shrink: 0;
}

.header__logo-img {
  width: 48px;
  height: 48px;
  object-fit: contain;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.3);
  transition: border-color var(--transition-base);
}

.header.scrolled .header__logo-img {
  border-color: rgba(0, 0, 0, 0.1);
}

.header__logo-text {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.05rem;
  color: #FFFFFF;
  line-height: 1.2;
  transition: color var(--transition-base);
}

.header__logo-text span {
  display: block;
  font-size: 0.7rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.6);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: color var(--transition-base);
}

.header.scrolled .header__logo-text {
  color: var(--text-primary);
}

.header.scrolled .header__logo-text span {
  color: var(--text-muted);
}

/* Навигация */
.nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav__link {
  position: relative;
  padding: 0.5rem 0.85rem;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav__link:hover {
  color: #FFFFFF;
  background: rgba(255, 255, 255, 0.12);
}

.nav__link.active {
  color: #FFFFFF;
  background: rgba(255, 255, 255, 0.15);
}

/* Scrolled state — тёмный текст */
.header.scrolled .nav__link {
  color: var(--text-secondary);
}

.header.scrolled .nav__link:hover {
  color: var(--color-primary);
  background: rgba(39, 135, 245, 0.08);
}

.header.scrolled .nav__link.active {
  color: var(--color-primary);
  background: rgba(39, 135, 245, 0.1);
}

.nav__link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 3px;
  background: currentColor;
  border-radius: 2px;
}

/* Бургер */
.burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  padding: 4px 0;
  cursor: pointer;
  z-index: calc(var(--z-header) + 1);
}

.burger__line {
  width: 100%;
  height: 3px;
  background: #FFFFFF;
  border-radius: 2px;
  transition: all var(--transition-base);
}

.header.scrolled .burger__line {
  background: var(--text-primary);
}

.burger.active .burger__line:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.burger.active .burger__line:nth-child(2) {
  opacity: 0;
}

.burger.active .burger__line:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Мобильная навигация */
@media (max-width: 768px) {
  .burger {
    display: flex;
  }

  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 100px 2rem 2rem;
    background: rgba(28, 58, 43, 0.98);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow-lg);
    transition: right var(--transition-base);
  }

  .nav.open {
    right: 0;
  }

  .nav__link {
    width: 100%;
    padding: 0.875rem 1rem;
    font-size: 1.05rem;
    color: rgba(255, 255, 255, 0.7);
  }

  .nav__link:hover,
  .nav__link.active {
    color: var(--text-light);
    background: rgba(255, 255, 255, 0.1);
  }

  .nav-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: calc(var(--z-header) - 1);
  }

  .nav-overlay.visible {
    display: block;
  }
}