/**
 * Single responsibility: Sticky navigation header styles including logo,
 * nav links, header actions, mobile hamburger menu, and frosted-glass scroll state.
 */

/* ─── Header Base ────────────────────────────────────────────────────────────── */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-nav);
  padding: var(--space-4) 0;
  transition:
    padding var(--transition-base),
    background var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base);
  border-bottom: 1px solid var(--color-border);
}

.site-header.is-scrolled {
  background: rgba(4, 11, 20, 0.88);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-3) 0;
  box-shadow: 0 4px 28px rgba(0, 0, 0, 0.35);
}

/* ─── Header Inner Layout ────────────────────────────────────────────────────── */
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-8);
}

/* ─── Logo ───────────────────────────────────────────────────────────────────── */
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  flex-shrink: 0;
  transition: opacity var(--transition-fast);
}

.site-logo:hover {
  opacity: 0.85;
}

.site-logo_img {
  height: 65px; /* Modern, clean height */
  width: auto;
  display: block;
}

/* ─── Desktop Navigation ─────────────────────────────────────────────────────── */
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--radius-pill);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.nav-link:hover,
.nav-link.is-active {
  color: var(--color-text-primary);
  background: rgba(255, 255, 255, 0.07);
}

/* ─── Header Actions ─────────────────────────────────────────────────────────── */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  flex-shrink: 0;
}

.header-phone {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.header-phone:hover {
  color: var(--color-text-primary);
}
.header-phone svg {
  width: 14px;
  height: 14px;
}

/* ─── Hamburger Button ───────────────────────────────────────────────────────── */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  cursor: pointer;
  background: none;
  border: none;
  padding: var(--space-2);
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.hamburger:hover {
  background: rgba(255, 255, 255, 0.07);
}

.hamburger_line {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: 2px;
  transition: all var(--transition-base);
  transform-origin: center;
}

.hamburger.is-open .hamburger_line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.hamburger.is-open .hamburger_line:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}
.hamburger.is-open .hamburger_line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ─── Mobile Menu Dropdown ───────────────────────────────────────────────────── */
.mobile-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: rgba(4, 11, 20, 0.97);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: var(--space-6);
  animation: slideDown 0.25s ease;
}

.mobile-menu.is-open {
  display: block;
}

.mobile-nav-link {
  display: block;
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-text-secondary);
  text-decoration: none;
  transition:
    color var(--transition-fast),
    background var(--transition-fast);
}

.mobile-nav-link:hover {
  color: var(--color-text-primary);
  background: rgba(255, 255, 255, 0.04);
}

.mobile-menu_actions {
  padding: var(--space-4) var(--space-6) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-3);
}

/* ─── Responsive ─────────────────────────────────────────────────────────────── */
@media (max-width: 960px) {
  .site-nav,
  .header-phone {
    display: none;
  }
  .hamburger {
    display: flex;
  }
}

@media (max-width: 480px) {
  .header-actions .btn-primary {
    display: none;
  }
}