/* =====================================================
   Helix Therapeutics — Header & Navigation
   ===================================================== */

.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: var(--color-white);
  height: var(--header-h);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.site-header.scrolled {
  border-bottom-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  gap: 1.5rem;
}

/* ---- Logo ---- */
.logo-link { display: flex; align-items: center; flex-shrink: 0; }
.logo { height: 52px; width: auto; }

/* ---- Main Nav ---- */
.main-nav { display: flex; align-items: center; }

.nav-list {
  display: flex;
  align-items: center;
  gap: .25rem;
}

.nav-item { position: relative; }

.nav-link {
  display: flex;
  align-items: center;
  gap: .3rem;
  padding: .5rem .85rem;
  font-size: .95rem;
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
  white-space: nowrap;
}
.nav-link i { font-size: .7rem; transition: transform var(--transition); }
.nav-item:hover .nav-link { color: var(--color-primary); }
.nav-item:hover .nav-link i { transform: rotate(180deg); }
.nav-link.active { color: var(--color-primary); }

/* ---- Dropdown ---- */
.dropdown {
  position: absolute;
  top: calc(100% + .5rem);
  left: 0;
  min-width: 220px;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: opacity var(--transition), visibility var(--transition), transform var(--transition);
  z-index: 100;
  padding: .5rem 0;
}

.nav-item:hover .dropdown,
.nav-item:focus-within .dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown li a {
  display: block;
  padding: .6rem 1.25rem;
  font-size: .9rem;
  color: var(--color-gray-800);
  transition: background var(--transition), color var(--transition);
}
.dropdown li a:hover {
  background: var(--color-gray-100);
  color: var(--color-primary);
}

/* ---- Header Actions ---- */
.header-actions {
  display: flex;
  align-items: center;
  gap: .75rem;
  flex-shrink: 0;
}

.cart-icon {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  color: var(--color-text);
  font-size: 1.05rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
}
.cart-icon:hover { color: var(--color-primary); background: var(--color-gray-100); }

.cart-badge {
  position: absolute;
  top: 2px; right: 2px;
  min-width: 16px; height: 16px;
  background: var(--color-accent);
  color: var(--color-white);
  font-size: .65rem;
  font-weight: 700;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 3px;
  line-height: 1;
}
.cart-badge[data-count="0"] { display: none; }

.header-login-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  color: var(--color-text);
  font-size: 1.05rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
}
.header-login-btn:hover { color: var(--color-primary); background: var(--color-gray-100); }

/* ---- Hamburger ---- */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 38px; height: 38px;
  padding: 8px;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}
.hamburger:hover { background: var(--color-gray-100); }
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
  transform-origin: center;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---- Mobile Menu ---- */
.mobile-menu {
  position: fixed;
  top: var(--header-h);
  left: 0; right: 0; bottom: 0;
  background: var(--color-white);
  overflow-y: auto;
  transform: translateX(100%);
  transition: transform 300ms ease;
  z-index: 999;
  padding: 1.5rem;
}
.mobile-menu.open { transform: translateX(0); }

.mobile-nav-list { padding: 0; }

.mobile-nav-item { border-bottom: 1px solid var(--color-border); }
.mobile-nav-item:last-child { border-bottom: none; }

.mobile-nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
  font-weight: 600;
  color: var(--color-text);
  font-size: 1rem;
}
.mobile-nav-link i { transition: transform var(--transition); color: var(--color-gray-400); }
.mobile-nav-link.open i { transform: rotate(180deg); }

.mobile-dropdown {
  display: none;
  padding-bottom: .75rem;
}
.mobile-dropdown.open { display: block; }
.mobile-dropdown li a {
  display: block;
  padding: .5rem 1rem;
  color: var(--color-gray-800);
  font-size: .95rem;
  border-radius: var(--radius-sm);
}
.mobile-dropdown li a:hover { background: var(--color-gray-100); color: var(--color-primary); }

.mobile-menu .btn-primary {
  display: block;
  text-align: center;
  margin-top: 1.5rem;
}

/* ---- Body offset ---- */
body { padding-top: var(--header-h); }

/* ---- Responsive ---- */
@media (max-width: 960px) {
  .main-nav { display: none; }
  .hamburger { display: flex; }
  .header-login-btn { display: none; }
}
@media (max-width: 480px) {
  .logo { height: 44px; }
}