/* ========================================
   Header 导航样式
   专业 B2B 设计 - Glassmorphism + 信任感
   ======================================== */

/* ========================================
   顶部信息栏
   ======================================== */
.top-bar {
  background-color: var(--color-bg-tertiary);
  border-bottom: 1px solid var(--color-border-light);
  padding: var(--space-2) 0;
  font-size: var(--text-sm);
}

.top-bar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.top-left,
.top-right {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.top-bar span {
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.top-bar .fa {
  color: var(--color-primary);
}

.join-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: all var(--transition-base) ease;
  min-height: 32px;
}

.join-link:hover {
  background-color: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
  color: var(--color-text-inverse);
}

.join-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ========================================
   主导航 - Glassmorphism 效果
   ======================================== */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-bottom: 1px solid var(--glass-border);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4) 0;
  transition: all var(--transition-base) ease;
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-6);
}

/* Logo 区域 */
.logo {
  flex-shrink: 0;
}

.logo a {
  display: block;
  line-height: 0;
}

.logo img {
  height: 36px;
  width: auto;
  transition: transform var(--transition-base) ease;
}

.logo a:hover img {
  transform: scale(1.05);
}

.logo a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

/* 导航菜单 */
.nav {
  display: none;
  align-items: center;
  gap: var(--space-2);
  flex: 1;
  justify-content: center;
}

@media (min-width: 1024px) {
  .nav {
    display: flex;
  }
}

.nav-item {
  position: relative;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-primary);
  border-radius: var(--radius-md);
  transition: all var(--transition-base) ease;
  white-space: nowrap;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  background: transparent;
  border: none;
}

.nav-item:hover {
  background-color: rgba(37, 99, 235, 0.08);
  color: var(--color-primary);
}

.nav-item:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* 当前页面激活状态 */
.nav-item.active,
.nav-item[aria-current="page"] {
  background-color: transparent;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-primary);
  border-radius: 0;
}

.nav-item.active:hover {
  background-color: rgba(37, 99, 235, 0.05);
}

/* ========================================
   移动端菜单按钮
   ======================================== */
.mobile-toggle {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  width: 44px;
  height: 44px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  z-index: var(--z-fixed);
  border-radius: var(--radius-md);
  transition: background-color var(--transition-base) ease;
}

.mobile-toggle:hover {
  background-color: rgba(37, 99, 235, 0.1);
}

.mobile-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

@media (min-width: 1024px) {
  .mobile-toggle {
    display: none;
  }
}

.mobile-toggle span {
  width: 100%;
  height: 3px;
  background-color: var(--color-text-primary);
  border-radius: var(--radius-full);
  transition: all var(--transition-base) ease;
}

.mobile-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
}

.mobile-toggle.active span:nth-child(2) {
  opacity: 0;
}

.mobile-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* ========================================
   移动端菜单
   ======================================== */
.mobile-menu {
  position: fixed;
  top: 0;
  right: -100%;
  width: 280px;
  max-width: 85vw;
  height: 100vh;
  background: var(--color-bg-primary);
  box-shadow: var(--shadow-xl);
  z-index: var(--z-modal);
  transition: right var(--transition-slow) ease;
  overflow-y: auto;
}

.mobile-menu.active {
  right: 0;
}

.mobile-menu-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-4) var(--space-6);
  border-bottom: 1px solid var(--color-border-light);
  background-color: var(--color-bg-secondary);
}

.mobile-menu-header span {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-primary);
}

.mobile-close {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-base) ease;
  color: var(--color-text-primary);
  font-size: var(--text-2xl);
}

.mobile-close:hover {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--color-error);
}

.mobile-close:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* 移动端导航链接 */
.mobile-nav {
  display: flex;
  flex-direction: column;
  padding: var(--space-4);
  gap: var(--space-2);
}

.mobile-nav a {
  display: flex;
  align-items: center;
  padding: var(--space-4) var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text-primary);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base) ease;
  min-height: 48px;
}

.mobile-nav a:hover {
  background-color: rgba(37, 99, 235, 0.1);
  color: var(--color-primary);
  transform: translateX(4px);
}

.mobile-nav a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.mobile-nav a.active {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* ========================================
   遮罩层
   ======================================== */
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: var(--z-modal-backdrop);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base) ease;
}

.overlay.active {
  opacity: 1;
  visibility: visible;
}

/* ========================================
   响应式优化
   ======================================== */
@media (max-width: 640px) {
  .top-bar {
    font-size: var(--text-xs);
  }
  
  .top-bar .container {
    justify-content: center;
  }
  
  .top-left span:first-child {
    display: none;
  }
  
  .logo img {
    height: 32px;
  }
  
  .header {
    padding: var(--space-3) 0;
  }
}

@media (min-width: 641px) and (max-width: 1023px) {
  .logo img {
    height: 36px;
  }
}

/* ========================================
   滚动时的导航效果
   ======================================== */
.header.scrolled {
  box-shadow: var(--shadow-md);
  padding: var(--space-3) 0;
}

.header.scrolled .logo img {
  height: 32px;
}

/* ========================================
   无障碍增强
   ======================================== */
@media (prefers-reduced-motion: reduce) {
  .mobile-menu {
    transition: none;
  }
  
  .overlay {
    transition: none;
  }
  
  .logo a:hover img {
    transform: none;
  }
}

/* ========================================
   打印样式
   ======================================== */
@media print {
  .top-bar,
  .mobile-toggle,
  .mobile-menu,
  .overlay {
    display: none !important;
  }
  
  .header {
    position: static;
    box-shadow: none;
    border-bottom: 2px solid #000;
  }
  
  .nav {
    display: none !important;
  }
}