.app-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
}

.app-header.is-scrolled {
  background: rgba(255, 255, 255, 0.97);
  box-shadow: var(--shadow-sm);
}

.app-header.is-menu-open {
  background: rgba(255, 255, 255, 0.98);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.logo-icon {
  width: 88px;
  height: 60px;
}

.logo-icon img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.logo-text {
  letter-spacing: -0.3px;
}

/* 导航菜单 */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-item {
  position: relative;
  padding: 8px 14px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.2px;
  transition:
    color 0.25s ease,
    transform 0.25s ease;
}

/* 底部指示线 */
.nav-item::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transform: translateX(-50%);
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-item:hover {
  color: var(--color-primary);
  transform: translateY(-2px);
}

.nav-item:hover::after {
  width: 60%;
}

.nav-item.active {
  color: var(--color-primary);
}

.nav-item.active::after {
  width: 100%;
}

/* 右侧操作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.btn-login {
  padding: 8px 20px;
  font-size: 14px;
}

.btn-primary {
  padding: 8px 20px;
  font-size: 14px;
}

/* 移动端菜单按钮 */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  gap: 5px;
  cursor: pointer;
}

.mobile-toggle span {
  width: 22px;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

.mobile-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-toggle.active span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0.4);
}

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

/* 响应式 */
@media (max-width: 1024px) {
  .nav-menu {
    gap: 0;
  }

  .nav-item {
    padding: 8px 12px;
    font-size: 14px;
  }
}

@media (max-width: 768px) {
  .header-inner {
    height: 60px;
  }

  .nav-menu {
    display: flex;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 16px;
    box-shadow: var(--shadow-lg);
    gap: 4px;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    max-height: 0;
    overflow: hidden;
    transform: translateY(-12px);
    transition:
      opacity 220ms ease,
      visibility 220ms ease,
      max-height 260ms ease,
      transform 260ms cubic-bezier(0.2, 0.8, 0.2, 1);
  }

  .nav-menu.is-open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    max-height: 420px;
    transform: translateY(0);
  }

  .nav-item {
    width: 100%;
    padding: 12px 16px;
    text-align: left;
    border-radius: var(--radius-md);
  }

  .nav-item:hover,
  .nav-item.active {
    background: var(--color-primary-bg);
    transform: translateX(4px);
  }

  .mobile-toggle {
    display: flex;
  }

  .btn-login {
    display: none;
  }
}