/* ============================================
   导航栏
   ============================================ */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  height: 64px;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
  transition: all var(--transition);
}

.navbar-scrolled {
  background: rgba(255,255,255,0.98);
  box-shadow: var(--shadow-sm);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-logo {
  font-size: 1.6rem;
}

.nav-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  color: var(--text-primary);
  font-weight: 700;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.theme-toggle {
  background: none; border: none; cursor: pointer;
  font-size: 1.2rem; padding: 4px 6px; border-radius: var(--radius-sm);
  transition: all var(--transition-fast); line-height: 1;
}
.theme-toggle:hover { background: var(--bg-light); }

.nav-links a {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-secondary);
  padding: 6px 4px;
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
}

.nav-links a:hover {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

@media (max-width: 768px) {
  .navbar {
    padding: 0 16px;
  }
  .nav-links {
    gap: 16px;
  }
  .nav-links a {
    font-size: 0.85rem;
  }
}

@media (max-width: 600px) {
  .hamburger {
    display: flex;
  }
  .nav-links {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg-white);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 12px;
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s ease;
    z-index: 99;
    box-shadow: var(--shadow-md);
  }
  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .nav-links a {
    font-size: 1rem;
    padding: 8px 0;
  }
  .theme-toggle {
    align-self: flex-start;
  }
}

/* 汉堡按钮 - 默认隐藏 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  background: none;
  border: none;
  z-index: 101;
}
.hamburger span {
  display: block;
  width: 22px;
  height: 2.5px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s ease;
}
.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.hamburger.active span:nth-child(2) {
  opacity: 0;
}
.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

[data-theme="dark"] .nav-links.open {
  background: var(--bg-white);
}