/* ================================================================
   导航系统 - Navigation System
   包含：导航栏、面包屑、菜单、下拉列表
   ================================================================ */

/* ============= 主导航栏 ============= */
.navbar {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(8px);
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 1.5rem;
  height: 72px;
}

/* 品牌标识 */
.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-primary);
  transition: var(--transition-base);
}

.nav-brand:hover {
  transform: scale(1.02);
}

.nav-brand a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  object-fit: cover;
}

/* 导航菜单 */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  transition: var(--transition-base);
}

.nav-link:hover {
  color: var(--accent-primary);
  background: var(--bg-tertiary);
}

/* 主题切换按钮 */
.theme-btn {
  background: none;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  transition: var(--transition-base);
  color: var(--text-secondary);
}

.theme-btn:hover {
  background: var(--bg-tertiary);
  transform: scale(1.1);
}

/* 登录按钮 */
.login-btn {
  background: var(--gradient-primary);
  color: white;
  border: none;
  padding: 0.6rem 1.5rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-weight: 500;
  transition: var(--transition-base);
}

.login-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

/* 用户信息 */
.user-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  position: relative;
}

.username {
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--text-primary);
}

/* 下拉菜单 */
.dropdown {
  position: relative;
}

.dropdown-btn {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--text-secondary);
  transition: var(--transition-base);
  border-radius: var(--radius-sm);
}

.dropdown-btn:hover {
  background: var(--bg-tertiary);
}

.dropdown-content {
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  min-width: 160px;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: var(--transition-base);
}

.dropdown:hover .dropdown-content {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-content a {
  display: block;
  padding: 0.75rem 1.25rem;
  color: var(--text-primary);
  font-size: 0.9rem;
  transition: var(--transition-base);
}

.dropdown-content a:hover,
.dropdown-content a.active {
  background: var(--bg-tertiary);
  color: var(--accent-primary);
}

/* GitHub链接 */
.github-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  margin-right: 1rem;
  color: var(--text-primary);
  text-decoration: none;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: var(--transition-base);
  background: var(--bg-primary);
}

.github-link:hover {
  background: var(--bg-tertiary);
  border-color: var(--accent-primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.github-link svg {
  flex-shrink: 0;
}

.github-link span {
  font-size: 0.9rem;
  white-space: nowrap;
  font-weight: 500;
}

/* ============= 响应式设计 ============= */

@media (max-width: 768px) {
  .action-buttons {
    flex-direction: column;
  }
  
  .action-buttons .action-btn {
    min-width: auto;
  }
  
  .charts-container {
    grid-template-columns: 1fr;
  }
  
  .history-stats {
    grid-template-columns: 1fr;
  }
  
  .favorites-controls {
    flex-direction: column;
  }
  
  .history-controls {
    flex-direction: column;
  }
  
  .time-range-selector {
    width: 100%;
    flex-wrap: wrap;
  }
  
  .error-content {
    flex-direction: column;
    text-align: center;
  }
  
  .github-link span {
    display: none;
  }
}

@media (max-width: 480px) {
  .favorites-list {
    grid-template-columns: 1fr;
  }
  
  .time-btn {
    flex: 1;
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
  }
}