/**
 * 大成焊接 - 交互增强样式 (Interaction Enhancements)
 * 版本: 1.0.0
 * 更新: 2026-05-07
 * 
 * 包含: 返回顶部、触摸反馈、滚动动画等
 */

/* ============================================
   1. 返回顶部按钮 (Back to Top)
   ============================================ */

.back-to-top {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary);
  color: #ffffff;
  border: none;
  border-radius: 50%;
  font-size: var(--text-xl);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-base);
  z-index: var(--z-fixed);
  box-shadow: var(--shadow-lg), var(--shadow-primary);
  
  /* 触摸友好 */
  min-width: 48px;
  min-height: 48px;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl), var(--shadow-primary);
}

.back-to-top:active {
  transform: translateY(0) scale(0.95);
}

/* 移动端位置调整 */
@media (max-width: 768px) {
  .back-to-top {
    bottom: var(--space-4);
    right: var(--space-4);
    width: 44px;
    height: 44px;
  }
}

/* iPhone 底部安全区 */
@supports (padding-bottom: env(safe-area-inset-bottom)) {
  .back-to-top {
    bottom: calc(var(--space-4) + env(safe-area-inset-bottom));
  }
}

/* ============================================
   2. 触摸反馈 (Touch Feedback)
   ============================================ */

/* 触摸时按下效果 */
.touch-active {
  opacity: 0.8;
  transform: scale(0.98);
}

.touch-active:active {
  transform: scale(0.95);
}

/* 按钮点击波纹效果 */
.btn {
  position: relative;
  overflow: hidden;
}

.btn .ripple {
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  transform: scale(0);
  animation: ripple 0.6s linear;
  pointer-events: none;
}

@keyframes ripple {
  to {
    transform: scale(4);
    opacity: 0;
  }
}

/* 卡片触摸效果 */
.card-interactive,
.article-card {
  will-change: transform;
  -webkit-tap-highlight-color: transparent;
}

.card-interactive:active,
.article-card:active {
  transform: translateY(-2px) scale(0.99);
}

/* ============================================
   3. 滚动动画 (Scroll Animations)
   ============================================ */

/* 默认隐藏状态 */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.animate-in {
  opacity: 1;
  transform: translateY(0);
}

/* 淡入效果 */
.fade-in {
  opacity: 0;
  transition: opacity 0.6s ease;
}

.fade-in.animate-in {
  opacity: 1;
}

/* 滑入效果 */
.slide-in-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.slide-in-left.animate-in {
  opacity: 1;
  transform: translateX(0);
}

.slide-in-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.slide-in-right.animate-in {
  opacity: 1;
  transform: translateX(0);
}

/* 缩放效果 */
.scale-in {
  opacity: 0;
  transform: scale(0.9);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.scale-in.animate-in {
  opacity: 1;
  transform: scale(1);
}

/* 延迟动画 */
.delay-100 { transition-delay: 100ms; }
.delay-200 { transition-delay: 200ms; }
.delay-300 { transition-delay: 300ms; }
.delay-400 { transition-delay: 400ms; }
.delay-500 { transition-delay: 500ms; }

/* ============================================
   4. 下拉刷新样式 (Pull to Refresh)
   ============================================ */

[data-pull-refresh] {
  position: relative;
}

.pull-indicator {
  position: absolute;
  top: -40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  color: var(--text-muted);
  opacity: 0;
  transition: opacity 0.3s ease;
}

[data-pull-refresh].pulling .pull-indicator,
[data-pull-refresh].refreshing .pull-indicator {
  opacity: 1;
}

.pull-indicator .spinner {
  width: 20px;
  height: 20px;
}

/* ============================================
   5. 长按效果 (Long Press)
   ============================================ */

.long-pressed {
  animation: long-press-pulse 0.3s ease;
}

@keyframes long-press-pulse {
  0% { transform: scale(1); }
  50% { transform: scale(0.95); }
  100% { transform: scale(1); }
}

/* ============================================
   6. 加载骨架屏增强
   ============================================ */

.skeleton-wrapper {
  padding: var(--space-4);
}

.skeleton-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

/* ============================================
   7. 搜索结果样式
   ============================================ */

.search-results {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  margin-top: var(--space-2);
  max-height: 400px;
  overflow-y: auto;
  z-index: var(--z-dropdown);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-lg);
}

.search-results.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.search-result-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.search-result-item:hover {
  background: var(--bg-secondary);
}

.search-result-item .title {
  font-weight: var(--font-medium);
  color: var(--text-primary);
}

.search-result-item .desc {
  font-size: var(--text-xs);
  color: var(--text-muted);
}

/* ============================================
   8. 移动端导航增强
   ============================================ */

/* 移动端菜单遮罩 */
.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: calc(var(--z-sticky) - 1);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
}

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

/* 移动端菜单动画 */
@media (max-width: 768px) {
  .navbar-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: 280px;
    max-width: 80vw;
    background: var(--bg-primary);
    border-left: 1px solid var(--border-color);
    flex-direction: column;
    padding: var(--space-6);
    gap: var(--space-2);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    z-index: var(--z-fixed);
    overflow-y: auto;
  }
  
  .navbar-nav.open {
    transform: translateX(0);
  }
}

/* ============================================
   9. 响应式表格
   ============================================ */

.table-responsive {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.table-responsive table {
  min-width: 600px;
}

/* ============================================
   10. 图片懒加载占位符
   ============================================ */

img[data-src] {
  opacity: 0;
  transition: opacity 0.3s ease;
}

img[data-src].loaded,
img:not([data-src]) {
  opacity: 1;
}

/* 占位符背景 */
.img-placeholder {
  background: linear-gradient(
    90deg,
    var(--bg-secondary) 0%,
    var(--bg-tertiary) 50%,
    var(--bg-secondary) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ============================================
   11. 响应式字体
   ============================================ */

.text-responsive {
  font-size: clamp(0.875rem, 2.5vw, 1rem);
}

.heading-responsive {
  font-size: clamp(1.5rem, 5vw, 2.5rem);
  line-height: 1.2;
}

/* ============================================
   12. 触摸滑动列表
   ============================================ */

.swipe-list {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scroll-snap-type: x mandatory;
  display: flex;
  gap: var(--space-4);
  padding-bottom: var(--space-4);
}

.swipe-item {
  flex: 0 0 auto;
  scroll-snap-align: start;
  width: calc(50% - var(--space-4));
  min-width: 280px;
}

@media (max-width: 768px) {
  .swipe-item {
    width: calc(100% - var(--space-4));
  }
}

/* ============================================
   13. 性能优化
   ============================================ */

/* 减少动画（尊重用户设置） */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  .animate-on-scroll {
    opacity: 1;
    transform: none;
  }
}

/* ============================================
   14. 打印样式
   ============================================ */

@media print {
  .back-to-top,
  .navbar-toggle,
  .no-print {
    display: none !important;
  }
  
  .back-to-top {
    display: none;
  }
  
  body {
    background: white;
    color: black;
  }
}