/* ==================== 统一过渡和动画系统 ==================== */
/* 替代所有重复的transition定义，提供标准化的动画效果 */

/* ========================================
   基础过渡类
   ======================================== */

/* 快速过渡 */
.transition-fast {
  transition: all var(--duration-fast) var(--ease-in-out);
}

.transition-fast-colors {
  transition: color var(--duration-fast) var(--ease-in-out), 
              background-color var(--duration-fast) var(--ease-in-out);
}

.transition-fast-transform {
  transition: transform var(--duration-fast) var(--ease-in-out);
}

.transition-fast-opacity {
  transition: opacity var(--duration-fast) var(--ease-in-out);
}

/* 标准过渡 */
.transition-base {
  transition: all var(--duration-normal) var(--ease-in-out);
}

.transition-base-colors {
  transition: color var(--duration-normal) var(--ease-in-out), 
              background-color var(--duration-normal) var(--ease-in-out);
}

.transition-base-transform {
  transition: transform var(--duration-normal) var(--ease-in-out);
}

.transition-base-opacity {
  transition: opacity var(--duration-normal) var(--ease-in-out);
}

/* 慢速过渡 */
.transition-slow {
  transition: all var(--duration-slow) var(--ease-in-out);
}

.transition-slow-colors {
  transition: color var(--duration-slow) var(--ease-in-out), 
              background-color var(--duration-slow) var(--ease-in-out);
}

.transition-slow-transform {
  transition: transform var(--duration-slow) var(--ease-in-out);
}

.transition-slow-opacity {
  transition: opacity var(--duration-slow) var(--ease-in-out);
}

/* ========================================
   悬停效果类
   ======================================== */

/* 悬停提升效果 */
.hover-lift {
  transition: transform var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out);
}

.hover-lift:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

/* 悬停缩放效果 */
.hover-scale-sm {
  transition: transform var(--duration-normal) var(--ease-out);
}

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

.hover-scale-md {
  transition: transform var(--duration-normal) var(--ease-out);
}

.hover-scale-md:hover {
  transform: scale(1.05);
}

.hover-scale-lg {
  transition: transform var(--duration-normal) var(--ease-out);
}

.hover-scale-lg:hover {
  transform: scale(1.08);
}

/* 悬停透明度效果 */
.hover-opacity {
  transition: opacity var(--duration-normal) var(--ease-in-out);
}

.hover-opacity:hover {
  opacity: var(--opacity-hover);
}

/* 悬停颜色效果 */
.hover-color {
  transition: color var(--duration-normal) var(--ease-in-out),
              background-color var(--duration-normal) var(--ease-in-out);
}

/* ========================================
   按钮效果类
   ======================================== */

/* 主要按钮 */
.btn-primary {
  transition: all var(--duration-normal) var(--ease-out);
  cursor: pointer;
}

.btn-primary:hover {
  background: var(--color-primary);
  color: var(--text-white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

/* 次要按钮 */
.btn-secondary {
  transition: all var(--duration-normal) var(--ease-out);
  cursor: pointer;
}

.btn-secondary:hover {
  opacity: var(--opacity-hover);
  transform: translateY(-1px);
}

/* ========================================
   卡片效果类
   ======================================== */

/* 卡片悬停效果 */
.card-hover {
  transition: transform var(--duration-normal) var(--ease-out),
              box-shadow var(--duration-normal) var(--ease-out);
}

.card-hover:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

/* 卡片图片悬停效果 */
.card-img-hover {
  transition: transform var(--duration-slow) var(--ease-out);
}

.card-hover:hover .card-img-hover {
  transform: scale(1.05);
}

/* ========================================
   导航效果类
   ======================================== */

/* 导航链接效果 */
.nav-link {
  position: relative;
  transition: color var(--duration-normal) var(--ease-in-out);
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0;
  height: 2px;
  background: currentColor;
  transition: width var(--duration-normal) var(--ease-in-out);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

/* ========================================
   滚动动画类
   ======================================== */

/* 淡入动画 */
.scroll-fade {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--duration-slower) var(--ease-out),
              transform var(--duration-slower) var(--ease-out);
}

.scroll-fade.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 缩放淡入动画 */
.scroll-scale {
  opacity: 0;
  transform: scale(0.95);
  transition: opacity var(--duration-slower) var(--ease-out),
              transform var(--duration-slower) var(--ease-out);
}

.scroll-scale.visible {
  opacity: 1;
  transform: scale(1);
}

/* 左滑入动画 */
.scroll-slide-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity var(--duration-slower) var(--ease-out),
              transform var(--duration-slower) var(--ease-out);
}

.scroll-slide-left.visible {
  opacity: 1;
  transform: translateX(0);
}

/* 右滑入动画 */
.scroll-slide-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity var(--duration-slower) var(--ease-out),
              transform var(--duration-slower) var(--ease-out);
}

.scroll-slide-right.visible {
  opacity: 1;
  transform: translateX(0);
}

/* ========================================
   移动端菜单动画
   ======================================== */

/* 移动端菜单滑入 */
.mobile-menu {
  transform: translateX(-100%);
  opacity: 0;
  transition: transform var(--duration-slow) var(--ease-out),
              opacity var(--duration-slow) var(--ease-out);
}

.mobile-menu.open {
  transform: translateX(0);
  opacity: 1;
}

/* 汉堡菜单按钮动画 */
.hamburger-btn {
  transition: all var(--duration-fast) var(--ease-in-out);
}

.hamburger-btn span {
  transition: all var(--duration-fast) var(--ease-in-out);
}

.hamburger-btn.active span:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6px);
}

.hamburger-btn.active span:nth-child(2) {
  opacity: 0;
}

.hamburger-btn.active span:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

/* ========================================
   图片和媒体效果
   ======================================== */

/* 图片模糊到清晰效果 */
.img-clarify {
  filter: blur(14px);
  transform: scale(1.04);
  transition: filter var(--duration-slower) var(--ease-out),
              transform var(--duration-slower) var(--ease-out);
}

.img-clarify.loaded {
  filter: blur(0);
  transform: scale(1);
}

/* 图片缩放淡入效果 */
.img-fade-in {
  opacity: 0;
  transform: scale(1.05);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.img-fade-in.visible {
  opacity: 1;
  transform: scale(1);
}

/* ========================================
   响应式工具类
   ======================================== */

/* 响应式显示/隐藏 */
@media screen and (max-width: 767px) {
  .mobile-hidden {
    display: none !important;
  }
  
  .mobile-visible {
    display: block !important;
  }
}

@media screen and (min-width: 768px) {
  .desktop-hidden {
    display: none !important;
  }
  
  .desktop-visible {
    display: block !important;
  }
}

/* ========================================
   可访问性增强
   ======================================== */

/* 减少动画模式 */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .scroll-fade,
  .scroll-scale,
  .scroll-slide-left,
  .scroll-slide-right {
    opacity: 1 !important;
    transform: none !important;
  }
}

/* 高对比度模式 */
@media (prefers-contrast: high) {
  .btn-primary:hover {
    border: 2px solid currentColor;
  }
  
  .card-hover:hover {
    border: 1px solid currentColor;
  }
}

/* 焦点样式 */
.focus-visible:focus-visible {
  outline: 2px solid #0066cc;
  outline-offset: 2px;
}

/* 触摸优化 */
.touch-optimized {
  min-width: 44px;
  min-height: 44px;
  touch-action: manipulation;
}

/* ========================================
   使用示例和文档
   ======================================== */

/*
使用示例：

<button class="btn-primary transition-base hover-lift">主要按钮</button>

<div class="card card-hover">
  <img class="card-img-hover" src="image.jpg" alt="卡片图片">
</div>

<nav class="nav-link transition-base-color">导航链接</nav>

<div class="scroll-fade">滚动时淡入的内容</div>

<div class="mobile-menu mobile-menu-slide">移动端菜单</div>

<button class="hamburger-btn hamburger-btn-animate">汉堡菜单</button>

<img class="img-clarify" src="image.jpg" alt="模糊到清晰的图片">

*/