/* ======================
   无障碍访问优化
====================== */

/* ======================
   键盘导航支持
====================== */

:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

button:focus:not(:focus-visible),
a:focus:not(:focus-visible) {
  outline: none;
}

/* ======================
   屏幕阅读器支持
====================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ======================
   颜色对比度优化
====================== */

/* ======================
   交互状态优化
====================== */

button:active,
a:active {
  transform: scale(0.97);
  transition: transform 0.1s ease;
}

button:focus,
a:focus {
  transform: scale(1.02);
  transition: transform 0.2s ease;
}

/* ======================
   跳过导航链接
====================== */

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--link);
  color: white;
  padding: 8px 16px;
  text-decoration: none;
  z-index: 100;
  transition: top 0.3s;
}

.skip-link:focus {
  top: 0;
  outline: 2px solid var(--link);
}

/* ======================
   加载状态优化
====================== */

.loading-with-retry {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 2rem;
}

.retry-button {
  background-color: var(--link);
  color: white;
  border: none;
  padding: 0.8rem 1.6rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.3s ease;
}

.retry-button:hover {
  background-color: var(--link-hover);
  transform: translateY(-2px);
}

.retry-button:focus {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

/* ======================
   平滑滚动
====================== */

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}