/* 全站样式 - UI风格8 - 布局F */
* { box-sizing: border-box; }
body { margin: 0; padding: 0; }
a { transition: all 0.3s ease; }
a:hover { opacity: 0.8; }
.container { animation: fadeIn 0.5s ease-in; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
@media (max-width: 768px) {
  .container { padding: 15px !important; }
  h1 { font-size: 24px !important; }
  h2 { font-size: 20px !important; }
}
/* 返回顶部按钮 */
#backToTop { position: fixed; bottom: 30px; right: 30px; background: #d32f2f; color: #fff; width: 50px; height: 50px; border-radius: 50%; border: none; cursor: pointer; display: none; font-size: 20px; box-shadow: 0 4px 12px rgba(0,0,0,0.3); transition: all 0.3s; z-index: 999; }
#backToTop:hover { background: #b71c1c; transform: translateY(-5px); }