我列出了我试过的代码……

toolbar{    animation-name: animation;    animation-duration: 5s;    animation-timing-function: ease-in-out;    animation-iteration-count: infinite;        animation-play-state: running;}@keyframes animation {    50.0%  {background-color:red;}}

我试图摆弄不透明度设置,没有运气.任何帮助表示赞赏.

@-webkit-keyframes animation {    0%     {background-color:red;}    50.0%  {background-color:#ff6666;} /* your chosen 'mid' color */    100.0%  {background-color:red;}}@keyframes animation {    0%     {background-color:red;}    50.0%  {background-color:#ff6666;}    100.0%  {background-color:red;}}

JSfiddle Demo