How font icons are rotated within button

<button class="btn anviz-btn-primary footer-search-btn" data-class=""><i class="footer-icon icon-more_line"></i></button>
<button class="btn anviz-btn-primary footer-search-btn" data-class=""><i class="footer-icon icon-loading"></i></button>

the two font icons are inside button, and the display effect is as follows:

style:

            .footer-search-btn{
                width: 40px;
                height: 40px;
                display: inline-block;
                    vertical-align: middle;
            }
            .footer-search-btn .footer-icon{
                font-size: 24px;
                display: flex;
                justify-content: center;
            }

Animation style:

            .animated-cycle{
                -webkit-animation:rotating 1s infinite linear ;
                -webkit-transform-origin: center center;
                  -ms-transform-origin: center center;
                  transform-origin: center center;
            }
            @-webkit-keyframes rotating{
                0%{
                    -webkit-transform: rotate(0deg);
                    -moz-transform: rotate(0deg);
                    -ms-transform: rotate(0deg);
                    transform: rotate(0deg);
                }
                100%{
                    -webkit-transform: rotate(360deg);
                    -moz-transform: rotate(360deg);
                    -ms-transform: rotate(360deg);
                    transform: rotate(360deg);
                }
            }

No matter how I write it, the font icon in buuton will not rotate. How should I write it? Thank you, thank you very much!