yarn: yarn add flickity-fullscreen --save

npm: npm install flickity-fullscreen

Bower: bower install flickity-fullscreen

/* 展开全屏按钮样式 */
.flickity-fullscreen-button-view{
  position: absolute;
  width:auto;
  height:auto;
  z-index: 999999;
  top: 0;
  right: 0;
  padding: 5px 10px;
  border-radius: 5px;
  box-shadow: 0 0 10px #0000000f;
}

/* 退出全屏按钮样式，
 * 设置display:none;是为了不让【展开全屏按钮】和【退出全屏按钮】同时显示在页面上
 */
.flickity-fullscreen-button-exit{
  display: none;
}

/* 点击全屏显示效果 */
.is-fullscreen {
  position: fixed;
  z-index: 1100;
  height: 100vh;
  width: 100vw;
  top: 0;
  left: 0;
  background: #0000009e;
 }

/* 当显示了全屏时，隐藏【展开全屏按钮】 */
.is-fullscreen .flickity-fullscreen-button-view{
  display: none;
}

/* 显示全屏时，显示【退出全屏按钮】设置按钮在页面右上方*/
.is-fullscreen .flickity-fullscreen-button-exit{
  display: block;
  position: absolute;
  width:auto;
  height:auto;  
  z-index: 999999;
  top: 0;
  padding: 5px 10px;
  border-radius: 5px;
  box-shadow: 0 0 10px #0000000f;
  right:0;
}

/* 设置被选中的图片大小为全屏*/
.is-fullscreen .is-selected{
  width: 100vw !important;
  height:100vh !important;
}

/* 设置选中的图片自适应屏幕大小，按屏幕大小进行缩放*/
.is-fullscreen .carousel-img{
  width:auto !important;
  height:auto !important;
  max-width: 100% !important;
  max-height: 100% !important;
}

/* 取消展开退出按钮点击的边框样式*/
.flickity-button:focus{
  box-shadow: unset;;
}

/* 设置展开退出按钮的宽度*/
.flickity-button-icon{
  width:20px;
}