message: refactor: Reorganize PopoutWrapper CSS
diff: position: fixed;
  }
  -.PopoutWrapper--masked .PopoutWrapper__overlay {
  - background: rgba(0, 0, 0, .4);
  -}
  -
  -.PopoutWrapper--closing .PopoutWrapper__overlay {
  - opacity: 0;
  -}
  -
  .PopoutWrapper__overlay {
  position: fixed;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 1;
  + animation: vkui-animation-full-fade-in .2s ease;
  +}
  +
  +.PopoutWrapper--closing .PopoutWrapper__overlay {
  + opacity: 0;
  + transition: opacity .2s var(--android-easing);
  +}
  +
  +.PopoutWrapper--masked .PopoutWrapper__overlay {
  + background: rgba(0, 0, 0, .4);
  }
  .PopoutWrapper--fixed .PopoutWrapper__overlay {
  */
  .PopoutWrapper--ios .PopoutWrapper__overlay {
  - animation: vkui-animation-full-fade-in .3s ease;
  + animation-duration: .3s;
  }
  .PopoutWrapper--ios.PopoutWrapper--closing .PopoutWrapper__overlay {
  transition: opacity .3s var(--ios-easing);
  }
  -/**
  - * Android version
  - */
  -
  -.PopoutWrapper--android .PopoutWrapper__overlay,
  -.PopoutWrapper--vkcom .PopoutWrapper__overlay {
  - animation: vkui-animation-full-fade-in .2s ease;
  -}
  -
  -.PopoutWrapper--android.PopoutWrapper--closing .PopoutWrapper__overlay,
  -.PopoutWrapper--vkcom.PopoutWrapper--closing .PopoutWrapper__overlay {
  - transition: opacity .2s var(--android-easing);
  -}
  -
  @keyframes vkui-animation-full-fade-in {
  from {
  opacity: 0;
  