Плавная анимация увеличения?

Сочиняю вот такую кнопку.
Немогу сделать плавное уменьшение/увеличение scale

помогите пж

Я хочу чтобы иконка плавно уеличивалась при наведении и "дрожала", ну и плавно уменьшалоь обратно

<ul class="social-icons-1">
     <li><ab>Phone</ab>
            <a href="#" class="a-phone" >
                <i class="fa fa-phone phone"></i> 
             </a>
    </li>
</ul>
<style>
ab {
  background: #eeeeee;
    padding: 7px 17px;
    font-size: 11px;
    position: absolute;
    top: 12px;
    left: -80px;
    border-radius: 7px;
}
 .social-icons-1 {
    padding: 0;
    list-style: none;
    margin: 10px;
}
.social-icons-1 li {
    display: block;
    position: relative;
    font-size: 24px;
    margin: 0.1em;
    line-height: 1;
}
.social-icons-1 i,
.social-icons-1 img {
    color: #fff;
    position: absolute;
    top: 11px;
    left: 11px;
    width: 24px;
    height: 24px;
    text-align:center;
    transition: all 0.3s ease-out;
}
.social-icons-1 a {
    display: inline-block;
}
.social-icons-1 a:before {
    transform: scale(1);
    content: "";
    width: 45px;
    height: 45px;
    border-radius: 100%;
    display: block;
    background: linear-gradient(45deg, #337AB7, #2d6b9f);
    box-shadow: 0 2px 5px rgba(0,0,0,0.2), 0 2px 4px rgba(0,0,0,0.2);
    transition: all 0.3s ease-out;
}
.social-icons-1 a:hover:before {
    transform: scale(0);
    transition: all 0.3s ease-in;
}
.social-icons-1 a:hover i {
    transform: rotate(15deg) scale(1.8);
    color: #337AB7;
    transition: all 0.3s ease-in;
}

</style>
/********************************************************/
<style>

       .social-icons-1 .a-phone:before  {
     background: linear-gradient(45deg,#55A0FF, #55A0FF);
}
.social-icons-1 a:hover .phone {
    color: #55A0FF;
}
.social-icons-1 a:hover .phone  {
   -webkit-animation: 1.2s ease-in-out 0s normal none infinite running phone-anima;
    -moz-animation: 1.2s ease-in-out 0s normal none infinite running phone-anima;
    -o-animation: 1.2s ease-in-out 0s normal none infinite running phone-anima;
    animation: 1.2s ease-in-out 0s normal none infinite running phone-anima;
}
@keyframes phone-anima {
   0%, 50%, 100% {
      transform: rotate(0deg) scale(1.8);
     -webkit-transform: rotate(0deg) scale(1.8);
     -moz-transform: rotate(0deg) scale(1.8);
     -o-transform: rotate(0deg) scale(1.8);
     -ms-transform: rotate(0deg) scale(1.8);
   }
   10%, 30% {
     transform: rotate(-10deg) scale(1.8);
     -webkit-transform: rotate(-10deg) scale(1.8);
     -moz-transform: rotate(-10deg) scale(1.8);
     -o-transform: rotate(-10deg) scale(1.8);
     -ms-transform: rotate(-10deg) scale(1.8);
   }
   20%, 40% {
     transform: rotate(10deg) scale(1.8);
     -webkit-transform: rotate(10deg) scale(1.8);
     -moz-transform: rotate(10deg) scale(1.8);
     -o-transform: rotate(10deg) scale(1.8);
     -ms-transform: rotate(10deg) scale(1.8);
   }
}
    </style>