[css] 버튼만들기

.btnx {
    width: 30px;
    height: 30px;
      display: inline-block;
      position: relative;
      transform: rotate(0deg);
      transition: transform 300ms;
}
.btnx:hover {
        transform: rotate(180deg);
        cursor:pointer;
        color: white;
        text-shadow: 1px 1px 2px black, 0 0 25px blue, 0 0 5px darkblue;
}
.cell {
        text-align : center;
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        font-size: 36px;
        font-weight: bold;
}
<div class="btnx">
    <div class="cell">×</div>
</div>

.btnx {
    width: 30px; height: 30px;
    display: inline-block;
    position: relative;
    outline: 2px solid #AAA;
}
.cell:hover {
    transform: translate(-50%, -50%) rotate(180deg);
    cursor:pointer;
    color: white;
    text-shadow: 1px 1px 2px black, 0 0 25px blue, 0 0 5px darkblue;
}
.cell {
    text-align : center;
    position: absolute;
    top: 50%;
    left: 50%;
    color: #AAA;
    font-size: 44px;
    font-weight: bold;
    transform: translate(-50%, -50%) rotate(0deg);
    transition: transform 300ms;
}

.btn_close {
        display: inline-block;
        width:50px;
        height:50px;
        background:#999;
        border-radius:50%;
        position: relative;
        transition: transform 300ms;
        transform: rotate(45deg);
}
.btn_close::before {
    content: '';
    position: absolute;
    height: 6px;
    width: 40px;
    border-radius: 6px;
    background: white;
    top: calc(50% - 3px);
    left: 5px;
}
.btn_close::after {
    content: '';
    position: absolute;
    height: 40px;
    width: 6px;
    border-radius: 6px;
    background: white;
    left: calc(50% - 3px);
    top: 5px;
}
.btn_close:hover {
        transform: rotate(225deg);
}
<div class="btn_close"></div>