input框placeholder文字颜色以及实现透明输入框

::-webkit-input-placeholder { /* WebKit, Blink, Edge */
color: #909;
}
:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
color: #909;
}
::-moz-placeholder { /* Mozilla Firefox 19+ */
color: #909;
}
:-ms-input-placeholder { /* Internet Explorer 10-11 */
color: #909;
}
.form-item>input::-webkit-input-placeholder {
/* placeholder颜色 */
color: #fff;
}

.form-item{border:1px solid #fff;width:400px;height:48px;border-radius:24px;margin:40px auto}
.form-item>input{
width:100%;height:100%;display: block;font-size:18px;
border-radius:24px;background: rgba(255,255,255,0.1);
text-align: center;color:#fff;border: 0;outline: none;
}