are you talking about the 'sign up now' button at the bottom?

if so, and you use position:fixed to fix it at the bottom of the screen, there may be problems in ios

you can change the layout, such as

<style>
html,body{
    height:100%
}
.page{
    box-sizing:border-box;
    height:100%;
    padding-bottom:40px;
    position:relative;
}
.con{
    height:100%;
    overflow:auto
}
.btn{
    position:'absolute';
    bottom:0;
    left:0;
    width:100%;
    hieght:40px;
    ...
}
</style>
<div class="page">
    <div class="con"></div>
    <a class="btn"></a>
</div>