style.css

body
{
    font-family : roboto;
    background: grey;
}
.inscription
{
    height: 65vh;
    margin : 2em 10%;
    background: #d0ff01;
    padding: .5em;
    border-radius : 5px;
    box-shadow : 1px 1px 5px #9501cfc2
}
.inscription form, .inscription .message
{
    text-align: center;
    width: 100%;
}
.clearfix:after 
{
    content: ".";
    display: block;
    clear: both;
    visibility: hidden;
    line-height: 0;
    height: 0;
}
.clearfix 
{
    display: block;
}
input
{
    width: 50%;
    height: 3em;
}
button
{
    width: 50%;
    height: 3em;
    background-color: hotpink;
    border: 1px solid orangered;
    color: blue;
}
html[xmlns] .clearfix 
{
    display: block;
}
* html .clearfix 
{
    height: 1%;
}
html 
{ 
    box-sizing : border-box
}
*, *:after, *:before 
{
    box-sizing: inherit
}