body{
    font: normal 18px/normal Arial, Helvetica, sans-serif;
}
.box{
    text-align: center;
    margin: 100px auto;
    width: 400px;
}
input {
    display: inline-block;
    border: 1px solid #b7b7b7;
    height: 35px;
    border-radius: 3px;
    color: #333;
    padding-left:10px;
    font-size: 16px;
    background: #ffffff;
    box-shadow: 1px 1px 3px 0 rgba(0,0,0,0.2) inset;
}
div .right{
    border: 2px solid lightgreen;
}
div .wrong{
    border: 2px solid red;
}
button{

    margin-left: 20px;
    display: inline-block;
    cursor: pointer;
    width: 70px;
    height: 40px;
    font-size: 16px;
    border-radius: 3px;
    color: #ffffff;
    background: #0199d9;
    border: 1px solid #0199d9;
}
#tip{
    float: left;
    margin: 10px 0 0 80px;
    color: #ccc
}