fieldset {
    border: 2px solid #000000;
    position: relative;
    color: #808080;
    box-sizing: border-box;
    width:100%;
    margin-bottom:40px;
}

    fieldset .filterInput {
        width: -moz-calc(100% - 25px);
        width: -webkit-calc(100% - 25px);
        width: calc(100% - 25px);
        padding: 10px;
        font-size: 22px;
        border: 0;
        margin-left: 25px;
        color: #000000;
        box-sizing: border-box;
    }

.filterInput:focus {
    outline: none;
}

    fieldset i {
        position:absolute;
        left:10px;
        top:11px;    
    }