div.filters {
    /*text-align: center;*/
    margin: 3px 0;
    clear: both;
}
div.float_block {
    float: left;
}
div.filter_block {
    width: 400px;
    background-color: #222;
    padding: 5px;
    border-radius: 5px;
    display: block;
    text-align: left;
    line-height: 2em;
    margin: 5px;
}

div.center_block {
    margin: 0 auto;
}

div.filter_block > div {
    display: flex;
    margin: 3px 0;
    align-items: baseline;
}

div.filter_block label {
    margin: 0 1em 0 0.5em;
}

div.filter_block input, div.filter_block select {
    box-sizing: border-box;
    flex: auto;
    margin-right: 0.5em;
    background-color: #555;
    color: #fff;
    border: 1px solid #777;
    border-radius: 5px;
    padding: 3px;
    min-width: 50px;
}

div.filters input[type="button"] {
    width: 100px;
    font-size: 1.2em;
    color: #FFF;
}