input 소스에 색상 넣고 싶어요

이렇게 있는데 색상 코드를 어디에 넣어야 할까요

<tr>
    <td class=write_head>경매 시작일시</td>
    <td class=write_main >
        <input type=text size=22 name=wr_1 id=wr_1 class=frm_input value="<?=$write[wr_1]?>" itemname="경매 시작일시" required readonly>
        <input type=button value="지금" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d H:i:s", G5_SERVER_TIME)?>';">
    <input type=button value="오늘자정" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d 00:00:00", G5_SERVER_TIME+60*60*24)?>';">
        <input type=button value="+2일뒤" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d 00:00:00", G5_SERVER_TIME+86400*2)?>';">
        <input type=button value="+3일뒤" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d 00:00:00", G5_SERVER_TIME+86400*3)?>';">
        <input type=button value="+5일뒤" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d 00:00:00", G5_SERVER_TIME+86400*5)?>';">
        <input type=button value="+7일뒤" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d 00:00:00", G5_SERVER_TIME+86400*7)?>';">
        <input type=button value="+10일뒤" onclick="document.getElementById('wr_1').value='<?=date("Y-m-d 00:00:00", G5_SERVER_TIME+86400*10)?>';">
    </td>
</tr>