Custom CSS

#boardNavDesktop {
    visibility: hidden;
}

div.postingMode.desktop {
    visibility: hidden;
}

div.sideArrows {
    visibility: hidden;
}

a.fileThumb img {
    image-rendering: optimizeQuality;
}

span.fileText {
    margin-left: 5px;
}

div.globalMessage.hideMobile h3 {
    text-align: center;
}

abovePostForm {
    visibility: none;
}

hr.abovePostForm {
    width: 0;
}

hr {
    width: 0;
}

tr.rules td {
}

table.postForm > tbody > tr > td:first-child {
    background-color: rgba(153, 136, 238, 0,8);
    color: rgb(0, 0, 0);
    font-weight: normal;
    border: 1px solid rgb(0, 0, 0);
    padding: 0px 0px;
    font-size: 10pt;
    vertical-align:top;
}

html, body {
    margin: 0;
    padding: 0;
}

div.globalMessage.hideMobile {
    color: black;
    text-align: left;
    width: 500px;
    border: 1px solid #ddd;
    padding: 5px 20px;
    background-color: #EEE;
    clear: both;
    margin-left: auto;
    margin-right: auto;
}

div.boardTitle {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 0 7px 7px;
    background-color: #eee;
    border-bottom: 1px solid #bbb;
    color: #555;
    text-align: left;
    z-index: 1;
}

div.boardBanner {
    background-color: #D8DCF2;
    border-bottom: 1px solid #BBB;
    margin-top: 26px;
    padding-bottom: 10px;
}

img.title {
    margin-top: 20px;
}

div.boardSubtitle {
    color: #555;
}

body {
    background-image: url('https://static.4chan.org/image/fade-blue.png';);
    background-repeat: repeat-x;
    background-attachment: fixed;
    background-position: left top;
    background-color: #EEF2FF;
    font-family: Arial,sans-serif;
    font-size: 12px;
    margin: 0;
}

a.quotelink {
    color: #6495ED;
}

div.board {
    border-top: 1px solid #DDD;
    padding-top: 20px;
}

div.thread {
    margin-top: 17px;
}

div.pagelist.desktop {
    background: #ddd;
    margin-left: 5px;
    border: 1px solid #ccc;
}

div.post.reply {
    background-color: rgba(238, 238, 238, 0.5);
    border: 1px solid #ddd;
    padding: 10px 0 15pxpxpxpx;
    width: 75%;
    margin-left: 20px;
    margin-bottom: 0;
    clear: both;
    float: left;
} div.post.reply:hover { background-color: rgba(238, 238, 238, 1);

}

span.summary.desktop {
    margin-left: 20px;
}

.flag {
    display: inline-block;
    width: 16px;
    height: 11px;
    position: relative;
    top: 1px;
    opacity: 0.8;
} .flag:hover { opacity: 1; }

.post-hidden .extButton, .post-hidden:not(#quote-preview) .postInfo {
opacity: 0.5;
visibility: collapse;
}

.post-hidden .extButton, .post-hidden:not(#quote-preview) .postInfo {
opacity: 0.5;
visibility: collapse;
}

I think it would be nice to customize/modernize the entire discussion boards.