Customize your whole forum page by using the selector .wt-body.

<style>
.wt-body {
    background-color: skyblue;
}
</style>

Use a different font for your forum by pasting Google font's code inside the Forum Head Tag HTML Code text box.

<link href="https://fonts.googleapis.com/css?family=Lato" rel="stylesheet">

Then specify your font using the selector *.

<style>
* {
    font-family: 'Lato', sans-serif;
}
</style>

Style your forum's header by using the selector header.

<style>
header {
    box-shadow: 0 0 30px rgba(0,0,0,0.5);
}
</style>

Style your forum's links by using the selector .wt-body a.

<style>
.wt-body a {
    font-weight: bold;
}
.wt-body a:hover {
    text-decoration: underline;
}
.wt-body a {
    color: #222 !important;
}
.wt-body a:visited {
    color: #555 !important;
}
</style>

Customize how avatars appear on your forum by using the selector .image-wrapper.

<style>
.image-wrapper {
    border-radius: 100%;
}
</style>

Customize how modals / dialogs appear on your forum by using the selector .modal-content.

<style>
.modal .modal-content {
    border-radius: 20px;
    overflow: hidden;
}
</style>

Customize how the title of your modals / popup dialogs appear on your forum by using the selector .modal-header.

<style>
.modal-header {
    background: black;
    color: white
}
</style>

Customize how the left slide panel and main menu appears on your forum by using the selector #slide-panel.

<style>
#slide-panel {
    background-color:#00ff00
}
</style>

Customize how the calendar appears on your forum by using the selector .calendar.

<style>
.calendar {
    width: 100% !important;
}
</style>

Customize how header image appears on your forum by using the selector .header-image.

<style>
.header-image {
    height: 185px;
    margin: 10px auto 20px;
}
</style>

Customize how the categories list page appears on your forum by using the selector .wt-categorie.

<style>
.wt-categories {
    width: 700px !important;
    margin-top: 50px;
}
</style>

Customize how the topics list page appears on your forum by using the selector .all-topics-list.

<style>
.all-topics-list {
    width: 800px !important;
}
</style>

Customize how the posts list pages appear on your forum by using the selector #posts-list.

<style>
#posts-list {
    margin: 0 auto;
    width: 72%;
}
</style>

Customize how posts appear on your forum by using the selector .post-body.

<style>
.post-body {
    background-color: #00ff00;
}
</style>

Customize how panels appear on your forum by using the selector .content-panel.

<style>
.content-panel {
    width: 70% !important;
}
</style>

Customize how the alert messages appear on your forum by using the selector .alert.

<style>
.alert {
    background: #f38282;
}
</style>

Customize how albums appear on your forum by using the selector .album-wrapper.

<style>
.album-wrapper {
    padding: 2px;
    border: 2px #eee solid;
}
</style>

Customize how form textboxes appear on your forum by using the selector .form-control.

<style>
.form-control {
    background: #c6dede !important;
    color: #019c9c;
}
</style>

Customize how buttons appear on your forum by using the selector .btn, .btn-primary, and .btn-subtle.

<style>
.btn {
    border-color: #d07c73 !important;
    background-color: #397373 !important;
    color: #242727 !important;
}
.btn-primary {
    border-color: #39d84f !important;
    background-color: #386f6f !important;
    color: #0d2b2b !important;
}
.btn-subtle {
    border-color: #969291 !important;
    background-color: #1bf9f9 !important;
    color: #4b5252 !important;
}
</style>

Customize how dropdown menus appear on your forum by using the selector .dropdown-menu.

<style>
.dropdown-menu {
    background-color: #b4dada
}
.dropdown-menu a:hover {
    background-color: #97caca !important;
}
</style>

Customize how your logo appears on your forum by using the selector #forum_logo.

<style>
#forum_logo {
    width: 50%;
    margin-left: 20%;
}
</style>