OctoprintKlipperPlugin/octoprint_klipper/static/css/klipper.css

#tab_plugin_klipper iframe {
   width: 100%;
   height: 600px;
   border: 1px solid #808080;
}

.plugin_klipper_log {
   padding: 0.5em;
   overflow-y: scroll;
   height: 400px;
   background-color: #efefef;
   border: 1px #eee;
   border-radius: 3px;
}

.plugin_klipper_log .log-item {
   margin: 0 auto 0.5em auto; 
}

.plugin_klipper_log .error {
   color: red;
}