body { margin: 0; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif; } #header { position: absolute; top: 0; left: 0; right: 0; height: 60px; box-sizing: border-box; background-color: #1e1e1e; border-bottom: 1px solid #333; padding: 0.3em 1.6em; color: #fff; } h1 { font-size: 18px; display: inline-block; margin-right: 15px; } #options { float: right; margin-top: 1em; } .options-group { margin-right: 30px; } #header span, #header label, #header input, #header a { display: inline-block; } #header a { font-weight: 600; color: rgb(101, 163, 221); } #header .label { font-weight: bold; } #header input { margin-left: 12px; margin-right: 6px; } #header label { color: #999; } .editor { position: absolute; top: 60px; bottom: 0; box-sizing: border-box; } #source { left: 0; width: 45%; } #output { left: 45%; width: 55%; } .highlight { background-color: rgba(46, 120, 190, 0.5); }