index.css

* {
    margin: 0px;
    padding: 0px;
    box-sizing: border-box;
}

body {
    height: 100vh;
    display: flex;
}

.code-area {
    background-color: #1B1A1E;
    display: flex;
    flex-direction: column;
    width: 60%;
    height: 100%;
    border-right: 1px solid #555;
    font-size: 16px !important;
}

.code-area textarea {
    resize: none;
    outline: none;
    width: 100%;
    height: 100%;
    padding: 10px;
    font-family: Arial, monospace;
}

.codeTab {
    height: 100%;
}

.preview-area {
    width: 40%;
}

.preview-area iframe {
    width: 40%;
    height: 100%;
    border: none;
    position: fixed;
}

#Placeholders {
    background-color: #fafafa;
    height: 100%;
}

table, tr, td {
    background-color: #1B1A1E;
    border: solid 1px #FFF;
    color: #FFF;
    border-collapse: collapse;
    width: 100%;
}

td {
    padding: 10px;
    width: 50% !important;
}

.w3-bar {
    padding: 10px;
    background-color: #1B1A1E;
    width: 100%;
    color: white;
    white-space: nowrap;
}

.w3-bar-item {
    padding: 8px;
    background-color: white;
}

.downloadButton {
    padding: 8px;
    color: #FFF;
    background-color: #1ebb1e;
}

.file {
    padding: 10px;
    color: white;
    background-color: #1B1A1E;
}