.container {
    padding: 0;
    margin: 14px !important;
}

.tbox {
    display: inline-block;
    border: 3px solid green;
    border-radius: 3px;
    padding: 2px;
    margin: 0px;
    width: 100%;
    height: 200px;
    text-align: center;
    background-color: #c2f0c2;
}

.code {
    display: inline-flex;
    z-index: 1;
    float: left;
    flex-direction: column;
    width: 100%;
    height: 400px;
    border: 3px solid blue;
}

.code textarea {
    resize: none;
    outline: none;
    width: 100%;
    height: 100%;
    font-size: 15px;
    background-color: #EBF5FB;
    padding: 15px;
}

.complete {
    height: 100%;
}

.preview {
    display: inline-flex;
    background: #ffffff;
    width: 100%;
    height: 400px;
}

.preview iframe {
    resize: none;
    outline: none;
    width: 100%;
    height: 100%;
    padding: 0px;
    border: 3px solid black;
}

h1 {
    text-align: center;
    color: #0A2E6B;
    font-family: serif;
}

h3 {
    font-family: serif;
    margin-left: 40px;
}

.ext_code {
    display: inline-flex;
    z-index: 1;
    float: left;
    flex-direction: column;
    width: 100%;
    height: 600px;
    border: 2px solid blue;
}

.ext_code textarea {
    resize: none;
    outline: none;
    width: 100%;
    height: 100%;
    font-size: 15px;
    background-color: #EBF5FB;
    padding: 15px;
}

.ext_preview {
    display: inline-flex;
    width: 100%;
    height: 600px;
}

.ext_preview iframe {
    resize: none;
    outline: none;
    width: 100%;
    height: 100%;
    padding: 0px;
    border: 2px solid black;
}