styles.css

html {
    height: 100%;
}
body {
    --background-header: #303641;
    --background-main: #373d47;
    --dark-grey: #959595;
    --font-color: #FFFFFF;
    --button-hover: #12E083;
    
    font-family: 'Lato', sans-serif;
    font-weight: 400;
    overflow-x: hidden;
    height: 100%;
}

.flex-container {
    display: flex;
    height: 100%;
}
.flex-column {
    display: flex;
    width: 100%;
    flex-direction: column
}

header {
    background-color: var(--background-header);
    padding: 0 1em;

    box-shadow: 0 2px 3px #0000004f;
    z-index: 0;
}

.top-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    
    box-sizing: border-box;
    height: 4em;
    padding: 0.5em 0;
    
    border-bottom: thin solid #939796;

    font-family: 'Russo One', sans-serif;
}

.logo {
    font-size: 2em;
    color: var(--font-color);
    text-transform: uppercase;
}

.config-page {
    display: flex;
    position: fixed;
    right: 1em;
    top: 0;
}

#start-togetherjs {
    font-family: arial;
    background-color: #FFF;
    border: thin solid #d5d5d5;
    font-size: 12px;
    cursor: pointer;
}

#start-togetherjs::before {
    display: inline-block;

    width: 12px; 
    height: 12px;

    background-image: url('img/together-icon.png');
    background-size: 12px 12px;
    content: "";
}

nav {
    display: flex;
    align-items: center;
    justify-content: space-between;

    height: 3em;
}

.error {
    color: var(--font-color);
}


.menu button {
    color: var(--font-color);
    
    border-radius: 8px;

    padding: 10px;

    transition: 400ms;
}

.menu button:not(:last-child)::after {
    margin-left: 1em;
    content: " \2011";
    color: var(--font-color);
}

.menu button:not(:disabled):hover {
    color: var(--button-hover);
    background-color: #404857;
}

.menu button:disabled {
    color: var(--dark-grey);
    cursor: default;
}

main {
    display: flex;
    flex-direction: row;
    flex-grow: 1;

    background-color: var(--background-main);

    padding: 0.5em;
    
    align-self: center;
    width: 100%;
    height: 70%;
 }

main .trace {
    box-shadow: 1px 3px rgba(0, 0, 0, 0.24), 1px 2px rgba(0, 0, 0, 0.24);
    outline-color: var(--background-header);
    border-radius: 4px;
    overflow: hidden;
    overflow-y: auto;
    display: hidden;
    flex-flow: column;
    background-color: #FFF;
 }

main .CodeMirror {
    display: flex;
    flex-direction: column;
    border-radius: 4px;
    flex-grow: 1;

    box-shadow: 1px 3px rgba(0, 0, 0, 0.24), 1px 2px rgba(0, 0, 0, 0.24);
    outline-color: var(--background-header);
    width: 50%;
    height: auto;
    margin: 0.8rem;
}

main .CodeMirror-code {
    cursor: text;
}

main div#myDiagramDiv {
    box-shadow: 1px 3px rgba(0, 0, 0, 0.24), 1px 2px rgba(0, 0, 0, 0.24);
    outline-color: var(--background-header);
    border-radius: 4px;
    overflow: hidden;
    overflow-y: auto;

    background-color: #FFF;
    margin: 0.8rem;
} 

.col-1 {
    width: 50%;
    flex-grow: 1;
}

.col-2 {
    width: 50%;
    flex-grow: 1;
}

.row-1 {
    height: 50%;
    flex-grow: 1;
}

.row-2 {
    height: 50%;
    flex-grow: 1;
}


.code {
    font-family:courier,arial,helvetica;
    cursor: text;
}

main .sequenceDiagram {
    background-color: #FFF;
 }

@media (max-width: 400px) {
    .flex-row-content {
        flex-direction: column;
        flex-grow: 0
    }
    .col-1 {
        width: 90vw;
        height: 105vh;
        display: flex;
        flex-direction: row;
    }
    .col-2 {
        width: 90vw;
        height: 95vh;
        display: flex;
        flex-direction: row;
    }


  }
@media (max-width: 830px) {
  .top-header {
    height: 3em;     
  }
  nav {
    height: 5em;
  }
}