textarea {
    width: 100% !important;
}

#ex2 {
    position: relative; 
    width: 100%;
    height: 75px;   
     border: 1px solid lightgray; 
}

#ex2 pre {
    padding: 0;
    margin: 0;
    border: 0;
}
#ex2 textarea, #ex2 code {
        line-height: normal;
    font-family:monospace;
    font-size: 14px;
    border: 0;
    height: 75px;
    width: 100%;
    margin: 0;
    padding: 0;
}
#ex2 textarea {
      resize: none;
    padding: 0px;
    position: absolute;
    background-color: transparent;
}
#ex2 code {
    position: absolute;
    color: transparent;
}
#ex2 code .bracket {
    text-decoration: underline;
    background-color: yellow;
}