I find the chat box width is too narrow and can make it cumbersome for the customer to reply.
With this simple fix you can extend the width of the chat window, making it responsive and change the colour of the chat tab.
After your Olark chat code, insert...
Code:
{literal}<style>div.olrk-state-compressed #habla_window_div { width: auto !important; } div.olrk-state-expanded #habla_window_div { width: 97% !important; } #habla_topbar_div { background: #2A36B1 !important; }</style>{/literal}