UI5 table theme

Hi Experts,

I want to change UI5 theme in table.

I m using following code for defining theme.

<script id="sap-ui-bootstrap"

type="text/javascript"

data-sap-ui-libs="sap.ui.commons,sap.ui.table"

data-sap-ui-theme="sap_goldreflection"

Now m using sap_goldreflection theme.

If i want to change some css in this theme like change header colour,is it possible?

How i can modify or create new theme for table?

Thanks in advance.

Regards,

Neha