Apply style to GridView using custom CSS in ASP.Net

I am trying to apply CSS in asp.net Gridview to make its look and feel good, just like bootstrap css.

Below is the code with css:

HTML

<asp:GridView ID="GridView1" runat="server" CssClass="table table-bordered table-hover" AllowPaging="True" 
 OnPageIndexChanging="OnPageIndexChanging" PageSize="5">                   
   <PagerStyle CssClass="pagination-ys" />
</asp:GridView>

C#

protected void Page_Load(object sender, EventArgs e)
{
    List<ClassMgmtRegion> dpt = new List<ClassMgmtRegion>()
        {
            new ClassMgmtRegion(){
                No=1,
                Name="Sabah",
                Code="PMO",
                Latitude="",
                Longitude=""
            },
            new ClassMgmtRegion(){
                No=1,
                Name="Sarawak",
                Code="PMO2",
                Latitude="",
                Longitude=""
            },
            new ClassMgmtRegion(){
                No=1,
                Name="Terenggaun",
                Code="PMO3",
                Latitude="",
                Longitude=""
            },
            new ClassMgmtRegion(){
                No=1,
                Name="Sabah",
                Code="PMO4",
                Latitude="",
                Longitude=""
            }
        };
    GridView1.DataSource = dpt;
    GridView1.DataBind();
}

protected void OnPageIndexChanging(object sender, GridViewPageEventArgs e)
{
    GridView1.PageIndex = e.NewPageIndex;
    GridView1.DataBind();
}

CSS

/*-----Gridview Style-----*/
.pagination-ys {
    padding-left: 0;
    margin: 20px 0;
    border-radius: 4px;
}

.pagination-ys table > tbody > tr > td {
    display: inline;
}
 
.pagination-ys table > tbody > tr > td > a,
.pagination-ys table > tbody > tr > td > span {
    position: relative;
    float: left;
    padding: 8px 12px;
    line-height: 1.42857143;
    text-decoration: none;
    color: black;
    background-color: #ffffff;
    border: 1px solid #dddddd;
    margin-left: -1px;
}
 
.pagination-ys table > tbody > tr > td > span {
    position: relative;
    float: left;
    padding: 8px 12px;
    line-height: 1.42857143;
    text-decoration: none;    
    margin-left: -1px;
    z-index: 2;
    color: white;
    background-color: #11AEA3;
    border-color: #dddddd;
    cursor: default;
}
 
.pagination-ys table > tbody > tr > td:first-child > a,
.pagination-ys table > tbody > tr > td:first-child > span {
    margin-left: 0;
    border-bottom-left-radius: 4px;
    border-top-left-radius: 4px;
}
 
.pagination-ys table > tbody > tr > td:last-child > a,
.pagination-ys table > tbody > tr > td:last-child > span {
    border-bottom-right-radius: 4px;
    border-top-right-radius: 4px;
}
 
.pagination-ys table > tbody > tr > td > a:hover,
.pagination-ys table > tbody > tr > td > span:hover,
.pagination-ys table > tbody > tr > td > a:focus,
.pagination-ys table > tbody > tr > td > span:focus {
    color: black;
    background-color: #eeeeee;
    border-color: #dddddd;
}

But the Header part of Griview looks like rows using above CSS. 

I want to make Gridview header text bold with some background color in it, to differentiate the Gridview Header with Gridview Rows.

I want to use bootstrap css to make Gridview look stylish.

Please help me how to achieve that using my CSS.

Thanks in advance