Kodlar:
<style type="text/css">
.redButton {
background-color: transparent;
border: 1px solid red;
color: red;
padding: 10px 27px;
text-align: center;
text-decoration: none;
display: inline-block;
font-size: 16px;
}
.redButton.active, .redButton:active:focus, .redButton:focus, .redButton:hover {
border-color: #e7505a;
color: white;
background-color: #e7505a;
transition: all .3s;
}</style>
<asp:Button CssClass="redButton" id="btRed" runat="server" Text="BUTTON">BUTTON</asp:button>