Hello All,
This is another post about ADF Skinning , in this post i am going to show you that how can we change button's style in af:query component
Actually this is very easy , if we define some styles for 
af:button component in our css file then it will be applicable on af:query's buttons (Search, Reset, Advanced, Save etc) too
Suppose i have defined this in css file 
af|button{
    color:navy;
    font-weight:bold;
}
 
 
Now it will change color of all buttons of application including af:query
See this snap after applying this skin 
But if you have a requirement to use different style in af:query buttons or you don't want to change color of all buttons
Then it is not that much easy as it seems 
☺
There is a selector to style buttons of af:query 
- af|query::button 
But this works only if buttons are af:commandButton not af:button
See from docs-
af|query::button
               Styles the buttons of the query
                                         component. Note that this skin selector is only present when
                                         the skin selector -tr-button-type is set to 'old', and the 
                                         query buttons are rendered as af:commandButtons. When the 
                                         -tr-button-type is set to 'unified', the query buttons are
                                         rendered as af:buttons and have the default stylings for 
                                         af:button applied, so that query buttons have the same 
                                         look and feel as all other buttons. Tip: If you skin this
                                         selector's background-image, you may
                                         also want to skin it for :hover,
                                         :active, :focus. The :disabled state is
                                         currently not supported. Please note
                                         that for buttons :active and :focus
                                         pseudo-classes do not work in IE7. IE7
                                         also does not allow disabled buttons to
                                         be styled. It is recommended that you
                                         use the .AFButton*:alias selectors as a
                                         shortcut to skin all button components
                                         the same.
So for this first i have to change -tr-button-type selector to old so that i can use 
af|query::button
Now see the css
af|query {
    -tr-button-type: old;
}
 af|query::button {
    color: red;
    font-weight:bold;
}
 af|query::button:hover {
    color: Orange;
    font-weight:bold;
}
 af|query::button:focus {
    color: maroon;
    font-weight:bold;
}
af|button{
    color:navy;
    font-weight:bold;
}
 
Check the output-
To use specific style for af:query you can create styleClass in css file and put this in styleClass property of af:query
Suppose i have two af:query components on page and i want to use different style for both
For this i have define two different styleClass in css file like this-
af|query {
    -tr-button-type: old;
}
 .mystyle1 af|query::button {
    color: red;
    font-weight:bold;
}
.mystyle2 af|query::button {
    color: darkgreen;
    font-weight:bold;
}
 
and on page put 
myStyle1 in styleClass property of first af:query component and 
myStyle2 in second af:query
See how it looks now -
Cheers, Happy Learning  ☺