Spotlight highlights a certain component on page. In this particular example, panel is highlighted on validation error.
<script>
    //<![CDATA[
    function handleForm(xhr, status, args) {
        if (args.validationFailed)
            PF('spot').show();
        else
            PF('spot').hide();
    }
    //]]>
</script>
<div class="card">
    <h:form>
        <p:growl id="growl"/>
        <p:panel id="pnl" header="New User">
            <p:messages id="messages"/>
            <h:panelGrid columns="3" id="grid" cellpadding="7">
                <p:outputLabel for="username" value="Username"/>
                <p:inputText id="username" value="#{spotlightView.username}" required="true">
                    <f:validateLength minimum="2"/>
                </p:inputText>
                <p:message for="username"/>
                <p:outputLabel for="email" value="Surname:"/>
                <p:inputText id="email" value="#{spotlightView.email}" required="true"/>
                <p:message for="email"/>
            </h:panelGrid>
            <p:commandButton value="Save" icon="pi pi-check" action="#{spotlightView.save}" update="growl grid"
                             oncomplete="handleForm(xhr, status, args)" styleClass="mt-3"/>
        </p:panel>
        <p:spotlight target="pnl" widgetVar="spot"/>
    </h:form>
</div>
package org.primefaces.showcase.view.misc;
import jakarta.enterprise.context.RequestScoped;
import jakarta.faces.application.FacesMessage;
import jakarta.faces.context.FacesContext;
import jakarta.inject.Named;
import io.quarkus.runtime.annotations.RegisterForReflection;
@Named
@RequestScoped
@RegisterForReflection(serialization = true)
public class SpotlightView {
    private String username;
    private String email;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public void save() {
        username = null;
        email = null;
        FacesContext.getCurrentInstance().addMessage(null, new FacesMessage("You've registered"));
    }
}