Make buttons on session more recognizable

Add light-gray border and some drop shadow.

Fixes #7

app/views/sessions/_session.html.erb

@@ -22,26 +22,26 @@
       </span>
       <ul class="absolute top-0 right-0 text-2xl only-loggedin hidden flex">
         <li>
-          <%= link_to conference_session_candidates_path(session.conference, session), class: "only-candidate hidden mx-0.5 p-0.5 bg-rose-400 bg-opacity-30 hover:bg-opacity-50 rounded-md border border-transparent hover:border-rose-400", title: "Withdraw", aria_label: "Withdraw", data: { turbo_method: :delete, turbo_frame: dom_id(session) }, method: :delete do %>
+          <%= link_to conference_session_candidates_path(session.conference, session), class: "only-candidate hidden mx-0.5 p-0.5 bg-rose-400 bg-opacity-30 hover:bg-opacity-50 rounded-md shadow shadow-md border border-gray-900/20 hover:border-rose-400", title: "Withdraw", aria_label: "Withdraw", data: { turbo_method: :delete, turbo_frame: dom_id(session) }, method: :delete do %>
             🙅
           <% end %>
         </li><li>
-          <%= link_to conference_session_candidates_path(session.conference, session), class: "only-no-candidate hidden mx-0.5 p-0.5 bg-green-400 bg-opacity-30 hover:bg-opacity-50 rounded-md border border-transparent hover:border-green-400", title: "Volunteer Myself", aria_label: "Volunteer Myself", data: { action: "session#verifyLanguages", turbo_method: :post, turbo_frame: dom_id(session) } do %>
+          <%= link_to conference_session_candidates_path(session.conference, session), class: "only-no-candidate hidden mx-0.5 p-0.5 bg-green-400 bg-opacity-30 hover:bg-opacity-50 rounded-md shadow shadow-md border border-gray-900/20 hover:border-green-400", title: "Volunteer Myself", aria_label: "Volunteer Myself", data: { action: "session#verifyLanguages", turbo_method: :post, turbo_frame: dom_id(session) } do %>
             🙋
           <% end %>
         </li><li>
           <%= form_with url: conference_session_candidates_path(session.conference, session), method: :post, class: "inline", data: { turbo_frame: dom_id(session) } do |form| %>
-          <%= link_to conference_session_candidates_path(session.conference, session), class: "only-no-candidate hidden mx-0.5 p-0.5 bg-green-400 bg-opacity-30 hover:bg-opacity-50 rounded-md border border-transparent hover:border-green-400", title: "Volunteer (with special skills)", aria_label: "Volunteer (with special skills)", data: { action: "session#verifyLanguages session#submitWithPrompt", prompt: "Why are you especially qualified? (Please keep it short, thanks)", turbo_prefetch:"false" } do %>
+          <%= link_to conference_session_candidates_path(session.conference, session), class: "only-no-candidate hidden mx-0.5 p-0.5 bg-green-400 bg-opacity-30 hover:bg-opacity-50 rounded-md shadow shadow-md border border-gray-900/20 hover:border-green-400", title: "Volunteer (with special skills)", aria_label: "Volunteer (with special skills)", data: { action: "session#verifyLanguages session#submitWithPrompt", prompt: "Why are you especially qualified? (Please keep it short, thanks)", turbo_prefetch:"false" } do %>
             🙌
           <% end %>
         <% end %>
         </li><li class="only-shiftcoordinator hidden">
           <span class="relative group inline-block">
-            <span class="mx-0.5 p-0.5 bg-slate-400 bg-opacity-30 group-hover:bg-opacity-60 rounded-md border border-transparent group-hover:border-slate-400">🔧</span>
+            <span class="mx-0.5 p-0.5 bg-slate-400 bg-opacity-30 group-hover:bg-opacity-60 rounded-md shadow shadow-md border border-gray-900/20 group-hover:border-slate-400">🔧</span>
             <ul class="absolute inset-x-0 top-7 pt-2 invisible group-hover:visible opacity-0 group-hover:opacity-100 motion-safe:duration-300 z-30">
               <li class="py-0.5">
                 <%= form_with url: update_notes_conference_session_path(session.conference, session), method: :patch, class: "inline", data: { turbo_frame: dom_id(session) } do |form| %>
-                  <%= link_to update_notes_conference_session_path(session.conference, session), class: "mx-0.5 p-0.5 bg-slate-400 bg-opacity-30 hover:bg-opacity-60 rounded-md border border-transparent hover:border-slate-400", title: "Edit Note", aria_label: "Edit Note", data: { action: "session#submitWithPrompt", prompt: "Please enter the note", prefill: session.notes, submitempty: true, turbo_prefetch:"false" } do %>📝<% end -%>
+                  <%= link_to update_notes_conference_session_path(session.conference, session), class: "mx-0.5 p-0.5 bg-slate-400 bg-opacity-30 hover:bg-opacity-60 rounded-md shadow shadow-md border border-gray-900/20 hover:border-slate-400", title: "Edit Note", aria_label: "Edit Note", data: { action: "session#submitWithPrompt", prompt: "Please enter the note", prefill: session.notes, submitempty: true, turbo_prefetch:"false" } do %>📝<% end -%>
                 <%- end -%>
               </li>
             </ul>