refactor(ui): R10 — .btn-primary recipe for the primary/action buttons

Add a paint-only .btn-primary recipe (solid accent bg + accent-fg text +
hover:opacity dim) in index.css @layer components, alongside the selection-paint
recipes (.pill/.chip/.is-current). Migrate ~38 primary/action buttons across 24
files off the hand-rolled 'bg-accent text-accent-fg hover:opacity-90', keeping
each site's geometry (padding/radius/font/gap/disabled/shadow).

Deliberately NOT migrated: accent BADGES/labels (spans), the chat message bubble,
selection toggles (tableHeader — R8 popover territory), and the round play FAB
(hover:scale, not the opacity-dim primary idiom). Three previously hover-less
primary buttons (SettingsPanel/SetupWizard/DraftSaveBar) gain the standard hover
dim for consistency.

Gate green (tsc/eslint-0/prettier/knip/vitest 79); self-E2E confirmed a migrated
button computes to accent/accent-fg and both recipe rules load.

frontend/src/components/About.tsx

@@ -72,7 +72,7 @@ export default function About({
 
       <button
         onClick={onOpenReleaseNotes}
-        className="mt-4 w-full inline-flex items-center justify-center gap-2 px-4 py-2 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+        className="mt-4 w-full inline-flex items-center justify-center gap-2 px-4 py-2 rounded-xl font-semibold btn-primary transition"
       >
         <Sparkles className="w-4 h-4" /> {t("about.whatsNew")}
       </button>

frontend/src/components/Banner.tsx

@@ -8,7 +8,7 @@ const TONES: Record<BannerTone, { bar: string; icon: string; action: string }> =
   accent: {
     bar: "bg-accent/15 border-accent/30",
     icon: "text-accent",
-    action: "bg-accent text-accent-fg hover:opacity-90",
+    action: "btn-primary",
   },
   warning: {
     bar: "bg-warn/15 border-warn/30",

frontend/src/components/ChannelPage.tsx

@@ -460,7 +460,7 @@ export default function ChannelPage({
                   <button
                     onClick={() => subscribe.mutate()}
                     disabled={subscribe.isPending}
-                    className="inline-flex items-center gap-1.5 px-3 py-2 rounded-lg text-sm bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50"
+                    className="inline-flex items-center gap-1.5 px-3 py-2 rounded-lg text-sm btn-primary disabled:opacity-50"
                   >
                     <Plus className="w-4 h-4" />
                     {t("channel.subscribe")}

frontend/src/components/ChatThread.tsx

@@ -216,7 +216,7 @@ export default function ChatThread({
           <button
             onClick={submit}
             disabled={!draft.trim() || send.isPending}
-            className="shrink-0 p-2.5 rounded-xl bg-accent text-accent-fg hover:opacity-90 transition disabled:opacity-40"
+            className="shrink-0 p-2.5 rounded-xl btn-primary transition disabled:opacity-40"
             aria-label={t("messages.send")}
             title={t("messages.send")}
           >

frontend/src/components/ConfirmProvider.tsx

@@ -116,11 +116,7 @@ export function ConfirmProvider({ children }: { children: ReactNode }) {
                 onClick={() => close(c.id)}
                 className={`px-4 py-2 rounded-lg text-sm font-semibold transition ${
                   multi ? "w-full" : ""
-                } ${
-                  c.danger
-                    ? "bg-danger text-danger-fg hover:opacity-90"
-                    : "bg-accent text-accent-fg hover:opacity-90"
-                }`}
+                } ${c.danger ? "bg-danger text-danger-fg hover:opacity-90" : "btn-primary"}`}
               >
                 {c.label || t("common.confirm")}
               </button>

frontend/src/components/DownloadCenter.tsx

@@ -390,7 +390,7 @@ function MetaEditModal({ job, onClose }: { job: DownloadJob; onClose: () => void
           <button
             onClick={() => save.mutate()}
             disabled={!name.trim() || save.isPending}
-            className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition"
+            className="px-3 py-1.5 rounded-lg text-sm font-medium btn-primary disabled:opacity-50 transition"
           >
             {t("downloads.edit.save")}
           </button>
@@ -448,7 +448,7 @@ function ErrorModal({
                 onRetry();
                 onClose();
               }}
-              className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 transition"
+              className="px-3 py-1.5 rounded-lg text-sm font-medium btn-primary transition"
             >
               {t("downloads.actions.retry")}
             </button>
@@ -607,7 +607,7 @@ function QuotaModal({
           <button
             onClick={() => save.mutate()}
             disabled={save.isPending}
-            className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition"
+            className="px-3 py-1.5 rounded-lg text-sm font-medium btn-primary disabled:opacity-50 transition"
           >
             {t("downloads.admin.save")}
           </button>
@@ -894,7 +894,7 @@ export default function DownloadCenter() {
               </button>
               <button
                 onClick={() => addUrl.trim() && setAddSource(addUrl.trim())}
-                className="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 transition shrink-0"
+                className="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium btn-primary transition shrink-0"
               >
                 <Plus className="w-4 h-4" /> {t("downloads.page.add")}
               </button>

frontend/src/components/DownloadDialog.tsx

@@ -98,7 +98,7 @@ export default function DownloadDialog({
         <button
           onClick={submit}
           disabled={busy || !chosen}
-          className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition"
+          className="px-3 py-1.5 rounded-lg text-sm font-medium btn-primary disabled:opacity-50 transition"
         >
           {t("downloads.dialog.submit")}
         </button>

frontend/src/components/ErrorDialog.tsx

@@ -14,7 +14,7 @@ export default function ErrorDialog() {
       <div className="flex justify-end mt-5">
         <button
           onClick={dismissError}
-          className="px-4 py-2 rounded-lg bg-accent text-accent-fg text-sm font-medium hover:opacity-90 transition"
+          className="px-4 py-2 rounded-lg btn-primary text-sm font-medium transition"
         >
           {t("errors.ok")}
         </button>

frontend/src/components/Feed.tsx

@@ -522,7 +522,7 @@ export default function Feed({
           {isDemo ? (
             <button
               onClick={() => setFilters({ ...filters, scope: "all" })}
-              className="inline-flex items-center justify-center gap-2 px-5 py-2.5 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+              className="inline-flex items-center justify-center gap-2 px-5 py-2.5 rounded-xl font-semibold btn-primary transition"
             >
               {t("feed.browseLibrary")}
             </button>
@@ -530,7 +530,7 @@ export default function Feed({
             <>
               <button
                 onClick={onOpenWizard}
-                className="inline-flex items-center justify-center gap-2 px-5 py-2.5 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+                className="inline-flex items-center justify-center gap-2 px-5 py-2.5 rounded-xl font-semibold btn-primary transition"
               >
                 {t("feed.setUp")}
               </button>
@@ -711,7 +711,7 @@ export default function Feed({
           {filters.q.trim() && !isDemo && (
             <button
               onClick={() => onYtSearch(filters.q.trim())}
-              className="mt-4 inline-flex items-center gap-2 px-4 py-2 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+              className="mt-4 inline-flex items-center gap-2 px-4 py-2 rounded-xl font-semibold btn-primary transition"
             >
               <Youtube className="w-4 h-4" />
               {t("feed.yt.searchFor", { query: filters.q.trim() })}

frontend/src/components/KeyGate.tsx

@@ -160,7 +160,7 @@ export default function KeyGate({ meId, compact = false }: { meId: number; compa
       <button
         onClick={submit}
         disabled={busy || !pass}
-        className="inline-flex items-center gap-2 px-4 py-2 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition disabled:opacity-40"
+        className="inline-flex items-center gap-2 px-4 py-2 rounded-xl font-semibold btn-primary transition disabled:opacity-40"
       >
         <Lock className="w-4 h-4" />
         {configured ? t("messages.unlock") : t("messages.setUp")}

frontend/src/components/Messages.tsx

@@ -125,7 +125,7 @@ function ConversationList({
         {ready && (
           <button
             onClick={onNew}
-            className="inline-flex items-center gap-1.5 text-xs px-2.5 py-1.5 rounded-lg bg-accent text-accent-fg hover:opacity-90 transition"
+            className="inline-flex items-center gap-1.5 text-xs px-2.5 py-1.5 rounded-lg btn-primary transition"
           >
             <SquarePen className="w-4 h-4" />
             {t("messages.new")}

frontend/src/components/OnboardingWizard.tsx

@@ -155,7 +155,7 @@ export default function OnboardingWizard({ me, onClose }: { me: Me; onClose: ()
               <div className="mt-5 flex flex-col gap-2">
                 <button
                   onClick={() => beginGrant("read")}
-                  className="inline-flex items-center justify-center gap-2 px-5 py-3 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+                  className="inline-flex items-center justify-center gap-2 px-5 py-3 rounded-xl font-semibold btn-primary transition"
                 >
                   <Youtube className="w-4 h-4" /> {t("onboarding.read.connect")}
                 </button>
@@ -221,7 +221,7 @@ export default function OnboardingWizard({ me, onClose }: { me: Me; onClose: ()
               <div className="mt-5 flex flex-col gap-2">
                 <button
                   onClick={() => beginGrant("write")}
-                  className="inline-flex items-center justify-center gap-2 px-5 py-3 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+                  className="inline-flex items-center justify-center gap-2 px-5 py-3 rounded-xl font-semibold btn-primary transition"
                 >
                   <ShieldCheck className="w-4 h-4" /> {t("onboarding.write.enableUnsubscribe")}
                 </button>
@@ -252,7 +252,7 @@ export default function OnboardingWizard({ me, onClose }: { me: Me; onClose: ()
                   endOnboarding(false);
                   onClose();
                 }}
-                className="inline-flex items-center justify-center gap-2 px-5 py-3 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition w-full"
+                className="inline-flex items-center justify-center gap-2 px-5 py-3 rounded-xl font-semibold btn-primary transition w-full"
               >
                 {t("onboarding.done.done")}
               </button>

frontend/src/components/PlayerModal.tsx

@@ -1088,7 +1088,7 @@ export default function PlayerModal({
                     href={`https://www.youtube.com/watch?v=${currentVideoId}`}
                     target="_blank"
                     rel="noreferrer"
-                    className="inline-flex items-center justify-center gap-2 px-4 py-2 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 transition"
+                    className="inline-flex items-center justify-center gap-2 px-4 py-2 rounded-xl font-semibold btn-primary transition"
                   >
                     <ExternalLink className="w-4 h-4" />
                     {t("player.openOnYoutube")}
@@ -1314,7 +1314,7 @@ export default function PlayerModal({
                   className={
                     "shrink-0 inline-flex items-center gap-1.5 text-sm px-3 py-1.5 rounded-lg transition " +
                     (watched
-                      ? "bg-accent text-accent-fg shadow-xs hover:opacity-90"
+                      ? "btn-primary shadow-xs"
                       : "text-muted hover:text-fg hover:bg-surface border border-border")
                   }
                 >

frontend/src/components/Playlists.tsx

@@ -630,7 +630,7 @@ export default function Playlists() {
                 <button
                   onClick={() => shown.length && setPlayingId(shown[0]!.id)}
                   disabled={!shown.length}
-                  className="inline-flex items-center gap-1.5 text-xs font-semibold px-3 py-1.5 rounded-lg bg-accent text-accent-fg disabled:opacity-40 hover:opacity-90 transition"
+                  className="inline-flex items-center gap-1.5 text-xs font-semibold px-3 py-1.5 rounded-lg btn-primary disabled:opacity-40 transition"
                 >
                   <Play className="w-3.5 h-3.5 fill-current" /> {t("playlists.playAll")}
                 </button>

frontend/src/components/PlexBrowse.tsx

@@ -673,7 +673,7 @@ function ActionBtn({
       onClick={onClick}
       disabled={disabled}
       className={`inline-flex items-center gap-2 rounded-xl px-3 py-2 text-sm font-medium transition disabled:opacity-50 ${
-        primary ? "bg-accent text-accent-fg shadow-xs hover:opacity-90" : "glass-card glass-hover"
+        primary ? "btn-primary shadow-xs" : "glass-card glass-hover"
       }`}
     >
       <Icon className="w-4 h-4 shrink-0" />

frontend/src/components/ProfileEditor.tsx

@@ -147,7 +147,7 @@ export default function ProfileEditor({ onClose }: { onClose: () => void }) {
       {!formOpen ? (
         <button
           onClick={startNew}
-          className="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 transition"
+          className="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium btn-primary transition"
         >
           <Plus className="w-4 h-4" /> {t("downloads.profiles.new")}
         </button>
@@ -272,7 +272,7 @@ export default function ProfileEditor({ onClose }: { onClose: () => void }) {
             <button
               onClick={() => save.mutate()}
               disabled={!name.trim() || save.isPending}
-              className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition"
+              className="px-3 py-1.5 rounded-lg text-sm font-medium btn-primary disabled:opacity-50 transition"
             >
               {editing ? t("downloads.profiles.save") : t("downloads.profiles.create")}
             </button>

frontend/src/components/SettingsPanel.tsx

@@ -480,7 +480,7 @@ function SignInMethods({ me }: { me: Me }) {
             <button
               type="submit"
               disabled={busy || !next}
-              className="px-3 py-1.5 rounded-lg text-sm bg-accent text-accent-fg font-medium disabled:opacity-40 transition"
+              className="px-3 py-1.5 rounded-lg text-sm btn-primary font-medium disabled:opacity-40 transition"
             >
               {busy ? t("settings.account.password.saving") : t("settings.account.password.save")}
             </button>

frontend/src/components/SetupWizard.tsx

@@ -278,7 +278,7 @@ export default function SetupWizard() {
             <button
               onClick={next}
               disabled={busy}
-              className="inline-flex items-center gap-1.5 px-4 py-2 rounded-xl text-sm bg-accent text-accent-fg font-medium shadow-md shadow-accent/20 disabled:opacity-50 transition"
+              className="inline-flex items-center gap-1.5 px-4 py-2 rounded-xl text-sm btn-primary font-medium shadow-md shadow-accent/20 disabled:opacity-50 transition"
             >
               {busy ? (
                 <Loader2 className="w-4 h-4 animate-spin" />

frontend/src/components/ShareDialog.tsx

@@ -216,7 +216,7 @@ function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }
           <button
             onClick={() => savePass.mutate(newPass.trim())}
             disabled={savePass.isPending || !newPass.trim()}
-            className="px-2 py-1 rounded-md text-xs font-semibold bg-accent text-accent-fg hover:opacity-90 disabled:opacity-40 transition"
+            className="px-2 py-1 rounded-md text-xs font-semibold btn-primary disabled:opacity-40 transition"
           >
             {t("downloads.share.savePassword")}
           </button>
@@ -352,7 +352,7 @@ function LinkShare({ job }: { job: DownloadJob }) {
             <button
               onClick={() => create.mutate()}
               disabled={create.isPending}
-              className={clsx(btnCls, "bg-accent text-accent-fg hover:opacity-90")}
+              className={clsx(btnCls, "btn-primary")}
             >
               {t("downloads.share.createLink")}
             </button>

frontend/src/components/VideoCard.tsx

@@ -277,7 +277,7 @@ function Thumb({
                 title={t("card.continueTitle")}
                 aria-label={t("card.continue")}
                 className={clsx(
-                  "inline-flex items-center justify-center gap-1.5 font-semibold bg-accent text-accent-fg shadow-lg hover:opacity-90 transition",
+                  "inline-flex items-center justify-center gap-1.5 font-semibold btn-primary shadow-lg transition",
                   small ? "w-9 h-9 rounded-full" : "px-3 py-1.5 rounded-lg text-sm",
                 )}
               >

frontend/src/components/VideoEditor.tsx

@@ -630,10 +630,7 @@ export default function VideoEditor({ job, onClose }: { job: DownloadJob; onClos
             <button
               onClick={() => create.mutate()}
               disabled={!valid || create.isPending}
-              className={clsx(
-                btnCls,
-                "bg-accent text-accent-fg hover:opacity-90 inline-flex items-center gap-1.5",
-              )}
+              className={clsx(btnCls, "btn-primary inline-flex items-center gap-1.5")}
             >
               {create.isPending ? (
                 <Loader2 className="w-4 h-4 animate-spin" />

frontend/src/components/WatchPage.tsx

@@ -196,7 +196,7 @@ export default function WatchPage() {
               <button
                 onClick={unlock}
                 disabled={!password || unlocking}
-                className="mt-4 w-full rounded-lg bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 py-2 text-sm font-medium transition"
+                className="mt-4 w-full rounded-lg btn-primary disabled:opacity-50 py-2 text-sm font-medium transition"
               >
                 {T.watch}
               </button>

frontend/src/components/Welcome.tsx

@@ -501,7 +501,7 @@ function AuthCard() {
             <button
               type="submit"
               disabled={busy}
-              className="px-4 py-2.5 rounded-xl font-semibold bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition"
+              className="px-4 py-2.5 rounded-xl font-semibold btn-primary disabled:opacity-50 transition"
             >
               {busy ? t("welcome.auth.working") : t(SUBMIT_KEY[mode])}
             </button>

frontend/src/components/ui/DraftSaveBar.tsx

@@ -71,7 +71,7 @@ export function DraftSaveBar({
           data-testid="draft-save"
           onClick={onSave}
           disabled={saving || !dirty}
-          className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm bg-accent text-accent-fg font-medium shadow-md shadow-accent/20 disabled:opacity-40 transition"
+          className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm btn-primary font-medium shadow-md shadow-accent/20 disabled:opacity-40 transition"
         >
           <Save className="w-4 h-4" />
           {saving ? labels.saving : labels.save}

frontend/src/index.css

@@ -496,6 +496,18 @@ body {
     color: var(--accent-fg);
     border-color: var(--accent);
   }
+  /* .btn-primary — the primary/ACTION button paint (solid accent). Distinct from the selection
+     recipes above: this is "the primary action", not "selected among options". PAINT-ONLY like
+     .chip-solid — a site keeps its own geometry (padding/radius/font/gap/disabled:opacity/transition).
+     Migrated sites MUST drop `bg-accent text-accent-fg hover:opacity-90` so this @layer-components
+     rule isn't beaten by those utilities. No focus-visible — @layer base already rings every button. */
+  .btn-primary {
+    background-color: var(--accent);
+    color: var(--accent-fg);
+  }
+  .btn-primary:hover:not(:disabled) {
+    opacity: 0.9;
+  }
 }
 .glass-hover:hover {
   border-color: color-mix(in srgb, var(--accent) 55%, transparent);