style(webui): refine skills mobile experience

webui/src/components/settings/SkillsCatalogSettings.tsx

@@ -146,7 +146,12 @@ export function SkillsCatalogSettings({ skills }: { skills: SkillSummary[] }) {
                 className="h-9 rounded-[11px] bg-background pl-9 text-[13px]"
               />
             </div>
-            <div className="flex items-center gap-1 rounded-[10px] bg-muted/65 p-1">
+            <div
+              className={cn(
+                "flex max-w-full items-center gap-1 overflow-x-auto rounded-[10px] bg-muted/65 p-1",
+                "scrollbar-thin scrollbar-track-transparent sm:w-auto",
+              )}
+            >
               {([
                 ["all", t("settings.skills.filterAll", { defaultValue: "All" }), skills.length],
                 [
@@ -165,7 +170,7 @@ export function SkillsCatalogSettings({ skills }: { skills: SkillSummary[] }) {
                   type="button"
                   onClick={() => setInstalledFilter(filter)}
                   className={cn(
-                    "rounded-[8px] px-2.5 py-1 text-[11px] font-medium transition-colors",
+                    "shrink-0 whitespace-nowrap rounded-[8px] px-2.5 py-1 text-[11px] font-medium transition-colors",
                     installedFilter === filter
                       ? "bg-background text-foreground shadow-sm"
                       : "text-muted-foreground hover:text-foreground",
@@ -314,6 +319,7 @@ function SkillDetailSheet({
   const [actionError, setActionError] = useState("");
   const [deleteOpen, setDeleteOpen] = useState(false);
   const [refreshKey, setRefreshKey] = useState(0);
+  const [descriptionExpanded, setDescriptionExpanded] = useState(false);
 
   useEffect(() => {
     if (!open || !skill) return;
@@ -323,6 +329,7 @@ function SkillDetailSheet({
     setLoadFailed(false);
     setActionError("");
     setDeleteOpen(false);
+    setDescriptionExpanded(false);
     fetchSkillDetail(token, skill.name)
       .then((payload) => {
         if (!cancelled) setDetail(payload);
@@ -349,6 +356,7 @@ function SkillDetailSheet({
     : activeSkill.available
       ? t("settings.skills.statusEnabled", { defaultValue: "Enabled" })
       : t("settings.skills.statusNeedsSetup", { defaultValue: "Needs setup" });
+  const descriptionExpandable = activeSkill.description.length > 240;
 
   const toggleEnabled = async () => {
     setActionBusy(true);
@@ -399,12 +407,25 @@ function SkillDetailSheet({
       <Sheet open={open} onOpenChange={onOpenChange}>
         <SheetContent
           side="right"
-          className="w-[min(34rem,calc(100vw-1rem))] max-w-none gap-0 overflow-hidden p-0 sm:max-w-none"
+          closeButtonClassName={cn(
+            "right-2 top-2 inline-flex h-10 w-10 items-center justify-center rounded-full opacity-100",
+            "text-muted-foreground transition-colors hover:bg-muted hover:text-foreground",
+            "sm:right-3 sm:top-3",
+          )}
+          className={cn(
+            "w-full max-w-none gap-0 overflow-hidden border-l-0 p-0",
+            "sm:w-[min(34rem,calc(100vw-1rem))] sm:max-w-none sm:border-l",
+          )}
         >
-          <div className="min-h-0 flex-1 overflow-y-auto px-5 py-5">
+          <div
+            className={cn(
+              "min-h-0 flex-1 overflow-y-auto px-4 py-4 sm:px-5 sm:py-5",
+              "pb-[max(1rem,env(safe-area-inset-bottom))]",
+            )}
+          >
             <div className="flex items-start gap-3 pr-8">
               <div className="min-w-0 flex-1">
-                <SheetTitle className="truncate text-[20px] font-semibold">
+                <SheetTitle className="truncate text-[19px] font-semibold sm:text-[20px]">
                   {activeSkill.name}
                 </SheetTitle>
                 <SheetDescription className="sr-only">
@@ -427,9 +448,26 @@ function SkillDetailSheet({
                     {statusLabel}
                   </Pill>
                 </div>
-                <p className="mt-3 text-[13px] leading-5 text-muted-foreground">
+                <p
+                  className={cn(
+                    "mt-3 text-[13px] leading-5 text-muted-foreground",
+                    descriptionExpandable && !descriptionExpanded && "line-clamp-5",
+                  )}
+                >
                   {activeSkill.description}
                 </p>
+                {descriptionExpandable ? (
+                  <button
+                    type="button"
+                    aria-expanded={descriptionExpanded}
+                    onClick={() => setDescriptionExpanded((value) => !value)}
+                    className="mt-1.5 min-h-8 rounded-full text-[12px] font-medium text-foreground/70 transition-colors hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+                  >
+                    {descriptionExpanded
+                      ? t("settings.skills.showLess", { defaultValue: "Show less" })
+                      : t("settings.skills.showMore", { defaultValue: "Show more" })}
+                  </button>
+                ) : null}
               </div>
             </div>
 
@@ -444,7 +482,7 @@ function SkillDetailSheet({
               </div>
             ) : (
               <div className="mt-6 space-y-5">
-                <div className="flex items-center justify-between gap-4 border-y border-border/45 px-1 py-3.5">
+                <div className="flex min-h-16 items-start justify-between gap-3 border-y border-border/45 px-1 py-3.5">
                   <div>
                     <p className="text-[13px] font-medium text-foreground">
                       {t("settings.skills.enabledControl", { defaultValue: "Use this skill" })}
@@ -467,15 +505,20 @@ function SkillDetailSheet({
                     disabled={actionBusy}
                     onClick={() => void toggleEnabled()}
                     className={cn(
-                      "relative h-6 w-11 shrink-0 rounded-full transition-colors",
+                      "relative -mr-1 h-10 w-14 shrink-0 rounded-full",
                       "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2",
                       "disabled:cursor-wait disabled:opacity-60",
-                      enabled ? "bg-foreground" : "bg-muted-foreground/30",
                     )}
                   >
                     <span
                       className={cn(
-                        "absolute left-0.5 top-0.5 h-5 w-5 rounded-full bg-background shadow-sm transition-transform",
+                        "absolute left-1.5 top-2 h-6 w-11 rounded-full transition-colors",
+                        enabled ? "bg-foreground" : "bg-muted-foreground/30",
+                      )}
+                    />
+                    <span
+                      className={cn(
+                        "absolute left-2 top-2.5 h-5 w-5 rounded-full bg-background shadow-sm transition-transform",
                         enabled ? "translate-x-5" : "translate-x-0",
                       )}
                     />
@@ -498,7 +541,7 @@ function SkillDetailSheet({
                 {detail ? <RawInstructionsBlock markdown={detail.raw_markdown} /> : null}
 
                 {deletable ? (
-                  <div className="flex items-center justify-between gap-4 border-t border-border/45 pt-5">
+                  <div className="flex flex-col items-stretch gap-3 border-t border-border/45 pt-5 sm:flex-row sm:items-center sm:justify-between sm:gap-4">
                     <div>
                       <p className="text-[13px] font-medium text-foreground">
                         {t("settings.skills.deleteTitle", { defaultValue: "Delete skill" })}
@@ -511,11 +554,14 @@ function SkillDetailSheet({
                     </div>
                     <Button
                       type="button"
-                      variant="destructive"
+                      variant="outline"
                       size="sm"
                       disabled={actionBusy}
                       onClick={() => setDeleteOpen(true)}
-                      className="shrink-0 rounded-full"
+                      className={cn(
+                        "h-10 w-full shrink-0 rounded-full border-destructive/20 text-destructive",
+                        "hover:bg-destructive/8 hover:text-destructive sm:h-9 sm:w-auto",
+                      )}
                     >
                       <Trash2 className="mr-1.5 h-3.5 w-3.5" aria-hidden />
                       {t("settings.skills.deleteAction", { defaultValue: "Delete" })}
@@ -571,7 +617,7 @@ function RawInstructionsBlock({ markdown }: { markdown: string }) {
 
   return (
     <details className="group rounded-[18px] border border-border/45 bg-muted/20 px-3 py-3">
-      <summary className="flex cursor-pointer select-none items-center justify-between gap-3 text-[13px] font-medium text-foreground/90 transition-colors hover:text-foreground">
+      <summary className="flex min-h-11 cursor-pointer select-none items-center justify-between gap-3 text-[13px] font-medium text-foreground/90 transition-colors hover:text-foreground">
         <span>
           {t("settings.skills.instructionsTitle", { defaultValue: "Skill instructions" })}
         </span>
@@ -657,7 +703,7 @@ function RequirementsSection({
               })}
               title={option.label}
               onClick={() => void copyCommand(option.command)}
-              className="flex h-7 w-7 shrink-0 items-center justify-center rounded-[8px] text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
+              className="flex h-9 w-9 shrink-0 items-center justify-center rounded-[9px] text-muted-foreground transition-colors hover:bg-muted hover:text-foreground sm:h-7 sm:w-7"
             >
               {copiedCommand === option.command ? (
                 <Check className="h-3.5 w-3.5 text-emerald-600" aria-hidden />
@@ -689,7 +735,7 @@ function RequirementsSection({
         variant="outline"
         size="sm"
         onClick={onRefresh}
-        className="mt-3 h-8 rounded-full bg-background/60 px-3 text-[11px]"
+        className="mt-3 h-9 rounded-full bg-background/60 px-3 text-[11px]"
       >
         <RefreshCw className="mr-1.5 h-3.5 w-3.5" aria-hidden />
         {t("settings.skills.checkAgain", { defaultValue: "Check again" })}

webui/src/components/settings/SkillsMarketplace.tsx

@@ -198,7 +198,7 @@ export function SkillsMarketplace({ installedSkills }: { installedSkills: SkillS
 
       {query.trim().length < 2 ? (
         <section className="overflow-hidden rounded-[22px] bg-settings-surface">
-            <div className="flex items-center justify-between border-b border-border/45 px-5 py-4">
+            <div className="flex flex-col items-start gap-2 border-b border-border/45 px-4 py-4 sm:flex-row sm:items-center sm:justify-between sm:px-5">
               <div>
                 <h2 className="text-[14px] font-semibold">
                   {t("settings.skills.marketplaceTrendingTitle", {
@@ -371,9 +371,9 @@ function MarketplaceSkillRow({
   const { t } = useTranslation();
 
   return (
-    <div className="flex min-w-0 items-center gap-3 px-2 py-3.5">
+    <div className="flex min-w-0 items-center gap-2 px-1 py-3.5 sm:gap-3 sm:px-2">
       {skill.rank ? (
-        <span className="w-7 shrink-0 text-right font-mono text-[12px] tabular-nums text-muted-foreground/65">
+        <span className="w-6 shrink-0 text-right font-mono text-[11px] tabular-nums text-muted-foreground/65 sm:w-7 sm:text-[12px]">
           #{skill.rank}
         </span>
       ) : null}
@@ -390,7 +390,7 @@ function MarketplaceSkillRow({
               name: skill.name,
               defaultValue: "Open {{name}} on skills.sh",
             })}
-            className="shrink-0 text-muted-foreground transition-colors hover:text-foreground"
+            className="inline-flex h-7 w-7 shrink-0 items-center justify-center rounded-full text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
           >
             <ExternalLink className="h-3.5 w-3.5" aria-hidden />
           </a>
@@ -418,7 +418,10 @@ function MarketplaceSkillRow({
         variant={installed ? "secondary" : "default"}
         disabled={installed || installBusy || installSupported === false}
         onClick={() => onSelect(skill)}
-        className={cn("min-w-[92px] rounded-full", installed && "text-emerald-700")}
+        className={cn(
+          "min-w-[82px] rounded-full px-2.5 sm:min-w-[92px] sm:px-3",
+          installed && "text-emerald-700",
+        )}
         title={
           installSupported === false
             ? t("settings.skills.marketplaceNpxRequired", {
@@ -512,7 +515,7 @@ function TrendingSkeleton() {
             <div className="h-3.5 w-48 max-w-[55%] animate-pulse rounded bg-muted" />
             <div className="h-3 w-32 max-w-[40%] animate-pulse rounded bg-muted/70" />
           </div>
-          <div className="h-8 w-[92px] animate-pulse rounded-full bg-muted" />
+          <div className="h-8 w-[82px] animate-pulse rounded-full bg-muted sm:w-[92px]" />
         </div>
       ))}
     </div>

webui/src/components/ui/sheet.tsx

@@ -57,13 +57,24 @@ const sheetVariants = cva(
 interface SheetContentProps
   extends React.ComponentPropsWithoutRef<typeof DialogPrimitive.Content>,
     VariantProps<typeof sheetVariants> {
+  closeButtonClassName?: string;
   showCloseButton?: boolean;
 }
 
 const SheetContent = React.forwardRef<
   React.ElementRef<typeof DialogPrimitive.Content>,
   SheetContentProps
->(({ side = "right", className, children, showCloseButton = true, ...props }, ref) => (
+>((
+  {
+    side = "right",
+    className,
+    children,
+    closeButtonClassName,
+    showCloseButton = true,
+    ...props
+  },
+  ref,
+) => (
   <SheetPortal>
     <SheetOverlay />
     <DialogPrimitive.Content
@@ -78,7 +89,14 @@ const SheetContent = React.forwardRef<
     >
       {children}
       {showCloseButton ? (
-        <DialogPrimitive.Close className="absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:pointer-events-none">
+        <DialogPrimitive.Close
+          className={cn(
+            "absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity",
+            "hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
+            "disabled:pointer-events-none",
+            closeButtonClassName,
+          )}
+        >
           <X className="h-4 w-4" />
           <span className="sr-only">Close</span>
         </DialogPrimitive.Close>

webui/src/tests/app-layout.test.tsx

@@ -378,6 +378,12 @@ describe("App layout", () => {
   });
 
   it("opens Skills from the main sidebar", async () => {
+    const longSkillDescription = [
+      "Work with GitHub repositories, issues, pull requests, releases, workflows,",
+      "and code search through the GitHub CLI.",
+      "Use this skill for repository maintenance, review automation, release preparation,",
+      "and other GitHub workflows that need authenticated command-line access.",
+    ].join(" ");
     mockFetchRoutes({
       "/api/settings": baseSettingsPayload(),
       "/api/settings/cli-apps": { apps: [], installed_count: 0, catalog_updated_at: "2026-04-18" },
@@ -413,7 +419,7 @@ describe("App layout", () => {
       },
       "/api/webui/skills/github": {
         name: "github",
-        description: "Work with GitHub.",
+        description: longSkillDescription,
         source: "builtin",
         enabled: true,
         deletable: false,
@@ -501,6 +507,13 @@ describe("App layout", () => {
     fireEvent.click(screen.getByRole("button", { name: "Open details for github" }));
 
     expect(await screen.findByRole("heading", { name: "github" })).toBeInTheDocument();
+    const showMore = await screen.findByRole("button", { name: "Show more" });
+    expect(showMore).toHaveAttribute("aria-expanded", "false");
+    fireEvent.click(showMore);
+    expect(screen.getByRole("button", { name: "Show less" })).toHaveAttribute(
+      "aria-expanded",
+      "true",
+    );
     expect(screen.getByText("Setup required")).toBeInTheDocument();
     expect(screen.getByText("brew install gh")).toBeInTheDocument();
     expect(screen.queryByText("Unavailable reason")).not.toBeInTheDocument();