style(webui): unify settings and dark mode surfaces (#5058)

webui/src/components/thread/PromptRail.tsx

@@ -188,7 +188,7 @@ export function PromptRail({
               className={cn(
                 "pointer-events-none absolute left-10 top-1/2 z-30 w-[34rem] max-w-[calc(100vw-4rem)] -translate-y-1/2 rounded-[20px] px-4 py-3 text-left",
                 "bg-popover/95 text-popover-foreground shadow-[0_18px_45px_rgba(0,0,0,0.12)] backdrop-blur-xl",
-                "dark:bg-[#2f2f2f]/95 dark:text-white dark:shadow-[0_18px_45px_rgba(0,0,0,0.45)]",
+                "dark:shadow-[0_18px_45px_rgba(0,0,0,0.45)]",
                 "-translate-x-2 scale-[0.98] opacity-0 transition-[opacity,transform] duration-150",
                 "group-hover/marker:translate-x-0 group-hover/marker:scale-100 group-hover/marker:opacity-100",
                 "group-focus-visible/marker:translate-x-0 group-focus-visible/marker:scale-100 group-focus-visible/marker:opacity-100",

webui/src/components/thread/ThreadComposer.tsx

@@ -2115,7 +2115,7 @@ export function ThreadComposer({
                   <TooltipContent
                     side="top"
                     align="center"
-                    className="flex items-center gap-2 rounded-full border border-border/70 bg-background px-3 py-1.5 text-[13px] font-medium text-foreground shadow-[0_8px_24px_rgba(15,23,42,0.13)] dark:border-white/10 dark:bg-neutral-900 dark:text-white"
+                    className="flex items-center gap-2 rounded-full border border-border/70 bg-popover px-3 py-1.5 text-[13px] font-medium text-popover-foreground shadow-[0_8px_24px_rgba(15,23,42,0.13)] dark:border-white/10"
                   >
                     <span>{voiceButtonTooltip}</span>
                     {voiceRecorder.state === "idle" ? (