diff --git a/frontend/components/messages/messages-view.tsx b/frontend/components/messages/messages-view.tsx
index 444cfc0..ea07eff 100644
--- a/frontend/components/messages/messages-view.tsx
+++ b/frontend/components/messages/messages-view.tsx
@@ -27,8 +27,25 @@ import {
 import { useTranslation } from "react-i18next";
 
 import { AppointmentDetailDialog } from "@/components/messages/appointment-detail-dialog";
+import {
+  Attachment,
+  AttachmentAction,
+  AttachmentActions,
+  AttachmentContent,
+  AttachmentDescription,
+  AttachmentMedia,
+  AttachmentTitle,
+  AttachmentTrigger,
+} from "@/components/ui/attachment";
 import { Avatar, AvatarFallback } from "@/components/ui/avatar";
+import { Bubble, BubbleContent } from "@/components/ui/bubble";
 import { Button } from "@/components/ui/button";
+import {
+  Message,
+  MessageContent,
+  MessageFooter,
+  MessageHeader,
+} from "@/components/ui/message";
 import {
   Dialog,
   DialogDescription,
@@ -91,75 +108,85 @@ function sameDay(a: string, b: string): boolean {
 // one sender label, one timestamp, tighter spacing.
 const GROUP_WINDOW_MS = 5 * 60 * 1000;
 
-// One sent attachment rendered in the thread: a downloadable file chip or a
-// shared-appointment card. Alignment (left/right) comes from the parent column.
+// One sent attachment rendered in the thread, built on the Attachment primitive:
+// a downloadable file, a shared-appointment card, or a password-reset notice.
+// Alignment (left/right) is inherited from the parent MessageContent.
 function SentAttachment({ att }: { att: MessageAttachment }) {
   const { t } = useTranslation();
   const router = useRouter();
   const [apptOpen, setApptOpen] = useState(false);
+
   if (att.kind === "passwordReset") {
     return (
-      <button
-        className="max-w-[75%] rounded-2xl border border-warning/40 bg-warning/5 p-3 text-left text-sm transition-colors hover:bg-warning/10"
-        onClick={() =>
-          router.push(
-            `/settings?tab=careTeam&member=${encodeURIComponent(att.userId)}`,
-          )
-        }
-        type="button"
-      >
-        <div className="flex items-center gap-1.5 text-warning text-xs">
-          <KeyRound className="size-3.5" />
-          {t("messages.system.label")}
-        </div>
-        <p className="mt-1 font-medium text-foreground">
-          {t("messages.system.passwordResetTitle")}
-        </p>
-        <p className="text-muted-foreground text-xs">
-          {t("messages.system.passwordResetBody", { name: att.userName })}
-        </p>
-      </button>
+      <Attachment className="max-w-[20rem] border-warning/40 bg-warning/5 hover:bg-warning/10">
+        <AttachmentTrigger
+          aria-label={t("messages.system.passwordResetTitle")}
+          onClick={() =>
+            router.push(
+              `/settings?tab=careTeam&member=${encodeURIComponent(att.userId)}`,
+            )
+          }
+        />
+        <AttachmentMedia className="bg-warning/15 text-warning">
+          <KeyRound />
+        </AttachmentMedia>
+        <AttachmentContent>
+          <AttachmentTitle>
+            {t("messages.system.passwordResetTitle")}
+          </AttachmentTitle>
+          <AttachmentDescription>
+            {t("messages.system.passwordResetBody", { name: att.userName })}
+          </AttachmentDescription>
+        </AttachmentContent>
+      </Attachment>
     );
   }
+
   if (att.kind === "file") {
     return (
-      <button
-        className="flex max-w-[75%] items-center gap-2 rounded-2xl border bg-card px-3 py-2 text-left text-foreground text-sm transition-colors hover:bg-accent"
-        onClick={() => {
-          void downloadAttachment(att.attachmentId, att.fileName).catch(() => {
-            /* ignore — surfaced by the browser */
-          });
-        }}
-        type="button"
-      >
-        <FileText className="size-4 shrink-0 text-muted-foreground" />
-        <span className="min-w-0 max-w-48 flex-1 truncate">{att.fileName}</span>
-        <Download className="size-4 shrink-0 text-muted-foreground" />
-      </button>
+      <Attachment className="max-w-[20rem]">
+        <AttachmentMedia>
+          <FileText />
+        </AttachmentMedia>
+        <AttachmentContent>
+          <AttachmentTitle>{att.fileName}</AttachmentTitle>
+        </AttachmentContent>
+        <AttachmentActions className="pr-1.5">
+          <AttachmentAction
+            aria-label={t("messages.attach.download")}
+            onClick={() => {
+              void downloadAttachment(att.attachmentId, att.fileName).catch(
+                () => {
+                  /* ignore — surfaced by the browser */
+                },
+              );
+            }}
+          >
+            <Download />
+          </AttachmentAction>
+        </AttachmentActions>
+      </Attachment>
     );
   }
+
   const a = att.appointment;
   return (
     <>
-      <button
-        className="max-w-[75%] rounded-2xl border bg-card p-3 text-left text-sm transition-colors hover:bg-accent"
-        onClick={() => setApptOpen(true)}
-        type="button"
-      >
-        <div className="flex items-center gap-1.5 text-muted-foreground text-xs">
-          <CalendarClock className="size-3.5" />
-          {t("messages.attach.apptCardLabel")}
-        </div>
-        <p className="mt-1 font-medium text-foreground">{a.name}</p>
-        <p className="text-muted-foreground text-xs">
-          {[a.date, a.time].filter(Boolean).join(" · ")}
-        </p>
-        {[a.type, a.provider].filter(Boolean).length > 0 && (
-          <p className="text-muted-foreground text-xs">
-            {[a.type, a.provider].filter(Boolean).join(" · ")}
-          </p>
-        )}
-      </button>
+      <Attachment className="max-w-[20rem]">
+        <AttachmentTrigger
+          aria-label={t("messages.attach.apptCardLabel")}
+          onClick={() => setApptOpen(true)}
+        />
+        <AttachmentMedia>
+          <CalendarClock />
+        </AttachmentMedia>
+        <AttachmentContent>
+          <AttachmentTitle>{a.name}</AttachmentTitle>
+          <AttachmentDescription>
+            {[a.date, a.time, a.type, a.provider].filter(Boolean).join(" · ")}
+          </AttachmentDescription>
+        </AttachmentContent>
+      </Attachment>
       <AppointmentDetailDialog
         appointment={a}
         onOpenChange={setApptOpen}
@@ -661,46 +688,34 @@ export function MessagesView() {
                           <div className="h-px flex-1 bg-border" />
                         </div>
                       )}
-                      <div
+                      <Message
+                        align={out ? "end" : "start"}
                         className={cn(
-                          "flex flex-col gap-1",
-                          out ? "items-end" : "items-start",
                           !newDay && (startsGroup ? "mt-4" : "mt-1"),
                         )}
                       >
-                        {selected.isGroup && !out && startsGroup && (
-                          <span className="px-1 text-muted-foreground text-[11px]">
-                            {m.senderName}
-                          </span>
-                        )}
-                        {m.body && (
-                          <div
-                            className={cn(
-                              "max-w-[75%] rounded-2xl px-3 py-2 text-sm",
-                              out
-                                ? "bg-primary text-primary-foreground"
-                                : "bg-muted text-foreground",
-                              !startsGroup &&
-                                (out ? "rounded-tr-md" : "rounded-tl-md"),
-                              !endsGroup &&
-                                (out ? "rounded-br-md" : "rounded-bl-md"),
-                            )}
-                          >
-                            {m.body}
-                          </div>
-                        )}
-                        {m.attachments?.map((att, ai) => (
-                          <SentAttachment
-                            att={att}
-                            key={`${m.id}-att-${ai}`}
-                          />
-                        ))}
-                        {endsGroup && (
-                          <span className="px-1 text-muted-foreground text-[11px]">
-                            {formatTime(m.createdAt)}
-                          </span>
-                        )}
-                      </div>
+                        <MessageContent>
+                          {selected.isGroup && !out && startsGroup && (
+                            <MessageHeader>{m.senderName}</MessageHeader>
+                          )}
+                          {m.body && (
+                            <Bubble
+                              align={out ? "end" : "start"}
+                              variant={out ? "default" : "muted"}
+                            >
+                              <BubbleContent>{m.body}</BubbleContent>
+                            </Bubble>
+                          )}
+                          {m.attachments?.map((att, ai) => (
+                            <SentAttachment att={att} key={`${m.id}-att-${ai}`} />
+                          ))}
+                          {endsGroup && (
+                            <MessageFooter>
+                              {formatTime(m.createdAt)}
+                            </MessageFooter>
+                          )}
+                        </MessageContent>
+                      </Message>
                     </Fragment>
                   );
                 })}
diff --git a/frontend/components/ui/attachment.tsx b/frontend/components/ui/attachment.tsx
new file mode 100644
index 0000000..5fa79cb
--- /dev/null
+++ b/frontend/components/ui/attachment.tsx
@@ -0,0 +1,209 @@
+import * as React from "react"
+import { mergeProps } from "@base-ui/react/merge-props"
+import { useRender } from "@base-ui/react/use-render"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+import { Button } from "@/components/ui/button"
+
+const attachmentVariants = cva(
+  "group/attachment relative flex w-fit max-w-full min-w-0 shrink-0 flex-wrap rounded-3xl border bg-card text-card-foreground transition-colors focus-within:ring-1 focus-within:ring-ring/30 has-[>a,>button]:hover:bg-muted/50 data-[state=error]:border-destructive/30 data-[state=idle]:border-dashed",
+  {
+    variants: {
+      size: {
+        default:
+          "gap-2 text-sm has-data-[slot=attachment-content]:px-2.5 has-data-[slot=attachment-content]:py-2 has-data-[slot=attachment-media]:p-2",
+        sm: "gap-2.5 text-xs has-data-[slot=attachment-content]:px-2 has-data-[slot=attachment-content]:py-1.5 has-data-[slot=attachment-media]:p-1.5",
+        xs: "gap-1.5 rounded-2xl text-xs has-data-[slot=attachment-content]:px-1.5 has-data-[slot=attachment-content]:py-1 has-data-[slot=attachment-media]:p-1",
+      },
+      orientation: {
+        horizontal: "min-w-40 items-center",
+        vertical: "w-24 flex-col has-data-[slot=attachment-content]:w-30",
+      },
+    },
+  }
+)
+
+function Attachment({
+  className,
+  state = "done",
+  size = "default",
+  orientation = "horizontal",
+  ...props
+}: React.ComponentProps<"div"> &
+  VariantProps<typeof attachmentVariants> & {
+    state?: "idle" | "uploading" | "processing" | "error" | "done"
+  }) {
+  const resolvedOrientation = orientation ?? "horizontal"
+
+  return (
+    <div
+      data-slot="attachment"
+      data-state={state}
+      data-size={size}
+      data-orientation={resolvedOrientation}
+      className={cn(attachmentVariants({ size, orientation }), className)}
+      {...props}
+    />
+  )
+}
+
+const attachmentMediaVariants = cva(
+  "relative flex aspect-square w-10 shrink-0 items-center justify-center overflow-hidden rounded-2xl bg-muted text-foreground group-data-[orientation=vertical]/attachment:w-full group-data-[size=sm]/attachment:w-8 group-data-[size=xs]/attachment:w-7 group-data-[size=xs]/attachment:rounded-xl group-data-[state=error]/attachment:bg-destructive/10 group-data-[state=error]/attachment:text-destructive group-data-[orientation=vertical]/attachment:*:data-[slot=spinner]:size-6! [&_svg]:pointer-events-none [&_svg:not([class*='size-'])]:size-4 group-data-[orientation=vertical]/attachment:[&_svg:not([class*='size-'])]:size-6 group-data-[size=xs]/attachment:[&_svg:not([class*='size-'])]:size-3.5",
+  {
+    variants: {
+      variant: {
+        icon: "",
+        image:
+          "opacity-60 group-data-[state=done]/attachment:opacity-100 group-data-[state=idle]/attachment:opacity-100 *:[img]:aspect-square *:[img]:w-full *:[img]:object-cover",
+      },
+    },
+    defaultVariants: {
+      variant: "icon",
+    },
+  }
+)
+
+function AttachmentMedia({
+  className,
+  variant = "icon",
+  ...props
+}: React.ComponentProps<"div"> & VariantProps<typeof attachmentMediaVariants>) {
+  return (
+    <div
+      data-slot="attachment-media"
+      data-variant={variant}
+      className={cn(attachmentMediaVariants({ variant }), className)}
+      {...props}
+    />
+  )
+}
+
+function AttachmentContent({
+  className,
+  ...props
+}: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="attachment-content"
+      className={cn(
+        "max-w-full min-w-0 flex-1 leading-tight group-data-[orientation=vertical]/attachment:px-1",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AttachmentTitle({
+  className,
+  ...props
+}: React.ComponentProps<"span">) {
+  return (
+    <span
+      data-slot="attachment-title"
+      className={cn(
+        "block max-w-full min-w-0 truncate font-medium group-data-[state=processing]/attachment:shimmer group-data-[state=uploading]/attachment:shimmer",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AttachmentDescription({
+  className,
+  ...props
+}: React.ComponentProps<"span">) {
+  return (
+    <span
+      data-slot="attachment-description"
+      className={cn(
+        "mt-0.5 block min-w-0 truncate text-xs text-muted-foreground group-data-[state=error]/attachment:text-destructive/80",
+        "max-w-full",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AttachmentActions({
+  className,
+  ...props
+}: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="attachment-actions"
+      className={cn(
+        "relative z-20 flex shrink-0 items-center group-data-[orientation=vertical]/attachment:absolute group-data-[orientation=vertical]/attachment:top-3 group-data-[orientation=vertical]/attachment:right-3 group-data-[orientation=vertical]/attachment:gap-1",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AttachmentAction({
+  className,
+  variant,
+  size = "icon-xs",
+  ...props
+}: React.ComponentProps<typeof Button>) {
+  return (
+    <Button
+      data-slot="attachment-action"
+      variant={variant ?? "ghost"}
+      size={size}
+      className={cn(className)}
+      {...props}
+    />
+  )
+}
+
+function AttachmentTrigger({
+  className,
+  render,
+  type,
+  ...props
+}: useRender.ComponentProps<"button">) {
+  return useRender({
+    defaultTagName: "button",
+    props: mergeProps<"button">(
+      {
+        type: render ? type : (type ?? "button"),
+        className: cn("absolute inset-0 z-10 outline-none", className),
+      },
+      props
+    ),
+    render,
+    state: {
+      slot: "attachment-trigger",
+    },
+  })
+}
+
+function AttachmentGroup({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="attachment-group"
+      className={cn(
+        "flex min-w-0 scroll-fade-x snap-x snap-mandatory scroll-px-1 scrollbar-none gap-3 overflow-x-auto overscroll-x-contain py-1 *:data-[slot=attachment]:flex-none *:data-[slot=attachment]:snap-start",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export {
+  Attachment,
+  AttachmentGroup,
+  AttachmentMedia,
+  AttachmentContent,
+  AttachmentTitle,
+  AttachmentDescription,
+  AttachmentActions,
+  AttachmentAction,
+  AttachmentTrigger,
+}
diff --git a/frontend/components/ui/bubble.tsx b/frontend/components/ui/bubble.tsx
new file mode 100644
index 0000000..5e7a290
--- /dev/null
+++ b/frontend/components/ui/bubble.tsx
@@ -0,0 +1,128 @@
+import * as React from "react"
+import { mergeProps } from "@base-ui/react/merge-props"
+import { useRender } from "@base-ui/react/use-render"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+
+function BubbleGroup({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="bubble-group"
+      className={cn("flex min-w-0 flex-col gap-2", className)}
+      {...props}
+    />
+  )
+}
+
+const bubbleVariants = cva(
+  "group/bubble relative flex w-fit max-w-[80%] min-w-0 flex-col gap-1 group-data-[align=end]/message:self-end data-[align=end]:self-end data-[variant=ghost]:max-w-full",
+  {
+    variants: {
+      variant: {
+        default:
+          "*:data-[slot=bubble-content]:bg-primary *:data-[slot=bubble-content]:text-primary-foreground [&>[data-slot=bubble-content]:is(button,a):hover]:bg-primary/80",
+        secondary:
+          "*:data-[slot=bubble-content]:bg-secondary *:data-[slot=bubble-content]:text-secondary-foreground [&>[data-slot=bubble-content]:is(button,a):hover]:bg-[color-mix(in_oklch,var(--secondary),var(--foreground)_5%)]",
+        muted:
+          "*:data-[slot=bubble-content]:bg-muted [&>[data-slot=bubble-content]:is(button,a):hover]:bg-[color-mix(in_oklch,var(--muted),var(--foreground)_5%)]",
+        tinted:
+          "*:data-[slot=bubble-content]:bg-[oklch(from_var(--primary)_0.93_calc(c*0.4)_h)] *:data-[slot=bubble-content]:text-foreground dark:*:data-[slot=bubble-content]:bg-[oklch(from_var(--primary)_0.3_calc(c*0.4)_h)] [&>[data-slot=bubble-content]:is(button,a):hover]:bg-[oklch(from_var(--primary)_0.88_calc(c*0.5)_h)] dark:[&>[data-slot=bubble-content]:is(button,a):hover]:bg-[oklch(from_var(--primary)_0.35_calc(c*0.5)_h)]",
+        outline:
+          "*:data-[slot=bubble-content]:border-border *:data-[slot=bubble-content]:bg-background [&>[data-slot=bubble-content]:is(button,a):hover]:bg-muted [&>[data-slot=bubble-content]:is(button,a):hover]:text-foreground dark:[&>[data-slot=bubble-content]:is(button,a):hover]:bg-input/30",
+        ghost:
+          "border-none *:data-[slot=bubble-content]:rounded-none *:data-[slot=bubble-content]:bg-transparent *:data-[slot=bubble-content]:p-0 [&>[data-slot=bubble-content]:is(button,a):hover]:bg-muted [&>[data-slot=bubble-content]:is(button,a):hover]:text-foreground dark:[&>[data-slot=bubble-content]:is(button,a):hover]:bg-muted/50",
+        destructive:
+          "*:data-[slot=bubble-content]:bg-destructive/10 *:data-[slot=bubble-content]:text-destructive dark:*:data-[slot=bubble-content]:bg-destructive/20 [&>[data-slot=bubble-content]:is(button,a):hover]:bg-destructive/20 dark:[&>[data-slot=bubble-content]:is(button,a):hover]:bg-destructive/30",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+    },
+  }
+)
+
+function Bubble({
+  variant = "default",
+  align = "start",
+  className,
+  ...props
+}: React.ComponentProps<"div"> &
+  VariantProps<typeof bubbleVariants> & {
+    align?: "start" | "end"
+  }) {
+  return (
+    <div
+      data-slot="bubble"
+      data-variant={variant}
+      data-align={align}
+      className={cn(bubbleVariants({ variant }), className)}
+      {...props}
+    />
+  )
+}
+
+function BubbleContent({
+  className,
+  render,
+  ...props
+}: useRender.ComponentProps<"div">) {
+  return useRender({
+    defaultTagName: "div",
+    props: mergeProps<"div">(
+      {
+        className: cn(
+          "w-fit max-w-full min-w-0 overflow-hidden rounded-3xl border border-transparent px-3.5 py-2.5 text-sm leading-relaxed wrap-break-word group-data-[align=end]/bubble:self-end [button]:text-left [button,a]:transition-colors [button,a]:outline-none [button,a]:focus-visible:border-ring [button,a]:focus-visible:ring-3 [button,a]:focus-visible:ring-ring/30",
+          className
+        ),
+      },
+      props
+    ),
+    render,
+    state: {
+      slot: "bubble-content",
+    },
+  })
+}
+
+const bubbleReactionsVariants = cva(
+  "absolute z-10 flex w-fit shrink-0 items-center justify-center gap-1 rounded-full bg-muted px-1.5 py-0.5 text-sm ring-3 ring-card has-[button]:p-0",
+  {
+    variants: {
+      side: {
+        top: "top-0 -translate-y-3/4",
+        bottom: "bottom-0 translate-y-3/4",
+      },
+      align: {
+        start: "left-3",
+        end: "right-3",
+      },
+    },
+    defaultVariants: {
+      side: "bottom",
+      align: "end",
+    },
+  }
+)
+
+function BubbleReactions({
+  side = "bottom",
+  align = "end",
+  className,
+  ...props
+}: React.ComponentProps<"div"> & {
+  align?: "start" | "end"
+  side?: "top" | "bottom"
+}) {
+  return (
+    <div
+      data-slot="bubble-reactions"
+      data-align={align}
+      data-side={side}
+      className={cn(bubbleReactionsVariants({ side, align }), className)}
+      {...props}
+    />
+  )
+}
+
+export { BubbleGroup, Bubble, BubbleContent, BubbleReactions }
diff --git a/frontend/components/ui/message.tsx b/frontend/components/ui/message.tsx
new file mode 100644
index 0000000..fbc5e9f
--- /dev/null
+++ b/frontend/components/ui/message.tsx
@@ -0,0 +1,92 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+function MessageGroup({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="message-group"
+      className={cn("flex min-w-0 flex-col gap-2", className)}
+      {...props}
+    />
+  )
+}
+
+function Message({
+  className,
+  align = "start",
+  ...props
+}: React.ComponentProps<"div"> & { align?: "start" | "end" }) {
+  return (
+    <div
+      data-slot="message"
+      data-align={align}
+      className={cn(
+        "group/message relative flex w-full min-w-0 gap-2 text-sm data-[align=end]:flex-row-reverse",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function MessageAvatar({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="message-avatar"
+      className={cn(
+        "flex w-fit min-w-8 shrink-0 items-center justify-center self-end overflow-hidden rounded-full bg-muted group-has-data-[slot=message-footer]/message:-translate-y-8",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function MessageContent({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="message-content"
+      className={cn(
+        "flex w-full min-w-0 flex-col gap-2.5 wrap-break-word group-data-[align=end]/message:*:data-slot:self-end",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function MessageHeader({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="message-header"
+      className={cn(
+        "flex max-w-full min-w-0 items-center px-3.5 text-xs font-medium text-muted-foreground group-has-data-[variant=ghost]/message:px-0",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function MessageFooter({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="message-footer"
+      className={cn(
+        "flex max-w-full min-w-0 items-center px-3.5 text-xs font-medium text-muted-foreground group-has-data-[variant=ghost]/message:px-0 group-data-[align=end]/message:justify-end",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export {
+  MessageGroup,
+  Message,
+  MessageAvatar,
+  MessageContent,
+  MessageFooter,
+  MessageHeader,
+}