src/components/FeedView.tsx

@@ -40,10 +40,16 @@ export interface FeedViewProps {
   now?: number;
   /** Another page can load; the phone feed ends with a loading slide. */
   hasMore?: boolean;
-  /** Phone layout only: the slide on screen changed (for the dock). */
   /** Phone layout only: experts for the featured slide after the second post. */
   featuredExperts?: DiscoverExpert[];
+  /** Phone layout only: the slide on screen changed (for the dock). */
   onCurrentChange?: (slide: CurrentSlide) => void;
+  /** Phone layout only: the dock's comments button, for the post on screen. */
+  onOpenComments?: (postId: string) => void;
+  /** Phone layout only: the dock's new-post button. */
+  onOpenComposer?: () => void;
+  /** Phone layout only: the dock's More button (the Discover sheet). */
+  onOpenMore?: () => void;
 }
 
 function Spinner() {

src/components/MobileDock.tsx

@@ -0,0 +1,102 @@
+"use client";
+
+import { useState } from "react";
+import { commentsLabel } from "@/lib/feed-model";
+import { SparkleButton } from "./Buttons";
+import type { CurrentSlide } from "./MobileFeed";
+import type { CardPost } from "@/lib/feed-model";
+
+const icon = {
+  viewBox: "0 0 24 24",
+  fill: "none",
+  stroke: "currentColor",
+  strokeWidth: 1.7,
+  strokeLinecap: "round" as const,
+  strokeLinejoin: "round" as const,
+  "aria-hidden": true,
+};
+
+export interface MobileDockProps {
+  /** The slide on screen; like and comments act on its post. */
+  slide: CurrentSlide;
+  onToggleLike?: (post: CardPost) => void;
+  likeBusy?: boolean;
+  onOpenComments?: (postId: string) => void;
+  onOpenComposer?: () => void;
+  onOpenMore?: () => void;
+}
+
+/** What the like and comment buttons show and whether they work, for the slide on screen. */
+export function dockState(slide: CurrentSlide, opts: { canLike?: boolean; likeBusy?: boolean } = {}) {
+  const post = slide.kind === "post" ? slide.post : null;
+  if (!post) {
+    return { post: null, liked: false, likes: null, comments: null, likeLabel: "Like", commentsLabel: "Comments", likeDisabled: true, commentsDisabled: true };
+  }
+  return {
+    post,
+    liked: post.isLiked,
+    likes: post.likesCount,
+    comments: post.commentsCount,
+    likeLabel: post.isLiked ? `Unlike, ${post.likesCount} likes` : `Like, ${post.likesCount} likes`,
+    commentsLabel: `Open comments, ${commentsLabel(post.commentsCount).toLowerCase()}`,
+    likeDisabled: !post.id || !opts.canLike || !!opts.likeBusy,
+    commentsDisabled: !post.id,
+  };
+}
+
+/**
+ * Phone dock (spec "Mobile layout" > "Bottom dock"): a frosted bar 16px above the
+ * bottom. Like and comments act on the post on screen and are disabled on the
+ * featured and loading slides. Liked state and counts come from the post itself,
+ * the same source as the desktop like button and double-tap.
+ */
+export function MobileDock({ slide, onToggleLike, likeBusy, onOpenComments, onOpenComposer, onOpenMore }: MobileDockProps) {
+  const s = dockState(slide, { canLike: !!onToggleLike, likeBusy });
+  const [beat, setBeat] = useState(false);
+  return (
+    <nav className="dock" aria-label="Post actions" data-testid="feed-dock">
+      <button
+        type="button"
+        className={`dk dk-like${s.liked ? " dk-like-on" : ""}${beat && s.liked ? " dk-beat" : ""}`}
+        aria-pressed={s.liked}
+        aria-label={s.likeLabel}
+        disabled={s.likeDisabled}
+        onClick={() => {
+          if (!s.post) return;
+          setBeat(!s.post.isLiked);
+          onToggleLike?.(s.post);
+        }}
+        onAnimationEnd={() => setBeat(false)}
+      >
+        <svg {...icon} fill={s.liked ? "currentColor" : "none"}>
+          <path d="M12 20.5s-7.5-4.4-9.4-9.1C1.3 8 3.1 4.5 6.6 4.5c2 0 3.5 1.1 4.3 2.4.5.7 1.7.7 2.2 0 .8-1.3 2.3-2.4 4.3-2.4 3.5 0 5.3 3.5 4 6.9-1.9 4.7-9.4 9.1-9.4 9.1z" />
+        </svg>
+        {s.likes !== null ? <span className="dk-n" data-testid="dock-likes">{s.likes}</span> : null}
+      </button>
+      <button
+        type="button"
+        className="dk dk-comments"
+        aria-label={s.commentsLabel}
+        disabled={s.commentsDisabled}
+        onClick={() => {
+          if (s.post?.id) onOpenComments?.(s.post.id);
+        }}
+      >
+        <svg {...icon}>
+          <path d="M21 12a8.5 8.5 0 0 1-12.4 7.6L3.5 21l1.4-4.6A8.5 8.5 0 1 1 21 12z" />
+        </svg>
+        {s.comments !== null ? <span className="dk-n" data-testid="dock-comments">{s.comments}</span> : null}
+      </button>
+      <SparkleButton variant="fab" label="New post" className="dk-plus" onClick={() => onOpenComposer?.()} />
+      <button type="button" className="dk dk-more" aria-label="View more" onClick={() => onOpenMore?.()}>
+        <svg {...icon}>
+          <rect x="3.5" y="3.5" width="7" height="7" rx="2" />
+          <rect x="13.5" y="3.5" width="7" height="7" rx="2" />
+          <rect x="3.5" y="13.5" width="7" height="7" rx="2" />
+          <rect x="13.5" y="13.5" width="7" height="7" rx="2" />
+        </svg>
+        More
+      </button>
+    </nav>
+  );
+}

src/components/MobileFeed.tsx

@@ -7,6 +7,7 @@ import { HexAvatar } from "./HexAvatar";
 import { PlayIcon, PostMenu } from "./PostCard";
 import { VideoPlayer } from "./VideoPlayer";
 import { FeaturedCarousel } from "./FeaturedCarousel";
+import { MobileDock } from "./MobileDock";
 import type { DiscoverExpert } from "@/lib/discover";
 import type { FeedViewProps } from "./FeedView";
 
@@ -415,6 +416,16 @@ export function MobileFeed(p: FeedViewProps) {
           />
         ) : null}
       </div>
+      {p.status !== "error" ? (
+        <MobileDock
+          slide={{ index, kind, post: currentPost }}
+          onToggleLike={p.onToggleLike}
+          likeBusy={currentPost ? p.likeBusy?.has(currentPost.key) : false}
+          onOpenComments={p.onOpenComments}
+          onOpenComposer={p.onOpenComposer}
+          onOpenMore={p.onOpenMore}
+        />
+      ) : null}
     </section>
   );
 }

src/styles/mobile.css

@@ -73,7 +73,7 @@
   position: absolute;
   left: 0;
   right: 0;
-  bottom: 84px;
+  bottom: 90px;
   z-index: 4;
   display: flex;
   justify-content: center;
@@ -320,12 +320,60 @@
 }
 .reel-pill > * { pointer-events: auto; }
 
+/* Bottom dock (spec "Bottom dock"): a frosted bar 16px above the bottom. Like and
+   comments act on the post on screen. Disabled buttons stay fully opaque and use
+   a solid muted ink instead of fading. */
+.dock {
+  position: absolute;
+  left: 12px;
+  right: 12px;
+  bottom: calc(16px + env(safe-area-inset-bottom, 0px));
+  z-index: 30;
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  padding: 6px;
+  border-radius: 22px;
+  background: var(--glass);
+  -webkit-backdrop-filter: blur(24px) saturate(1.8);
+  backdrop-filter: blur(24px) saturate(1.8);
+  box-shadow: var(--shadow-pop), inset 0 0 0 1px var(--line);
+}
+.dk {
+  appearance: none;
+  flex: 1;
+  min-width: 44px;
+  height: 52px;
+  padding: 0;
+  border: 0;
+  border-radius: 16px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  background: transparent;
+  color: var(--ink);
+  font-size: 14px;
+  font-weight: 700;
+  font-variant-numeric: tabular-nums;
+  cursor: pointer;
+  transition: background-color .25s, color .25s;
+}
+.dk svg { width: 22px; height: 22px; flex: none; }
+@media (hover: hover) { .dk:hover:not(:disabled) { background: var(--tile-3); } }
+.dk:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }
+.dk.dk-like-on { color: var(--accent); }
+.dk-beat svg { animation: post-beat .5s cubic-bezier(.2,.9,.3,1.4); }
+.dk:disabled { opacity: 1; color: var(--ink-3); cursor: default; }
+.btn-spark.btn-spark-fab.dk-plus { flex: 0 0 64px; width: 64px; height: 52px; }
+
 @media (prefers-reduced-motion: reduce) {
   .is-cur .slide-meta,
   .is-cur .slide-quote-w,
   .slide-skel i,
   .slide-burst,
   .slide-hint svg,
-  .reel-pill { animation: none !important; }
+  .reel-pill,
+  .dk-beat svg { animation: none !important; }
   .slide-art { transition: none !important; }
 }

tests/mobile-dock.test.ts

@@ -0,0 +1,80 @@
+import { describe, expect, it } from "vitest";
+import { createElement } from "react";
+import { renderToStaticMarkup } from "react-dom/server";
+import { readFileSync } from "node:fs";
+import { FeedView, type FeedViewProps } from "@/components/FeedView";
+import { MobileDock, dockState } from "@/components/MobileDock";
+import { CompactLayoutContext } from "@/components/layout-context";
+import { toCardPosts } from "@/lib/feed-model";
+
+const item = (id: string, likes: number, comments: number, liked = false) => ({
+  type: "post",
+  publishedAt: "2026-10-19T11:00:00Z",
+  likesCount: likes,
+  commentsCount: comments,
+  isLiked: liked,
+  post: { id, content: `text ${id}`, author: { id: "a", displayName: `Author ${id}` }, mediaItems: [] },
+});
+const POSTS = toCardPosts([item("p1", 12, 3), item("p2", 40, 1, true)]);
+
+function feed(over: Partial<FeedViewProps>, compact = true) {
+  const props: FeedViewProps = {
+    posts: POSTS, status: "ready", loadingMore: false, loadMoreFailed: false,
+    newCount: 0, onRetry: () => {}, onShowNew: () => {}, onToggleLike: () => {}, ...over,
+  };
+  return renderToStaticMarkup(createElement(CompactLayoutContext.Provider, { value: compact }, createElement(FeedView, props)));
+}
+
+describe("dock state", () => {
+  it("shows the counts and liked state of the post on screen", () => {
+    const s = dockState({ index: 1, kind: "post", post: POSTS[1] }, { canLike: true });
+    expect(s.likes).toBe(POSTS[1].likesCount);
+    expect(s.comments).toBe(POSTS[1].commentsCount);
+    expect(s.liked).toBe(POSTS[1].isLiked);
+    expect(s.likeDisabled).toBe(false);
+    expect(s.commentsDisabled).toBe(false);
+  });
+  it("disables like and comments on the featured and loading slides", () => {
+    for (const kind of ["featured", "load"] as const) {
+      const s = dockState({ index: 2, kind, post: null });
+      expect(s.likeDisabled).toBe(true);
+      expect(s.commentsDisabled).toBe(true);
+      expect(s.likes).toBeNull();
+    }
+  });
+  it("disables like while the like call is in flight", () => {
+    expect(dockState({ index: 0, kind: "post", post: POSTS[0] }, { canLike: true, likeBusy: true }).likeDisabled).toBe(true);
+  });
+});
+
+describe("dock markup", () => {
+  it("renders like with aria-pressed, comments, the sparkle new-post button and More", () => {
+    const out = renderToStaticMarkup(createElement(MobileDock, { slide: { index: 1, kind: "post", post: POSTS[1] }, onToggleLike: () => {} }));
+    expect(out).toContain('aria-label="Post actions"');
+    expect(out).toMatch(/class="dk dk-like dk-like-on"[^>]*aria-pressed="true"/);
+    expect(out).toContain(`>${POSTS[1].likesCount}</span>`);
+    expect(out).toContain(`Open comments, ${POSTS[1].commentsCount} comment`);
+    expect(out).toContain("btn-spark btn-spark-fab dk-plus");
+    expect(out).not.toContain("btn-spark-fold");
+    expect(out).toContain('aria-label="View more"');
+  });
+  it("is part of the phone feed and follows the first slide", () => {
+    const out = feed({});
+    expect(out).toContain('data-testid="feed-dock"');
+    expect(out).toContain(`data-testid="dock-likes">${POSTS[0].likesCount}<`);
+  });
+  it("is absent on desktop", () => {
+    expect(feed({}, false)).not.toContain("feed-dock");
+  });
+});
+
+describe("dock stylesheet", () => {
+  const css = readFileSync("src/styles/mobile.css", "utf8");
+  it("floats 16px above the bottom on frosted glass", () => {
+    expect(css).toMatch(/\.dock \{[^}]*bottom: calc\(16px[^}]*backdrop-filter: blur/);
+  });
+  it("keeps touch targets at least 44px and disabled buttons fully opaque", () => {
+    expect(css).toMatch(/\.dk \{[^}]*min-width: 44px;[^}]*height: 52px/);
+    expect(css).toMatch(/\.dk:disabled \{ opacity: 1;/);
+  });
+});