qdpqut37t: Add the frosted bottom dock that likes and comments on the post on screen

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; }
 }