Make the armed reset a centred, unwinding ring in the button flash colour

The old confirmation ring was a scaling, fading border. It sat off-centre —
the ::before had no top/left, so it landed on its static position in the
grid rather than over the icon — and it read as a shrinking circle rather
than time running out.

It's now an SVG ring animated on stroke-dashoffset (0 to 113.1, the
circumference at r=18) and rotated -90deg to start at 12 o'clock, so it
unwinds like a progress ring in reverse over the same 2s as the timeout.
Explicitly centred on the button.

The stroke is currentColor against #reset.armed{color:var(--icon-hot)},
so it uses the pale flash every button already shows on :active instead of
the theme accent, and no longer changes with the colour setting.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

public_html/README.md

@@ -35,7 +35,7 @@ except installation and the service worker.
 - The bar under the big time is the delay draining. When it empties you get a
   soft tick and your reserve starts moving. That's the moment worth hearing.
 - **Reset** returns to the starting position. It takes two taps: the first arms
-  the button — it turns your accent colour and a ring drains — and a second tap
+  the button — it lights up and a ring unwinds around it — and a second tap
   within those two seconds does it. One stray thumb can't wipe a live game.
 - **Pause** freezes mid-turn and resumes exactly where it stopped, delay
   included. Opening settings pauses automatically, and leaves it paused so the

public_html/index.html

@@ -149,18 +149,29 @@
   .btn svg[hidden]{display:none}
   .btn:focus-visible{outline:2px solid var(--icon-hot);outline-offset:-6px;border-radius:8px}
 
-  /* reset armed for a second tap — the ring drains over the same 2s as the timeout */
+  /* reset armed for a second tap — the ring unwinds over the same 2s as the timeout */
   #reset{position:relative}
-  #reset.armed{color:var(--accent)}
-  #reset.armed::before{
-    content:"";position:absolute;
-    width:clamp(36px,9vw,48px);aspect-ratio:1;
-    border-radius:50%;border:2px solid var(--accent);
-    animation:drain 2s linear forwards;
+  #reset.armed{color:var(--icon-hot)}
+  #reset .ring{
+    position:absolute;
+    top:50%;left:50%;
+    width:clamp(36px,9.6vw,48px);height:clamp(36px,9.6vw,48px);
+    transform:translate(-50%,-50%) rotate(-90deg);   /* start the arc at 12 o'clock */
+    display:none;
+    pointer-events:none;
   }
-  @keyframes drain{
-    from{opacity:1;transform:scale(1)}
-    to{opacity:0;transform:scale(.72)}
+  #reset.armed .ring{display:block}
+  #reset .ring circle{
+    fill:none;
+    stroke:currentColor;                             /* the same flash the buttons use */
+    stroke-width:2.6;
+    stroke-linecap:round;
+    stroke-dasharray:113.1;                          /* 2πr, r=18 */
+    animation:unwind 2s linear forwards;
+  }
+  @keyframes unwind{
+    from{stroke-dashoffset:0}
+    to{stroke-dashoffset:113.1}
   }
 
   /* ---------- settings sheet ---------- */
@@ -292,6 +303,7 @@
 
   <div class="bar">
     <button class="btn" id="reset" aria-label="Reset clock">
+      <svg class="ring" viewBox="0 0 40 40" aria-hidden="true"><circle cx="20" cy="20" r="18"/></svg>
       <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.2" stroke-linecap="round" stroke-linejoin="round">
         <path d="M20 5v6h-6"/><path d="M20 11a8 8 0 1 0-2.3 5.3"/>
       </svg>