Log an event that happened "now" in one tap

Logging a quick pee/poo/meal/sleep boundary took two taps: open the note
dialog, then Save. Make a single tap on a quick-action log the event
immediately at the current time.

Non-weight quick actions now call addEvent(type, "", Date.now()) directly
and show a brief snackbar with Undo (deletes the just-added event) and Add
note (opens the edit dialog for it), so notes, photos and custom times are
never lost. Weigh-ins still open the dialog since they need a value.
addEvent now returns the created event so the snackbar can reference it.

src/app.js

@@ -258,7 +258,7 @@
   function addEvent(type, note, at, photoId, weight) {
     const events = loadAll();
     const now = Date.now();
-    events.push({
+    const ev = {
       id: uuid(),
       type,
       at: Number.isFinite(at) ? at : now,
@@ -266,10 +266,12 @@
       photoId: photoId || "",
       weight: Number.isFinite(weight) ? weight : undefined,
       updatedAt: now,
-    });
+    };
+    events.push(ev);
     saveAll(events);
     scheduleSync();
     render();
+    return ev;
   }
 
   function updateEvent(id, patch) {
@@ -1602,9 +1604,59 @@
     }
   });
 
+  // ---------- quick-log snackbar ----------
+  // A single tap on a quick-action logs the event at the current instant, then
+  // shows a brief snackbar to undo it or add detail — so the two-tap dialog flow
+  // is never required for a plain pee/poo/meal/sleep boundary. Weigh-ins still
+  // open the dialog since they need a value.
+  const snackbar     = document.getElementById("snackbar");
+  const snackbarMsg  = document.getElementById("snackbar-msg");
+  const snackbarUndo = document.getElementById("snackbar-undo");
+  const snackbarNote = document.getElementById("snackbar-note");
+  let snackbarEvent  = null;
+  let snackbarTimer  = null;
+
+  function hideSnackbar() {
+    clearTimeout(snackbarTimer);
+    snackbarTimer = null;
+    snackbarEvent = null;
+    snackbar.classList.remove("show");
+    snackbar.hidden = true;
+  }
+
+  function showSnackbar(msg, ev) {
+    snackbarEvent = ev;
+    snackbarMsg.textContent = msg;
+    snackbar.hidden = false;
+    void snackbar.offsetWidth; // reflow so the fade-in transition runs
+    snackbar.classList.add("show");
+    clearTimeout(snackbarTimer);
+    snackbarTimer = setTimeout(hideSnackbar, 5000);
+  }
+
+  function quickLog(type) {
+    const ev = addEvent(type, "", Date.now());
+    showSnackbar(`${EVENT_LABELS[type]} logged`, ev);
+  }
+
+  snackbarUndo.addEventListener("click", () => {
+    if (snackbarEvent) deleteEvent(snackbarEvent.id);
+    hideSnackbar();
+  });
+  snackbarNote.addEventListener("click", () => {
+    const ev = snackbarEvent;
+    hideSnackbar();
+    if (ev) openEditDialog(ev);
+  });
+
   // ---------- wiring ----------
   document.querySelectorAll("button.action").forEach(btn => {
-    btn.addEventListener("click", () => openNoteDialog(btn.dataset.type));
+    btn.addEventListener("click", () => {
+      const type = btn.dataset.type;
+      // Weigh-ins need a typed value, so they keep the full dialog.
+      if (type === "weight") { openNoteDialog(type); return; }
+      quickLog(type);
+    });
   });
 
   dayPicker.value = ymd(new Date());

src/index.html

@@ -303,6 +303,13 @@
       <img id="lightbox-img" alt="" />
     </dialog>
 
+    <!-- Brief confirmation after a one-tap quick log, with Undo / Add note. -->
+    <div id="snackbar" class="snackbar" hidden role="status" aria-live="polite">
+      <span id="snackbar-msg" class="snackbar-msg"></span>
+      <button type="button" id="snackbar-note" class="snackbar-action">Add note</button>
+      <button type="button" id="snackbar-undo" class="snackbar-action">Undo</button>
+    </div>
+
     <script src="app.js"></script>
   </body>
 </html>

src/style.css

@@ -696,3 +696,46 @@ input.switch:checked::after { transform: translateX(18px); }
   border: 1px solid rgba(255, 255, 255, 0.6);
 }
 .update-banner-btn:hover { filter: brightness(0.97); }
+
+/* ---------- quick-log snackbar ---------- */
+.snackbar {
+  position: fixed;
+  left: 50%;
+  bottom: calc(16px + env(safe-area-inset-bottom, 0));
+  transform: translate(-50%, 12px);
+  z-index: 60;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  max-width: calc(100% - 32px);
+  padding: 8px 8px 8px 16px;
+  background: var(--surface);
+  color: var(--text);
+  border: 1px solid var(--border);
+  border-radius: 999px;
+  box-shadow: var(--shadow);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity 0.18s ease, transform 0.18s ease;
+}
+.snackbar[hidden] { display: none; }
+.snackbar.show {
+  opacity: 1;
+  transform: translate(-50%, 0);
+  pointer-events: auto;
+}
+.snackbar-msg {
+  font-size: 0.9rem;
+  font-weight: 500;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+.snackbar-action {
+  background: transparent;
+  color: var(--accent);
+  font-weight: 700;
+  padding: 6px 10px;
+  flex-shrink: 0;
+}
+.snackbar-action:hover { filter: none; background: var(--accent-soft); }