Toast new events into the Event Log button

When the Event Log is collapsed, a freshly-arrived event now flashes as
a toast anchored above the button, then animates down and fades into it.
Suppressed on the initial state load and on rollback reseeds so it only
fires for genuinely new events; clicking the toast opens the log.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

TODO.md

@@ -18,7 +18,7 @@
 
 - [x] The back button on the admin page should go back to the active game, not the join screen
 
-- [ ] Add a toast pop-up for new events entering the event log, that then fades into the event log button
+- [x] Add a toast pop-up for new events entering the event log, that then fades into the event log button
 
 - [ ] When you get a gat, there should be a pop up to enter a description of it, as with your name
 

frontend/src/components/EventLog.svelte

@@ -35,6 +35,11 @@
     let atBottom = true;
     let error = '';
     let timelineVersion = null;
+    // Toast that briefly previews a freshly-arrived event while the log is
+    // collapsed, then animates down into the Event Log button.
+    let toast = null;        // { id, message, kind }
+    let initialized = false; // suppresses a toast flood on the first state load
+
 
     // Rollback buttons appear during a scene, for Admins and Deep players (server-enforced too).
     $: canRollback = state.game?.phase === 'scene'
@@ -57,20 +62,24 @@
         // action from a rolled-back state truncates the abandoned future and bumps the
         // version, which tells us to drop what we'd accumulated and reseed.
         const version = state.game?.rollback_timeline_version ?? 0;
+        let reset = false;
         if (timelineVersion !== null && version !== timelineVersion) {
             events = [];
             seenIds = new Set();
+            reset = true;
         }
         timelineVersion = version;
         if (events.length === 0) {
             haveMore = state.events_have_more ?? polled.length >= PAGE_SIZE;
         }
         let added = false;
+        let newest = null;
         for (const e of polled) {
             if (!seenIds.has(e.id)) {
                 seenIds.add(e.id);
                 events.push(e);
                 added = true;
+                newest = e;
             }
         }
         if (added) {
@@ -79,8 +88,21 @@
                 await tick();
                 scrollToBottom();
             }
+            // Toast only for genuinely new events (not the initial seed or a
+            // rollback reseed) and only while the log is closed.
+            if (initialized && !reset && !open && newest) {
+                toast = { id: newest.id, message: newest.message, kind: newest.kind || 'info' };
             }
         }
+        initialized = true;
+    }
+
+    // Opening the log makes the preview redundant.
+    $: if (open) toast = null;
+
+    function clearToast(id) {
+        if (toast && toast.id === id) toast = null;
+    }
 
     function scrollToBottom() {
         if (logEl) logEl.scrollTop = logEl.scrollHeight;
@@ -149,6 +171,19 @@
 </script>
 
 <div class="floating-event-log {open ? 'open' : ''}">
+    {#if toast && !open}
+        {#key toast.id}
+            <button
+                class="event-toast log-kind-{toast.kind}"
+                title="Open the Event Log"
+                on:click={toggleOpen}
+                on:animationend={() => clearToast(toast.id)}
+            >
+                <span class="log-icon">{KIND_ICONS[toast.kind] || KIND_ICONS.info}</span>
+                <span class="toast-message">{toast.message}</span>
+            </button>
+        {/key}
+    {/if}
     <button class="toggle-log-btn" on:click={toggleOpen}>
         {open ? '⬇️ Hide Log' : '📜 Event Log'}
     </button>
@@ -352,6 +387,48 @@
         filter: brightness(1.1);
     }
 
+    /* Toast preview of a fresh event, anchored above the button */
+    .event-toast {
+        position: absolute;
+        bottom: calc(100% + 8px);
+        right: 0;
+        width: 320px;
+        max-width: 80vw;
+        display: flex;
+        align-items: center;
+        gap: 8px;
+        text-align: left;
+        padding: 10px 12px;
+        background: color-mix(in srgb, var(--bg-deep) 95%, transparent);
+        border: 1px solid var(--edge);
+        border-left: 4px solid var(--accent);
+        border-radius: var(--radius-md);
+        box-shadow: var(--shadow-deep);
+        backdrop-filter: blur(10px);
+        color: var(--text);
+        font-family: var(--font-body);
+        cursor: pointer;
+        transform-origin: bottom right;
+        animation: event-toast-into-button 3.4s ease-in forwards;
+    }
+    .event-toast .toast-message {
+        flex: 1;
+        font-size: 0.85rem;
+        overflow: hidden;
+        display: -webkit-box;
+        -webkit-line-clamp: 2;
+        -webkit-box-orient: vertical;
+    }
+    @keyframes event-toast-into-button {
+        0%   { opacity: 0; transform: translateY(-6px) scale(0.96); }
+        8%   { opacity: 1; transform: translateY(0) scale(1); }
+        75%  { opacity: 1; transform: translateY(0) scale(1); }
+        100% { opacity: 0; transform: translateY(40px) scale(0.4); }
+    }
+    @media (prefers-reduced-motion: reduce) {
+        .event-toast { animation-duration: 2.5s; animation-timing-function: linear; }
+    }
+
     /* Accent colors by event kind */
     .log-kind-challenge { border-left-color: var(--danger); }
     .log-kind-card { border-left-color: var(--deep); }