diff --git a/.claude/settings.json b/.claude/settings.json
new file mode 100644
index 0000000..7c09765
--- /dev/null
+++ b/.claude/settings.json
@@ -0,0 +1,18 @@
+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "if": "Bash(gh pr *)",
+            "command": "cmd=$(jq -r '.tool_input.command'); echo \"$cmd\" | grep -q 'gh pr create' || exit 0; (cd src-tauri && cargo fmt) 2>/dev/null; git diff --quiet src-tauri/src/ || { git add src-tauri/src/ && git commit -m 'style: apply cargo fmt'; }",
+            "statusMessage": "Running cargo fmt…",
+            "timeout": 60
+          }
+        ]
+      }
+    ]
+  }
+}
diff --git a/PRODUCT.md b/PRODUCT.md
new file mode 100644
index 0000000..a25f359
--- /dev/null
+++ b/PRODUCT.md
@@ -0,0 +1,36 @@
+# Product
+
+## Register
+
+product
+
+## Users
+
+Developers wanting a fast, local PDF compression tool — no account setup, no cloud dependency, no nonsense. Also "stumblers": people who find it on GitHub looking for the simplest solution that doesn't upload their files anywhere.
+
+## Product Purpose
+
+Compress PDFs entirely on-device. No internet, no account, no file size limits. Output goes where you tell it, stays on your machine. The value proposition is what it *doesn't* do: no uploads, no tracking, no friction.
+
+## Brand Personality
+
+Quiet competence. Unpretentious. Gets out of the way. A good tool doesn't announce itself — it just works. Three words: straightforward, capable, unobtrusive.
+
+## Anti-references
+
+- SaaS dashboards with hero metrics, gradient branding, and upsell nudges
+- Consumer apps with mascots, confetti, and celebration copy
+- Cloud services that make simple tasks feel like an onboarding flow
+- Anything that feels like a web app bolted into a native shell
+
+## Design Principles
+
+1. **Function is the feature** — every element earns its place by helping the user compress files, nothing else
+2. **Quiet when idle, clear when active** — feedback is proportional to what happened; don't over-celebrate routine tasks
+3. **Native to the OS** — feels like it could have shipped with macOS developer tools, not like a web app in a wrapper
+4. **Trust the user** — no hand-holding copy, no confirmation theater for reversible actions
+5. **Invisible when it works** — the best interaction is the one the user doesn't consciously notice
+
+## Accessibility & Inclusion
+
+Respects `prefers-reduced-motion` (already implemented). Supports system dark/light mode (already implemented). No additional requirements stated. WCAG AA color contrast as a baseline.
diff --git a/src/lib/components/ActionBar.svelte b/src/lib/components/ActionBar.svelte
index 839e6c3..764092f 100644
--- a/src/lib/components/ActionBar.svelte
+++ b/src/lib/components/ActionBar.svelte
@@ -1,5 +1,8 @@
 <script lang="ts">
   import { get, derived } from "svelte/store";
+  import { scale } from "svelte/transition";
+  import { cubicOut } from "svelte/easing";
+  const reducedMotion = typeof window !== "undefined" && window.matchMedia("(prefers-reduced-motion: reduce)").matches;
   import { invoke } from "@tauri-apps/api/core";
   import { listen } from "@tauri-apps/api/event";
   import { onDestroy, onMount } from "svelte";
@@ -124,7 +127,7 @@
   {/if}
   {#if $doneCount > 0 || $errorCount > 0}
     <div class="status-summary">
-      {#if $doneCount > 0}<span class="done-count">{$doneCount} done</span>{/if}
+      {#if $doneCount > 0}<span class="done-count" in:scale={{ duration: reducedMotion ? 0 : 200, start: 0.6, easing: cubicOut }}>{$doneCount} done</span>{/if}
       {#if $errorCount > 0}<span class="error-count">{$errorCount} error{$errorCount > 1 ? "s" : ""}</span>{/if}
     </div>
   {/if}
@@ -147,8 +150,13 @@
 
 <style>
   .action-bar { height: var(--action-bar-height); padding: 8px 12px; border-top: 1px solid var(--border); display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
-  .compress-btn { flex: 1; height: 36px; background: var(--accent); color: white; border: none; border-radius: var(--radius-md); font-size: 13px; font-weight: 600; font-family: var(--font-ui); cursor: pointer; transition: background 0.1s, opacity 0.15s; }
-  .compress-btn:hover:not(:disabled) { background: var(--accent-hover); }
+  .compress-btn { flex: 1; height: 36px; background: var(--accent); color: white; border: none; border-radius: var(--radius-md); font-size: 13px; font-weight: 600; font-family: var(--font-ui); cursor: pointer; transition: background 0.1s, opacity 0.15s, transform 0.08s, box-shadow 0.12s; }
+  .compress-btn:hover:not(:disabled) { background: var(--accent-hover); box-shadow: 0 2px 10px oklch(59% 0.17 251 / 0.38); transform: translateY(-1px); }
+  .compress-btn:active:not(:disabled) { transform: scale(0.97); box-shadow: none; }
+  @media (prefers-reduced-motion: reduce) {
+    .compress-btn:hover:not(:disabled) { transform: none; }
+    .compress-btn { transition: background 0.1s, opacity 0.15s; }
+  }
   .compress-btn:disabled { opacity: 0.4; cursor: not-allowed; }
   .clear-btn { height: 36px; padding: 0 14px; background: none; border: 1px solid var(--border); border-radius: var(--radius-md); color: var(--text-secondary); font-size: 13px; cursor: pointer; white-space: nowrap; transition: background 0.1s; }
   .clear-btn:hover { background: var(--bg-tertiary); }
diff --git a/src/lib/components/DetailPanel.svelte b/src/lib/components/DetailPanel.svelte
index e2a6259..1f5349a 100644
--- a/src/lib/components/DetailPanel.svelte
+++ b/src/lib/components/DetailPanel.svelte
@@ -1,5 +1,8 @@
 <script lang="ts">
   import { derived } from "svelte/store";
+  import { tweened } from "svelte/motion";
+  import { cubicOut } from "svelte/easing";
+  import { fly } from "svelte/transition";
   import { open } from "@tauri-apps/plugin-dialog";
   import { queue, type Preset } from "$lib/stores/queueStore";
   import { selectedFileId } from "$lib/stores/selectionStore";
@@ -9,6 +12,10 @@
 
   const selectedFile = derived([queue, selectedFileId], ([$q, $id]) => $q.find((e) => e.id === $id) ?? null);
 
+  const reducedMotion = typeof window !== "undefined" && window.matchMedia("(prefers-reduced-motion: reduce)").matches;
+  const animatedPct = tweened(0, { duration: reducedMotion ? 0 : 700, easing: cubicOut });
+  const animatedRatio = tweened(0, { duration: reducedMotion ? 0 : 750, easing: cubicOut });
+
   $: hasFiles = $queue.length > 0;
 
   function savingsPct(original: number, compressed: number): string {
@@ -37,6 +44,24 @@
   $: sliderMax = presetDpiRanges[currentPreset][2];
   $: sliderValue = $selectedFile?.dpiOverride ?? presetDpiRanges[currentPreset][1];
 
+  $: {
+    if ($selectedFile?.status === "done" && $selectedFile.compressedSize !== undefined) {
+      const pct = Math.round((($selectedFile.size - $selectedFile.compressedSize) / $selectedFile.size) * 100);
+      const ratio = ($selectedFile.size - $selectedFile.compressedSize) / $selectedFile.size;
+      (async () => {
+        await Promise.all([
+          animatedPct.set(0, { duration: 0 }),
+          animatedRatio.set(0, { duration: 0 }),
+        ]);
+        animatedPct.set(pct);
+        animatedRatio.set(ratio);
+      })();
+    } else {
+      animatedPct.set(0, { duration: 0 });
+      animatedRatio.set(0, { duration: 0 });
+    }
+  }
+
   let outputMode: "same_as_source" | "custom_folder" = $settings.output_mode;
   let naming: "suffix" | "overwrite" = $settings.naming;
 
@@ -78,8 +103,11 @@
       <div class="sizes">
         <div class="size-row"><span class="label">Original</span><span>{formatBytes($selectedFile.size)}</span></div>
         {#if $selectedFile.status === "done" && $selectedFile.compressedSize !== undefined}
-          <div class="result-block">
-            <div class="savings-pct">{savingsPct($selectedFile.size, $selectedFile.compressedSize)}</div>
+          <div class="result-block" in:fly={{ y: 6, duration: reducedMotion ? 0 : 280, easing: cubicOut }}>
+            <div class="savings-pct">−{Math.round($animatedPct)}%</div>
+            <div class="savings-bar-track" aria-hidden="true">
+              <div class="savings-bar-fill" style="transform: scaleX({$animatedRatio})"></div>
+            </div>
             <div class="size-story">
               {formatBytes($selectedFile.size)} → {formatBytes($selectedFile.compressedSize)}
               · saved {formatBytes($selectedFile.size - $selectedFile.compressedSize)}
@@ -217,6 +245,21 @@
   .label { color: var(--text-tertiary); }
 
   .result-block { display: flex; flex-direction: column; gap: 6px; margin-top: 4px; }
+  .savings-bar-track {
+    height: 2px;
+    background: var(--border);
+    border-radius: 1px;
+    overflow: hidden;
+    margin: 0 0 2px;
+  }
+  .savings-bar-fill {
+    height: 100%;
+    width: 100%;
+    background: var(--success);
+    border-radius: 1px;
+    transform-origin: left;
+    transform: scaleX(0);
+  }
   .savings-pct {
     font-family: var(--font-display);
     font-size: 28px;
diff --git a/src/lib/components/Sidebar.svelte b/src/lib/components/Sidebar.svelte
index 2cc7c7a..e282226 100644
--- a/src/lib/components/Sidebar.svelte
+++ b/src/lib/components/Sidebar.svelte
@@ -1,16 +1,33 @@
 <script lang="ts">
   import { onMount, onDestroy } from "svelte";
+  import { scale, fly } from "svelte/transition";
+  import { cubicOut } from "svelte/easing";
+  const reducedMotion = typeof window !== "undefined" && window.matchMedia("(prefers-reduced-motion: reduce)").matches;
   import { listen } from "@tauri-apps/api/event";
   import { queue } from "$lib/stores/queueStore";
   import { selectedFileId } from "$lib/stores/selectionStore";
   import { addFiles, addPath } from "$lib/fileActions";
 
   let isDragOver = false;
+  let dragDepth = 0;
   let unlistenDrop: (() => void) | undefined;
 
+  function onDragEnter() {
+    dragDepth++;
+    isDragOver = true;
+  }
+
+  function onDragLeave() {
+    if (--dragDepth <= 0) {
+      dragDepth = 0;
+      isDragOver = false;
+    }
+  }
+
   onMount(async () => {
     unlistenDrop = await listen<{ paths: string[] }>("tauri://drag-drop", (event) => {
       isDragOver = false;
+      dragDepth = 0;
       for (const path of event.payload.paths) addPath(path);
     });
   });
@@ -21,14 +38,15 @@
 <aside
   class="sidebar"
   class:drag-over={isDragOver}
-  on:dragover|preventDefault={() => (isDragOver = true)}
-  on:dragleave={() => (isDragOver = false)}
+  on:dragenter={onDragEnter}
+  on:dragleave={onDragLeave}
+  on:dragover|preventDefault={() => {}}
   role="region"
   aria-label="File queue"
 >
   <div class="header">
     Queue
-    {#if $queue.length > 0}<span class="count">{$queue.length}</span>{/if}
+    {#if $queue.length > 0}<span class="count" in:scale={{ duration: reducedMotion ? 0 : 200, start: 0.5, easing: cubicOut }}>{$queue.length}</span>{/if}
   </div>
 
   {#if $queue.length === 0}
@@ -47,9 +65,11 @@
           on:click={() => selectedFileId.set(entry.id)}
           tabindex="0"
           on:keydown={(e) => e.key === "Enter" && selectedFileId.set(entry.id)}
+          in:fly={{ y: reducedMotion ? 0 : -6, duration: reducedMotion ? 0 : 180, easing: cubicOut }}
+          out:fly={{ x: reducedMotion ? 0 : -12, duration: reducedMotion ? 0 : 130, easing: cubicOut }}
         >
           <span class="status-icon" class:done={entry.status === "done"} class:error={entry.status === "error"} class:processing={entry.status === "processing"}>
-            {#if entry.status === "done"}✓{:else if entry.status === "error"}✕{:else if entry.status === "processing"}<span class="spinner"></span>{:else}○{/if}
+            {#if entry.status === "done"}<span in:scale={{ duration: reducedMotion ? 0 : 220, start: 0.4, easing: cubicOut }}>✓</span>{:else if entry.status === "error"}✕{:else if entry.status === "processing"}<span class="spinner"></span>{:else}○{/if}
           </span>
           <span class="filename">{entry.name}</span>
           <button
@@ -75,9 +95,23 @@
     border-top: 1px solid var(--border);
     overflow: hidden;
     flex-shrink: 0;
+    transition: background 0.2s, border-top-color 0.2s;
+  }
+  .sidebar.drag-over {
+    background: color-mix(in oklch, var(--bg-secondary), var(--accent) 8%);
+    border-top-color: var(--accent);
+  }
+  .sidebar.drag-over .empty {
+    border-color: var(--accent);
+    color: var(--accent);
+    box-shadow: 0 0 0 3px color-mix(in oklch, var(--accent), transparent 80%);
+    animation: drop-zone-enter 0.35s cubic-bezier(0.16, 1, 0.3, 1) both;
+  }
+  @keyframes drop-zone-enter {
+    0%   { transform: scale(1); }
+    55%  { transform: scale(1.022); }
+    100% { transform: scale(1.01); }
   }
-  .sidebar.drag-over { background: color-mix(in oklch, var(--bg-secondary), var(--accent) 8%); }
-  .sidebar.drag-over .empty { border-color: var(--accent); color: var(--accent); }
   .header {
     padding: 8px 12px 4px;
     font-size: var(--text-sm);
@@ -112,7 +146,13 @@
     margin: 8px;
     border: 1.5px dashed var(--border);
     border-radius: var(--radius-md);
-    transition: border-color 0.15s, color 0.15s;
+    transform-origin: center;
+    transition: border-color 0.2s, color 0.2s, box-shadow 0.2s, transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
+  }
+  @media (prefers-reduced-motion: reduce) {
+    .sidebar { transition: none; }
+    .empty { transition: border-color 0.15s, color 0.15s; }
+    .sidebar.drag-over .empty { animation: none; box-shadow: none; }
   }
   .empty-title { font-size: 12px; color: var(--text-secondary); font-weight: var(--weight-medium); }
   .empty-sub { font-size: 10px; color: var(--text-tertiary); margin-top: 4px; }