diff --git a/src/automata/npda.rs b/src/automata/npda.rs
index 52af692..6519b32 100644
--- a/src/automata/npda.rs
+++ b/src/automata/npda.rs
@@ -211,8 +211,9 @@ impl Npda {
                                 State(0)
                             }
                         };
-                        if states.insert(ident, state).is_some() {
+                        if let Some(old) = states.insert(ident, state) {
                             ctx.emit_error("state redefined", item.1);
+                            states.insert(ident, old);
                         }
                     }
 
@@ -284,8 +285,9 @@ impl Npda {
                                 Symbol(0)
                             }
                         };
-                        if stack_symbols.insert(ident, symbol).is_some() {
+                        if let Some(old) = stack_symbols.insert(ident, symbol) {
                             ctx.emit_error("stack symbol redefined", item.1);
+                            stack_symbols.insert(ident, old);
                         }
                     }
 
diff --git a/web/root/assets/icon.jpg b/web/root/assets/icon.jpg
new file mode 100644
index 0000000..f5d649c
Binary files /dev/null and b/web/root/assets/icon.jpg differ
diff --git a/web/root/index.html b/web/root/index.html
index efb9044..7964d62 100644
--- a/web/root/index.html
+++ b/web/root/index.html
@@ -6,6 +6,7 @@
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Automata</title>
 
+    <link rel="icon" type="image/x-icon" href="icon.jpg">
     <link href="style.css" rel="stylesheet">
 </head>
 
@@ -36,7 +37,7 @@
 
         <div class="hSplit" style="--split-default: 50%" title="Drag to resize canvas height"></div>
 
-        <div style="padding-bottom: 10px">
+        <div class="flexCol">
             <div class="controls" style="background: var(--bg-0)">
                 <button id="togglePhysics" class="btn btn-toggle active" title="Toggle physics layout">
                     Physics: ON
diff --git a/web/root/src/controls.ts b/web/root/src/controls.ts
index c4d2441..58a6f38 100644
--- a/web/root/src/controls.ts
+++ b/web/root/src/controls.ts
@@ -27,6 +27,7 @@ togglePhysicsBtn.onclick = () => {
   const enabled = !togglePhysicsBtn.classList.contains("active");
   setPhysicsButtonUI(enabled);
   network.setOptions({ physics: { enabled } });
+  network.setOptions({edges: {smooth: enabled}});
 };
 
 setPhysicsButtonUI(togglePhysicsBtn.classList.contains("active"));
diff --git a/web/root/src/splitters.ts b/web/root/src/splitters.ts
index a321282..89bc5ba 100644
--- a/web/root/src/splitters.ts
+++ b/web/root/src/splitters.ts
@@ -154,10 +154,7 @@ export function enableFlexSplitters() {
     const gap = splitter.getBoundingClientRect().width || 8;
     splitter.style.flex = `0 0 ${gap}px`;
 
-    // Optional per-splitter CSS vars:
-    // --split-default: 30% (right pane width)
-    // --split-min-a: 220px (min left)
-    // --split-min-b: 220px (min right)
+
     const defPct = getVarPct(splitter, "--split-default", 50);
     const minA = getVarPx(splitter, "--split-min-a", 220);
     const minB = getVarPx(splitter, "--split-min-b", 220);
diff --git a/web/root/src/theme.ts b/web/root/src/theme.ts
index 1fd5944..8dd0244 100644
--- a/web/root/src/theme.ts
+++ b/web/root/src/theme.ts
@@ -1,10 +1,4 @@
-import { invalidateGraphThemeCache, network } from "./visualizer.ts";
-
-function cssVar(name: string, fallback = ""): string {
-  return getComputedStyle(document.documentElement)
-    .getPropertyValue(name)
-    .trim() || fallback;
-}
+import { updateGraphTheme } from "./visualizer.ts";
 
 const themeBtn = document.getElementById("themeToggle") as HTMLButtonElement;
 
@@ -28,60 +22,25 @@ function setTheme(theme: Theme) {
 
   // update button label
   themeBtn.textContent = theme === "dark" ? "🌙 Dark" : "☀️ Light";
-  applyGraphTheme();
+  updateGraphTheme();
 }
 
+
+setTheme(getPreferredTheme());
+
+themeBtn.addEventListener("click", toggleTheme);
 function toggleTheme() {
   const current = (document.documentElement.dataset.theme as Theme) || "dark";
   setTheme(current === "dark" ? "light" : "dark");
 }
 
-// init
-setTheme(getPreferredTheme());
 
-// click handler
-themeBtn.addEventListener("click", toggleTheme);
 
-// optional: respond to OS theme changes (only if user hasn't chosen a theme)
 globalThis.window.matchMedia?.("(prefers-color-scheme: light)")
   ?.addEventListener("change", () => {
-    if (localStorage.getItem("theme")) return; // user has chosen, don't override
+    if (localStorage.getItem("theme")) return;
     setTheme(getPreferredTheme());
   });
 
-function applyGraphTheme() {
-  invalidateGraphThemeCache();
-
-  network.setOptions({
-    nodes: {
-      font: {
-        color: cssVar("--graph-node-text"),
-      },
-    },
-    edges: {
-      labelHighlightBold: true,
-      font: { 
-        align: "middle", 
-        color: cssVar("--fg-0"),
-        strokeColor: cssVar("--bg-0"),
-        bold: {
-          color: cssVar("--fg-1"),
-          mod: ''
-        },
-      },
-      color: {
-        color: cssVar("--graph-edge"),
-        highlight: cssVar("--graph-edge-active"),
-        hover: cssVar("--graph-edge-hover"),
-      },
-      shadow: {
-        enabled: true,
-        color: cssVar("--bg-2")
-      }
-    },
-  });
-}
-
-
 
 
diff --git a/web/root/src/visualizer.ts b/web/root/src/visualizer.ts
index 6fd2e68..526d123 100644
--- a/web/root/src/visualizer.ts
+++ b/web/root/src/visualizer.ts
@@ -6,6 +6,106 @@ import * as vis from "npm:vis-network/standalone";
 export const nodes = new vis.DataSet<vis.Node>();
 export const edges = new vis.DataSet<vis.Edge>();
 
+
+type Color = string;
+type GraphTheme = {
+  bg_0: Color;
+  bg_1: Color;
+  bg_2: Color;
+  fg_0: Color;
+  fg_1: Color;
+  fg_2: Color;
+
+  node_anchor: Color;
+  node_border: Color;
+  current_node_border: Color;
+
+  edge: Color;
+  edge_hover: Color;
+  edge_active: Color;
+
+  edge_font_size: number,
+  node_font_size: number,
+};
+
+let _graphTheme: GraphTheme | null = null;
+
+function invalidateGraphThemeCache() {
+  _graphTheme = null;
+}
+
+function getGraphTheme(): GraphTheme {
+  function cssVar(name: string, fallback = ""): string {
+    return getComputedStyle(document.documentElement)
+      .getPropertyValue(name)
+      .trim() || fallback;
+  }
+
+  if (_graphTheme) return _graphTheme;
+
+  _graphTheme = {
+    bg_0: cssVar("--graph-bg-0"),
+    bg_1: cssVar("--graph-bg-1"),
+    bg_2: cssVar("--graph-bg-2"),
+    fg_0: cssVar("--graph-fg-0"),
+    fg_1: cssVar("--graph-fg-1"),
+    fg_2: cssVar("--graph-fg-2"),
+
+    node_anchor: cssVar("--graph-node-anchor"),
+    node_border: cssVar("--graph-node-border"),
+    current_node_border: cssVar("--graph-current-node-border"),
+    
+    edge: cssVar("--graph-edge"),
+    edge_hover: cssVar("--graph-edge-hover"),
+    edge_active: cssVar("--graph-edge-active"),
+    
+    edge_font_size: Number(cssVar("--graph-edge-font-size")),
+    node_font_size: Number(cssVar("--graph-node-font-size")),
+  };
+
+  return _graphTheme;
+}
+
+export function updateGraphTheme() {
+  invalidateGraphThemeCache();
+  const gt = getGraphTheme();
+
+  network.setOptions({
+    nodes: {
+      font: {
+        color: gt.fg_0,
+        bold: {
+          color: gt.fg_1,
+          mod: ''
+        },
+      },
+    },
+    edges: {
+      labelHighlightBold: true,
+      font: { 
+        align: "top", 
+        size: gt.edge_font_size,
+        color: gt.fg_0,
+        strokeColor: gt.bg_0,
+        bold: {
+          color: gt.fg_1,
+          size: gt.edge_font_size,
+          mod: ''
+        },
+      },
+      color: {
+        color: gt.edge,
+        hover: gt.edge_hover,
+        highlight: gt.edge_active,
+      },
+      shadow: {
+        enabled: false,
+      }
+    },
+  });
+}
+
+
 type StateId = string;
 type GraphDef = {
   initial: StateId;
@@ -50,9 +150,13 @@ export function setAutomaton(auto: GraphDef) {
   // Populate edges
   for (const [k, v] of Object.entries(automaton.transitions)) {
     const to_from = k.split("#");
+    const font = {
+      vadjust: -getGraphTheme().edge_font_size*Math.floor(((v.match(/\n/g) || '').length + 1)/2)
+    };
     if (edges.get(k)) {
       edges.update({
         id: k,
+        font,
         from: to_from[0],
         to: to_from[1],
         label: v,
@@ -60,6 +164,7 @@ export function setAutomaton(auto: GraphDef) {
     } else {
       edges.add({
         id: k,
+        font,
         from: to_from[0],
         to: to_from[1],
         label: v,
@@ -108,13 +213,14 @@ function createGraph(): vis.Network {
       layout: { improvedLayout: true },
       physics: {
         enabled: true,
-        solver: "barnesHut",
-        barnesHut: {
-          gravitationalConstant: -8000,
-          springLength: 120,
-          springConstant: 0.04,
-        },
-        stabilization: { iterations: 200 },
+        solver: "forceAtlas2Based",
+        // solver: "barnesHut",
+        // barnesHut: {
+        //   gravitationalConstant: -8000,
+        //   springLength: 120,
+        //   springConstant: 0.04,
+        // },
+        // stabilization: { iterations: 200 },
       },
       interaction: {
         dragNodes: true,
@@ -124,20 +230,14 @@ function createGraph(): vis.Network {
         selectConnectedEdges: false,
       },
       nodes: {
-        font: { color: "#c9d1d9" },
-        color: {
-          background: "#1f6feb",
-          border: "#79c0ff",
-          highlight: { background: "#388bfd", border: "#a5d6ff" },
-        },
+        shape: "custom",
+        size: 18,
         // // @ts-expect-error  bad library
         // chosen: {
         //   node: chosen_node,
         // },
-        shape: "custom",
         // @ts-expect-error  bad library
         ctxRenderer: renderNode,
-        size: 18,
       },
       edges: {
         chosen: {
@@ -145,10 +245,6 @@ function createGraph(): vis.Network {
           // edge: chosen_edge,
         },
         arrowStrikethrough: false,
-        font: { align: "middle", color: "#000000ff" },
-        color: { color: "rgba(201,209,217,0.35)", highlight: "#c9d1d9" },
-        // @ts-expect-error  bad library
-        smooth: { type: "dynamic" },
         arrows: "to",
       },
     },
@@ -167,56 +263,6 @@ function createGraph(): vis.Network {
   return network;
 }
 
-export type GraphTheme = {
-  bg_0: string;
-  bg_1: string;
-  bg_2: string;
-  fg_0: string;
-
-  anchor: string;
-  selected: string;
-  node: string;
-  current: string;
-  edge: string;
-  glow: string;
-};
-
-let _graphTheme: GraphTheme | null = null;
-
-export function invalidateGraphThemeCache() {
-  _graphTheme = null;
-}
-
-function getGraphTheme(): GraphTheme {
-  function cssVar(name: string, fallback = ""): string {
-    return getComputedStyle(document.documentElement)
-      .getPropertyValue(name)
-      .trim() || fallback;
-  }
-
-  if (_graphTheme) return _graphTheme;
-
-  _graphTheme = {
-    bg_0: cssVar("--bg-0"),
-    bg_1: cssVar("--bg-1"),
-    bg_2: cssVar("--bg-2"),
-    fg_0: cssVar("--fg-0"),
-
-    selected: cssVar("--bg-2"),
-
-    node: cssVar("--focus"),
-    current: cssVar("--success"),
-
-    anchor: cssVar("--warning"),
-
-    edge: cssVar("--graph-edge", "rgba(201,209,217,0.55)"),
-
-    glow: cssVar("--accent", "#79c0ff"),
-  };
-
-  return _graphTheme;
-}
-
 function renderNode({
   ctx,
   id,
@@ -238,8 +284,8 @@ function renderNode({
       const isFinal = id === "q1"; // <-- change if your schema differs
       const isActive = id === "q0"; // <-- change if your schema differs
 
-      const fill = selected ? t.glow : hover ? t.bg_1 : t.bg_0;
-      const stroke = isActive ? t.current : t.node;
+      const fill = selected ? t.bg_2 : hover ? t.bg_1 : t.bg_0;
+      const stroke = isActive ? t.current_node_border : t.node_border;
 
       const emphasis = (selected ? 1 : 0) + (hover ? 0.6 : 0);
 
@@ -308,7 +354,7 @@ function renderNode({
 
       const physicsOff = node.physics === false;
       if (physicsOff) {
-        drawPinIndicator(ctx, x, y, r, t.anchor);
+        drawPinIndicator(ctx, x, y, r, t.node_anchor);
       }
 
       ctx.restore();
diff --git a/web/root/src/wasm.ts b/web/root/src/wasm.ts
index 74f9084..80bf4a2 100644
--- a/web/root/src/wasm.ts
+++ b/web/root/src/wasm.ts
@@ -9,7 +9,7 @@ try{
     wasm.init();
 }catch(e){
     console.error("Failed to start: " + e);
-    document.getElementById("the_canvas_id")!.remove();
+    document.getElementById("app")!.remove();
     document.getElementById("center_text")!.innerHTML = `
         <p>
             An error occurred during loading:
@@ -20,6 +20,7 @@ try{
         <p style="font-size:14px">
             Make sure you use a modern browser with WebGL and WASM enabled.
         </p>`;
+    throw e;
 }
 
 export default wasm
\ No newline at end of file
diff --git a/web/root/style/editor.scss b/web/root/style/editor.scss
index ccb0e06..a09ed24 100644
--- a/web/root/style/editor.scss
+++ b/web/root/style/editor.scss
@@ -18,6 +18,10 @@
   color: var(--fg-0);
 }
 
+.cm-content{
+  caret-color: var(--fg-0)!important;
+}
+
 .cm-gutters {
   background: var(--bg-2) !important;
   color: var(--fg-muted);
diff --git a/web/root/style/style.scss b/web/root/style/style.scss
index 928212e..d294bdb 100644
--- a/web/root/style/style.scss
+++ b/web/root/style/style.scss
@@ -29,7 +29,17 @@ body {
 
 .vscroll {
   height: 100%;
-  overflow-x: scroll;
+  overflow-y: scroll;
+}
+
+.flexCol{
+  display: flex;
+  flex-direction: column;
+}
+
+.flexRow{
+  display: flex;
+  flex-direction: row;
 }
 
 .hSplit {
@@ -37,6 +47,8 @@ body {
         cursor: col-resize;
     }
     height: 8px;
+    min-height: 8px;
+    max-height: 8px;
     background: var(--separator-bg);
     transition:
         background var(--dur-med) var(--ease-standard),
@@ -48,6 +60,8 @@ body {
         cursor: col-resize;
     }
     width: 8px;
+    min-width: 8px;
+    max-width: 8px;
     background: var(--separator-bg);
     transition:
         background var(--dur-med) var(--ease-standard),
diff --git a/web/root/style/themes.scss b/web/root/style/themes.scss
index 58710a4..ac86de9 100644
--- a/web/root/style/themes.scss
+++ b/web/root/style/themes.scss
@@ -29,6 +29,25 @@
   --dur-med: 160ms;
   --dur-slow: 240ms;
   --ease-standard: cubic-bezier(0.2, 0, 0, 1);
+
+
+  --graph-bg-0: var(--bg-0);
+  --graph-bg-1: var(--bg-1);
+  --graph-bg-2: var(--bg-2);
+  --graph-fg-0: var(--fg-0);
+  --graph-fg-1: var(--fg-1);
+  --graph-fg-2: var(--fg-2);
+
+  --graph-node-font-size: 14;
+  --graph-edge-font-size: 10;
+
+  --graph-node-border: var(--focus);
+  --graph-current-node-border: var(--success);
+  --graph-node-anchor: var(--warning);
+
+  --graph-edge: var(--fg-muted);
+  --graph-edge-hover: var(--accent);
+  --graph-edge-active: var(--focus);
 }
 
 :root[data-theme="dark"] {
@@ -52,20 +71,6 @@
   --warning: #f2cc60;
   --error: #f85149;
 
-  --graph-bg: var(--bg-0);
-
-  --graph-node-bg: #1f6feb;
-  --graph-node-border: #388bfd;
-  --graph-node-text: var(--fg-0);
-
-  --graph-node-active-bg: #79c0ff;
-  --graph-node-active-border: #ff0000;
-
-  --graph-edge: rgba(201, 209, 217, 0.55);
-  --graph-edge-hover: rgba(201, 209, 217, 0.864);
-  --graph-edge-active: var(--accent);
-
-
   --ansi-fg-30: #0b0f14;   /* black */
   --ansi-fg-31: #ff7b72;   /* red */
   --ansi-fg-32: #7ee787;   /* green */
@@ -115,21 +120,6 @@
   --warning: #9a6700;
   --error: #cf222e;
 
-  --graph-bg: var(--bg-0);
-
-  --graph-node-bg: #1f6feb;
-  --graph-node-border: #0969da;
-  --graph-node-text: #ffffff;
-
-  --graph-node-active-bg: #54aeff;
-  --graph-node-active-border: #0969da;
-
-  --graph-edge: rgba(31, 41, 55, 0.45);
-  --graph-edge-hover: #0969da;
-  --graph-edge-active: #54aeff;
-
-
-
   --ansi-fg-30: #111827;   /* black */
   --ansi-fg-31: #b42318;   /* red */
   --ansi-fg-32: #1a7f37;   /* green */
diff --git a/web/tools/build.ts b/web/tools/build.ts
index bc88fe0..fa4834d 100644
--- a/web/tools/build.ts
+++ b/web/tools/build.ts
@@ -14,11 +14,14 @@ async function run(cmd: string[], cwd?: string) {
   }
 }
 
-// Clean dist
+console.log("clean dist...");
 await Deno.remove(DIST, { recursive: true }).catch(() => {});
 await Deno.mkdir(DIST, { recursive: true });
 
 
+console.log("copy assets");
+await copyFolder(new URL("assets/", ROOT), DIST);
+
 console.log("compiling scss...");
 const result = sass.compile(String(new URL("style/style.scss", ROOT).pathname), {
   style: "compressed",
@@ -40,3 +43,23 @@ if (!bundleRes.success) {
 }
 
 console.log("Build complete: dist/");
+
+
+
+export async function copyFolder(
+  srcDir: URL,
+  destDir: URL,
+): Promise<void> {
+  await Deno.mkdir(destDir, { recursive: true });
+
+  for await (const entry of Deno.readDir(srcDir)) {
+    const srcPath = new URL(entry.name, srcDir.href);
+    const destPath = new URL(entry.name, destDir.href);
+  
+    if (entry.isDirectory) {
+      await copyFolder(srcPath, destPath);
+    } else if (entry.isFile) {
+      await Deno.copyFile(srcPath, destPath);
+    }
+  }
+}
\ No newline at end of file