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/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/theme.ts b/web/root/src/theme.ts
index 1fd5944..88f7625 100644
--- a/web/root/src/theme.ts
+++ b/web/root/src/theme.ts
@@ -1,4 +1,4 @@
-import { invalidateGraphThemeCache, network } from "./visualizer.ts";
+import { getGraphTheme, invalidateGraphThemeCache, network } from "./visualizer.ts";
 
 function cssVar(name: string, fallback = ""): string {
   return getComputedStyle(document.documentElement)
@@ -56,16 +56,22 @@ function applyGraphTheme() {
     nodes: {
       font: {
         color: cssVar("--graph-node-text"),
+        bold: {
+          color: cssVar("--fg-1"),
+          mod: ''
+        },
       },
     },
     edges: {
       labelHighlightBold: true,
       font: { 
-        align: "middle", 
+        align: "top", 
+        size: getGraphTheme().edge_font_size,
         color: cssVar("--fg-0"),
         strokeColor: cssVar("--bg-0"),
         bold: {
           color: cssVar("--fg-1"),
+          size: getGraphTheme().edge_font_size,
           mod: ''
         },
       },
diff --git a/web/root/src/visualizer.ts b/web/root/src/visualizer.ts
index 6fd2e68..0e9712b 100644
--- a/web/root/src/visualizer.ts
+++ b/web/root/src/visualizer.ts
@@ -50,9 +50,13 @@ 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 +64,7 @@ export function setAutomaton(auto: GraphDef) {
     } else {
       edges.add({
         id: k,
+        font,
         from: to_from[0],
         to: to_from[1],
         label: v,
@@ -108,13 +113,14 @@ 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 +130,14 @@ 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 +145,6 @@ 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",
       },
     },
@@ -179,6 +175,7 @@ export type GraphTheme = {
   current: string;
   edge: string;
   glow: string;
+  edge_font_size: number,
 };
 
 let _graphTheme: GraphTheme | null = null;
@@ -187,7 +184,7 @@ export function invalidateGraphThemeCache() {
   _graphTheme = null;
 }
 
-function getGraphTheme(): GraphTheme {
+export function getGraphTheme(): GraphTheme {
   function cssVar(name: string, fallback = ""): string {
     return getComputedStyle(document.documentElement)
       .getPropertyValue(name)
@@ -212,6 +209,7 @@ function getGraphTheme(): GraphTheme {
     edge: cssVar("--graph-edge", "rgba(201,209,217,0.55)"),
 
     glow: cssVar("--accent", "#79c0ff"),
+    edge_font_size: 10,
   };
 
   return _graphTheme;
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);