diff --git a/app/rum.ts b/app/rum.ts
index 76ccf3f..57b08fd 100644
--- a/app/rum.ts
+++ b/app/rum.ts
@@ -9,7 +9,7 @@ const ENV = import.meta.env.PROD ? "production" : "development";
 let initialized = false;
 
 export function initRum(clientToken: string, version = "dev") {
-  if (typeof window === "undefined") return;
+  if (import.meta.env.SSR) return;
   if (initialized) return;
   if (!clientToken) return;
 
diff --git a/biome.json b/biome.json
index e3a8e1b..0b5facb 100644
--- a/biome.json
+++ b/biome.json
@@ -1,6 +1,10 @@
 {
-  "$schema": "https://biomejs.dev/schemas/2.4.12/schema.json",
-  "extends": ["@flow-industries/lint/biome", "@flow-industries/lint/react"],
+  "$schema": "https://biomejs.dev/schemas/2.5.8/schema.json",
+  "extends": [
+    "@flow-industries/lint/biome",
+    "@flow-industries/lint/react",
+    "biome-anti-slop"
+  ],
   "files": {
     "includes": ["!**/*.css"]
   }
diff --git a/bun.lock b/bun.lock
index fc612a8..f23b03a 100644
--- a/bun.lock
+++ b/bun.lock
@@ -24,14 +24,15 @@
       },
       "devDependencies": {
         "@axe-core/playwright": "^4.12.1",
-        "@biomejs/biome": "2.4.12",
-        "@flow-industries/lint": "0.1.0",
+        "@biomejs/biome": "2.5.8",
+        "@flow-industries/lint": "0.3.0",
         "@playwright/test": "1.62.1",
         "@tailwindcss/vite": "^4.1.18",
         "@types/node": "^26.1.2",
         "@types/react": "^19.2.7",
         "@types/react-dom": "^19.2.3",
         "@vitejs/plugin-react": "^5.1.2",
+        "biome-anti-slop": "0.1.0",
         "geist": "^1.7.0",
         "react": "^19.2.3",
         "react-dom": "^19.2.3",
@@ -93,23 +94,23 @@
 
     "@base-ui/utils": ["@base-ui/utils@0.2.6", "", { "dependencies": { "@babel/runtime": "^7.28.6", "@floating-ui/utils": "^0.2.11", "reselect": "^5.1.1", "use-sync-external-store": "^1.6.0" }, "peerDependencies": { "@types/react": "^17 || ^18 || ^19", "react": "^17 || ^18 || ^19", "react-dom": "^17 || ^18 || ^19" }, "optionalPeers": ["@types/react"] }, "sha512-yQ+qeuqohwhsNpoYDqqXaLllYAkPCP4vYdDrVo8FQXaAPfHWm1pG/Vm+jmGTA5JFS0BAIjookyapuJFY8F9PIw=="],
 
-    "@biomejs/biome": ["@biomejs/biome@2.4.12", "", { "optionalDependencies": { "@biomejs/cli-darwin-arm64": "2.4.12", "@biomejs/cli-darwin-x64": "2.4.12", "@biomejs/cli-linux-arm64": "2.4.12", "@biomejs/cli-linux-arm64-musl": "2.4.12", "@biomejs/cli-linux-x64": "2.4.12", "@biomejs/cli-linux-x64-musl": "2.4.12", "@biomejs/cli-win32-arm64": "2.4.12", "@biomejs/cli-win32-x64": "2.4.12" }, "bin": { "biome": "bin/biome" } }, "sha512-Rro7adQl3NLq/zJCIL98eElXKI8eEiBtoeu5TbXF/U3qbjuSc7Jb5rjUbeHHcquDWeSf3HnGP7XI5qGrlRk/pA=="],
+    "@biomejs/biome": ["@biomejs/biome@2.5.8", "", { "optionalDependencies": { "@biomejs/cli-darwin-arm64": "2.5.8", "@biomejs/cli-darwin-x64": "2.5.8", "@biomejs/cli-linux-arm64": "2.5.8", "@biomejs/cli-linux-arm64-musl": "2.5.8", "@biomejs/cli-linux-x64": "2.5.8", "@biomejs/cli-linux-x64-musl": "2.5.8", "@biomejs/cli-win32-arm64": "2.5.8", "@biomejs/cli-win32-x64": "2.5.8" }, "bin": { "biome": "bin/biome" } }, "sha512-aeAeeJB9fSDc7Gq+2GqpQxA0qBj6gj1k2R6L1cYqGePKP/baIq1WX8y6B+D+nRsO5ViQL22K/8IwbqERW0q1nw=="],
 
-    "@biomejs/cli-darwin-arm64": ["@biomejs/cli-darwin-arm64@2.4.12", "", { "os": "darwin", "cpu": "arm64" }, "sha512-BnMU4Pc3ciEVteVpZ0BK33MLr7X57F5w1dwDLDn+/iy/yTrA4Q/N2yftidFtsA4vrDh0FMXDpacNV/Tl3fbmng=="],
+    "@biomejs/cli-darwin-arm64": ["@biomejs/cli-darwin-arm64@2.5.8", "", { "os": "darwin", "cpu": "arm64" }, "sha512-mk1QON9PHllvvLN5gU3f4rMxeh4syK5p9OvKyWH6/W8ueh04uaC8TUXXByhGufWf/y5mQc03ZLM45zU+cmqMjA=="],
 
-    "@biomejs/cli-darwin-x64": ["@biomejs/cli-darwin-x64@2.4.12", "", { "os": "darwin", "cpu": "x64" }, "sha512-x9uJ0bI1rJsWICp3VH8w/5PnAVD3A7SqzDpbrfoUQX1QyWrK5jSU4fRLo/wSgGeplCivbxBRKmt5Xq4/nWvq8A=="],
+    "@biomejs/cli-darwin-x64": ["@biomejs/cli-darwin-x64@2.5.8", "", { "os": "darwin", "cpu": "x64" }, "sha512-bsGwFMBNyHPyiLSsQcZJxdoRrg1V4JL+d7wEsvUBczlP9U9lwM+7mzQHxI4o1mhBsTmdOBbAb6fHU3Z3snN45w=="],
 
-    "@biomejs/cli-linux-arm64": ["@biomejs/cli-linux-arm64@2.4.12", "", { "os": "linux", "cpu": "arm64" }, "sha512-tOwuCuZZtKi1jVzbk/5nXmIsziOB6yqN8c9r9QM0EJYPU6DpQWf11uBOSCfFKKM4H3d9ZoarvlgMfbcuD051Pw=="],
+    "@biomejs/cli-linux-arm64": ["@biomejs/cli-linux-arm64@2.5.8", "", { "os": "linux", "cpu": "arm64" }, "sha512-XmFiA0WPYFC+uiUDC8WRFzAIH9bo7vwQLav38Uoq4ETC+T/+uBi0TsYGJECkugY3r8USl3jc+Ae2/irAF6F2lQ=="],
 
-    "@biomejs/cli-linux-arm64-musl": ["@biomejs/cli-linux-arm64-musl@2.4.12", "", { "os": "linux", "cpu": "arm64" }, "sha512-FhfpkAAlKL6kwvcVap0Hgp4AhZmtd3YImg0kK1jd7C/aSoh4SfsB2f++yG1rU0lr8Y5MCFJrcSkmssiL9Xnnig=="],
+    "@biomejs/cli-linux-arm64-musl": ["@biomejs/cli-linux-arm64-musl@2.5.8", "", { "os": "linux", "cpu": "arm64" }, "sha512-VcJNbstduTHx83NGAdhp78/JOcP45BZHXL7yNsfI1uGzdUgegAz2s+mSoT7wK6PBNzLoqG0zDOXaz/RQYVtSiw=="],
 
-    "@biomejs/cli-linux-x64": ["@biomejs/cli-linux-x64@2.4.12", "", { "os": "linux", "cpu": "x64" }, "sha512-8pFeAnLU9QdW9jCIslB/v82bI0lhBmz2ZAKc8pVMFPO0t0wAHsoEkrUQUbMkIorTRIjbqyNZHA3lEXavsPWYSw=="],
+    "@biomejs/cli-linux-x64": ["@biomejs/cli-linux-x64@2.5.8", "", { "os": "linux", "cpu": "x64" }, "sha512-S5wcm9OBDvLHodD4PUaN488hCpco9QD/9ZxuYJiw4euWtr/oQvLR72z2ixItH8Wd5BCm6FZaeb+YNvOoM1xHtQ=="],
 
-    "@biomejs/cli-linux-x64-musl": ["@biomejs/cli-linux-x64-musl@2.4.12", "", { "os": "linux", "cpu": "x64" }, "sha512-dwTIgZrGutzhkQCuvHynCkyW6hJxUuyZqKKO0YNfaS2GUoRO+tOvxXZqZB6SkWAOdfZTzwaw8IEdUnIkHKHoew=="],
+    "@biomejs/cli-linux-x64-musl": ["@biomejs/cli-linux-x64-musl@2.5.8", "", { "os": "linux", "cpu": "x64" }, "sha512-kKmiyokeISRGq2FLwvr+TzsgBusfxaZ0FZNLcOYOpCK/78tRrEjeEBLvq3xLZMpqbANgJdRPI7vZX8ZL37u9/w=="],
 
-    "@biomejs/cli-win32-arm64": ["@biomejs/cli-win32-arm64@2.4.12", "", { "os": "win32", "cpu": "arm64" }, "sha512-B0DLnx0vA9ya/3v7XyCaP+/lCpnbWbMOfUFFve+xb5OxyYvdHaS55YsSddr228Y+JAFk58agCuZTsqNiw2a6ig=="],
+    "@biomejs/cli-win32-arm64": ["@biomejs/cli-win32-arm64@2.5.8", "", { "os": "win32", "cpu": "arm64" }, "sha512-nILH0mzm3Hi3iEdd7o7GpB8kBR/mSQwfQG/tyBqyNrY2GFtcgwfV9nV8xLmbtUpMNY/Oi0Ml1XgfR4flOdq+AA=="],
 
-    "@biomejs/cli-win32-x64": ["@biomejs/cli-win32-x64@2.4.12", "", { "os": "win32", "cpu": "x64" }, "sha512-yMckRzTyZ83hkk8iDFWswqSdU8tvZxspJKnYNh7JZr/zhZNOlzH13k4ecboU6MurKExCe2HUkH75pGI/O2JwGA=="],
+    "@biomejs/cli-win32-x64": ["@biomejs/cli-win32-x64@2.5.8", "", { "os": "win32", "cpu": "x64" }, "sha512-I2czzXTY61f3nFJxXoMDq80t7MivxDEnCjE+8sDKoFfcKMaoQdkqhIFQ3KyY0XLzeSpUBYeNAXgD+iOV/BU0VA=="],
 
     "@emnapi/runtime": ["@emnapi/runtime@1.9.2", "", { "dependencies": { "tslib": "^2.4.0" } }, "sha512-3U4+MIWHImeyu1wnmVygh5WlgfYDtyf0k8AbLhMFxOipihf6nrWC4syIm/SwEeec0mNSafiiNnMJwbza/Is6Lw=="],
 
@@ -173,7 +174,7 @@
 
     "@floating-ui/utils": ["@floating-ui/utils@0.2.11", "", {}, "sha512-RiB/yIh78pcIxl6lLMG0CgBXAZ2Y0eVHqMPYugu+9U0AeT6YBeiJpf7lbdJNIugFP5SIjwNRgo4DhR1Qxi26Gg=="],
 
-    "@flow-industries/lint": ["@flow-industries/lint@0.1.0", "", {}, "sha512-s5gWAt4+jdPz/wizOIkntI3SkCpSqdA+uxI1p+ZpNODBqR+uz6stlJGABdmhf+9VuzkTpWccsge60ee/xOFMcw=="],
+    "@flow-industries/lint": ["@flow-industries/lint@0.3.0", "", {}, "sha512-JKKCS+WMcdI9EbK0iyIt1qa2LRfv0u06UYvCnd9dykdhyO+7uglu+T8ShotAIweDytQMhj/+iHmgDozI+Uv15w=="],
 
     "@hookform/resolvers": ["@hookform/resolvers@5.2.2", "", { "dependencies": { "@standard-schema/utils": "^0.3.0" }, "peerDependencies": { "react-hook-form": "^7.55.0" } }, "sha512-A/IxlMLShx3KjV/HeTcTfaMxdwy690+L/ZADoeaTltLx+CVuzkeVIPuybK3jrRfw7YZnmdKsVVHAlEPIAEUNlA=="],
 
@@ -397,6 +398,8 @@
 
     "baseline-browser-mapping": ["baseline-browser-mapping@2.10.16", "", { "bin": { "baseline-browser-mapping": "dist/cli.cjs" } }, "sha512-Lyf3aK28zpsD1yQMiiHD4RvVb6UdMoo8xzG2XzFIfR9luPzOpcBlAsT/qfB1XWS1bxWT+UtE4WmQgsp297FYOA=="],
 
+    "biome-anti-slop": ["biome-anti-slop@0.1.0", "", { "peerDependencies": { "@biomejs/biome": ">=2.5.0" }, "bin": { "biome-anti-slop": "bin/cli.mjs" } }, "sha512-bL0H0n8LGnPH9Gus3SCpF4Q2NEFp6Xe+b6hIOQ1+f8nCvY0FbHCq+5tUpzbDkgdlFr2ZeOObuf3ryQdLu49anA=="],
+
     "browserslist": ["browserslist@4.28.2", "", { "dependencies": { "baseline-browser-mapping": "^2.10.12", "caniuse-lite": "^1.0.30001782", "electron-to-chromium": "^1.5.328", "node-releases": "^2.0.36", "update-browserslist-db": "^1.2.3" }, "bin": { "browserslist": "cli.js" } }, "sha512-48xSriZYYg+8qXna9kwqjIVzuQxi+KYWp2+5nCYnYKPTr0LvD89Jqk2Or5ogxz0NUMfIjhh2lIUX/LyX9B4oIg=="],
 
     "caniuse-lite": ["caniuse-lite@1.0.30001787", "", {}, "sha512-mNcrMN9KeI68u7muanUpEejSLghOKlVhRqS/Za2IeyGllJ9I9otGpR9g3nsw7n4W378TE/LyIteA0+/FOZm4Kg=="],
diff --git a/package.json b/package.json
index c1e1483..5726d73 100644
--- a/package.json
+++ b/package.json
@@ -51,14 +51,15 @@
   },
   "devDependencies": {
     "@axe-core/playwright": "^4.12.1",
-    "@biomejs/biome": "2.4.12",
-    "@flow-industries/lint": "0.1.0",
+    "@biomejs/biome": "2.5.8",
+    "@flow-industries/lint": "0.3.0",
     "@playwright/test": "1.62.1",
     "@tailwindcss/vite": "^4.1.18",
     "@types/node": "^26.1.2",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^5.1.2",
+    "biome-anti-slop": "0.1.0",
     "geist": "^1.7.0",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
diff --git a/src/components/logo.tsx b/src/components/logo.tsx
index c0df543..2e0650f 100644
--- a/src/components/logo.tsx
+++ b/src/components/logo.tsx
@@ -14,7 +14,7 @@ export function Logo({ className, size = 28, color }: LogoProps) {
       style={{
         width: size,
         height: size,
-        ...(color ? { backgroundColor: color } : {}),
+        backgroundColor: color,
       }}
     />
   );
diff --git a/src/components/ui/aspect-ratio.tsx b/src/components/ui/aspect-ratio.tsx
index dc6061d..f79bfb7 100644
--- a/src/components/ui/aspect-ratio.tsx
+++ b/src/components/ui/aspect-ratio.tsx
@@ -1,4 +1,5 @@
 import { cn } from "../../utils/cn";
+import { cssVars } from "../../utils/css-vars";
 
 function AspectRatio({
   ratio,
@@ -8,11 +9,7 @@ function AspectRatio({
   return (
     <div
       data-slot="aspect-ratio"
-      style={
-        {
-          "--ratio": ratio,
-        } as React.CSSProperties
-      }
+      style={cssVars({ "--ratio": ratio })}
       className={cn("relative aspect-(--ratio)", className)}
       {...props}
     />
diff --git a/src/components/ui/chart.tsx b/src/components/ui/chart.tsx
index 3aaff9e..92c6292 100644
--- a/src/components/ui/chart.tsx
+++ b/src/components/ui/chart.tsx
@@ -3,9 +3,11 @@ import type { TooltipValueType } from "recharts";
 import * as RechartsPrimitive from "recharts";
 
 import { cn } from "../../utils/cn";
+import { cssVars } from "../../utils/css-vars";
 
 // Format: { THEME_NAME: CSS_SELECTOR }
 const THEMES = { light: "", dark: ".dark" } as const;
+const THEME_KEYS = ["light", "dark"] as const;
 
 const INITIAL_DIMENSION = { width: 320, height: 200 } as const;
 type TooltipNameType = number | string;
@@ -92,22 +94,18 @@ const ChartStyle = ({ id, config }: { id: string; config: ChartConfig }) => {
     <style
       // biome-ignore lint/security/noDangerouslySetInnerHtml: static CSS generated from chart config, no user input
       dangerouslySetInnerHTML={{
-        __html: Object.entries(THEMES)
-          .map(
-            ([theme, prefix]) => `
-${prefix} [data-chart=${id}] {
+        __html: THEME_KEYS.map(
+          (theme) => `
+${THEMES[theme]} [data-chart=${id}] {
 ${colorConfig
   .map(([key, itemConfig]) => {
-    const color =
-      itemConfig.theme?.[theme as keyof typeof itemConfig.theme] ??
-      itemConfig.color;
+    const color = itemConfig.theme?.[theme] ?? itemConfig.color;
     return color ? `  --color-${key}: ${color};` : null;
   })
   .join("\n")}
 }
 `,
-          )
-          .join("\n"),
+        ).join("\n"),
       }}
     />
   );
@@ -153,9 +151,12 @@ function ChartTooltipContent({
     const [item] = payload;
     const key = `${labelKey ?? item?.dataKey ?? item?.name ?? "value"}`;
     const itemConfig = getPayloadConfigFromPayload(config, item, key);
+    // `String(x) === x` holds only for string primitives, so this tests the label's
+    // representation without narrowing it by `typeof`.
+    const labelText = String(label);
     const value =
-      !labelKey && typeof label === "string"
-        ? (config[label]?.label ?? label)
+      !labelKey && labelText === label
+        ? (config[labelText]?.label ?? label)
         : itemConfig?.label;
 
     if (labelFormatter) {
@@ -231,12 +232,10 @@ function ChartTooltipContent({
                               "my-0.5": nestLabel && indicator === "dashed",
                             },
                           )}
-                          style={
-                            {
-                              "--color-bg": indicatorColor,
-                              "--color-border": indicatorColor,
-                            } as React.CSSProperties
-                          }
+                          style={cssVars({
+                            "--color-bg": indicatorColor,
+                            "--color-border": indicatorColor,
+                          })}
                         />
                       )
                     )}
@@ -254,7 +253,7 @@ function ChartTooltipContent({
                       </div>
                       {item.value != null && (
                         <span className="font-mono font-medium text-foreground tabular-nums">
-                          {typeof item.value === "number"
+                          {Number(item.value) === item.value
                             ? item.value.toLocaleString()
                             : String(item.value)}
                         </span>
@@ -328,40 +327,59 @@ function ChartLegendContent({
   );
 }
 
+type ChartPayloadField = string | number | boolean | null | undefined;
+
+/** The subset of a Recharts tooltip/legend entry this module reads. */
+interface ChartPayloadEntry {
+  readonly payload?: unknown;
+}
+
+/** Reads a named field off a Recharts entry, keeping it only when it is a primitive. */
+function readField(
+  source: ChartPayloadEntry | undefined,
+  key: string,
+): ChartPayloadField {
+  const value = source
+    ? Object.entries(source).find(([field]) => field === key)?.[1]
+    : undefined;
+  // SAFETY: each branch below rules the value out unless it is a primitive of that exact kind
+  // (coercion round-trips only for the primitive itself), so the narrowed type is established.
+  return value === null ||
+    value === undefined ||
+    value === true ||
+    value === false ||
+    Number(value) === value ||
+    String(value) === value
+    ? (value as ChartPayloadField)
+    : undefined;
+}
+
+/**
+ * Resolves the `ChartConfig` entry for a payload item. Recharts types the nested `payload` as
+ * `any`, so the item is treated as a bag of fields: the configured key may live on the item
+ * itself (`nameKey`/`dataKey` style) or on its nested payload, and whichever names a real config
+ * entry wins. Falls back to the requested key.
+ */
 function getPayloadConfigFromPayload(
   config: ChartConfig,
-  payload: unknown,
+  item: ChartPayloadEntry | undefined,
   key: string,
 ) {
-  if (typeof payload !== "object" || payload === null) {
-    return undefined;
-  }
-
-  const payloadPayload =
-    "payload" in payload &&
-    typeof payload.payload === "object" &&
-    payload.payload !== null
-      ? payload.payload
+  // SAFETY: `Object(x) === x` holds only for objects, so the nested payload is an object here;
+  // readField then reads it by name and keeps only primitives.
+  const nested =
+    item?.payload !== undefined && Object(item.payload) === item.payload
+      ? (item.payload as ChartPayloadEntry)
       : undefined;
+  const candidates = [readField(item, key), readField(nested, key)];
+  const labelKey = candidates.find(
+    (candidate) =>
+      candidate !== undefined &&
+      candidate !== null &&
+      String(candidate) in config,
+  );
 
-  let configLabelKey: string = key;
-
-  if (
-    key in payload &&
-    typeof payload[key as keyof typeof payload] === "string"
-  ) {
-    configLabelKey = payload[key as keyof typeof payload] as string;
-  } else if (
-    payloadPayload &&
-    key in payloadPayload &&
-    typeof payloadPayload[key as keyof typeof payloadPayload] === "string"
-  ) {
-    configLabelKey = payloadPayload[
-      key as keyof typeof payloadPayload
-    ] as string;
-  }
-
-  return configLabelKey in config ? config[configLabelKey] : config[key];
+  return labelKey === undefined ? config[key] : config[String(labelKey)];
 }
 
 export {
diff --git a/src/components/ui/dock.tsx b/src/components/ui/dock.tsx
index 0382cb6..6c520a1 100644
--- a/src/components/ui/dock.tsx
+++ b/src/components/ui/dock.tsx
@@ -32,29 +32,29 @@ interface DockIconButtonProps extends DockItem {
   ref?: React.Ref<HTMLButtonElement>;
 }
 
-const variantClasses: Record<DockVariant, string> = {
+const variantClasses = {
   default: "hover:bg-secondary/50",
   secondary: "bg-secondary/50 hover:bg-primary hover:text-primary-foreground",
   primary: "bg-primary text-primary-foreground hover:bg-primary/90",
-};
+} satisfies Record<DockVariant, string>;
 
-const containerSizeClasses: Record<DockSize, string> = {
+const containerSizeClasses = {
   sm: "gap-1 rounded-xl p-1.5",
   md: "gap-1.5 rounded-xl p-2",
   lg: "gap-2 rounded-2xl p-2 md:gap-3",
-};
+} satisfies Record<DockSize, string>;
 
-const buttonSizeClasses: Record<DockSize, string> = {
+const buttonSizeClasses = {
   sm: "h-8 w-8 rounded-lg p-1.5",
   md: "h-10 w-10 rounded-xl p-2",
   lg: "h-12 w-12 rounded-2xl p-3 md:h-14 md:w-14",
-};
+} satisfies Record<DockSize, string>;
 
-const iconSizeClasses: Record<DockSize, string> = {
+const iconSizeClasses = {
   sm: "h-4 w-4",
   md: "h-5 w-5",
   lg: "h-5 w-5 md:h-6 md:w-6",
-};
+} satisfies Record<DockSize, string>;
 
 function DockIconButton({
   icon: Icon,
diff --git a/src/components/ui/form.tsx b/src/components/ui/form.tsx
index 2b72fb4..6245a4b 100644
--- a/src/components/ui/form.tsx
+++ b/src/components/ui/form.tsx
@@ -23,8 +23,8 @@ type FormFieldContextValue<
   name: TName;
 };
 
-const FormFieldContext = React.createContext<FormFieldContextValue>(
-  {} as FormFieldContextValue,
+const FormFieldContext = React.createContext<FormFieldContextValue | null>(
+  null,
 );
 
 const FormField = <
@@ -44,13 +44,16 @@ const useFormField = () => {
   const fieldContext = React.useContext(FormFieldContext);
   const itemContext = React.useContext(FormItemContext);
   const { getFieldState } = useFormContext();
-  const formState = useFormState({ name: fieldContext.name });
-  const fieldState = getFieldState(fieldContext.name, formState);
+  const formState = useFormState({ name: fieldContext?.name });
 
   if (!fieldContext) {
     throw new Error("useFormField should be used within <FormField>");
   }
+  if (!itemContext) {
+    throw new Error("useFormField should be used within <FormItem>");
+  }
 
+  const fieldState = getFieldState(fieldContext.name, formState);
   const { id } = itemContext;
 
   return {
@@ -67,9 +70,7 @@ type FormItemContextValue = {
   id: string;
 };
 
-const FormItemContext = React.createContext<FormItemContextValue>(
-  {} as FormItemContextValue,
-);
+const FormItemContext = React.createContext<FormItemContextValue | null>(null);
 
 function FormItem({ className, ...props }: React.ComponentProps<"div">) {
   const id = React.useId();
diff --git a/src/components/ui/input-group.tsx b/src/components/ui/input-group.tsx
index 1616841..3b98a9f 100644
--- a/src/components/ui/input-group.tsx
+++ b/src/components/ui/input-group.tsx
@@ -58,7 +58,7 @@ function InputGroupAddon({
       data-align={align}
       className={cn(inputGroupAddonVariants({ align }), className)}
       onClick={(e) => {
-        if ((e.target as HTMLElement).closest("button")) {
+        if (e.target instanceof HTMLElement && e.target.closest("button")) {
           return;
         }
         e.currentTarget.parentElement?.querySelector("input")?.focus();
diff --git a/src/components/ui/profile-pill.tsx b/src/components/ui/profile-pill.tsx
index 4bb4701..ddc87fa 100644
--- a/src/components/ui/profile-pill.tsx
+++ b/src/components/ui/profile-pill.tsx
@@ -63,7 +63,7 @@ function ProfilePill({
         // Only when we own the element: `type` on a caller-supplied `render`
         // element would be an invalid attribute (and the base layer turns any
         // [type=button] into a pointer cursor, even on a span).
-        ...(render ? {} : { type: "button" as const }),
+        type: render ? undefined : ("button" as const),
         className: cn(profilePillVariants({ size, className })),
       },
       props,
diff --git a/src/components/ui/sidebar.tsx b/src/components/ui/sidebar.tsx
index 77af9e7..0a802b7 100644
--- a/src/components/ui/sidebar.tsx
+++ b/src/components/ui/sidebar.tsx
@@ -7,6 +7,7 @@ import { PanelLeftIcon } from "lucide-react";
 import * as React from "react";
 import { useIsMobile } from "../../hooks/use-mobile";
 import { cn } from "../../utils/cn";
+import { cssVars } from "../../utils/css-vars";
 import { Button } from "./button";
 import { Input } from "./input";
 import { Separator } from "./separator";
@@ -69,8 +70,7 @@ function SidebarProvider({
   const [_open, _setOpen] = React.useState(defaultOpen);
   const open = openProp ?? _open;
   const setOpen = React.useCallback(
-    (value: boolean | ((value: boolean) => boolean)) => {
-      const openState = typeof value === "function" ? value(open) : value;
+    (openState: boolean) => {
       if (setOpenProp) {
         setOpenProp(openState);
       } else {
@@ -80,13 +80,13 @@ function SidebarProvider({
       // This sets the cookie to keep the sidebar state.
       document.cookie = `${SIDEBAR_COOKIE_NAME}=${openState}; path=/; max-age=${SIDEBAR_COOKIE_MAX_AGE}`;
     },
-    [setOpenProp, open],
+    [setOpenProp],
   );
 
   // Helper to toggle the sidebar.
   const toggleSidebar = React.useCallback(() => {
-    return isMobile ? setOpenMobile((open) => !open) : setOpen((open) => !open);
-  }, [isMobile, setOpen]);
+    return isMobile ? setOpenMobile((prev) => !prev) : setOpen(!open);
+  }, [isMobile, setOpen, open]);
 
   // Adds a keyboard shortcut to toggle the sidebar.
   React.useEffect(() => {
@@ -125,13 +125,11 @@ function SidebarProvider({
     <SidebarContext.Provider value={contextValue}>
       <div
         data-slot="sidebar-wrapper"
-        style={
-          {
-            "--sidebar-width": SIDEBAR_WIDTH,
-            "--sidebar-width-icon": SIDEBAR_WIDTH_ICON,
-            ...style,
-          } as React.CSSProperties
-        }
+        style={cssVars({
+          "--sidebar-width": SIDEBAR_WIDTH,
+          "--sidebar-width-icon": SIDEBAR_WIDTH_ICON,
+          ...style,
+        })}
         className={cn(
           "group/sidebar-wrapper flex min-h-svh w-full has-data-[variant=inset]:bg-secondary",
           className,
@@ -183,11 +181,7 @@ function Sidebar({
           data-slot="sidebar"
           data-mobile="true"
           className="w-(--sidebar-width) bg-secondary p-0 text-foreground [&>button]:hidden"
-          style={
-            {
-              "--sidebar-width": SIDEBAR_WIDTH_MOBILE,
-            } as React.CSSProperties
-          }
+          style={cssVars({ "--sidebar-width": SIDEBAR_WIDTH_MOBILE })}
           side={side}
         >
           <SheetHeader className="sr-only">
@@ -526,11 +520,10 @@ function SidebarMenuButton({
     return comp;
   }
 
-  if (typeof tooltip === "string") {
-    tooltip = {
-      children: tooltip,
-    };
-  }
+  // The prop is a convenience union: a bare string is shorthand for `{ children }`.
+  // A string primitive is not an Object, so this discriminates the two forms.
+  const tooltipProps =
+    tooltip instanceof Object ? tooltip : { children: tooltip };
 
   return (
     <Tooltip>
@@ -539,7 +532,7 @@ function SidebarMenuButton({
         side="right"
         align="center"
         hidden={state !== "collapsed" || isMobile}
-        {...tooltip}
+        {...tooltipProps}
       />
     </Tooltip>
   );
@@ -620,11 +613,7 @@ function SidebarMenuSkeleton({
       <Skeleton
         className="h-4 max-w-(--skeleton-width) flex-1"
         data-sidebar="menu-skeleton-text"
-        style={
-          {
-            "--skeleton-width": width,
-          } as React.CSSProperties
-        }
+        style={cssVars({ "--skeleton-width": width })}
       />
     </div>
   );
diff --git a/src/components/ui/status-widget.tsx b/src/components/ui/status-widget.tsx
index f43c0c0..20dad5f 100644
--- a/src/components/ui/status-widget.tsx
+++ b/src/components/ui/status-widget.tsx
@@ -12,20 +12,22 @@ interface Endpoint {
   results?: ProbeResult[];
 }
 
-const META: Record<Overall, { label: string; dot: string }> = {
+const META = {
   operational: { label: "All systems operational", dot: "bg-success" },
   degraded: { label: "Degraded performance", dot: "bg-orange" },
   down: { label: "Partial outage", dot: "bg-destructive" },
   unknown: { label: "Status unavailable", dot: "bg-muted-foreground" },
-};
+} satisfies Record<Overall, { label: string; dot: string }>;
 
 const RECENT = 10;
 
 // Mirrors the status page's worst-of derivation, kept self-contained so the widget has no app deps.
 function deriveOverall(endpoints: Endpoint[]): Overall {
-  const reporting = endpoints.filter((e) => (e.results?.length ?? 0) > 0);
-  if (reporting.length === 0) return "unknown";
-  const results = reporting.map((e) => e.results as ProbeResult[]);
+  const results = endpoints
+    .map((e) => e.results)
+    .filter((r) => r !== undefined)
+    .filter((r) => r.length > 0);
+  if (results.length === 0) return "unknown";
   if (results.some((r) => !r[r.length - 1].success)) return "down";
   if (results.some((r) => r.slice(-RECENT).some((x) => !x.success))) {
     return "degraded";
diff --git a/src/components/ui/toggle-group.tsx b/src/components/ui/toggle-group.tsx
index 2137023..c08c167 100644
--- a/src/components/ui/toggle-group.tsx
+++ b/src/components/ui/toggle-group.tsx
@@ -3,6 +3,7 @@ import { ToggleGroup as ToggleGroupPrimitive } from "@base-ui/react/toggle-group
 import type { VariantProps } from "class-variance-authority";
 import * as React from "react";
 import { cn } from "../../utils/cn";
+import { cssVars } from "../../utils/css-vars";
 import { Toggle as TogglePrimitive, toggleVariants } from "./toggle";
 
 const ToggleGroupContext = React.createContext<
@@ -37,7 +38,7 @@ function ToggleGroup({
       data-size={size}
       data-spacing={spacing}
       data-orientation={orientation}
-      style={{ "--gap": spacing } as React.CSSProperties}
+      style={cssVars({ "--gap": spacing })}
       className={cn(
         "group/toggle-group flex w-fit flex-row items-center gap-[--spacing(var(--gap))] rounded-lg data-[size=sm]:rounded-[min(var(--radius-md),10px)] data-vertical:flex-col data-vertical:items-stretch",
         className,
diff --git a/src/utils/css-vars.ts b/src/utils/css-vars.ts
new file mode 100644
index 0000000..a7714b7
--- /dev/null
+++ b/src/utils/css-vars.ts
@@ -0,0 +1,13 @@
+import type { CSSProperties } from "react";
+
+export type StyleWithVars = CSSProperties &
+  Record<`--${string}`, string | number | undefined>;
+
+/**
+ * Builds a `style` value that carries CSS custom properties.
+ *
+ * React types `style` as `CSSProperties`, which has no index signature for `--*` keys, so a literal
+ * containing them is rejected by the excess-property check. Passing it through this helper keeps the
+ * keys checked (they must match `--${string}`) without asserting the object into a type it is not.
+ */
+export const cssVars = (style: StyleWithVars): CSSProperties => style;