diff --git a/src/app/components/LivePreview.module.css b/src/app/components/LivePreview.module.css
index 7754e60..f154807 100644
--- a/src/app/components/LivePreview.module.css
+++ b/src/app/components/LivePreview.module.css
@@ -25,41 +25,8 @@
   box-sizing: border-box;
 }
 
-/* Segmented control — the four fit modes (spec §04). */
-.fit {
-  display: inline-flex;
-  border: var(--border-width) solid var(--border-strong);
-}
-
-.fitOption {
-  appearance: none;
-  border: none;
-  background: var(--bg);
-  color: var(--text-secondary);
-  font: inherit;
-  font-size: 12px;
-  line-height: 1;
-  padding: var(--space-2) var(--space-3);
-  cursor: pointer;
-  transition:
-    background var(--dur-fast) var(--ease),
-    color var(--dur-fast) var(--ease);
-}
-
-.fitOption + .fitOption {
-  border-left: var(--border-width) solid var(--border-strong);
-}
-
-.fitOption:hover {
-  background: var(--layer-01);
-  color: var(--text);
-}
-
-.fitActive,
-.fitActive:hover {
-  background: var(--accent);
-  color: var(--accent-contrast);
-}
+/* Fit-mode segmented control (spec §04) styling now lives in
+   SegmentedControl.module.css; the per-mode sizing classes below stay here. */
 
 /*
  * Chart sizing. The host (passed to vega-embed) is branded `.vega-embed`
diff --git a/src/app/components/LivePreview.tsx b/src/app/components/LivePreview.tsx
index 5953af2..462de5a 100644
--- a/src/app/components/LivePreview.tsx
+++ b/src/app/components/LivePreview.tsx
@@ -62,9 +62,6 @@ function FitControl() {
       options={FIT_OPTIONS}
       value={fitMode}
       onChange={setFitMode}
-      className={styles.fit}
-      optionClassName={styles.fitOption}
-      activeClassName={styles.fitActive}
     />
   );
 }
diff --git a/src/app/components/SegmentedControl.module.css b/src/app/components/SegmentedControl.module.css
new file mode 100644
index 0000000..1006e43
--- /dev/null
+++ b/src/app/components/SegmentedControl.module.css
@@ -0,0 +1,42 @@
+/*
+ * Shared look for every SegmentedControl. The control's appearance is owned here
+ * — once — so the Draft/Published and fit-mode instances can't drift apart again.
+ * Selected option uses --layer-02 (a neutral high-contrast fill, per Carbon's
+ * content switcher); --accent stays reserved for primary actions (e.g. Publish),
+ * so "current selection" never reads as "the action to take". Call sites may still
+ * pass className/optionClassName/activeClassName for layout-specific additions.
+ */
+.group {
+  display: inline-flex;
+  border: var(--border-width) solid var(--border-strong);
+}
+
+.option {
+  appearance: none;
+  border: none;
+  background: var(--bg);
+  color: var(--text-secondary);
+  font: inherit;
+  font-size: 12px;
+  line-height: 1;
+  padding: var(--space-2) var(--space-3);
+  cursor: pointer;
+  transition:
+    background var(--dur-fast) var(--ease),
+    color var(--dur-fast) var(--ease);
+}
+
+.option + .option {
+  border-left: var(--border-width) solid var(--border-strong);
+}
+
+.option:hover {
+  background: var(--layer-01);
+  color: var(--text);
+}
+
+.active,
+.active:hover {
+  background: var(--layer-02);
+  color: var(--text);
+}
diff --git a/src/app/components/SegmentedControl.tsx b/src/app/components/SegmentedControl.tsx
index c9479f3..b725b16 100644
--- a/src/app/components/SegmentedControl.tsx
+++ b/src/app/components/SegmentedControl.tsx
@@ -9,10 +9,13 @@
  * move focus *and* select. Native `<button>` gives Enter/Space-to-select for
  * free. One widget so every segmented control gets the same, documented model.
  *
- * Styling is injected via class props so each call site keeps its own look.
+ * The control owns its base look (SegmentedControl.module.css) so every instance
+ * stays visually consistent; call sites may pass class props for layout-specific
+ * additions, which compose on top of the base classes.
  */
 
 import { useRef } from 'react';
+import styles from './SegmentedControl.module.css';
 
 export interface SegmentedOption<T extends string> {
   value: T;
@@ -25,11 +28,11 @@ interface SegmentedControlProps<T extends string> {
   options: ReadonlyArray<SegmentedOption<T>>;
   value: T;
   onChange: (value: T) => void;
-  /** Class for the radiogroup container. */
+  /** Extra class for the radiogroup container (composed onto the base look). */
   className?: string;
-  /** Class for each option button. */
+  /** Extra class for each option button (composed onto the base look). */
   optionClassName?: string;
-  /** Extra class applied to the selected option. */
+  /** Extra class applied to the selected option (composed onto the base active look). */
   activeClassName?: string;
 }
 
@@ -74,7 +77,11 @@ export function SegmentedControl<T extends string>({
   };
 
   return (
-    <div className={className} role="radiogroup" aria-label={label}>
+    <div
+      className={[styles.group, className].filter(Boolean).join(' ')}
+      role="radiogroup"
+      aria-label={label}
+    >
       {options.map((opt, i) => {
         const selected = opt.value === value;
         return (
@@ -89,7 +96,14 @@ export function SegmentedControl<T extends string>({
             // Roving tabindex: only the selected option is a tab stop; arrows
             // move within the group.
             tabIndex={selected ? 0 : -1}
-            className={[optionClassName, selected ? activeClassName : ''].filter(Boolean).join(' ')}
+            className={[
+              styles.option,
+              optionClassName,
+              selected && styles.active,
+              selected && activeClassName,
+            ]
+              .filter(Boolean)
+              .join(' ')}
             onClick={() => onChange(opt.value)}
             onKeyDown={(e) => onKeyDown(e, i)}
           >
diff --git a/src/app/components/SpecEditor.module.css b/src/app/components/SpecEditor.module.css
index 3f05ea3..9064eeb 100644
--- a/src/app/components/SpecEditor.module.css
+++ b/src/app/components/SpecEditor.module.css
@@ -19,41 +19,7 @@
   flex: 1 1 auto;
 }
 
-/* Draft / Published segmented toggle. */
-.viewToggle {
-  display: inline-flex;
-  border: var(--border-width) solid var(--border-strong);
-}
-
-.viewOption {
-  appearance: none;
-  border: none;
-  background: var(--bg);
-  color: var(--text-secondary);
-  font: inherit;
-  font-size: 12px;
-  line-height: 1;
-  padding: var(--space-2) var(--space-3);
-  cursor: pointer;
-  transition:
-    background var(--dur-fast) var(--ease),
-    color var(--dur-fast) var(--ease);
-}
-
-.viewOption + .viewOption {
-  border-left: var(--border-width) solid var(--border-strong);
-}
-
-.viewOption:hover {
-  background: var(--layer-01);
-  color: var(--text);
-}
-
-.viewActive,
-.viewActive:hover {
-  background: var(--layer-02);
-  color: var(--text);
-}
+/* Draft/Published toggle styling now lives in SegmentedControl.module.css. */
 
 /* Publish / Revert buttons. */
 .action {
diff --git a/src/app/components/SpecEditor.tsx b/src/app/components/SpecEditor.tsx
index a1b8924..fa8776d 100644
--- a/src/app/components/SpecEditor.tsx
+++ b/src/app/components/SpecEditor.tsx
@@ -81,9 +81,6 @@ function EditorToolbar() {
         options={VIEW_OPTIONS}
         value={editorView}
         onChange={setEditorView}
-        className={styles.viewToggle}
-        optionClassName={styles.viewOption}
-        activeClassName={styles.viewActive}
       />
 
       <span className={styles.spacer} />