diff --git a/package-lock.json b/package-lock.json
index 1d93359..96536ff 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@ioai/rosview",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@ioai/rosview",
-      "version": "1.5.0",
+      "version": "1.5.1",
       "license": "MIT",
       "devDependencies": {
         "@eslint/js": "^9.39.4",
diff --git a/package.json b/package.json
index f03350e..f794939 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ioai/rosview",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "description": "High-performance robotics data visualization for MCAP, ROS bag, ROS2 db3, HDF5 and BVH — embeddable React component and standalone SPA",
   "keywords": [
     "ros",
diff --git a/src/features/panels/Plot/PlotLegendSettings.tsx b/src/features/panels/Plot/PlotLegendSettings.tsx
index a673f86..9ceeabc 100644
--- a/src/features/panels/Plot/PlotLegendSettings.tsx
+++ b/src/features/panels/Plot/PlotLegendSettings.tsx
@@ -1,36 +1,46 @@
 import React, { useEffect, useMemo, useRef } from 'react';
 import { useIntl } from 'react-intl';
-import { SettingsSection } from '../framework/settings/SettingsPrimitives';
 import { ScrollArea } from '@/shared/ui/scroll-area';
 import type { PlotConfig } from './defaults';
 import {
   isPlotLegendVisible,
   plotLegendSelectionState,
-  setAllPlotLegendVisible,
+  setPlotLegendGroupVisible,
   setPlotLegendVisible,
 } from './plotLegendVisibility';
 import { usePlotLegendEntries } from './plotPanelRuntimeStore';
 
 interface PlotLegendSettingsProps {
   panelId: string;
+  seriesId: string;
   config: PlotConfig;
   setConfig: (next: PlotConfig | ((prev: PlotConfig) => PlotConfig)) => void;
 }
 
-function legendInputId(panelId: string, index: number): string {
-  return `plot-legend-${panelId}-${index}`;
+function legendKeyPrefix(seriesId: string): string {
+  return `${seriesId}:`;
+}
+
+function legendInputId(panelId: string, seriesId: string, index: number): string {
+  return `plot-legend-${panelId}-${seriesId}-${index}`;
 }
 
 export function PlotLegendSettings({
   panelId,
+  seriesId,
   config,
   setConfig,
 }: PlotLegendSettingsProps): React.ReactNode {
   const { formatMessage } = useIntl();
-  const entries = usePlotLegendEntries(panelId);
+  const allEntries = usePlotLegendEntries(panelId);
+  const prefix = legendKeyPrefix(seriesId);
+  const entries = useMemo(
+    () => allEntries.filter((entry) => entry.key.startsWith(prefix)),
+    [allEntries, prefix],
+  );
   const hiddenKeys = config.hiddenLegendKeys;
   const selectAllRef = useRef<HTMLInputElement>(null);
-  const selectAllId = `plot-legend-${panelId}-all`;
+  const selectAllId = `plot-legend-${panelId}-${seriesId}-all`;
 
   const selection = useMemo(
     () => plotLegendSelectionState(entries, hiddenKeys),
@@ -48,6 +58,10 @@ export function PlotLegendSettings({
     input.indeterminate = selection === 'partial';
   }, [selection]);
 
+  if (entries.length <= 1) {
+    return null;
+  }
+
   const setHiddenKeys = (next: string[]) => {
     setConfig((prev) => ({ ...prev, hiddenLegendKeys: next }));
   };
@@ -57,21 +71,25 @@ export function PlotLegendSettings({
   };
 
   const toggleAll = (visible: boolean) => {
-    setHiddenKeys(setAllPlotLegendVisible(entries.map((entry) => entry.key), visible));
+    setHiddenKeys(
+      setPlotLegendGroupVisible(
+        hiddenKeys,
+        entries.map((entry) => entry.key),
+        visible,
+      ),
+    );
   };
 
   return (
-    <SettingsSection
-      title={formatMessage({ id: 'panels.plot.settings.section.legend' })}
-      description={formatMessage({ id: 'panels.plot.settings.legend.description' })}
-    >
-      {entries.length === 0 ? (
-        <p className="px-1 text-[11px] text-muted-foreground">
-          {formatMessage({ id: 'panels.plot.settings.legend.empty' })}
-        </p>
-      ) : (
-        <>
-          <div className="mb-1.5 flex items-center gap-2 rounded border border-border bg-muted/30 px-2 py-1">
+    <div className="space-y-1 border-t border-border pt-2">
+      <p className="text-[10px] font-medium text-muted-foreground">
+        {formatMessage({ id: 'panels.plot.settings.series.legend.title' })}
+      </p>
+      <p className="px-0.5 text-[10px] text-muted-foreground">
+        {formatMessage({ id: 'panels.plot.settings.legend.description' })}
+      </p>
+      <>
+          <div className="flex items-center gap-2 rounded border border-border bg-muted/30 px-2 py-1">
             <input
               ref={selectAllRef}
               id={selectAllId}
@@ -88,10 +106,10 @@ export function PlotLegendSettings({
               )}
             </label>
           </div>
-          <ScrollArea className="max-h-72 rounded border border-border">
+          <ScrollArea className="max-h-48 rounded border border-border">
             <div className="flex flex-col py-0.5">
               {entries.map((entry, index) => {
-                const inputId = legendInputId(panelId, index);
+                const inputId = legendInputId(panelId, seriesId, index);
                 const visible = isPlotLegendVisible(hiddenKeys, entry.key);
                 return (
                   <label
@@ -111,7 +129,10 @@ export function PlotLegendSettings({
                       style={{ backgroundColor: entry.color }}
                       aria-hidden
                     />
-                    <span className="min-w-0 flex-1 truncate text-[11px] leading-tight text-foreground" title={entry.label}>
+                    <span
+                      className="min-w-0 flex-1 truncate text-[11px] leading-tight text-foreground"
+                      title={entry.label}
+                    >
                       {entry.label}
                     </span>
                   </label>
@@ -119,8 +140,7 @@ export function PlotLegendSettings({
               })}
             </div>
           </ScrollArea>
-        </>
-      )}
-    </SettingsSection>
+      </>
+    </div>
   );
 }
diff --git a/src/features/panels/Plot/PlotPanel.tsx b/src/features/panels/Plot/PlotPanel.tsx
index aba5931..e90f710 100644
--- a/src/features/panels/Plot/PlotPanel.tsx
+++ b/src/features/panels/Plot/PlotPanel.tsx
@@ -31,6 +31,9 @@ import { usePlotPanelData } from './usePlotPanelData';
 import { usePlotTopicDetection } from './usePlotTopicDetection';
 import { timeToSec } from '@/core/analysis/timeSeries';
 
+/** Stable empty array for activeTopics when no topics are configured. */
+const EMPTY_TOPICS: string[] = [];
+
 interface PlotPanelProps {
   player: Player;
   panelId: string;
@@ -87,10 +90,14 @@ export const PlotPanel: React.FC<PlotPanelProps> = ({ player, panelId, config, s
 
   const plottableTopics = useMemo(() => filterPlottableTopics(topics), [topics]);
   const topicByName = useMemo(() => buildTopicByName(topics), [topics]);
-  const activeTopics = useMemo(
-    () => selectActivePlotTopics(config, topicByName),
+  const activeTopicsKey = useMemo(
+    () => selectActivePlotTopics(config, topicByName).join('\n'),
     [config, topicByName],
   );
+  const activeTopics = useMemo(
+    () => (activeTopicsKey === '' ? EMPTY_TOPICS : activeTopicsKey.split('\n')),
+    [activeTopicsKey],
+  );
   const hasPlotPaths = useMemo(() => hasConfiguredPlotPaths(config), [config]);
   const hasEnabledSeries = useMemo(() => hasEnabledPlotPaths(config), [config]);
   const primary = selectPrimarySeries(config);
@@ -216,7 +223,10 @@ export const PlotPanel: React.FC<PlotPanelProps> = ({ player, panelId, config, s
   const handleChartClick = (event: React.MouseEvent<HTMLDivElement>) => {
     const chart = uplotRef.current;
     if (!chart || config.xAxisMode !== 'timestamp') return;
-    const rect = chart.root.getBoundingClientRect();
+    // posToVal expects a position relative to the plotting area (the `over`
+    // element), which is what hover/cursor uses. Using `root` here would add the
+    // left Y-axis width as a fixed offset, shifting the seek target to the right.
+    const rect = chart.over.getBoundingClientRect();
     const x = chart.posToVal(event.clientX - rect.left, 'x');
     if (Number.isFinite(x)) {
       player.seek(secToTime(x));
diff --git a/src/features/panels/Plot/PlotPanelSettings.tsx b/src/features/panels/Plot/PlotPanelSettings.tsx
index f5dcefe..a737930 100644
--- a/src/features/panels/Plot/PlotPanelSettings.tsx
+++ b/src/features/panels/Plot/PlotPanelSettings.tsx
@@ -142,7 +142,6 @@ export function PlotPanelSettings({
 
   return (
     <div className="space-y-2">
-      <PlotLegendSettings panelId={panelId} config={config} setConfig={setConfig} />
       <SettingsSection title={formatMessage({ id: 'panels.plot.settings.section.plot' })}>
         <SettingsField label={formatMessage({ id: 'panels.plot.settings.field.xAxis' })}>
           <SettingsSelect<PlotXAxisMode>
@@ -353,6 +352,12 @@ export function PlotPanelSettings({
                 }
               />
             </SettingsField>
+            <PlotLegendSettings
+              panelId={panelId}
+              seriesId={series.id}
+              config={config}
+              setConfig={setConfig}
+            />
           </div>
         ))}
         <button
diff --git a/src/features/panels/Plot/plotConfigSelectors.test.ts b/src/features/panels/Plot/plotConfigSelectors.test.ts
index 8b6ba40..ba9e245 100644
--- a/src/features/panels/Plot/plotConfigSelectors.test.ts
+++ b/src/features/panels/Plot/plotConfigSelectors.test.ts
@@ -6,6 +6,7 @@ import {
   plotDataConfigKey,
   plotEnabledSeriesIds,
   plotEnabledSeriesKey,
+  plotSeriesVisualKey,
   selectActivePlotTopics,
 } from './plotConfigSelectors';
 import type { TopicInfo } from '@/core/types/ros';
@@ -64,6 +65,52 @@ describe('plotEnabledSeriesKey / plotEnabledSeriesIds', () => {
   });
 });
 
+describe('plotSeriesVisualKey', () => {
+  it('changes when line style or size changes but data key does not', () => {
+    const base = defaultPlotConfig();
+    const a = {
+      ...base,
+      series: [createPlotSeries({ id: 's1', topic: '/a', path: 'data', lineStyle: 'solid', lineSize: 1.5 })],
+    };
+    const b = { ...a, series: [{ ...a.series[0], lineStyle: 'dashed' as const }] };
+    const c = { ...a, series: [{ ...a.series[0], lineSize: 3 }] };
+    expect(plotSeriesVisualKey(a)).not.toBe(plotSeriesVisualKey(b));
+    expect(plotSeriesVisualKey(a)).not.toBe(plotSeriesVisualKey(c));
+    // Visual-only changes must never trigger a range re-read.
+    expect(plotDataConfigKey(a)).toBe(plotDataConfigKey(b));
+    expect(plotDataConfigKey(a)).toBe(plotDataConfigKey(c));
+  });
+
+  it('changes when color or label changes', () => {
+    const base = defaultPlotConfig();
+    const a = {
+      ...base,
+      series: [createPlotSeries({ id: 's1', topic: '/a', path: 'data', color: '#111', label: 'A' })],
+    };
+    const b = { ...a, series: [{ ...a.series[0], color: '#222' }] };
+    const c = { ...a, series: [{ ...a.series[0], label: 'B' }] };
+    expect(plotSeriesVisualKey(a)).not.toBe(plotSeriesVisualKey(b));
+    expect(plotSeriesVisualKey(a)).not.toBe(plotSeriesVisualKey(c));
+  });
+});
+
+describe('legend visibility vs range read', () => {
+  it('does not change active topics key or plotDataConfigKey when hiddenLegendKeys toggles', () => {
+    const base = defaultPlotConfig();
+    const config = {
+      ...base,
+      series: [
+        createPlotSeries({ id: 's1', topic: '/a', path: 'data', enabled: true }),
+        createPlotSeries({ id: 's2', topic: '/b', path: 'data', enabled: true }),
+      ],
+    };
+    const hidden = { ...config, hiddenLegendKeys: ['s1'] };
+    const topicsKey = (c: typeof config) => selectActivePlotTopics(c, topicByName).join('\n');
+    expect(topicsKey(config)).toBe(topicsKey(hidden));
+    expect(plotDataConfigKey(config)).toBe(plotDataConfigKey(hidden));
+  });
+});
+
 describe('selectActivePlotTopics', () => {
   it('includes topics for disabled series too (so toggling does not refetch)', () => {
     const base = defaultPlotConfig();
diff --git a/src/features/panels/Plot/plotConfigSelectors.ts b/src/features/panels/Plot/plotConfigSelectors.ts
index 03eea08..553d45a 100644
--- a/src/features/panels/Plot/plotConfigSelectors.ts
+++ b/src/features/panels/Plot/plotConfigSelectors.ts
@@ -97,6 +97,19 @@ export function plotEnabledSeriesIds(config: PlotConfig): Set<string> {
   return new Set(config.series.filter((s) => s.enabled).map((s) => s.id));
 }
 
+/**
+ * Stable key for per-series visual config (label/color/line style/size).
+ *
+ * Changing these should re-render the dataset visuals (a cheap rebuild) but
+ * never trigger a range re-read — that is why it is tracked separately from
+ * {@link plotDataConfigKey}.
+ */
+export function plotSeriesVisualKey(config: PlotConfig): string {
+  return config.series
+    .map((s) => `${s.id}|${s.label}|${s.color}|${s.lineStyle}|${s.lineSize}`)
+    .join(';');
+}
+
 /** Stable key for uPlot series topology (rebuild when this changes). */
 export function plotChartTopologyKey(dataset: {
   series: ReadonlyArray<{
diff --git a/src/features/panels/Plot/plotDatasetAccumulator.test.ts b/src/features/panels/Plot/plotDatasetAccumulator.test.ts
index 96793fa..61e8387 100644
--- a/src/features/panels/Plot/plotDatasetAccumulator.test.ts
+++ b/src/features/panels/Plot/plotDatasetAccumulator.test.ts
@@ -161,4 +161,42 @@ describe('PlotDatasetAccumulator', () => {
     const onlyS2 = accumulator.buildDataset(new Set(['s2']));
     expect(onlyS2.series.map((s) => s.key.startsWith('s2:') ? 's2' : 's1')).toEqual(['s2']);
   });
+
+  it('applies live visual config (line style/size/color) at build time without re-ingest', () => {
+    const baseSeries = defaultPlotConfig().series[0];
+    const config = {
+      ...defaultPlotConfig(),
+      downsampleMode: 'none' as const,
+      series: [
+        {
+          ...baseSeries,
+          id: 's1',
+          topic: '/a',
+          path: 'data',
+          timestampMode: 'receiveTime' as const,
+          lineStyle: 'solid' as const,
+          lineSize: 1.5,
+          color: '#111',
+        },
+      ],
+    };
+    const events = [
+      event('/a', 1, { data: 1 }, 'std_msgs/msg/Float64'),
+      event('/a', 2, { data: 2 }, 'std_msgs/msg/Float64'),
+    ];
+
+    const accumulator = new PlotDatasetAccumulator(config);
+    accumulator.append(events);
+
+    // Build with a live config carrying updated visuals (no new data appended).
+    const liveConfig = {
+      ...config,
+      series: [{ ...config.series[0], lineStyle: 'dashed' as const, lineSize: 4, color: '#abcdef' }],
+    };
+    const dataset = accumulator.buildDataset(new Set(['s1']), liveConfig);
+
+    expect(dataset.series[0].lineStyle).toBe('dashed');
+    expect(dataset.series[0].lineSize).toBe(4);
+    expect(dataset.series[0].color).toBe('#abcdef');
+  });
 });
diff --git a/src/features/panels/Plot/plotDatasetAccumulator.ts b/src/features/panels/Plot/plotDatasetAccumulator.ts
index b81f6ba..258ad42 100644
--- a/src/features/panels/Plot/plotDatasetAccumulator.ts
+++ b/src/features/panels/Plot/plotDatasetAccumulator.ts
@@ -6,6 +6,7 @@ import type { MessageEvent } from '@/core/types/ros';
 import type { BuildPlotDatasetOptions, PlotDataset, PointBucket } from './types';
 import { alignBuckets } from './plotAlign';
 import {
+  applySeriesConfigVisuals,
   assignBucketColors,
   collectCustomPoints,
   collectIndexPoints,
@@ -46,6 +47,7 @@ function datasetFromBuckets(
   options: PlotDatasetAccumulatorOptions,
   warnings: PlotDatasetWarning[],
   enabledSeriesIds?: ReadonlySet<string>,
+  visualConfig?: PlotConfig,
 ): PlotDataset {
   // Filter buckets to those whose owning series is currently enabled.
   // The accumulator deliberately ingests buckets for *all configured* series
@@ -60,6 +62,10 @@ function datasetFromBuckets(
           ),
         );
 
+  // Apply live visuals before palette assignment so user color overrides on
+  // single-bucket series are respected while multi-bucket series still get
+  // palette colors.
+  applySeriesConfigVisuals(filteredBuckets.values(), visualConfig ?? config);
   assignBucketColors(filteredBuckets);
   const seriesBuckets = [...filteredBuckets.values()];
   const shouldDownsample = options.forceDownsample === true || config.downsampleMode === 'minMaxLast';
@@ -115,7 +121,13 @@ export class PlotDatasetAccumulator {
    * buckets owned by those series are emitted — letting callers re-render
    * after visibility toggles without re-ingesting data.
    */
-  buildDataset(enabledSeriesIds?: ReadonlySet<string>): PlotDataset {
+  buildDataset(
+    enabledSeriesIds?: ReadonlySet<string>,
+    visualConfig?: PlotConfig,
+  ): PlotDataset {
+    // Live config used only to overlay current visuals (line style/size/color).
+    // Structure (paths, axis mode, ...) still comes from the ingest-time config.
+    const visuals = visualConfig ?? this._config;
     if (this._messageCount === 0) {
       return {
         ...EMPTY_DATASET,
@@ -133,7 +145,7 @@ export class PlotDatasetAccumulator {
       // Re-collect at build time so we can apply the live enabled filter.
       const filteredConfig = this._configWithSeriesFilter(seriesFilter);
       const buckets = collectIndexPoints([...this._latestByTopic.values()], filteredConfig);
-      return datasetFromBuckets(buckets, filteredConfig, this._options, warnings);
+      return datasetFromBuckets(buckets, filteredConfig, this._options, warnings, undefined, visuals);
     }
 
     if (this._config.xAxisMode === 'currentCustom') {
@@ -145,7 +157,7 @@ export class PlotDatasetAccumulator {
         true,
         warnings,
       );
-      return datasetFromBuckets(buckets, filteredConfig, this._options, warnings);
+      return datasetFromBuckets(buckets, filteredConfig, this._options, warnings, undefined, visuals);
     }
 
     const warnings = Array.from(this._warnings.values());
@@ -163,6 +175,7 @@ export class PlotDatasetAccumulator {
       this._options,
       warnings,
       new Set(this._config.series.filter(seriesFilter).map((s) => s.id)),
+      visuals,
     );
   }
 
diff --git a/src/features/panels/Plot/plotLegendVisibility.test.ts b/src/features/panels/Plot/plotLegendVisibility.test.ts
index a94edb2..9bcf4bd 100644
--- a/src/features/panels/Plot/plotLegendVisibility.test.ts
+++ b/src/features/panels/Plot/plotLegendVisibility.test.ts
@@ -5,6 +5,7 @@ import {
   plotLegendSelectionState,
   pruneHiddenLegendKeys,
   setAllPlotLegendVisible,
+  setPlotLegendGroupVisible,
   setPlotLegendVisible,
 } from './plotLegendVisibility';
 
@@ -28,6 +29,15 @@ describe('plotLegendVisibility', () => {
     expect(setAllPlotLegendVisible(['a', 'b'], false)).toEqual(['a', 'b']);
   });
 
+  it('toggles a legend group without affecting other series keys', () => {
+    expect(setPlotLegendGroupVisible(['s1:a', 's2:x'], ['s1:a', 's1:b'], true)).toEqual(['s2:x']);
+    expect(setPlotLegendGroupVisible(['s2:x'], ['s1:a', 's1:b'], false)).toEqual([
+      's2:x',
+      's1:a',
+      's1:b',
+    ]);
+  });
+
   it('maps hidden keys to chart series indices', () => {
     expect([...hiddenSeriesIndices(entries, ['b'])]).toEqual([1]);
   });
diff --git a/src/features/panels/Plot/plotLegendVisibility.ts b/src/features/panels/Plot/plotLegendVisibility.ts
index f43f6c7..b2af50d 100644
--- a/src/features/panels/Plot/plotLegendVisibility.ts
+++ b/src/features/panels/Plot/plotLegendVisibility.ts
@@ -13,10 +13,28 @@ export function setPlotLegendVisible(
   return hiddenKeys.includes(key) ? [...hiddenKeys] : [...hiddenKeys, key];
 }
 
+/** @deprecated Prefer {@link setPlotLegendGroupVisible} for per-series toggles. */
 export function setAllPlotLegendVisible(allKeys: readonly string[], visible: boolean): string[] {
   return visible ? [] : [...allKeys];
 }
 
+/** Toggle visibility for a subset of legend keys without affecting other series. */
+export function setPlotLegendGroupVisible(
+  hiddenKeys: readonly string[],
+  groupKeys: readonly string[],
+  visible: boolean,
+): string[] {
+  const group = new Set(groupKeys);
+  if (visible) {
+    return hiddenKeys.filter((key) => !group.has(key));
+  }
+  const next = new Set(hiddenKeys);
+  for (const key of groupKeys) {
+    next.add(key);
+  }
+  return [...next];
+}
+
 export function pruneHiddenLegendKeys(
   hiddenKeys: readonly string[],
   validKeys: readonly string[],
diff --git a/src/features/panels/Plot/plotPointCollector.ts b/src/features/panels/Plot/plotPointCollector.ts
index 4207187..dad8fe6 100644
--- a/src/features/panels/Plot/plotPointCollector.ts
+++ b/src/features/panels/Plot/plotPointCollector.ts
@@ -81,6 +81,27 @@ export function pushPoint(
   bucket.points.push({ x, y });
 }
 
+/**
+ * Overlay live config visuals (line style/size/color) onto already-accumulated
+ * buckets. The accumulator captures visuals at ingest time, so without this
+ * a later config change (e.g. dashed -> solid, thicker line) would not surface
+ * until a full re-read. Color is applied before {@link assignBucketColors} so
+ * the palette still wins for multi-bucket series (e.g. JointState arrays).
+ */
+export function applySeriesConfigVisuals(
+  buckets: Iterable<PointBucket>,
+  config: PlotConfig,
+): void {
+  const seriesById = new Map(config.series.map((series) => [series.id, series]));
+  for (const bucket of buckets) {
+    const series = seriesById.get(bucket.seriesConfigId);
+    if (!series) continue;
+    bucket.series.lineStyle = series.lineStyle;
+    bucket.series.lineSize = series.lineSize;
+    if (series.color) bucket.series.color = series.color;
+  }
+}
+
 export function assignBucketColors(buckets: Map<string, PointBucket>): void {
   const bucketsBySeries = new Map<string, PointBucket[]>();
   for (const bucket of buckets.values()) {
diff --git a/src/features/panels/Plot/usePlotChart.test.ts b/src/features/panels/Plot/usePlotChart.test.ts
index eaafc7b..382e21e 100644
--- a/src/features/panels/Plot/usePlotChart.test.ts
+++ b/src/features/panels/Plot/usePlotChart.test.ts
@@ -40,10 +40,16 @@ describe('diffSeriesTopology', () => {
     expect(diffSeriesTopology(a, b)).toEqual({ kind: 'remount' });
   });
 
-  it('falls back to remount on meta change for same key', () => {
-    const a = [sig('a', 'l|#000|solid|1')];
-    const b = [sig('a', 'l|#fff|solid|1')];
-    expect(diffSeriesTopology(a, b)).toEqual({ kind: 'remount' });
+  it('returns styleUpdate on meta change for same keys (no remount)', () => {
+    const a = [sig('a', 'l|#000|solid|1'), sig('b', 'l|#111|solid|1')];
+    const b = [sig('a', 'l|#fff|solid|1'), sig('b', 'l|#111|dashed|2')];
+    expect(diffSeriesTopology(a, b)).toEqual({ kind: 'styleUpdate', changed: [0, 1] });
+  });
+
+  it('reports only the changed indices in styleUpdate', () => {
+    const a = [sig('a', 'l|#000|solid|1'), sig('b', 'l|#111|solid|1')];
+    const b = [sig('a', 'l|#000|solid|1'), sig('b', 'l|#111|solid|3')];
+    expect(diffSeriesTopology(a, b)).toEqual({ kind: 'styleUpdate', changed: [1] });
   });
 
   it('falls back to remount when prefix differs (mixed insertion)', () => {
diff --git a/src/features/panels/Plot/usePlotChart.ts b/src/features/panels/Plot/usePlotChart.ts
index d7efc60..bb475c5 100644
--- a/src/features/panels/Plot/usePlotChart.ts
+++ b/src/features/panels/Plot/usePlotChart.ts
@@ -4,7 +4,7 @@ import { timeToSec } from '@/core/analysis/timeSeries';
 import type { Player } from '@/core/types/player';
 import type { Time } from '@/core/types/ros';
 import { scheduleFrame } from '@/shared/utils/rafScheduler';
-import type { PlotDataset } from './datasets';
+import type { PlotDataset, PlotRuntimeSeries } from './datasets';
 import type { PlotConfig } from './defaults';
 import {
   buildPlotSeriesOption,
@@ -53,14 +53,16 @@ function seriesSignatures(
 
 type DiffResult =
   | { kind: 'identical' }
+  | { kind: 'styleUpdate'; changed: number[] }
   | { kind: 'pureAdd'; added: SeriesSignature[]; addedAt: number }
   | { kind: 'pureDel'; removedFrom: number; removedCount: number }
   | { kind: 'remount' };
 
 /**
  * Cheap topology diff so we can keep uPlot mounted across the most common
- * case: new series buckets appearing late during a range read (e.g. a
- * JointState topic exposing additional joints). Anything more complex than
+ * cases: new series buckets appearing late during a range read (e.g. a
+ * JointState topic exposing additional joints), and pure visual changes
+ * (line style/size/color) on existing series. Anything more complex than
  * a clean append/truncate at the tail falls back to a remount.
  *
  * Exported for unit testing.
@@ -70,14 +72,20 @@ export function diffSeriesTopology(
   next: SeriesSignature[],
 ): DiffResult {
   if (prev.length === next.length) {
-    let allMatch = true;
+    let keysMatch = true;
+    const changed: number[] = [];
     for (let i = 0; i < prev.length; i++) {
-      if (prev[i].key !== next[i].key || prev[i].meta !== next[i].meta) {
-        allMatch = false;
+      if (prev[i].key !== next[i].key) {
+        keysMatch = false;
         break;
       }
+      if (prev[i].meta !== next[i].meta) changed.push(i);
+    }
+    if (keysMatch) {
+      // Same series identities & order: either nothing changed, or only
+      // visual metadata changed (apply in place, no remount).
+      return changed.length === 0 ? { kind: 'identical' } : { kind: 'styleUpdate', changed };
     }
-    if (allMatch) return { kind: 'identical' };
   }
 
   // Pure appended series at the tail
@@ -126,6 +134,26 @@ export function plotChartYSeriesCount(chart: uPlot): number {
   return chart.series.length - 1;
 }
 
+/** Mutable view of a uPlot series including its internal path cache. */
+type MutablePlotSeries = uPlot.Series & { _paths?: unknown };
+
+/**
+ * Apply a series' visual config (color/width/dash/label) onto a live uPlot
+ * series in place. uPlot's `setSeries` only supports `show`/`focus`, so style
+ * changes must mutate the series object directly: `width`/`dash` are read each
+ * draw, `stroke` is re-resolved via `cacheStrokeFill`, and nulling `_paths`
+ * forces a path rebuild for the new width. The caller must `redraw(true)`.
+ */
+function applyRuntimeSeriesStyle(chart: uPlot, index: number, series: PlotRuntimeSeries): void {
+  const target = chart.series[index + 1] as MutablePlotSeries | undefined;
+  if (!target) return;
+  target.label = series.label;
+  target.stroke = () => series.color;
+  target.width = series.lineSize;
+  target.dash = series.lineStyle === 'dashed' ? [6, 4] : [];
+  target._paths = null;
+}
+
 /**
  * Returns true when incremental add/del would be unsafe and the chart should remount.
  * Exported for unit tests.
@@ -265,6 +293,12 @@ export function usePlotChart({
         // Remove from the tail; uPlot series indices are 1-based (0 = x-axis).
         chart.delSeries(diff.removedFrom + 1);
       }
+    } else if (diff.kind === 'styleUpdate') {
+      // Pure visual change (line style/size/color): mutate series in place
+      // instead of remounting, preserving zoom/pan state.
+      for (const index of diff.changed) {
+        applyRuntimeSeriesStyle(chart, index, dataset.series[index]);
+      }
     }
 
     // Sync show flags for stable indices.
@@ -275,6 +309,11 @@ export function usePlotChart({
     // setData second arg = false avoids a hard scale reset every batch, which is
     // what made the chart flash while data was streaming in.
     chart.setData(dataset.data, false);
+    // Style mutations are read at draw time, so force one rebuild+redraw to
+    // surface the new width/dash/stroke immediately.
+    if (diff.kind === 'styleUpdate') {
+      chart.redraw(true);
+    }
     seriesSignaturesRef.current = nextSignatures;
   }, [config.followingViewWidthSec, config.xAxisMode, containerRef, dataset, destroyChart, hiddenSeries, mountChart]);
 
diff --git a/src/features/panels/Plot/usePlotPanelData.ts b/src/features/panels/Plot/usePlotPanelData.ts
index 0bd9b29..2518c65 100644
--- a/src/features/panels/Plot/usePlotPanelData.ts
+++ b/src/features/panels/Plot/usePlotPanelData.ts
@@ -8,6 +8,7 @@ import {
   plotDataConfigKey,
   plotEnabledSeriesIds,
   plotEnabledSeriesKey,
+  plotSeriesVisualKey,
 } from './plotConfigSelectors';
 import { readPlotRangeIncremental, type PlotRangeReadProgress } from './rangeReader';
 import type { PlotDatasetWarning } from './plotWarnings';
@@ -60,11 +61,18 @@ export function usePlotPanelData({
 
   const dataConfigKey = useMemo(() => plotDataConfigKey(config), [config]);
   const enabledSeriesKey = useMemo(() => plotEnabledSeriesKey(config), [config]);
+  const seriesVisualKey = useMemo(() => plotSeriesVisualKey(config), [config]);
   const enabledSeriesIds = useMemo(() => plotEnabledSeriesIds(config), [config]);
   const enabledSeriesIdsRef = useRef(enabledSeriesIds);
   useEffect(() => {
     enabledSeriesIdsRef.current = enabledSeriesIds;
   }, [enabledSeriesIds]);
+  // Latest config for live visual overlays (line style/size/color) applied at
+  // dataset build time without re-ingesting data.
+  const configRef = useRef(config);
+  useEffect(() => {
+    configRef.current = config;
+  }, [config]);
   const accumulatorRef = useRef<PlotDatasetAccumulator | null>(null);
 
   const progressRef = useRef<PlotRangeReadProgress | null>(null);
@@ -134,7 +142,7 @@ export function usePlotPanelData({
       datasetTimeoutRef.current = null;
       if (controller.signal.aborted) return;
       lastDatasetFlushMsRef.current = performance.now();
-      setDataset(accumulator.buildDataset(enabledSeriesIdsRef.current));
+      setDataset(accumulator.buildDataset(enabledSeriesIdsRef.current, configRef.current));
     };
 
     const scheduleDatasetFlush = () => {
@@ -210,8 +218,17 @@ export function usePlotPanelData({
   useEffect(() => {
     const accumulator = accumulatorRef.current;
     if (!accumulator) return;
-    setDataset(accumulator.buildDataset(enabledSeriesIdsRef.current));
+    setDataset(accumulator.buildDataset(enabledSeriesIdsRef.current, configRef.current));
   }, [enabledSeriesKey]);
 
+  // Changing a series' visual config (line style/size/color/label) rebuilds the
+  // dataset with the live visuals overlaid — a cheap re-render that never
+  // re-ingests data and lets the chart apply styles incrementally.
+  useEffect(() => {
+    const accumulator = accumulatorRef.current;
+    if (!accumulator) return;
+    setDataset(accumulator.buildDataset(enabledSeriesIdsRef.current, configRef.current));
+  }, [seriesVisualKey]);
+
   return { dataset, loading, progress, error };
 }
diff --git a/src/shared/intl/messages/en/panels.json b/src/shared/intl/messages/en/panels.json
index 91e096e..495491e 100644
--- a/src/shared/intl/messages/en/panels.json
+++ b/src/shared/intl/messages/en/panels.json
@@ -14,10 +14,11 @@
   "panels.plot.warning.missingXPath": "Missing X path for {topic}.{path}",
   "panels.plot.warning.mismatchedXY": "Mismatched X/Y lengths for {topic}: {xPath} vs {yPath}",
   "panels.plot.settings.section.legend": "Legend",
-  "panels.plot.settings.legend.description": "Choose curves to compare on the chart. Uncheck to hide a series.",
-  "panels.plot.settings.legend.empty": "Legend entries appear after data is loaded",
+  "panels.plot.settings.series.legend.title": "Curves",
+  "panels.plot.settings.legend.description": "Select which curves from this topic to display on the chart. Uncheck to hide a curve.",
+  "panels.plot.settings.legend.empty": "Curve list appears after data is loaded",
   "panels.plot.settings.legend.selectedCount": "{visible} / {total} selected",
-  "panels.plot.settings.legend.selectAllAria": "Select all legend entries",
+  "panels.plot.settings.legend.selectAllAria": "Select all curves for this series",
   "panels.plot.settings.section.plot": "Plot",
   "panels.plot.settings.section.series": "Series",
   "panels.plot.settings.field.xAxis": "X axis",
diff --git a/src/shared/intl/messages/ja/panels.json b/src/shared/intl/messages/ja/panels.json
index 0ed349f..2a1e9d3 100644
--- a/src/shared/intl/messages/ja/panels.json
+++ b/src/shared/intl/messages/ja/panels.json
@@ -14,10 +14,11 @@
   "panels.plot.warning.missingXPath": "X パスがありません: {topic}.{path}",
   "panels.plot.warning.mismatchedXY": "X/Y の長さが一致しません {topic}: {xPath} vs {yPath}",
   "panels.plot.settings.section.legend": "凡例",
-  "panels.plot.settings.legend.description": "グラフで比較表示する系列を選択します。チェックを外すと非表示になります。",
-  "panels.plot.settings.legend.empty": "データ読み込み後に凡例が表示されます",
+  "panels.plot.settings.series.legend.title": "曲線",
+  "panels.plot.settings.legend.description": "このトピックからグラフに表示する曲線を選択します。チェックを外すと非表示になります。",
+  "panels.plot.settings.legend.empty": "データ読み込み後に曲線リストが表示されます",
   "panels.plot.settings.legend.selectedCount": "選択 {visible} / {total}",
-  "panels.plot.settings.legend.selectAllAria": "凡例をすべて選択",
+  "panels.plot.settings.legend.selectAllAria": "この系列の曲線をすべて選択",
   "panels.plot.settings.section.plot": "プロット",
   "panels.plot.settings.section.series": "系列",
   "panels.plot.settings.field.xAxis": "X 軸",
diff --git a/src/shared/intl/messages/zh/panels.json b/src/shared/intl/messages/zh/panels.json
index 5fea47d..398a620 100644
--- a/src/shared/intl/messages/zh/panels.json
+++ b/src/shared/intl/messages/zh/panels.json
@@ -14,10 +14,11 @@
   "panels.plot.warning.missingXPath": "缺少 X 路径：{topic}.{path}",
   "panels.plot.warning.mismatchedXY": "X/Y 长度不匹配 {topic}：{xPath} vs {yPath}",
   "panels.plot.settings.section.legend": "图例",
-  "panels.plot.settings.legend.description": "选择要在图表中对比显示的曲线。取消勾选可隐藏对应图例。",
-  "panels.plot.settings.legend.empty": "加载数据后将显示图例列表",
+  "panels.plot.settings.series.legend.title": "曲线",
+  "panels.plot.settings.legend.description": "选择本 Topic 要在图表中显示的曲线。取消勾选可隐藏对应曲线。",
+  "panels.plot.settings.legend.empty": "加载数据后将显示曲线列表",
   "panels.plot.settings.legend.selectedCount": "已选 {visible} / {total}",
-  "panels.plot.settings.legend.selectAllAria": "全选图例",
+  "panels.plot.settings.legend.selectAllAria": "全选本序列的曲线",
   "panels.plot.settings.section.plot": "图表",
   "panels.plot.settings.section.series": "序列",
   "panels.plot.settings.field.xAxis": "X 轴",