diff --git a/COMPONENT_GUIDE.md b/COMPONENT_GUIDE.md
index 10d62f6..e055aef 100644
--- a/COMPONENT_GUIDE.md
+++ b/COMPONENT_GUIDE.md
@@ -10,6 +10,7 @@
 - Page-level attention banner → **Alert**
 - Temporary non-blocking feedback → **Toast** (via `useToast`)
 - Destructive action confirmation → **AlertDialog**
+- Destructive action needing typed confirmation → **ConfirmDialog**
 - Generic dialog with custom content → **Modal**
 
 ### "I need a form input"
@@ -19,6 +20,8 @@
 - Yes/no with label → **Checkbox**
 - One of N options (≤5) → **RadioGroup** + **RadioItem**
 - One of N options (>5) → **Select**
+- Select multiple from a list → **MultiSelect**
+- Edit text inline without a form → **InlineEdit**
 - Date/time → **DateTimePicker**
 - Date range → **DateRangePicker**
 - Wrap any input with label/error/hint → **FormField**
@@ -58,6 +61,7 @@
 - Collapsible sections (standalone) → **Collapsible**
 - Multiple collapsible sections (one/many open) → **Accordion**
 - Tabbed content → **Tabs**
+- Tab switching with pill/segment style → **SegmentedTabs**
 - Side panel inspector → **DetailPanel**
 - Section with title + action → **SectionHeader**
 - Empty content placeholder → **EmptyState**
@@ -79,6 +83,7 @@
 ### "I need filtering"
 - Filter pill/chip → **FilterPill**
 - Full filter bar with search → **FilterBar**
+- Select multiple from a list → **MultiSelect**
 
 ## Composition Patterns
 
@@ -157,6 +162,7 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | CodeBlock | primitive | Syntax-highlighted code/JSON display |
 | Collapsible | primitive | Single expand/collapse section |
 | CommandPalette | composite | Full-screen search and command interface |
+| ConfirmDialog | composite | Type-to-confirm destructive action dialog built on Modal. Props: open, onClose, onConfirm, title, message, confirmText, confirmLabel, cancelLabel, variant, loading, className |
 | DataTable | composite | Sortable, paginated data table with row actions. Use `flush` prop when embedded inside a container that provides its own border/radius |
 | DateRangePicker | primitive | Date range selection with presets |
 | DateTimePicker | primitive | Single date/time input |
@@ -169,12 +175,14 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | FilterPill | primitive | Individual filter chip (active/inactive), supports forwardRef |
 | FormField | primitive | Wrapper adding label, hint, error to any input |
 | InfoCallout | primitive | Inline contextual note with variant colors |
+| InlineEdit | primitive | Click-to-edit text field. Enter saves, Escape/blur cancels. Props: value, onSave, placeholder, disabled, className |
 | Input | primitive | Single-line text input with optional icon |
 | KeyboardHint | primitive | Keyboard shortcut display |
 | Label | primitive | Form label with optional required asterisk |
 | LineChart | composite | Time series line visualization |
 | MenuItem | composite | Sidebar navigation item with health/count |
 | Modal | composite | Generic dialog overlay with backdrop |
+| MultiSelect | composite | Dropdown with searchable checkbox list and Apply action. Props: options, value, onChange, placeholder, searchable, disabled, className |
 | MonoText | primitive | Inline monospace text (xs, sm, md) |
 | Pagination | primitive | Page navigation controls |
 | Popover | composite | Click-triggered floating panel with arrow |
@@ -183,6 +191,7 @@ URL-driven progressive filtering: /agents → /agents/:appId → /agents/:appId/
 | RadioGroup | primitive | Single-select option group (use with RadioItem) |
 | RadioItem | primitive | Individual radio option within RadioGroup |
 | SectionHeader | primitive | Section title with optional action button |
+| SegmentedTabs | composite | Pill-style segmented tab bar with sliding animated indicator. Same API as Tabs but with elevated active state. Props: tabs, active, onChange, trailing, trailingValue, className |
 | Select | primitive | Dropdown select input |
 | ShortcutsBar | composite | Keyboard shortcuts reference bar |
 | Skeleton | primitive | Loading placeholder (text, circular, rectangular) |
diff --git a/src/design-system/composites/SegmentedTabs/SegmentedTabs.module.css b/src/design-system/composites/SegmentedTabs/SegmentedTabs.module.css
new file mode 100644
index 0000000..33fe866
--- /dev/null
+++ b/src/design-system/composites/SegmentedTabs/SegmentedTabs.module.css
@@ -0,0 +1,79 @@
+.bar {
+  position: relative;
+  display: inline-flex;
+  align-items: center;
+  border-radius: var(--radius-md);
+  background: var(--bg-inset);
+  padding: 3px;
+  gap: 1px;
+}
+
+/* Sliding indicator behind the active tab */
+.indicator {
+  position: absolute;
+  top: 3px;
+  bottom: 3px;
+  background: var(--bg-surface);
+  border: 1px solid var(--border-subtle);
+  border-radius: calc(var(--radius-md) - 2px);
+  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
+  transition: left 0.2s ease, width 0.2s ease;
+  pointer-events: none;
+}
+
+.tab {
+  position: relative;
+  z-index: 1;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 6px;
+  padding: 6px 14px;
+  font-size: 13px;
+  font-weight: 500;
+  font-family: var(--font-body);
+  color: var(--text-muted);
+  background: transparent;
+  border: 1px solid transparent;
+  border-radius: calc(var(--radius-md) - 2px);
+  cursor: pointer;
+  transition: color 0.15s;
+  white-space: nowrap;
+  line-height: 1.2;
+}
+
+.tab:hover {
+  color: var(--text-primary);
+}
+
+.active {
+  color: var(--text-primary);
+  font-weight: 600;
+}
+
+.label {
+  line-height: 1;
+}
+
+.count {
+  font-family: var(--font-mono);
+  font-size: 10px;
+  font-weight: 600;
+  background: var(--bg-hover);
+  color: var(--text-muted);
+  padding: 1px 5px;
+  border-radius: 8px;
+  line-height: 1.4;
+}
+
+.active .count {
+  background: var(--amber-bg);
+  color: var(--amber);
+}
+
+/* Trailing tab — a div, not a button, hosting custom content */
+.trailingTab {
+  cursor: default;
+  gap: 4px;
+  padding: 6px 10px;
+}
diff --git a/src/design-system/composites/SegmentedTabs/SegmentedTabs.test.tsx b/src/design-system/composites/SegmentedTabs/SegmentedTabs.test.tsx
new file mode 100644
index 0000000..e7ba098
--- /dev/null
+++ b/src/design-system/composites/SegmentedTabs/SegmentedTabs.test.tsx
@@ -0,0 +1,43 @@
+import { describe, it, expect, vi } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { SegmentedTabs } from './SegmentedTabs'
+
+const TABS = [
+  { label: 'Users', value: 'users' },
+  { label: 'Groups', value: 'groups', count: 4 },
+  { label: 'Roles', value: 'roles' },
+]
+
+describe('SegmentedTabs', () => {
+  it('renders all tabs', () => {
+    render(<SegmentedTabs tabs={TABS} active="users" onChange={vi.fn()} />)
+    expect(screen.getByRole('tab', { name: /Users/ })).toBeInTheDocument()
+    expect(screen.getByRole('tab', { name: /Groups/ })).toBeInTheDocument()
+    expect(screen.getByRole('tab', { name: /Roles/ })).toBeInTheDocument()
+  })
+
+  it('marks the active tab with aria-selected', () => {
+    render(<SegmentedTabs tabs={TABS} active="groups" onChange={vi.fn()} />)
+    expect(screen.getByRole('tab', { name: /Groups/ })).toHaveAttribute('aria-selected', 'true')
+    expect(screen.getByRole('tab', { name: /Users/ })).toHaveAttribute('aria-selected', 'false')
+  })
+
+  it('calls onChange when a tab is clicked', async () => {
+    const onChange = vi.fn()
+    const user = userEvent.setup()
+    render(<SegmentedTabs tabs={TABS} active="users" onChange={onChange} />)
+    await user.click(screen.getByRole('tab', { name: /Roles/ }))
+    expect(onChange).toHaveBeenCalledWith('roles')
+  })
+
+  it('renders count badge when provided', () => {
+    render(<SegmentedTabs tabs={TABS} active="users" onChange={vi.fn()} />)
+    expect(screen.getByText('4')).toBeInTheDocument()
+  })
+
+  it('has tablist role on container', () => {
+    render(<SegmentedTabs tabs={TABS} active="users" onChange={vi.fn()} />)
+    expect(screen.getByRole('tablist')).toBeInTheDocument()
+  })
+})
diff --git a/src/design-system/composites/SegmentedTabs/SegmentedTabs.tsx b/src/design-system/composites/SegmentedTabs/SegmentedTabs.tsx
new file mode 100644
index 0000000..09ad67b
--- /dev/null
+++ b/src/design-system/composites/SegmentedTabs/SegmentedTabs.tsx
@@ -0,0 +1,101 @@
+import { useRef, useEffect, useState as useLocalState, useCallback, useMemo, type ReactNode } from 'react'
+import styles from './SegmentedTabs.module.css'
+
+interface TabItem {
+  label: ReactNode
+  count?: number
+  value: string
+}
+
+interface SegmentedTabsProps {
+  tabs: TabItem[]
+  active: string
+  onChange: (value: string) => void
+  /** Extra element rendered as the last "tab" — participates in indicator animation.
+   *  Use `trailingValue` to assign it a value for active state matching. */
+  trailing?: ReactNode
+  trailingValue?: string
+  className?: string
+}
+
+export function SegmentedTabs({ tabs, active, onChange, trailing, trailingValue, className }: SegmentedTabsProps) {
+  const barRef = useRef<HTMLDivElement>(null)
+  const tabRefs = useRef<Map<string, HTMLElement>>(new Map())
+  const [indicator, setIndicator] = useLocalState<{ left: number; width: number } | null>(null)
+
+  // Recalculate when labels change (e.g. dynamic date range text)
+  const tabsKey = useMemo(() => tabs.map((t) => `${t.value}:${typeof t.label === 'string' ? t.label : ''}`).join('|'), [tabs])
+
+  const updateIndicator = useCallback(() => {
+    const bar = barRef.current
+    const activeEl = tabRefs.current.get(active)
+    if (!bar || !activeEl) return
+    const barRect = bar.getBoundingClientRect()
+    const elRect = activeEl.getBoundingClientRect()
+    setIndicator({
+      left: elRect.left - barRect.left,
+      width: elRect.width,
+    })
+  }, [active, tabsKey]) // eslint-disable-line react-hooks/exhaustive-deps
+
+  useEffect(() => {
+    const id = requestAnimationFrame(updateIndicator)
+    return () => cancelAnimationFrame(id)
+  }, [updateIndicator])
+
+  useEffect(() => {
+    window.addEventListener('resize', updateIndicator)
+    return () => window.removeEventListener('resize', updateIndicator)
+  }, [updateIndicator])
+
+  // Observe DOM mutations (e.g. trailing content text changes) to resize indicator
+  useEffect(() => {
+    const bar = barRef.current
+    if (!bar) return
+    const observer = new MutationObserver(() => {
+      requestAnimationFrame(updateIndicator)
+    })
+    observer.observe(bar, { childList: true, subtree: true, characterData: true })
+    return () => observer.disconnect()
+  }, [updateIndicator])
+
+  const trailingActive = trailingValue !== undefined && active === trailingValue
+
+  return (
+    <div ref={barRef} className={`${styles.bar} ${className ?? ''}`} role="tablist">
+      {indicator && (
+        <span
+          className={styles.indicator}
+          style={{ left: indicator.left, width: indicator.width }}
+          aria-hidden="true"
+        />
+      )}
+      {tabs.map((tab) => (
+        <button
+          key={tab.value}
+          ref={(el) => { if (el) tabRefs.current.set(tab.value, el); else tabRefs.current.delete(tab.value) }}
+          role="tab"
+          aria-selected={tab.value === active}
+          className={`${styles.tab} ${tab.value === active ? styles.active : ''}`}
+          onClick={() => onChange(tab.value)}
+          type="button"
+        >
+          <span className={styles.label}>{tab.label}</span>
+          {tab.count !== undefined && (
+            <span className={styles.count}>{tab.count}</span>
+          )}
+        </button>
+      ))}
+      {trailing && trailingValue && (
+        <div
+          ref={(el) => { if (el) tabRefs.current.set(trailingValue, el); else tabRefs.current.delete(trailingValue) }}
+          role="tab"
+          aria-selected={trailingActive}
+          className={`${styles.tab} ${styles.trailingTab} ${trailingActive ? styles.active : ''}`}
+        >
+          {trailing}
+        </div>
+      )}
+    </div>
+  )
+}
diff --git a/src/design-system/composites/index.ts b/src/design-system/composites/index.ts
index 8b236b6..2273c02 100644
--- a/src/design-system/composites/index.ts
+++ b/src/design-system/composites/index.ts
@@ -25,6 +25,7 @@ export { Popover } from './Popover/Popover'
 export { ProcessorTimeline } from './ProcessorTimeline/ProcessorTimeline'
 export type { ProcessorStep } from './ProcessorTimeline/ProcessorTimeline'
 export { ShortcutsBar } from './ShortcutsBar/ShortcutsBar'
+export { SegmentedTabs } from './SegmentedTabs/SegmentedTabs'
 export { Tabs } from './Tabs/Tabs'
 export { ToastProvider, useToast } from './Toast/Toast'
 export { TreeView } from './TreeView/TreeView'
diff --git a/src/design-system/primitives/DateRangePicker/DateRangePicker.test.tsx b/src/design-system/primitives/DateRangePicker/DateRangePicker.test.tsx
index f433261..4c6e5a6 100644
--- a/src/design-system/primitives/DateRangePicker/DateRangePicker.test.tsx
+++ b/src/design-system/primitives/DateRangePicker/DateRangePicker.test.tsx
@@ -4,15 +4,17 @@ import userEvent from '@testing-library/user-event'
 import { DateRangePicker } from './DateRangePicker'
 
 describe('DateRangePicker', () => {
-  it('renders two datetime inputs', () => {
-    const { container } = render(
+  it('renders two datetime picker triggers', () => {
+    render(
       <DateRangePicker
-        value={{ start: new Date(), end: new Date() }}
+        value={{ start: new Date('2026-03-19T10:00'), end: new Date('2026-03-19T11:00') }}
         onChange={() => {}}
       />,
     )
-    const inputs = container.querySelectorAll('input[type="datetime-local"]')
-    expect(inputs.length).toBe(2)
+    // DateTimePicker renders button triggers with formatted date text
+    const buttons = screen.getAllByRole('button')
+    // At least 2 buttons are the from/to date picker triggers (plus preset pills)
+    expect(buttons.length).toBeGreaterThanOrEqual(2)
   })
 
   it('renders preset buttons', () => {
diff --git a/src/design-system/primitives/DateTimePicker/DateTimePicker.module.css b/src/design-system/primitives/DateTimePicker/DateTimePicker.module.css
index 338df51..f679662 100644
--- a/src/design-system/primitives/DateTimePicker/DateTimePicker.module.css
+++ b/src/design-system/primitives/DateTimePicker/DateTimePicker.module.css
@@ -12,26 +12,217 @@
   letter-spacing: 0.5px;
 }
 
-.input {
-  width: 100%;
-  padding: 6px 10px;
+.trigger {
+  padding: 0 4px;
+  border: none;
+  background: transparent;
+  color: var(--text-primary);
+  font-family: var(--font-mono);
+  font-size: 11px;
+  text-align: left;
+  cursor: pointer;
+  border-radius: var(--radius-sm);
+  transition: color 0.15s;
+  line-height: 1;
+}
+
+.trigger:hover {
+  color: var(--amber);
+}
+
+.trigger:focus-visible {
+  outline: 1px solid var(--amber);
+  outline-offset: 1px;
+}
+
+/* Panel */
+.panel {
+  position: fixed;
+  z-index: 600;
+  background: var(--bg-surface);
+  border: 1px solid var(--border-subtle);
+  border-radius: var(--radius-md);
+  box-shadow: var(--shadow-lg);
+  padding: 12px;
+  width: 260px;
+  animation: panelIn 0.12s ease-out;
+}
+
+@keyframes panelIn {
+  from { opacity: 0; transform: translateY(-4px); }
+  to   { opacity: 1; transform: translateY(0); }
+}
+
+/* Month navigation */
+.monthNav {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin-bottom: 8px;
+}
+
+.monthLabel {
+  font-size: 13px;
+  font-weight: 600;
+  color: var(--text-primary);
+  font-family: var(--font-body);
+}
+
+.navBtn {
+  border: none;
+  background: none;
+  color: var(--text-muted);
+  font-size: 10px;
+  cursor: pointer;
+  padding: 4px 8px;
+  border-radius: var(--radius-sm);
+  transition: background 0.1s, color 0.1s;
+}
+
+.navBtn:hover {
+  background: var(--bg-hover);
+  color: var(--text-primary);
+}
+
+/* Calendar grid */
+.calendar {
+  display: grid;
+  grid-template-columns: repeat(7, 1fr);
+  gap: 2px;
+  margin-bottom: 10px;
+}
+
+.dayHeader {
+  font-size: 10px;
+  font-weight: 600;
+  color: var(--text-faint);
+  text-align: center;
+  padding: 4px 0;
+  text-transform: uppercase;
+  letter-spacing: 0.3px;
+}
+
+.dayEmpty {
+  /* placeholder for offset days */
+}
+
+.day {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 32px;
+  height: 32px;
+  border: none;
+  border-radius: var(--radius-sm);
+  background: none;
+  color: var(--text-primary);
+  font-size: 12px;
+  font-family: var(--font-body);
+  cursor: pointer;
+  transition: background 0.1s;
+}
+
+.day:hover {
+  background: var(--bg-hover);
+}
+
+.dayToday {
+  font-weight: 700;
+  color: var(--amber);
+}
+
+.daySelected {
+  background: var(--amber);
+  color: #fff;
+  font-weight: 600;
+}
+
+.daySelected:hover {
+  background: var(--amber-hover);
+}
+
+/* Time selector */
+.timeRow {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  padding: 8px 0;
+  border-top: 1px solid var(--border-subtle);
+}
+
+.timeLabel {
+  font-size: 11px;
+  font-weight: 500;
+  color: var(--text-muted);
+  margin-right: auto;
+}
+
+.timeInput {
+  width: 32px;
+  padding: 4px 6px;
   border: 1px solid var(--border);
   border-radius: var(--radius-sm);
   background: var(--bg-raised);
   color: var(--text-primary);
   font-family: var(--font-mono);
-  font-size: 12px;
+  font-size: 13px;
+  text-align: center;
   outline: none;
-  transition: border-color 0.15s, box-shadow 0.15s;
-  cursor: pointer;
 }
 
-.input:focus {
+.timeInput:focus {
   border-color: var(--amber);
-  box-shadow: 0 0 0 3px var(--amber-bg);
+  box-shadow: 0 0 0 2px var(--amber-bg);
 }
 
-.input::-webkit-calendar-picker-indicator {
-  opacity: 0.5;
-  cursor: pointer;
+.timeSep {
+  font-size: 14px;
+  font-weight: 600;
+  color: var(--text-muted);
+}
+
+/* Actions */
+.actions {
+  display: flex;
+  justify-content: space-between;
+  padding-top: 8px;
+  border-top: 1px solid var(--border-subtle);
+}
+
+.todayBtn {
+  border: none;
+  background: none;
+  color: var(--amber);
+  font-size: 12px;
+  font-weight: 500;
+  font-family: var(--font-body);
+  cursor: pointer;
+  padding: 4px 8px;
+  border-radius: var(--radius-sm);
+}
+
+.todayBtn:hover {
+  background: var(--amber-bg);
+}
+
+.doneBtn {
+  padding: 4px 16px;
+  border: none;
+  border-radius: var(--radius-sm);
+  background: var(--amber);
+  color: #fff;
+  font-family: var(--font-body);
+  font-size: 12px;
+  font-weight: 600;
+  cursor: pointer;
+  transition: opacity 0.15s;
+}
+
+.doneBtn:hover {
+  opacity: 0.85;
+}
+
+.doneBtn:disabled {
+  opacity: 0.4;
+  cursor: not-allowed;
 }
diff --git a/src/design-system/primitives/DateTimePicker/DateTimePicker.tsx b/src/design-system/primitives/DateTimePicker/DateTimePicker.tsx
index afbfc38..e9b7ca5 100644
--- a/src/design-system/primitives/DateTimePicker/DateTimePicker.tsx
+++ b/src/design-system/primitives/DateTimePicker/DateTimePicker.tsx
@@ -1,51 +1,204 @@
+import { useState, useRef, useEffect, useCallback } from 'react'
+import { createPortal } from 'react-dom'
 import styles from './DateTimePicker.module.css'
-import { forwardRef, type InputHTMLAttributes } from 'react'
 
-interface DateTimePickerProps extends Omit<InputHTMLAttributes<HTMLInputElement>, 'type' | 'value' | 'onChange'> {
+interface DateTimePickerProps {
   value?: Date
   onChange?: (date: Date | null) => void
   label?: string
+  placeholder?: string
+  className?: string
 }
 
-function toLocalDateTimeString(date: Date): string {
-  const pad = (n: number) => String(n).padStart(2, '0')
+const DAYS = ['Mo', 'Tu', 'We', 'Th', 'Fr', 'Sa', 'Su']
+
+function getDaysInMonth(year: number, month: number): number {
+  return new Date(year, month + 1, 0).getDate()
+}
+
+function getFirstDayOfWeek(year: number, month: number): number {
+  const day = new Date(year, month, 1).getDay()
+  return day === 0 ? 6 : day - 1 // Monday = 0
+}
+
+function formatDisplay(d: Date | undefined): string {
+  if (!d) return '—'
+  const date = d.toLocaleDateString(undefined, { month: 'short', day: 'numeric' })
+  const time = d.toLocaleTimeString(undefined, { hour: '2-digit', minute: '2-digit', hour12: false })
+  return `${date}\u2009${time}`
+}
+
+function pad(n: number): string {
+  return String(n).padStart(2, '0')
+}
+
+export function DateTimePicker({ value, onChange, label, placeholder, className }: DateTimePickerProps) {
+  const [open, setOpen] = useState(false)
+  const [viewYear, setViewYear] = useState(value?.getFullYear() ?? new Date().getFullYear())
+  const [viewMonth, setViewMonth] = useState(value?.getMonth() ?? new Date().getMonth())
+  const [selectedDate, setSelectedDate] = useState<Date | null>(value ?? null)
+  const [hour, setHour] = useState(value ? pad(value.getHours()) : pad(new Date().getHours()))
+  const [minute, setMinute] = useState(value ? pad(value.getMinutes()) : pad(new Date().getMinutes()))
+
+  const triggerRef = useRef<HTMLButtonElement>(null)
+  const panelRef = useRef<HTMLDivElement>(null)
+  const [pos, setPos] = useState({ top: 0, left: 0 })
+
+  // Sync when value changes externally
+  useEffect(() => {
+    if (value) {
+      setSelectedDate(value)
+      setHour(pad(value.getHours()))
+      setMinute(pad(value.getMinutes()))
+      setViewYear(value.getFullYear())
+      setViewMonth(value.getMonth())
+    }
+  }, [value])
+
+  const reposition = useCallback(() => {
+    if (!triggerRef.current) return
+    const rect = triggerRef.current.getBoundingClientRect()
+    setPos({
+      top: rect.bottom + 4,
+      left: rect.left,
+    })
+  }, [])
+
+  useEffect(() => {
+    if (open) {
+      const id = requestAnimationFrame(reposition)
+      return () => cancelAnimationFrame(id)
+    }
+  }, [open, reposition])
+
+  // Close on Escape only — panel closes via Apply/Now buttons
+  useEffect(() => {
+    if (!open) return
+    function handleKey(e: KeyboardEvent) {
+      if (e.key === 'Escape') setOpen(false)
+    }
+    document.addEventListener('keydown', handleKey)
+    return () => document.removeEventListener('keydown', handleKey)
+  }, [open])
+
+  function handleDone() {
+    if (selectedDate) {
+      const d = new Date(selectedDate)
+      d.setHours(parseInt(hour, 10) || 0, parseInt(minute, 10) || 0, 0, 0)
+      onChange?.(d)
+    }
+    setOpen(false)
+  }
+
+  function handleDayClick(day: number) {
+    const d = new Date(viewYear, viewMonth, day)
+    setSelectedDate(d)
+  }
+
+  function handleNow() {
+    const now = new Date()
+    onChange?.(now)
+    setOpen(false)
+  }
+
+  function prevMonth() {
+    if (viewMonth === 0) { setViewMonth(11); setViewYear((y) => y - 1) }
+    else setViewMonth((m) => m - 1)
+  }
+
+  function nextMonth() {
+    if (viewMonth === 11) { setViewMonth(0); setViewYear((y) => y + 1) }
+    else setViewMonth((m) => m + 1)
+  }
+
+  const daysInMonth = getDaysInMonth(viewYear, viewMonth)
+  const firstDay = getFirstDayOfWeek(viewYear, viewMonth)
+  const today = new Date()
+
+  const monthLabel = new Date(viewYear, viewMonth).toLocaleDateString(undefined, { month: 'long', year: 'numeric' })
+
   return (
-    date.getFullYear() +
-    '-' +
-    pad(date.getMonth() + 1) +
-    '-' +
-    pad(date.getDate()) +
-    'T' +
-    pad(date.getHours()) +
-    ':' +
-    pad(date.getMinutes())
+    <div className={`${styles.wrapper} ${className ?? ''}`}>
+      {label && <span className={styles.label}>{label}</span>}
+      <button
+        ref={triggerRef}
+        type="button"
+        className={styles.trigger}
+        onClick={() => setOpen(!open)}
+      >
+        {value ? formatDisplay(value) : (placeholder ?? '—')}
+      </button>
+
+      {open && createPortal(
+        <div
+          ref={panelRef}
+          className={styles.panel}
+          style={{ top: pos.top, left: pos.left }}
+        >
+          {/* Month navigation */}
+          <div className={styles.monthNav}>
+            <button type="button" className={styles.navBtn} onClick={prevMonth} aria-label="Previous month">&#9664;</button>
+            <span className={styles.monthLabel}>{monthLabel}</span>
+            <button type="button" className={styles.navBtn} onClick={nextMonth} aria-label="Next month">&#9654;</button>
+          </div>
+
+          {/* Calendar grid */}
+          <div className={styles.calendar}>
+            {DAYS.map((d) => (
+              <span key={d} className={styles.dayHeader}>{d}</span>
+            ))}
+            {Array.from({ length: firstDay }, (_, i) => (
+              <span key={`pad-${i}`} className={styles.dayEmpty} />
+            ))}
+            {Array.from({ length: daysInMonth }, (_, i) => {
+              const day = i + 1
+              const isToday = viewYear === today.getFullYear() && viewMonth === today.getMonth() && day === today.getDate()
+              const isSelected = selectedDate && viewYear === selectedDate.getFullYear() && viewMonth === selectedDate.getMonth() && day === selectedDate.getDate()
+              return (
+                <button
+                  key={day}
+                  type="button"
+                  className={[styles.day, isToday ? styles.dayToday : '', isSelected ? styles.daySelected : ''].filter(Boolean).join(' ')}
+                  onClick={() => handleDayClick(day)}
+                >
+                  {day}
+                </button>
+              )
+            })}
+          </div>
+
+          {/* Time selector */}
+          <div className={styles.timeRow}>
+            <span className={styles.timeLabel}>Time</span>
+            <input
+              type="text"
+              className={styles.timeInput}
+              value={hour}
+              onChange={(e) => setHour(e.target.value.replace(/\D/g, '').slice(0, 2))}
+              maxLength={2}
+              aria-label="Hour"
+            />
+            <span className={styles.timeSep}>:</span>
+            <input
+              type="text"
+              className={styles.timeInput}
+              value={minute}
+              onChange={(e) => setMinute(e.target.value.replace(/\D/g, '').slice(0, 2))}
+              maxLength={2}
+              aria-label="Minute"
+            />
+          </div>
+
+          {/* Actions */}
+          <div className={styles.actions}>
+            <button type="button" className={styles.todayBtn} onClick={handleNow}>Now</button>
+            <button type="button" className={styles.doneBtn} onClick={handleDone} disabled={!selectedDate}>Apply</button>
+          </div>
+        </div>,
+        document.body,
+      )}
+    </div>
   )
 }
 
-export const DateTimePicker = forwardRef<HTMLInputElement, DateTimePickerProps>(
-  ({ value, onChange, label, className, ...rest }, ref) => {
-    const inputValue = value ? toLocalDateTimeString(value) : ''
-
-    function handleChange(e: React.ChangeEvent<HTMLInputElement>) {
-      if (!onChange) return
-      const v = e.target.value
-      onChange(v ? new Date(v) : null)
-    }
-
-    return (
-      <div className={`${styles.wrapper} ${className ?? ''}`}>
-        {label && <label className={styles.label}>{label}</label>}
-        <input
-          ref={ref}
-          type="datetime-local"
-          className={styles.input}
-          value={inputValue}
-          onChange={handleChange}
-          {...rest}
-        />
-      </div>
-    )
-  },
-)
-
 DateTimePicker.displayName = 'DateTimePicker'
diff --git a/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.module.css b/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.module.css
index b1c9a98..8798325 100644
--- a/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.module.css
+++ b/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.module.css
@@ -1,78 +1,11 @@
-/* ── Integrated readout cell ──────────────────────────────
-   First child of the ButtonGroup — styled as a recessed
-   instrument-panel display, not a clickable control.       */
-
-.readout {
+.rangeRow {
   display: inline-flex;
   align-items: center;
-  padding: 4px 12px;
-  height: 28px;
-  border: 1px solid var(--border);
-  background: var(--bg-inset);
-  box-shadow: inset 0 1px 3px rgba(44, 37, 32, 0.06);
-  font-family: var(--font-mono);
-  font-size: 11px;
-  font-weight: 500;
-  letter-spacing: 0.02em;
-  color: var(--text-secondary);
-  white-space: nowrap;
-  cursor: default;
-  user-select: none;
+  gap: 6px;
 }
 
-[data-theme="dark"] .readout {
-  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.2);
-}
-
-/* ── Custom date picker panel ────────────────────────── */
-
-.panel {
-  position: absolute;
-  display: flex;
-  flex-direction: column;
-  gap: 10px;
-  padding: 12px;
-  min-width: 220px;
-  background: var(--bg-surface);
-  border: 1px solid var(--border-subtle);
-  border-radius: var(--radius-md);
-  box-shadow: var(--shadow-lg);
-  z-index: 500;
-  animation: panelIn 150ms ease-out;
-}
-
-@keyframes panelIn {
-  from {
-    opacity: 0;
-    transform: scale(0.97);
-  }
-  to {
-    opacity: 1;
-    transform: scale(1);
-  }
-}
-
-.applyBtn {
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  padding: 5px 14px;
-  border: none;
-  border-radius: var(--radius-sm);
-  background: var(--amber);
-  color: #fff;
-  font-family: var(--font-body);
+.rangeSep {
   font-size: 12px;
-  font-weight: 600;
-  cursor: pointer;
-  transition: opacity 0.15s;
-}
-
-.applyBtn:hover {
-  opacity: 0.85;
-}
-
-.applyBtn:disabled {
-  opacity: 0.4;
-  cursor: not-allowed;
+  color: var(--text-faint);
+  flex-shrink: 0;
 }
diff --git a/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.tsx b/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.tsx
index 46466f8..f7b5d60 100644
--- a/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.tsx
+++ b/src/design-system/primitives/TimeRangeDropdown/TimeRangeDropdown.tsx
@@ -1,41 +1,10 @@
-import { useState, useRef, useEffect, useCallback, useMemo } from 'react'
-import { createPortal } from 'react-dom'
+import { useState, useEffect } from 'react'
 import styles from './TimeRangeDropdown.module.css'
-import { FilterPill } from '../FilterPill/FilterPill'
-import { ButtonGroup } from '../ButtonGroup/ButtonGroup'
+import { SegmentedTabs } from '../../composites/SegmentedTabs/SegmentedTabs'
 import { DateTimePicker } from '../DateTimePicker/DateTimePicker'
 import { computePresetRange } from '../../utils/timePresets'
 import type { TimeRange } from '../../providers/GlobalFilterProvider'
 
-function formatRangeLabel(range: TimeRange): string {
-  const start = range.preset ? computePresetRange(range.preset).start : range.start
-
-  const time = (d: Date) =>
-    d.toLocaleTimeString(undefined, { hour: '2-digit', minute: '2-digit', hour12: false })
-  const dateTime = (d: Date) =>
-    d.toLocaleDateString(undefined, { month: 'short', day: 'numeric' }) + '\u2009' + time(d)
-
-  // Preset ranges are open-ended ("since X"), so only show the start
-  if (range.preset) {
-    const now = new Date()
-    const sameDay =
-      start.getFullYear() === now.getFullYear() &&
-      start.getMonth() === now.getMonth() &&
-      start.getDate() === now.getDate()
-    return sameDay ? `${time(start)}\u2009\u2013\u2009now` : `${dateTime(start)}\u2009\u2013\u2009now`
-  }
-
-  // Custom range: show both ends
-  const end = range.end
-  const sameDay =
-    start.getFullYear() === end.getFullYear() &&
-    start.getMonth() === end.getMonth() &&
-    start.getDate() === end.getDate()
-
-  if (sameDay) return `${time(start)}\u2009\u2013\u2009${time(end)}`
-  return `${dateTime(start)}\u2009\u2013\u2009${dateTime(end)}`
-}
-
 const PRESETS = [
   { value: 'last-1h', label: '1h' },
   { value: 'last-3h', label: '3h' },
@@ -45,6 +14,8 @@ const PRESETS = [
   { value: 'last-7d', label: '7d' },
 ]
 
+const CUSTOM_VALUE = '__custom__'
+
 interface TimeRangeDropdownProps {
   value: TimeRange
   onChange: (range: TimeRange) => void
@@ -52,112 +23,78 @@ interface TimeRangeDropdownProps {
 }
 
 export function TimeRangeDropdown({ value, onChange, className }: TimeRangeDropdownProps) {
-  const [open, setOpen] = useState(false)
-  const [customFrom, setCustomFrom] = useState<Date | null>(value.start)
-  const [customTo, setCustomTo] = useState<Date | null>(value.end)
-  const customRef = useRef<HTMLButtonElement>(null)
-  const panelRef = useRef<HTMLDivElement>(null)
-  const [panelPos, setPanelPos] = useState({ top: 0, left: 0 })
+  const [customFrom, setCustomFrom] = useState<Date>(value.start)
+  const [customTo, setCustomTo] = useState<Date>(value.end)
+  const [toIsSet, setToIsSet] = useState(false)
+
   const isCustom = value.preset === null || value.preset === 'custom'
+  const activeValue = isCustom ? CUSTOM_VALUE : (value.preset ?? 'last-1h')
 
-  const reposition = useCallback(() => {
-    if (!customRef.current) return
-    const rect = customRef.current.getBoundingClientRect()
-    const panelWidth = panelRef.current?.offsetWidth ?? 240
-    setPanelPos({
-      top: rect.bottom + window.scrollY + 8,
-      left: rect.right + window.scrollX - panelWidth,
-    })
-  }, [])
-
+  // Sync local state when value changes from presets
   useEffect(() => {
-    if (open) {
-      const id = requestAnimationFrame(reposition)
-      return () => cancelAnimationFrame(id)
-    }
-  }, [open, reposition])
+    setCustomFrom(value.start)
+    setCustomTo(value.end)
+  }, [value.start, value.end])
 
-  useEffect(() => {
-    if (!open) return
-    function handleMouseDown(e: MouseEvent) {
-      if (
-        customRef.current?.contains(e.target as Node) ||
-        panelRef.current?.contains(e.target as Node)
-      ) return
-      setOpen(false)
-    }
-    function handleKey(e: KeyboardEvent) {
-      if (e.key === 'Escape') setOpen(false)
-    }
-    document.addEventListener('mousedown', handleMouseDown)
-    document.addEventListener('keydown', handleKey)
-    return () => {
-      document.removeEventListener('mousedown', handleMouseDown)
-      document.removeEventListener('keydown', handleKey)
-    }
-  }, [open])
+  function handleTabChange(tabValue: string) {
+    if (tabValue === CUSTOM_VALUE) return
+    setToIsSet(false)
+    const range = computePresetRange(tabValue)
+    onChange({ ...range, preset: tabValue })
+  }
 
-  const rangeLabel = useMemo(() => formatRangeLabel(value), [value])
+  function handleFromChange(d: Date | null) {
+    if (!d) return
+    setCustomFrom(d)
+    // Only set preset to null; keep to-date as "now" if not explicitly set
+    if (toIsSet) {
+      onChange({ start: d, end: customTo, preset: null })
+    } else {
+      onChange({ start: d, end: new Date(), preset: null })
+    }
+  }
+
+  function handleToChange(d: Date | null) {
+    if (!d) return
+    setCustomTo(d)
+    setToIsSet(true)
+    onChange({ start: customFrom, end: d, preset: null })
+  }
+
+  // Show "now" when to-date is not explicitly set
+  const showNow = !isCustom || !toIsSet
+
+  const rangeContent = (
+    <div className={styles.rangeRow}>
+      <DateTimePicker
+        value={isCustom ? customFrom : value.start}
+        onChange={handleFromChange}
+      />
+      <span className={styles.rangeSep}>–</span>
+      {showNow ? (
+        <DateTimePicker
+          value={undefined}
+          onChange={handleToChange}
+          placeholder="now"
+        />
+      ) : (
+        <DateTimePicker
+          value={customTo}
+          onChange={handleToChange}
+        />
+      )}
+    </div>
+  )
 
   return (
-    <>
-      <ButtonGroup className={className}>
-        {PRESETS.map((preset) => (
-          <FilterPill
-            key={preset.value}
-            label={preset.label}
-            active={value.preset === preset.value}
-            onClick={() => {
-              setOpen(false)
-              const range = computePresetRange(preset.value)
-              onChange({ ...range, preset: preset.value })
-            }}
-          />
-        ))}
-        <FilterPill
-          ref={customRef}
-          label="Custom"
-          active={isCustom}
-          onClick={() => setOpen((prev) => !prev)}
-        />
-        <span className={styles.readout} aria-label="Active time range">
-          {rangeLabel}
-        </span>
-      </ButtonGroup>
-
-      {open && createPortal(
-        <div
-          ref={panelRef}
-          className={styles.panel}
-          style={{ top: panelPos.top, left: panelPos.left }}
-          role="dialog"
-        >
-          <DateTimePicker
-            label="From"
-            value={customFrom ?? undefined}
-            onChange={(d) => setCustomFrom(d)}
-          />
-          <DateTimePicker
-            label="To"
-            value={customTo ?? undefined}
-            onChange={(d) => setCustomTo(d)}
-          />
-          <button
-            type="button"
-            className={styles.applyBtn}
-            disabled={!customFrom || !customTo}
-            onClick={() => {
-              if (customFrom && customTo) {
-                onChange({ start: customFrom, end: customTo, preset: null })
-                setOpen(false)
-              }
-            }}
-          >
-            Apply
-          </button>
-        </div>,
-        document.body,
-      )}
-    </>
+    <div className={className}>
+      <SegmentedTabs
+        tabs={PRESETS}
+        active={activeValue}
+        onChange={handleTabChange}
+        trailing={rangeContent}
+        trailingValue={CUSTOM_VALUE}
+      />
+    </div>
   )
 }
diff --git a/src/pages/Inventory/Inventory.module.css b/src/pages/Inventory/Inventory.module.css
index fc58819..463f7a6 100644
--- a/src/pages/Inventory/Inventory.module.css
+++ b/src/pages/Inventory/Inventory.module.css
@@ -81,6 +81,21 @@
   color: var(--text-primary);
 }
 
+.navSubLink {
+  display: block;
+  font-size: 12px;
+  color: var(--text-muted);
+  text-decoration: none;
+  padding: 2px 8px 2px 20px;
+  border-radius: var(--radius-sm);
+  line-height: 1.5;
+}
+
+.navSubLink:hover {
+  background: var(--bg-hover);
+  color: var(--text-primary);
+}
+
 .content {
   flex: 1;
   min-width: 0;
diff --git a/src/pages/Inventory/Inventory.tsx b/src/pages/Inventory/Inventory.tsx
index a57c1eb..a215ddb 100644
--- a/src/pages/Inventory/Inventory.tsx
+++ b/src/pages/Inventory/Inventory.tsx
@@ -4,10 +4,86 @@ import { PrimitivesSection } from './sections/PrimitivesSection'
 import { CompositesSection } from './sections/CompositesSection'
 import { LayoutSection } from './sections/LayoutSection'
 
-const NAV_ITEMS = [
-  { label: 'Primitives', href: '#primitives' },
-  { label: 'Composites', href: '#composites' },
-  { label: 'Layout', href: '#layout' },
+const NAV_SECTIONS = [
+  {
+    label: 'Primitives',
+    href: '#primitives',
+    components: [
+      { label: 'Alert', href: '#alert' },
+      { label: 'Avatar', href: '#avatar' },
+      { label: 'Badge', href: '#badge' },
+      { label: 'Button', href: '#button' },
+      { label: 'Card', href: '#card' },
+      { label: 'Checkbox', href: '#checkbox' },
+      { label: 'CodeBlock', href: '#codeblock' },
+      { label: 'Collapsible', href: '#collapsible' },
+      { label: 'DateRangePicker', href: '#daterangepicker' },
+      { label: 'DateTimePicker', href: '#datetimepicker' },
+      { label: 'EmptyState', href: '#emptystate' },
+      { label: 'FilterPill', href: '#filterpill' },
+      { label: 'FormField', href: '#formfield' },
+      { label: 'InfoCallout', href: '#infocallout' },
+      { label: 'InlineEdit', href: '#inline-edit' },
+      { label: 'Input', href: '#input' },
+      { label: 'KeyboardHint', href: '#keyboardhint' },
+      { label: 'Label', href: '#label' },
+      { label: 'MonoText', href: '#monotext' },
+      { label: 'Pagination', href: '#pagination' },
+      { label: 'ProgressBar', href: '#progressbar' },
+      { label: 'Radio', href: '#radio' },
+      { label: 'SectionHeader', href: '#sectionheader' },
+      { label: 'Select', href: '#select' },
+      { label: 'Skeleton', href: '#skeleton' },
+      { label: 'Sparkline', href: '#sparkline' },
+      { label: 'Spinner', href: '#spinner' },
+      { label: 'StatCard', href: '#statcard' },
+      { label: 'StatusDot', href: '#statusdot' },
+      { label: 'Tag', href: '#tag' },
+      { label: 'Textarea', href: '#textarea' },
+      { label: 'Toggle', href: '#toggle' },
+      { label: 'Tooltip', href: '#tooltip' },
+    ],
+  },
+  {
+    label: 'Composites',
+    href: '#composites',
+    components: [
+      { label: 'Accordion', href: '#accordion' },
+      { label: 'AlertDialog', href: '#alertdialog' },
+      { label: 'AreaChart', href: '#areachart' },
+      { label: 'AvatarGroup', href: '#avatargroup' },
+      { label: 'BarChart', href: '#barchart' },
+      { label: 'Breadcrumb', href: '#breadcrumb' },
+      { label: 'CommandPalette', href: '#commandpalette' },
+      { label: 'ConfirmDialog', href: '#confirm-dialog' },
+      { label: 'DataTable', href: '#datatable' },
+      { label: 'DetailPanel', href: '#detailpanel' },
+      { label: 'Dropdown', href: '#dropdown' },
+      { label: 'EventFeed', href: '#eventfeed' },
+      { label: 'FilterBar', href: '#filterbar' },
+      { label: 'GroupCard', href: '#groupcard' },
+      { label: 'LineChart', href: '#linechart' },
+      { label: 'MenuItem', href: '#menuitem' },
+      { label: 'Modal', href: '#modal' },
+      { label: 'MultiSelect', href: '#multi-select' },
+      { label: 'Popover', href: '#popover' },
+      { label: 'ProcessorTimeline', href: '#processortimeline' },
+      { label: 'SegmentedTabs', href: '#segmented-tabs' },
+      { label: 'ShortcutsBar', href: '#shortcutsbar' },
+      { label: 'Tabs', href: '#tabs' },
+      { label: 'Toast', href: '#toast' },
+      { label: 'TreeView', href: '#treeview' },
+    ],
+  },
+  {
+    label: 'Layout',
+    href: '#layout',
+    components: [
+      { label: 'AppShell', href: '#appshell' },
+      { label: 'Sidebar', href: '#sidebar' },
+      { label: 'TopBar', href: '#topbar' },
+    ],
+  },
 ]
 
 export function Inventory() {
@@ -20,14 +96,16 @@ export function Inventory() {
 
       <div className={styles.body}>
         <nav className={styles.nav} aria-label="Component categories">
-          <div className={styles.navSection}>
-            <span className={styles.navLabel}>Categories</span>
-            {NAV_ITEMS.map((item) => (
-              <a key={item.href} href={item.href} className={styles.navLink}>
-                {item.label}
-              </a>
-            ))}
-          </div>
+          {NAV_SECTIONS.map((section) => (
+            <div key={section.href} className={styles.navSection}>
+              <span className={styles.navLabel}>{section.label}</span>
+              {section.components.map((component) => (
+                <a key={component.href} href={component.href} className={styles.navSubLink}>
+                  {component.label}
+                </a>
+              ))}
+            </div>
+          ))}
         </nav>
 
         <main className={styles.content}>
diff --git a/src/pages/Inventory/sections/CompositesSection.tsx b/src/pages/Inventory/sections/CompositesSection.tsx
index c2c8d44..bbc5959 100644
--- a/src/pages/Inventory/sections/CompositesSection.tsx
+++ b/src/pages/Inventory/sections/CompositesSection.tsx
@@ -21,6 +21,7 @@ import {
   MultiSelect,
   Popover,
   ProcessorTimeline,
+  SegmentedTabs,
   ShortcutsBar,
   Tabs,
   ToastProvider,
@@ -227,6 +228,7 @@ export function CompositesSection() {
     { label: 'Agents', value: 'agents', count: 6 },
   ]
   const [activeTab, setActiveTab] = useState('overview')
+  const [segTab, setSegTab] = useState('account')
 
   // 21. TreeView
   const [selectedNode, setSelectedNode] = useState<string | undefined>('proc1')
@@ -636,6 +638,28 @@ export function CompositesSection() {
           </div>
         </DemoCard>
 
+        {/* 19b. SegmentedTabs */}
+        <DemoCard
+          id="segmented-tabs"
+          title="SegmentedTabs"
+          description="Pill-style segmented tab bar with elevated active state. Same API as Tabs."
+        >
+          <div className={styles.demoAreaColumn} style={{ width: '100%' }}>
+            <SegmentedTabs
+              tabs={[
+                { label: 'Account', value: 'account' },
+                { label: 'Password', value: 'password' },
+                { label: 'Notifications', value: 'notifications', count: 3 },
+              ]}
+              active={segTab}
+              onChange={setSegTab}
+            />
+            <div style={{ fontSize: 13, color: 'var(--text-muted)' }}>
+              Active tab: <strong>{segTab}</strong>
+            </div>
+          </div>
+        </DemoCard>
+
         {/* 20. Toast */}
         <DemoCard
           id="toast"