diff --git a/new-frontend/src/App.tsx b/new-frontend/src/App.tsx
index 542319c..6c621e5 100644
--- a/new-frontend/src/App.tsx
+++ b/new-frontend/src/App.tsx
@@ -1,4 +1,5 @@
 import { BrowserRouter, Routes, Route, Navigate } from 'react-router-dom'
+import { ThemeProvider } from './contexts/ThemeContext'
 import { AuthProvider } from './contexts/AuthContext'
 import { TimerProvider } from './contexts/TimerContext'
 import { LandingPage } from './pages/LandingPage'
@@ -18,11 +19,12 @@ import { ProfilePage } from './pages/ProfilePage'
 export function App() {
   return (
     <BrowserRouter>
-      <AuthProvider>
-        <TimerProvider>
-          <Routes>
-            {/* Rotas Públicas */}
-            <Route path="/" element={<LandingPage />} />
+      <ThemeProvider>
+        <AuthProvider>
+          <TimerProvider>
+            <Routes>
+              {/* Rotas Públicas */}
+              <Route path="/" element={<LandingPage />} />
             <Route path="/login" element={<AuthPage />} />
             <Route path="/register" element={<AuthPage />} />
 
@@ -49,8 +51,9 @@ export function App() {
             {/* Fallback */}
             <Route path="*" element={<Navigate to="/" replace />} />
           </Routes>
-        </TimerProvider>
-      </AuthProvider>
+          </TimerProvider>
+        </AuthProvider>
+      </ThemeProvider>
     </BrowserRouter>
   )
 }
diff --git a/new-frontend/src/components/landing/Navbar.tsx b/new-frontend/src/components/landing/Navbar.tsx
index cfa5fad..d1b4217 100644
--- a/new-frontend/src/components/landing/Navbar.tsx
+++ b/new-frontend/src/components/landing/Navbar.tsx
@@ -1,8 +1,10 @@
 import { Link } from "react-router-dom"
 import { Button, Chip, ChipLabel } from "@heroui/react"
-import { ArrowRight } from "lucide-react"
+import { ArrowRight, Sun, Moon } from "lucide-react"
+import { useTheme } from "../../contexts/ThemeContext"
 
 export const Navbar = () => {
+  const { theme, toggleTheme } = useTheme()
   return (
     <header className="sticky top-0 z-50 backdrop-blur-md bg-surface/85 border-b border-border-soft transition-all duration-200">
       <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 h-20 flex items-center justify-between">
@@ -62,6 +64,20 @@ export const Navbar = () => {
 
         {/* Actions */}
         <div className="flex items-center gap-3">
+          <button
+            type="button"
+            onClick={toggleTheme}
+            title={theme === 'dark' ? 'Mudar para tema claro' : 'Mudar para tema escuro'}
+            className="p-2 rounded-xl border border-border bg-surface text-muted hover:text-foreground hover:bg-surface-raised transition-colors shadow-xs"
+            aria-label="Alternar tema"
+          >
+            {theme === 'dark' ? (
+              <Sun className="w-4 h-4 text-amber-400" />
+            ) : (
+              <Moon className="w-4 h-4 text-brand" />
+            )}
+          </button>
+
           <Link
             to="/login"
             className="text-sm font-semibold text-text-main hover:text-brand px-3 py-2 transition-colors"
diff --git a/new-frontend/src/components/layout/Header.tsx b/new-frontend/src/components/layout/Header.tsx
index 9cdbb8d..a1266d1 100644
--- a/new-frontend/src/components/layout/Header.tsx
+++ b/new-frontend/src/components/layout/Header.tsx
@@ -17,11 +17,14 @@ import {
   PlusCircle,
   Menu as MenuIcon,
   Check,
+  Square,
+  Sun,
+  Moon,
 } from 'lucide-react'
 import { useAuth } from '../../contexts/AuthContext'
+import { useTheme } from '../../contexts/ThemeContext'
 import { useTimer } from '../../contexts/TimerContext'
 import { formatSecondsToTimer } from '../../lib/timeUtils'
-import { Square } from 'lucide-react'
 
 interface HeaderProps {
   onToggleMobileSidebar: () => void
@@ -29,6 +32,7 @@ interface HeaderProps {
 
 export const Header = ({ onToggleMobileSidebar }: HeaderProps) => {
   const { user, activeOrg, setActiveOrg, logout } = useAuth()
+  const { theme, toggleTheme } = useTheme()
   const { activeTask, activeSeconds, stopTimer } = useTimer()
   const [showOrgDropdown, setShowOrgDropdown] = useState(false)
   const [showUserDropdown, setShowUserDropdown] = useState(false)
@@ -206,6 +210,21 @@ export const Header = ({ onToggleMobileSidebar }: HeaderProps) => {
           <span className="hidden sm:inline">Tarefas</span>
         </Button>
 
+        {/* Theme Toggle Button */}
+        <button
+          type="button"
+          onClick={toggleTheme}
+          title={theme === 'dark' ? 'Mudar para modo claro' : 'Mudar para modo escuro'}
+          className="p-2 rounded-xl border border-border bg-surface text-muted hover:text-foreground hover:bg-surface-raised transition-colors shadow-xs flex items-center justify-center"
+          aria-label="Alternar tema claro e escuro"
+        >
+          {theme === 'dark' ? (
+            <Sun className="w-4 h-4 text-amber-400 hover:rotate-45 transition-transform" />
+          ) : (
+            <Moon className="w-4 h-4 text-brand hover:-rotate-12 transition-transform" />
+          )}
+        </button>
+
         {/* User Profile Menu Dropdown */}
         <div ref={userRef} className="relative">
           <button
@@ -270,6 +289,24 @@ export const Header = ({ onToggleMobileSidebar }: HeaderProps) => {
                   <Settings className="w-4 h-4 text-brand" />
                   Configurações do Workspace
                 </Link>
+
+                <button
+                  type="button"
+                  onClick={toggleTheme}
+                  className="w-full flex items-center justify-between p-2 rounded-xl text-xs font-semibold text-text-muted hover:text-text-main hover:bg-surface-muted transition-colors text-left"
+                >
+                  <div className="flex items-center gap-2.5">
+                    {theme === 'dark' ? (
+                      <Sun className="w-4 h-4 text-amber-400" />
+                    ) : (
+                      <Moon className="w-4 h-4 text-brand" />
+                    )}
+                    <span>Tema {theme === 'dark' ? 'Claro' : 'Escuro'}</span>
+                  </div>
+                  <span className="text-[10px] uppercase font-bold text-muted bg-surface-raised px-1.5 py-0.5 rounded-md border border-border">
+                    {theme}
+                  </span>
+                </button>
               </div>
 
               <div className="border-t border-border-soft pt-1 mt-1">
diff --git a/new-frontend/src/components/layout/Sidebar.tsx b/new-frontend/src/components/layout/Sidebar.tsx
index 61cd747..005d791 100644
--- a/new-frontend/src/components/layout/Sidebar.tsx
+++ b/new-frontend/src/components/layout/Sidebar.tsx
@@ -9,9 +9,12 @@ import {
   Settings,
   X,
   Building2,
+  Sun,
+  Moon,
 } from 'lucide-react'
 import { Chip, ChipLabel } from '@heroui/react'
 import { useAuth } from '../../contexts/AuthContext'
+import { useTheme } from '../../contexts/ThemeContext'
 
 interface SidebarProps {
   isMobileOpen: boolean
@@ -20,6 +23,7 @@ interface SidebarProps {
 
 export const Sidebar = ({ isMobileOpen, onCloseMobile }: SidebarProps) => {
   const { activeOrg } = useAuth()
+  const { theme, toggleTheme } = useTheme()
 
   const navItems = [
     {
@@ -111,18 +115,34 @@ export const Sidebar = ({ isMobileOpen, onCloseMobile }: SidebarProps) => {
 
       {/* Bottom Workspace Card Info */}
       <div className="p-4 border-t border-border-soft">
-        <div className="p-3 rounded-2xl bg-surface-muted/70 border border-border-soft flex items-center gap-3">
-          <div className="w-8 h-8 rounded-xl bg-brand-soft text-brand flex items-center justify-center font-bold text-xs shrink-0">
-            <Building2 className="w-4 h-4 text-brand" />
-          </div>
-          <div className="truncate flex-1 min-w-0">
-            <p className="text-xs font-bold text-text-main truncate">
-              {activeOrg?.name || 'Workspace Padrão'}
-            </p>
-            <span className="text-[10px] font-semibold text-text-muted uppercase tracking-wider">
-              {activeOrg?.roles[0] || 'Ativo'}
-            </span>
+        <div className="p-3 rounded-2xl bg-surface-muted/70 border border-border-soft flex items-center justify-between gap-2">
+          <div className="flex items-center gap-2.5 truncate flex-1 min-w-0">
+            <div className="w-8 h-8 rounded-xl bg-brand-soft text-brand flex items-center justify-center font-bold text-xs shrink-0">
+              <Building2 className="w-4 h-4 text-brand" />
+            </div>
+            <div className="truncate flex-1 min-w-0">
+              <p className="text-xs font-bold text-text-main truncate">
+                {activeOrg?.name || 'Workspace Padrão'}
+              </p>
+              <span className="text-[10px] font-semibold text-text-muted uppercase tracking-wider">
+                {activeOrg?.roles[0] || 'Ativo'}
+              </span>
+            </div>
           </div>
+
+          <button
+            type="button"
+            onClick={toggleTheme}
+            title={theme === 'dark' ? 'Mudar para tema claro' : 'Mudar para tema escuro'}
+            className="p-1.5 rounded-lg border border-border-soft bg-surface text-muted hover:text-foreground hover:bg-surface-raised transition-colors shrink-0"
+            aria-label="Alternar tema"
+          >
+            {theme === 'dark' ? (
+              <Sun className="w-3.5 h-3.5 text-amber-400" />
+            ) : (
+              <Moon className="w-3.5 h-3.5 text-brand" />
+            )}
+          </button>
         </div>
       </div>
     </div>
diff --git a/new-frontend/src/contexts/ThemeContext.tsx b/new-frontend/src/contexts/ThemeContext.tsx
new file mode 100644
index 0000000..4bbb3ff
--- /dev/null
+++ b/new-frontend/src/contexts/ThemeContext.tsx
@@ -0,0 +1,56 @@
+import React, { createContext, useContext, useState, useEffect } from 'react'
+
+type Theme = 'light' | 'dark'
+
+interface ThemeContextType {
+  theme: Theme
+  toggleTheme: () => void
+  setTheme: (theme: Theme) => void
+}
+
+const ThemeContext = createContext<ThemeContextType | undefined>(undefined)
+
+export const ThemeProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [theme, setThemeState] = useState<Theme>(() => {
+    const saved = localStorage.getItem('bee_theme') as Theme | null
+    if (saved === 'light' || saved === 'dark') {
+      return saved
+    }
+    // Default to dark theme for modern developer dashboard experience
+    return 'dark'
+  })
+
+  useEffect(() => {
+    const root = document.documentElement
+    if (theme === 'dark') {
+      root.classList.add('dark')
+      root.classList.remove('light')
+    } else {
+      root.classList.remove('dark')
+      root.classList.add('light')
+    }
+    localStorage.setItem('bee_theme', theme)
+  }, [theme])
+
+  const toggleTheme = () => {
+    setThemeState((prev) => (prev === 'dark' ? 'light' : 'dark'))
+  }
+
+  const setTheme = (newTheme: Theme) => {
+    setThemeState(newTheme)
+  }
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggleTheme, setTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  )
+}
+
+export const useTheme = (): ThemeContextType => {
+  const ctx = useContext(ThemeContext)
+  if (!ctx) {
+    throw new Error('useTheme must be used within a ThemeProvider')
+  }
+  return ctx
+}
diff --git a/new-frontend/src/index.css b/new-frontend/src/index.css
index b8a5e24..d12ec7e 100644
--- a/new-frontend/src/index.css
+++ b/new-frontend/src/index.css
@@ -1,37 +1,85 @@
 @import "tailwindcss";
 @config "../tailwind.config.js";
 
+:root {
+  --app-bg: #f5f1e8;
+  --app-bg-strong: #ebe4d7;
+  --surface: #ffffff;
+  --surface-muted: #f6efe2;
+  --surface-raised: #fbf8f1;
+  --surface-sunken: #ece5d6;
+  --border: #e2d7c3;
+  --border-soft: #e7dcc9;
+  --border-strong: #cdbba0;
+  --text-main: #1c1917;
+  --text-muted: #78716c;
+  --foreground: #1c1917;
+  --muted: #78716c;
+  --brand-soft: #ccfbf1;
+  --accent-soft: #ffedd5;
+  --shadow-panel: 0 22px 60px rgba(79, 62, 35, 0.08), 0 6px 18px rgba(79, 62, 35, 0.06);
+  color-scheme: light;
+}
+
+.dark {
+  --app-bg: #090d16;
+  --app-bg-strong: #0f141f;
+  --surface: #111726;
+  --surface-muted: #171e30;
+  --surface-raised: #182033;
+  --surface-sunken: #0c111c;
+  --border: #1e293b;
+  --border-soft: #1e293b;
+  --border-strong: #334155;
+  --text-main: #f8fafc;
+  --text-muted: #94a3b8;
+  --foreground: #f8fafc;
+  --muted: #94a3b8;
+  --brand-soft: rgba(15, 118, 110, 0.2);
+  --accent-soft: rgba(217, 119, 6, 0.2);
+  --shadow-panel: 0 22px 60px rgba(0, 0, 0, 0.4), 0 6px 18px rgba(0, 0, 0, 0.25);
+  color-scheme: dark;
+}
+
 @theme {
   --font-sans: 'Plus Jakarta Sans', ui-sans-serif, system-ui, sans-serif;
   --font-mono: 'JetBrains Mono', ui-monospace, monospace;
 
-  --color-app-bg: #f5f1e8;
-  --color-app-bg-strong: #ebe4d7;
-  --color-surface: #fffdf8;
-  --color-surface-muted: #f6efe2;
-  --color-border-soft: #e7dcc9;
-  --color-border-strong: #cdbba0;
-  --color-text-main: #1f2937;
-  --color-text-muted: #6b7280;
+  --color-app-bg: var(--app-bg);
+  --color-app-bg-strong: var(--app-bg-strong);
+  --color-surface: var(--surface);
+  --color-surface-muted: var(--surface-muted);
+  --color-surface-raised: var(--surface-raised);
+  --color-surface-sunken: var(--surface-sunken);
+  --color-border: var(--border);
+  --color-border-soft: var(--border-soft);
+  --color-border-strong: var(--border-strong);
+  --color-text-main: var(--text-main);
+  --color-text-muted: var(--text-muted);
+  --color-foreground: var(--foreground);
+  --color-muted: var(--muted);
+
   --color-brand: #0f766e;
+  --color-brand-hover: #115e59;
   --color-brand-strong: #115e59;
-  --color-brand-soft: #ccfbf1;
+  --color-brand-soft: var(--brand-soft);
+
   --color-accent: #d97706;
-  --color-accent-soft: #ffedd5;
+  --color-accent-hover: #b45309;
+  --color-accent-soft: var(--accent-soft);
 
   --color-success: #10b981;
-  --color-success-soft: #ecfdf5;
+  --color-success-soft: rgba(16, 185, 129, 0.15);
   --color-warning: #f59e0b;
-  --color-warning-soft: #fffbeb;
+  --color-warning-soft: rgba(245, 158, 11, 0.15);
   --color-danger: #ef4444;
-  --color-danger-soft: #fef2f2;
+  --color-danger-soft: rgba(239, 68, 68, 0.15);
 
-  --shadow-panel:
-    0 22px 60px rgba(79, 62, 35, 0.08), 0 6px 18px rgba(79, 62, 35, 0.06);
+  --shadow-panel: var(--shadow-panel);
 }
 
 :root {
-  color: var(--color-text-main);
+  color: var(--color-foreground);
   background-color: var(--color-app-bg);
   font-family: var(--font-sans);
   font-synthesis: none;
@@ -52,8 +100,19 @@ body,
 
 body {
   margin: 0;
-  background:
-    radial-gradient(circle at top left, rgba(217, 119, 6, 0.12), transparent 28%),
-    radial-gradient(circle at top right, rgba(15, 118, 110, 0.14), transparent 24%),
-    linear-gradient(180deg, var(--color-app-bg) 0%, #f8f5ef 100%);
+  transition: background-color 0.2s ease, color 0.2s ease;
+}
+
+html.dark body {
+  background:
+    radial-gradient(circle at top left, rgba(217, 119, 6, 0.08), transparent 28%),
+    radial-gradient(circle at top right, rgba(15, 118, 110, 0.12), transparent 24%),
+    linear-gradient(180deg, var(--app-bg) 0%, #060910 100%);
+}
+
+html:not(.dark) body {
+  background:
+    radial-gradient(circle at top left, rgba(217, 119, 6, 0.08), transparent 28%),
+    radial-gradient(circle at top right, rgba(15, 118, 110, 0.08), transparent 24%),
+    linear-gradient(180deg, var(--app-bg) 0%, #faf7f0 100%);
 }