smart.json

{
  "knowledge": {
    "programming": {
      "javascript closure": "A closure allows a function to remember variables from its outer scope even after the outer function has returned. Example: function counter(){ let n=0; return ()=>++n; }",
      "javascript promise": "Promises represent eventual completion or failure of async operations. Use .then()/.catch() or async/await. Example: fetch(url).then(r=>r.json()).then(data=>console.log(data));",
      "javascript async await": "async/await makes asynchronous code look synchronous. async function getData(){ const res = await fetch(url); return await res.json(); }",
      "javascript event loop": "The JavaScript event loop processes asynchronous callbacks via call stack, Web APIs, callback queue, and microtask queue.",
      "javascript dom": "DOM manipulation: document.getElementById('id'), document.querySelector('.class'), element.innerHTML, element.style.color, element.addEventListener('click', fn)",
      "javascript array methods": "Arrays: map(), filter(), reduce(), forEach(), find(), some(), every(), flat(), flatMap(), includes(), indexOf(), splice(), slice()",
      "javascript es6": "ES6+ features: arrow functions, template literals, destructuring, spread/rest, default params, modules (import/export), classes, let/const, optional chaining (?.), nullish coalescing (??)",
      "javascript fetch": "fetch(url, {method:'POST', headers:{'Content-Type':'application/json'}, body:JSON.stringify(data)}).then(r=>r.json()).catch(err=>console.error(err))",
      "javascript regex": "Regular expressions: /pattern/flags. Methods: test(), match(), replace(), split(). Example: /^[a-z]+$/i.test('Hello') // true",
      "javascript localStorage": "localStorage.setItem('key','value'); localStorage.getItem('key'); localStorage.removeItem('key'); stores strings persistently in browser.",
      "javascript prototype": "Every JS object has a prototype chain. Prototypal inheritance: Object.create(proto), class Foo extends Bar{}. Prototype methods are shared across instances.",
      "javascript modules": "ES modules: export default function(){}, export const x=1; import Foo from './foo.js'; import {x} from './mod.js'; Dynamic: await import('./mod.js')",
      "javascript websocket": "WebSocket for real-time: const ws=new WebSocket('ws://host'); ws.onmessage=e=>console.log(e.data); ws.send('hello');",
      "javascript error handling": "try{ riskyCode(); }catch(e){ console.error(e.message); }finally{ cleanup(); } Custom: throw new Error('msg'); class MyError extends Error{}",
      "react basics": "React: functional components with hooks. useState for state, useEffect for side effects, useRef for DOM refs, useContext for global state, useMemo/useCallback for optimization.",
      "react hooks": "useState(init), useEffect(fn, deps), useRef(init), useContext(ctx), useMemo(fn, deps), useCallback(fn, deps), useReducer(reducer, init), custom hooks: function useName(){}",
      "react component": "function MyComp({name}){ const [count,setCount]=useState(0); return <div onClick={()=>setCount(c=>c+1)}>{name}: {count}</div>; }",
      "vue basics": "Vue 3 Composition API: setup(), ref(), reactive(), computed(), watch(), onMounted(). Template: v-bind, v-on, v-if, v-for, v-model.",
      "node.js basics": "Node.js: server-side JavaScript. require('fs'), require('path'), require('http'). Use npm for packages. CommonJS (require) or ESM (import).",
      "node.js express": "Express: const app=require('express')(); app.get('/',(req,res)=>res.json({ok:true})); app.listen(3000); Middleware: app.use(express.json());",
      "python basics": "Python: print(), input(), len(), range(), type(). Variables don't need declaration. Indentation defines blocks. f-strings: f'Hello {name}'",
      "python functions": "def greet(name, greeting='Hello'): return f'{greeting}, {name}!'\nLambda: fn = lambda x: x*2\n*args and **kwargs for variable arguments.",
      "python list comprehension": "[x*2 for x in range(10) if x%2==0] — creates [0,4,8,12,16]. Dict comprehension: {k:v for k,v in items.items()}",
      "python classes": "class Animal:\n  def __init__(self,name): self.name=name\n  def speak(self): return f'{self.name} speaks'\nclass Dog(Animal):\n  def speak(self): return 'Woof!'",
      "python decorators": "A decorator wraps a function: @decorator above def. Example: def timer(fn): def wrapper(*a): t=time(); fn(*a); print(time()-t); return wrapper",
      "python async": "import asyncio\nasync def main(): await asyncio.sleep(1); print('done')\nasyncio.run(main())\naiohttp for async HTTP requests.",
      "python data science": "pandas: df=pd.read_csv('file.csv'); df.head(); df.describe(); df.groupby('col').mean(). numpy: np.array(), np.zeros(), np.dot(). matplotlib for plotting.",
      "python flask": "from flask import Flask,request,jsonify; app=Flask(__name__)\n@app.route('/api',methods=['POST'])\ndef api(): return jsonify({'result':42})\napp.run(debug=True)",
      "python django": "Django: models.py defines DB schema, views.py handles requests, urls.py routes, templates for HTML. Migrations: python manage.py makemigrations && migrate.",
      "html basics": "HTML5 semantic: <header>,<nav>,<main>,<article>,<section>,<aside>,<footer>. Forms: <input type='text/email/password/checkbox/radio'>, <select>, <textarea>, <button>.",
      "html forms": "<form action='/submit' method='POST'><input name='email' type='email' required><input name='pass' type='password'><button type='submit'>Go</button></form>",
      "html canvas": "<canvas id='c'></canvas><script>const ctx=document.getElementById('c').getContext('2d'); ctx.fillStyle='purple'; ctx.fillRect(10,10,100,50);</script>",
      "css basics": "CSS selectors: element, .class, #id, [attr], :hover, ::before. Box model: margin, border, padding, content. Cascade: specificity, inheritance, importance.",
      "css flexbox": "display:flex; flex-direction:row|column; justify-content:center|space-between|flex-start; align-items:center|stretch; flex-wrap:wrap; gap:16px;",
      "css grid": "display:grid; grid-template-columns:repeat(3,1fr); grid-template-rows:auto; gap:16px; grid-column:span 2; place-items:center;",
      "css animations": "@keyframes slide{from{transform:translateX(-100%)}to{transform:translateX(0)}} .el{animation:slide 0.3s ease-out forwards;}",
      "css variables": ":root{--primary:#7a2cff;--bg:#1b0f33;} .btn{background:var(--primary);} Override: el.style.setProperty('--primary','red');",
      "css responsive": "@media(max-width:768px){.grid{grid-template-columns:1fr;}} @media(prefers-color-scheme:dark){body{background:#000;}}",
      "typescript basics": "TypeScript adds static types to JS. Types: string, number, boolean, any, unknown, never, void. Interface, type alias, generics<T>, enums. Compile: tsc file.ts",
      "typescript interface": "interface User{id:number; name:string; email?:string;} function greet(u:User):string{ return `Hi ${u.name}`; }",
      "sql basics": "SELECT name,age FROM users WHERE age>18 ORDER BY name ASC LIMIT 10; INSERT INTO users(name,age) VALUES('Alice',25); UPDATE users SET age=26 WHERE id=1;",
      "sql joins": "INNER JOIN: matching rows both tables. LEFT JOIN: all left + matching right. FULL JOIN: all rows both sides. Example: SELECT u.name,o.total FROM users u LEFT JOIN orders o ON u.id=o.user_id;",
      "sql indexes": "CREATE INDEX idx_email ON users(email); Speeds up WHERE/ORDER BY on indexed columns. B-tree index (default), hash index, composite index. EXPLAIN to check query plan.",
      "sql transactions": "BEGIN; UPDATE accounts SET balance=balance-100 WHERE id=1; UPDATE accounts SET balance=balance+100 WHERE id=2; COMMIT; -- or ROLLBACK on error",
      "nosql mongodb": "MongoDB: documents in collections. db.users.insertOne({name:'Alice'}); db.users.find({age:{$gt:18}}); db.users.updateOne({_id:id},{$set:{name:'Bob'}}); Mongoose for Node.js ORM.",
      "nosql redis": "Redis: in-memory key-value store. SET key value EX 3600; GET key; DEL key; LPUSH list val; LRANGE list 0 -1; HSET hash field val; Great for caching, sessions, queues.",
      "data structures": "Array O(1) access, O(n) search. Linked list O(n) access, O(1) insert at head. Hash map O(1) avg. Binary tree O(log n). Heap O(log n) insert/extract. Graph: BFS/DFS.",
      "algorithms sorting": "Bubble O(n²), Selection O(n²), Insertion O(n²) best O(n). Merge O(n log n) stable. Quick O(n log n) avg O(n²) worst. Heap O(n log n). Counting O(n+k).",
      "algorithms searching": "Linear O(n). Binary O(log n) — requires sorted array. BFS O(V+E) shortest path unweighted. DFS O(V+E) cycle detect, topo sort. Dijkstra O(E log V).",
      "algorithms dynamic programming": "DP: solve subproblems, store results (memoization/tabulation). Classic problems: Fibonacci, knapsack, longest common subsequence, coin change, edit distance.",
      "big o notation": "O(1) constant, O(log n) logarithmic, O(n) linear, O(n log n) linearithmic, O(n²) quadratic, O(2^n) exponential. Space complexity same analysis.",
      "design patterns": "Singleton: one instance. Factory: create objects. Observer: event system. Strategy: swap algorithms. Decorator: add behavior. MVC: Model-View-Controller separation.",
      "git basics": "git init, git clone url, git add ., git commit -m 'msg', git push origin main, git pull, git branch name, git checkout -b new-branch, git merge branch, git log --oneline",
      "git advanced": "git rebase main, git cherry-pick hash, git stash / git stash pop, git reset --hard HEAD~1, git reflog, git bisect, git tag v1.0, git submodule add url",
      "docker basics": "docker build -t name ., docker run -p 3000:3000 name, docker ps, docker stop id, docker-compose up -d, Dockerfile: FROM node:18, WORKDIR /app, COPY . ., RUN npm install, CMD ['node','index.js']",
      "kubernetes basics": "kubectl apply -f deployment.yaml, kubectl get pods, kubectl logs pod-name, kubectl exec -it pod -- bash. Deployment: replicas, rollingUpdate. Service: ClusterIP, NodePort, LoadBalancer.",
      "rest api": "REST: GET /users, POST /users, PUT /users/:id, DELETE /users/:id. Status codes: 200 OK, 201 Created, 400 Bad Request, 401 Unauthorized, 404 Not Found, 500 Server Error.",
      "graphql": "GraphQL: single endpoint, typed schema. Query: {users{id name}}. Mutation: mutation{createUser(name:'Bob'){id}}. Subscriptions for real-time. Apollo Client/Server popular.",
      "websockets": "ws = new WebSocket('wss://host'); ws.onopen=()=>ws.send('hi'); ws.onmessage=e=>console.log(e.data); Server: Node ws package or Socket.io for rooms/namespaces.",
      "machine learning": "ML types: supervised (labeled data), unsupervised (clustering), reinforcement (rewards). Libraries: scikit-learn, TensorFlow, PyTorch. Concepts: training/test split, overfitting, cross-validation.",
      "neural networks": "Layers: input, hidden, output. Activation: ReLU, sigmoid, softmax. Loss: MSE, cross-entropy. Optimizer: Adam, SGD. Backpropagation updates weights via gradients.",
      "system design": "Key concepts: load balancer, CDN, caching (Redis/Memcached), database sharding, microservices, message queues (Kafka/RabbitMQ), API gateway, rate limiting, circuit breaker.",
      "cloud aws": "AWS core: EC2 (compute), S3 (storage), RDS (database), Lambda (serverless), API Gateway, CloudFront (CDN), Route53 (DNS), IAM (access control), VPC (networking).",
      "security web": "XSS: sanitize input, CSP headers. SQL injection: parameterized queries. CSRF: tokens. Auth: JWT (stateless), sessions (stateful). HTTPS always. bcrypt for passwords. Rate limiting.",
      "linux basics": "ls, cd, mkdir, rm -rf, cp, mv, cat, grep, find, chmod, chown, ps aux, kill, top, df -h, du -sh, ssh user@host, scp file user@host:/path, curl, wget, tar -xzf",
      "regex": "^start, end$, . any char, * zero+, + one+, ? optional, [abc] class, [^abc] not, \\d digit, \\w word, \\s space, (group), | or, {n,m} count. Flags: g global, i case-insensitive, m multiline.",
      "web performance": "Minimize/bundle JS/CSS. Lazy load images. Use CDN. Enable gzip/brotli. HTTP/2. Cache headers. Code splitting. Tree shaking. Critical CSS inline. Service workers for offline.",
      "pwa": "Progressive Web App: manifest.json for installability, service worker for offline caching, push notifications, responsive, HTTPS required. Lighthouse score target 90+.",
      "testing": "Unit: jest, mocha, pytest. Integration: supertest, Cypress. E2E: Playwright, Selenium. TDD: write test first. Coverage: aim 80%+. Mocking: jest.mock(), unittest.mock.",
      "typescript generics": "function identity<T>(arg:T):T{return arg;} interface Box<T>{value:T;} Generic constraints: <T extends {length:number}>. Utility types: Partial<T>, Required<T>, Pick<T,K>, Omit<T,K>.",
      "functional programming": "Pure functions (no side effects), immutability, higher-order functions, function composition, map/filter/reduce, currying, monads. Avoids shared mutable state.",
      "rust basics": "Rust: memory safety without GC. Ownership, borrowing, lifetimes. let mut x=5; fn add(a:i32,b:i32)->i32{a+b} struct Point{x:f64,y:f64} impl Point{fn dist(&self)->f64{}}",
      "go basics": "Go: statically typed, fast compile. package main; import 'fmt'; func main(){ fmt.Println('hello') } Goroutines: go func(){...}() Channels: ch:=make(chan int); ch<-1; val:=<-ch",
      "example js file": "// JavaScript Example\nfunction greet(name) {\n  return `Hello, ${name}!`;\n}\n\nasync function fetchData(url) {\n  const res = await fetch(url);\n  return await res.json();\n}\n\nconst nums = [1,2,3,4,5];\nconst doubled = nums.map(n => n * 2);\nconsole.log(greet('Dolores'));\nconsole.log('Doubled:', doubled);",
      "example python file": "# Python Example\ndef greet(name):\n    return f'Hello, {name}!'\n\ndef add(a, b):\n    return a + b\n\nnums = [1,2,3,4,5]\ndoubled = [n*2 for n in nums]\n\nprint(greet('Dolores'))\nprint('Sum:', sum(nums))\nprint('Doubled:', doubled)",
      "example html file": "<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n  <meta charset=\"UTF-8\">\n  <title>Dolores Page</title>\n  <style>\n    body { background:#1b0f33; color:white; font-family:Arial,sans-serif; text-align:center; padding:40px; }\n    h1 { background:linear-gradient(135deg,#7a2cff,#d38cff); -webkit-background-clip:text; -webkit-text-fill-color:transparent; }\n    button { background:#7a2cff; color:white; border:none; padding:10px 24px; border-radius:8px; cursor:pointer; font-size:16px; }\n  </style>\n</head>\n<body>\n  <h1>Hello from Dolores!</h1>\n  <p>Nerevions Assistant</p>\n  <button onclick=\"alert('Hello!')\">Click Me</button>\n</body>\n</html>",
      "example css file": "/* Dolores Theme CSS */\n:root {\n  --purple-dark: #1b0f33;\n  --purple-mid: #7a2cff;\n  --purple-light: #d38cff;\n}\nbody {\n  background: var(--purple-dark);\n  color: white;\n  font-family: Arial, sans-serif;\n  margin: 0; padding: 20px;\n}\nh1 {\n  background: linear-gradient(135deg, var(--purple-mid), var(--purple-light));\n  -webkit-background-clip: text;\n  -webkit-text-fill-color: transparent;\n}\n.card {\n  background: #2b1a54;\n  border-radius: 12px;\n  padding: 16px;\n  margin: 12px 0;\n}",
      "example react file": "import { useState, useEffect } from 'react';\n\nexport default function App() {\n  const [count, setCount] = useState(0);\n  const [data, setData] = useState(null);\n\n  useEffect(() => {\n    fetch('https://api.example.com/data')\n      .then(r => r.json())\n      .then(setData);\n  }, []);\n\n  return (\n    <div>\n      <h1>Count: {count}</h1>\n      <button onClick={() => setCount(c => c + 1)}>Add</button>\n      {data && <pre>{JSON.stringify(data, null, 2)}</pre>}\n    </div>\n  );\n}",
      "example java file": "// Java Example\nimport java.util.Arrays;\nimport java.util.List;\nimport java.util.stream.Collectors;\n\npublic class Main {\n    public static String greet(String name) {\n        return \"Hello, \" + name + \"!\";\n    }\n\n    public static void main(String[] args) {\n        System.out.println(greet(\"Dolores\"));\n        List<Integer> nums = Arrays.asList(1,2,3,4,5);\n        List<Integer> doubled = nums.stream().map(n->n*2).collect(Collectors.toList());\n        System.out.println(\"Doubled: \" + doubled);\n    }\n}",
      "example cpp file": "// C++ Example\n#include <iostream>\n#include <vector>\n#include <algorithm>\n\nstd::string greet(std::string name) {\n    return \"Hello, \" + name + \"!\";\n}\n\nint main() {\n    std::cout << greet(\"Dolores\") << std::endl;\n    std::vector<int> nums = {1,2,3,4,5};\n    std::transform(nums.begin(),nums.end(),nums.begin(),[](int n){return n*2;});\n    for(int n:nums) std::cout << n << \" \";\n    std::cout << std::endl;\n    return 0;\n}"
    },
    "science": {
      "gravity": "Gravity is the force attracting masses together. F=Gm₁m₂/r². Earth's gravity: 9.81 m/s². Described by Newton's law and more precisely by Einstein's general relativity.",
      "atom": "Atoms: protons (positive) + neutrons (neutral) in nucleus, electrons (negative) in shells. Atomic number = protons. Isotopes have same protons, different neutrons.",
      "quantum mechanics": "QM describes matter at subatomic scales. Wave-particle duality, Heisenberg uncertainty principle, superposition, quantum entanglement, Schrödinger equation. Basis of modern electronics.",
      "relativity": "Special relativity: speed of light constant, time dilation, length contraction, E=mc². General relativity: gravity = spacetime curvature, predicts black holes, gravitational waves.",
      "thermodynamics": "Laws: 1st energy conserved, 2nd entropy always increases, 3rd absolute zero unattainable. Concepts: heat, work, enthalpy, entropy, Carnot efficiency, heat engines.",
      "electromagnetism": "Maxwell's equations unify electricity and magnetism. F=qE+qv×B. Light is electromagnetic wave. Electric potential V, current I=V/R, power P=IV. AC/DC circuits.",
      "optics": "Light travels at 3×10⁸ m/s in vacuum. Reflection, refraction (Snell's law), diffraction, interference. Lenses: convex converges, concave diverges. Lasers: coherent light.",
      "nuclear physics": "Fission: heavy nuclei split (nuclear reactors, bombs). Fusion: light nuclei combine (sun, fusion reactors). Radioactive decay: alpha, beta, gamma. Half-life concept.",
      "chemistry basics": "Periodic table: 118 elements. Groups (columns) share properties. Periods (rows) = electron shells. Metals, nonmetals, metalloids. Electronegativity, ionization energy, atomic radius.",
      "chemical bonding": "Ionic: electron transfer (NaCl). Covalent: electron sharing (H₂O, CO₂). Metallic: delocalized electrons. Hydrogen bonds: between H and O/N/F — gives water unique properties.",
      "organic chemistry": "Carbon compounds. Functional groups: hydroxyl (-OH), carbonyl (C=O), carboxyl (-COOH), amino (-NH₂), ether (-O-). Alkanes, alkenes, alkynes, aromatics (benzene ring).",
      "biology basics": "Cell types: prokaryote (no nucleus, bacteria) and eukaryote (nucleus, plants/animals/fungi). Cell organelles: nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi.",
      "genetics": "DNA is double helix of base pairs (A-T, G-C). Genes encoded in DNA. Transcription: DNA→RNA. Translation: RNA→protein. Mutation, natural selection, Mendelian inheritance.",
      "evolution": "Natural selection: heritable variation + differential reproduction = adaptation. Evidence: fossil record, DNA similarity, comparative anatomy, direct observation of evolution.",
      "human anatomy": "Organ systems: skeletal, muscular, circulatory, respiratory, digestive, nervous, endocrine, immune, urinary, reproductive. Heart pumps ~5L blood/min. Brain: ~86 billion neurons.",
      "astronomy": "Solar system: Sun + 8 planets. Light year: distance light travels in 1 year (~9.46×10¹² km). Galaxy: ~100–400 billion stars. Observable universe: ~93 billion light years across.",
      "black holes": "Black holes form from collapsed massive stars. Event horizon: point of no return. Singularity: infinite density. Hawking radiation: quantum effect causing slow evaporation.",
      "climate science": "Greenhouse gases (CO₂, CH₄, N₂O) trap heat. Global warming: avg temp up ~1.2°C since 1880. Effects: sea level rise, extreme weather, ecosystem disruption. Paris Agreement: limit to 1.5°C.",
      "physics energy": "Energy types: kinetic (½mv²), potential (mgh), thermal, chemical, nuclear, electromagnetic. Conservation of energy. Power = energy/time. Efficiency = useful output/total input.",
      "waves": "Wave properties: wavelength, frequency, amplitude, speed. v=fλ. Mechanical waves need medium (sound). Electromagnetic waves don't (light). Doppler effect: frequency shifts with motion."
    },
    "math": {
      "derivative": "A derivative represents the rate of change. d/dx[xⁿ]=nxⁿ⁻¹. Product rule, chain rule, quotient rule. dy/dx at a point = slope of tangent. Applications: optimization, physics.",
      "integral": "Integration is anti-differentiation. ∫xⁿdx = xⁿ⁺¹/(n+1)+C. Definite integral = area under curve. Fundamental theorem: ∫[a,b]f(x)dx = F(b)-F(a). Integration by parts, substitution.",
      "matrix": "Matrix: grid of numbers. Addition: element-wise. Multiplication: row×column dot products. Identity matrix I. Inverse: A×A⁻¹=I. Determinant. Applications: linear systems, 3D graphics.",
      "linear algebra": "Vectors: magnitude and direction. Dot product: a·b=|a||b|cos θ. Cross product gives perpendicular vector. Eigenvalues/eigenvectors: Av=λv. Basis, span, linear independence.",
      "probability": "P(A) = favorable/total. P(A∪B) = P(A)+P(B)-P(A∩B). Conditional: P(A|B)=P(A∩B)/P(B). Bayes theorem. Distributions: normal, binomial, Poisson, uniform.",
      "statistics": "Mean = sum/n. Median = middle value. Mode = most frequent. Variance = avg squared deviation. Std dev = √variance. Correlation (-1 to 1). Hypothesis testing: p-value, t-test, chi-square.",
      "calculus limits": "lim(x→a)f(x): value f approaches as x→a. L'Hôpital's rule for 0/0 or ∞/∞ forms. Continuity: limit exists, f(a) defined, they're equal. Derivatives defined via limits.",
      "number theory": "Prime numbers: divisible only by 1 and themselves. Fundamental theorem of arithmetic: unique prime factorization. GCD, LCM. Modular arithmetic. Fermat's little theorem.",
      "discrete math": "Sets, logic (AND/OR/NOT/XOR), propositional calculus, graph theory (nodes/edges), trees, combinatorics (permutations n!, combinations nCr=n!/(r!(n-r)!)), Boolean algebra.",
      "geometry": "Euclidean: points, lines, planes, angles, triangles, circles. Pythagorean theorem: a²+b²=c². Circle: area=πr², circumference=2πr. Trigonometry: sin, cos, tan, SOH-CAH-TOA.",
      "trigonometry": "sin θ = opposite/hypotenuse, cos θ = adjacent/hypotenuse, tan θ = opposite/adjacent. Unit circle. sin²+cos²=1. sin(a+b)=sin a cos b + cos a sin b. Radians vs degrees.",
      "complex numbers": "Complex: a+bi where i=√(-1). Operations like real numbers. Magnitude |z|=√(a²+b²). Euler's formula: e^(iθ)=cos θ+i sin θ. Fundamental theorem of algebra.",
      "algebra basics": "Solve equations by inverse operations. Quadratic: ax²+bx+c=0, x=(-b±√(b²-4ac))/2a. Systems of equations: substitution, elimination, matrices. Inequalities, absolute value."
    },
    "history": {
      "world history overview": "Major eras: Prehistoric, Ancient (3000 BCE–500 CE), Medieval (500–1500), Early Modern (1500–1800), Modern (1800–present). Key: agriculture revolution, writing, industrialization, digital age.",
      "ancient civilizations": "Mesopotamia (Sumer, Babylon), Ancient Egypt (pharaohs, pyramids), Indus Valley, Ancient China (dynasties), Ancient Greece (democracy, philosophy), Roman Empire.",
      "world war 1": "WW1 (1914–1918): triggered by assassination of Archduke Franz Ferdinand. Triple Alliance vs Triple Entente. Trench warfare, 17M+ deaths. Ended with Treaty of Versailles.",
      "world war 2": "WW2 (1939–1945): Nazi Germany invaded Poland. Allied vs Axis powers. Holocaust: 6M+ Jewish people killed. Ended with atomic bombs on Japan. Founded UN, Cold War began.",
      "cold war": "Cold War (1947–1991): USA vs USSR ideological conflict. Arms race, space race, proxy wars (Korea, Vietnam, Afghanistan). Berlin Wall. Cuban Missile Crisis. Ended with USSR collapse.",
      "civil rights movement": "US Civil Rights Movement (1954–1968): ended racial segregation. Key figures: MLK Jr, Rosa Parks, Malcolm X. Brown v Board, March on Washington, Civil Rights Act 1964.",
      "industrial revolution": "1760–1840: mechanized production, steam power, urbanization. Began in Britain. Textile mills, railways, steel production. Transformed society from agrarian to industrial.",
      "renaissance": "14th–17th century European cultural rebirth. Art (da Vinci, Michelangelo), science (Galileo, Copernicus), literature (Shakespeare). Humanism, perspective, printing press.",
      "french revolution": "1789–1799: overthrew French monarchy. Liberty, equality, fraternity. Declaration of Rights of Man. Reign of Terror, guillotine. Led to Napoleon Bonaparte's rise.",
      "american history": "1776 Declaration of Independence. Constitution 1787. Civil War 1861–1865 ended slavery. Reconstruction, industrialization, WWI, Great Depression, WWII, Civil Rights, Cold War, 9/11."
    },
    "geography": {
      "world geography": "7 continents: Asia (largest), Africa, North America, South America, Antarctica, Europe, Australia/Oceania. 5 oceans: Pacific (largest), Atlantic, Indian, Southern, Arctic.",
      "countries capitals": "USA-Washington DC, UK-London, France-Paris, Germany-Berlin, Japan-Tokyo, China-Beijing, India-New Delhi, Brazil-Brasília, Russia-Moscow, Australia-Canberra, Canada-Ottawa.",
      "world rivers": "Longest rivers: Nile (Africa, 6650km), Amazon (S. America, 6400km), Yangtze (China, 6300km), Mississippi (USA, 6275km), Yenisei (Russia), Yellow River (China).",
      "world mountains": "Highest peaks: Everest (8849m, Nepal/Tibet), K2 (8611m), Kangchenjunga (8586m). Major ranges: Himalayas, Andes, Alps, Rockies, Appalachians, Atlas, Urals.",
      "climate zones": "Tropical (near equator, hot/wet), Subtropical (dry/wet seasons), Temperate (4 seasons), Continental (hot summers, cold winters), Polar (always cold), Tundra, Desert, Mediterranean."
    },
    "economics": {
      "economics basics": "Economics: allocation of scarce resources. Microeconomics: individual/firm decisions. Macroeconomics: national/global economy. Supply and demand, markets, GDP, inflation, unemployment.",
      "supply and demand": "Supply increases → price decreases. Demand increases → price increases. Equilibrium: quantity supplied = quantity demanded. Elasticity: how responsive quantity is to price change.",
      "gdp": "GDP = C + I + G + (X-M). Consumption + Investment + Government spending + Net exports. Measures economic output. GDP per capita = GDP/population. Real GDP adjusts for inflation.",
      "inflation": "Inflation: general rise in price level. CPI measures consumer price changes. Causes: demand-pull, cost-push, monetary. Central banks use interest rates to control inflation. Target ~2%.",
      "personal finance": "Budget: income - expenses. Emergency fund: 3-6 months expenses. Invest early (compound interest). Diversify portfolio. 401k/IRA for retirement. Credit score: payment history, utilization, length.",
      "investing": "Stocks: ownership shares, higher risk/return. Bonds: loans to companies/govts, lower risk. Index funds: diversified, low cost. Rule of 72: 72/interest rate = years to double. Dollar-cost averaging.",
      "cryptocurrency": "Blockchain: distributed ledger of transactions. Bitcoin: first crypto, limited to 21M coins. Ethereum: smart contracts platform. Proof of work vs proof of stake. Highly volatile.",
      "stock market": "NYSE, NASDAQ major US exchanges. Bull market: rising prices. Bear market: falling 20%+. P/E ratio: price/earnings per share. Diversification reduces risk. Long-term historically positive."
    },
    "psychology": {
      "psychology basics": "Psychology: study of mind and behavior. Branches: clinical, cognitive, developmental, social, neuropsychology. Methods: experiments, observations, surveys, case studies.",
      "cognitive biases": "Common biases: confirmation bias (seek info confirming beliefs), anchoring (rely on first info), availability heuristic (recent events seem more likely), Dunning-Kruger effect.",
      "motivation": "Maslow's hierarchy: physiological → safety → belonging → esteem → self-actualization. Intrinsic motivation (internal rewards) vs extrinsic (external rewards). Flow state.",
      "memory": "Memory types: sensory (1-3 sec), short-term/working (20 sec, 7±2 items), long-term (unlimited). Encoding, storage, retrieval. Mnemonics, spaced repetition, sleep improves memory.",
      "learning": "Classical conditioning (Pavlov), operant conditioning (Skinner: rewards/punishment). Observational learning (Bandura). Growth mindset: intelligence can be developed with effort.",
      "mental health": "Common conditions: anxiety disorders (most common), depression, PTSD, OCD, ADHD, bipolar. Treatments: CBT (cognitive behavioral therapy), medication, mindfulness, exercise, social support."
    },
    "philosophy": {
      "philosophy basics": "Major branches: metaphysics (nature of reality), epistemology (knowledge), ethics (morality), logic (reasoning), aesthetics (beauty). Ancient Greeks laid foundations.",
      "ethics": "Ethical theories: consequentialism (judge by outcomes, utilitarianism), deontology (duty-based, Kant's categorical imperative), virtue ethics (character), contractarianism (social contract).",
      "logic": "Deductive: valid if conclusion follows from premises. Inductive: probable conclusions from observations. Fallacies: ad hominem, straw man, false dichotomy, slippery slope, appeal to authority.",
      "famous philosophers": "Socrates (know thyself), Plato (forms, republic), Aristotle (logic, virtue ethics), Descartes (cogito ergo sum), Kant (categorical imperative), Nietzsche (will to power, nihilism).",
      "existentialism": "Focus on individual freedom, choice, responsibility. Sartre: existence precedes essence. Camus: absurdism. Heidegger: being and time. We create our own meaning."
    },
    "writing": {
      "writing email": "Subject line clear and specific. Opening: context/reason. Body: one main point per paragraph, be concise. Closing: action item or next step. Sign-off: Best/Thanks/Regards + name.",
      "writing essay": "5-paragraph structure: intro (hook + thesis), 3 body paragraphs (claim + evidence + analysis), conclusion (restate thesis + broader significance). Use transitions between paragraphs.",
      "writing story": "Story elements: character (want + flaw), conflict (external/internal), setting, plot (inciting incident, rising action, climax, falling action, resolution). Show don't tell. Subtext.",
      "writing resume": "One page if under 10 years experience. Sections: summary, experience (STAR format: situation, task, action, result), skills, education. Tailor to each job. Use keywords from posting.",
      "grammar tips": "Active voice stronger than passive. Vary sentence length. Avoid filler words (very, really, just, that). Consistent tense. Oxford comma. Em dash for emphasis — like this. Proofread.",
      "technical writing": "Technical writing: clarity over style. Define acronyms on first use. Use numbered steps for procedures. Headers and white space improve readability. Know your audience's technical level."
    },
    "health": {
      "nutrition basics": "Macronutrients: carbs (4 cal/g, main energy), protein (4 cal/g, muscle/repair), fat (9 cal/g, hormones/brain). Micronutrients: vitamins, minerals. Hydration: ~2L water/day.",
      "exercise": "Cardio: improves heart health, burns calories. Strength training: builds muscle, boosts metabolism. Flexibility: reduces injury. Aim: 150 min moderate or 75 min vigorous cardio + 2x strength/week.",
      "sleep": "Adults need 7-9 hours. Sleep stages: light, deep (NREM), REM (dreaming). Functions: memory consolidation, tissue repair, immune function. Tips: consistent schedule, dark/cool room.",
      "mental wellness": "Mental health practices: mindfulness/meditation, regular exercise, social connection, therapy/counseling, journaling, limiting alcohol/caffeine, nature exposure, creative activities.",
      "vitamins minerals": "Vitamin D: immune/bone health (sunlight, dairy). Vitamin C: antioxidant/immune (citrus). B12: nerve/blood (meat, eggs). Iron: oxygen transport (red meat, leafy greens). Calcium: bones (dairy, leafy greens)."
    },
    "technology": {
      "artificial intelligence": "AI: machines performing tasks requiring human intelligence. ML: learn from data. Deep learning: neural networks with many layers. NLP: language understanding. Computer vision: image recognition.",
      "blockchain": "Decentralized ledger of transactions in cryptographically linked blocks. Consensus mechanisms: proof of work, proof of stake. Smart contracts: self-executing code on blockchain.",
      "internet of things": "IoT: physical devices connected to internet. Smart home (thermostats, lights), industrial sensors, wearables. Protocols: MQTT, HTTP, CoAP. Security challenges with many endpoints.",
      "cybersecurity": "Threats: phishing, ransomware, SQL injection, XSS, DDoS, man-in-the-middle. Defense: firewalls, encryption, 2FA, regular updates, principle of least privilege, security audits.",
      "virtual reality": "VR: fully immersive digital environment (headset blocks real world). AR: digital overlay on real world (phone/glasses). MR: physical and digital interact. Applications: gaming, training, medicine.",
      "tech history": "1940s: first computers (ENIAC). 1970s: personal computers. 1990s: World Wide Web. 2000s: smartphones, social media. 2010s: cloud, AI, big data. 2020s: AI/LLM revolution, spatial computing."
    },
    "music": {
      "music theory basics": "Notes: A B C D E F G (+ sharps/flats). Octaves: 12 semitones. Scales: major (bright), minor (dark). Intervals: unison, 2nd, 3rd, 4th, 5th, 6th, 7th, octave.",
      "music chords": "Chord: 3+ notes played together. Major chord: root + major 3rd + perfect 5th (bright). Minor: root + minor 3rd + perfect 5th (sad). 7th chords, suspended chords, inversions.",
      "music rhythm": "Beat: basic pulse. Tempo (BPM): speed. Time signatures: 4/4 (most common), 3/4 (waltz), 6/8. Note values: whole, half, quarter, eighth, sixteenth. Syncopation: off-beat emphasis.",
      "music genres": "Classical (Bach, Mozart, Beethoven), Jazz (improvisation, swing), Blues (12-bar), Rock (electric guitar), Hip-hop (beats, rap), Electronic (synthesizers, EDM), Pop (hooks, verse-chorus)."
    },
    "languages": {
      "learning languages": "Most spoken: Mandarin, Spanish, English, Hindi, Arabic, French, Bengali, Russian, Portuguese, Urdu. Tips: immersion, spaced repetition (Anki), speaking from day 1, comprehensible input.",
      "english grammar": "Parts of speech: noun, verb, adjective, adverb, pronoun, preposition, conjunction, interjection. Tenses: simple, continuous, perfect, perfect continuous. Active/passive voice.",
      "spanish basics": "Hola (hello), gracias (thank you), por favor (please), ¿Cómo estás? (how are you?). Ser vs estar both mean 'to be'. Nouns have gender (masculine/feminine). Verb conjugation by person.",
      "french basics": "Bonjour (hello), merci (thank you), s'il vous plaît (please), Comment allez-vous? (how are you?). Silent letters common. Nasal vowels. Gendered nouns. Liaison between words."
    }
  },
  "debug": {
    "undefined variable": "Declare the variable using let, const, or var before using it.",
    "null reference": "Check if object is null/undefined before accessing properties. Use optional chaining: obj?.property. Use nullish coalescing: value ?? 'default'.",
    "cors error": "Enable Access-Control-Allow-Origin headers on the server. For development use a proxy. In Express: app.use(require('cors')()). CORS is a browser security feature.",
    "python indentation": "Python requires consistent indentation. Use 4 spaces (PEP8 standard). Don't mix tabs and spaces. IndentationError means wrong level.",
    "type error": "TypeError: operating on wrong type. Check variable types with typeof (JS) or type() (Python). Ensure you're not calling non-functions or accessing properties of null.",
    "async not waiting": "Forgetting await: use async/await or .then(). Make sure the containing function is async. In loops use Promise.all([promises]) or for...of with await.",
    "infinite loop": "Check loop condition terminates. Ensure loop variable is modified. For recursion: verify base case exists and is reachable. Use debugger or add console.log to trace.",
    "memory leak": "JS: clear event listeners (removeEventListener), clear intervals (clearInterval), avoid unintended closures holding large data. Node: watch for unclosed connections/streams.",
    "404 not found": "Check URL is correct. Verify route is defined on server. Check file path exists. In SPAs configure server to serve index.html for all routes.",
    "500 server error": "Server-side error. Check server logs. Add try/catch around async operations. Validate input before processing. Return proper error responses with status codes.",
    "git merge conflict": "git status to see conflicted files. Edit files to resolve <<<<<<<, =======, >>>>>>> markers. git add resolved files. git commit to complete merge.",
    "npm install error": "Delete node_modules and package-lock.json, run npm install again. Check Node version (nvm use). Try npm cache clean --force. Check for peer dependency conflicts."
  }
}