diff --git a/.github/workflows/deploy-cloudflare-pages.yml b/.github/workflows/deploy-cloudflare-pages.yml
index 81d5072..21f818c 100644
--- a/.github/workflows/deploy-cloudflare-pages.yml
+++ b/.github/workflows/deploy-cloudflare-pages.yml
@@ -23,11 +23,7 @@ jobs:
           node-version: 20
           cache: npm
       - run: npm ci
-      - run: npm run build
-        env:
-          # Force root basePath: CF Pages serves the site at the project root
-          # (loto.pages.dev), unlike GH Pages which prefixes with /loto.
-          NEXT_BASE_PATH: ""
+      - run: npm run build:cf
       - name: Publish to Cloudflare Pages
         uses: cloudflare/wrangler-action@v3
         with:
diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 0ac60fb..d9382f8 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -24,7 +24,7 @@ jobs:
           node-version: 20
           cache: npm
       - run: npm ci
-      - run: npx next build
+      - run: npm run build:gh
       - uses: actions/upload-pages-artifact@v3
         with:
           path: out
diff --git a/docs/deployment-guide.md b/docs/deployment-guide.md
index fdfe53b..ec520a3 100644
--- a/docs/deployment-guide.md
+++ b/docs/deployment-guide.md
@@ -1,29 +1,45 @@
 # Deployment Guide
 
+## Build Profiles
+
+Two named profiles select the basePath for the deploy target:
+
+| Script | basePath | Target URL |
+|---|---|---|
+| `npm run build:gh` | `/loto` | `https://tiennm99.github.io/loto` |
+| `npm run build:cf` | `""` (root) | `https://loto.miti99.com` |
+| `npm run build` | `/loto` | legacy default — same as `build:gh` |
+
+Implementation: `next.config.mjs` reads `BUILD_PROFILE` (`gh` or `cf`) and
+picks the basePath. `NEXT_BASE_PATH` overrides everything for one-off
+custom-domain builds.
+
 ## Production Deployment
 
-### GitHub Pages (default)
+### GitHub Pages
 
-Auto-deploys from `master` via `.github/workflows/deploy.yml`. Static export is
-written to `out/`, then uploaded as a Pages artifact. Reachable at
-`https://{user}.github.io/loto`.
+Auto-deploys from `master` via `.github/workflows/deploy.yml`. Runs
+`npm run build:gh`, then uploads `out/` as a Pages artifact.
 
-basePath is set to `/loto` because GH Pages serves the project under that path
-prefix. See `next.config.mjs`.
+URL: `https://tiennm99.github.io/loto`. basePath `/loto` because GH Pages
+serves the project under that path prefix.
 
 ### Cloudflare Pages
 
-Two ways to wire it up:
+Custom domain target: `https://loto.miti99.com` (basePath `""`).
 
 **Option A — Dashboard:**
-1. dash.cloudflare.com → Workers & Pages → Create → Pages → Connect to Git → pick the repo
+1. dash.cloudflare.com → Workers & Pages → Create → Pages → Connect to Git
+   → pick the repo
 2. Build settings:
    - Framework preset: `Next.js (Static HTML Export)`
-   - Build command: `npm run build`
+   - Build command: `npm run build:cf`
    - Build output directory: `out`
    - Production branch: `master`
-3. No env vars needed — `next.config.mjs` detects `CF_PAGES=1` (auto-injected by
-   Cloudflare) and switches basePath to root automatically.
+3. After first deploy, add the custom domain:
+   Project → Custom domains → `loto.miti99.com`. Cloudflare gives DNS
+   records to add at your registrar (or auto-configures if `miti99.com` is
+   on Cloudflare DNS).
 
 **Option B — GitHub Actions (`.github/workflows/deploy-cloudflare-pages.yml`):**
 
@@ -32,17 +48,18 @@ Add two repo secrets:
   `Pages — Edit` template
 - `CLOUDFLARE_ACCOUNT_ID` — visible in the dash sidebar
 
-Then push to `master` and the workflow uses `cloudflare/wrangler-action@v3` to
-publish `out/` to a Pages project named `loto`. The workflow sets
-`NEXT_BASE_PATH=""` explicitly so the build produces root-relative asset paths.
+The workflow runs `npm run build:cf`, then publishes `out/` via
+`cloudflare/wrangler-action@v3` to a Pages project named `loto`. Custom
+domain setup is the same dashboard step as Option A — done once.
 
-The two providers can run in parallel — they don't conflict. Disable whichever
-you stop wanting by deleting its workflow file.
+The two providers can run in parallel — different artifacts, different
+URLs. Drop whichever you stop wanting by deleting its workflow file.
 
 ### Manual Deploy
 
 ```bash
-npm run build
+npm run build:gh   # for GH Pages
+npm run build:cf   # for CF Pages / any root-served host
 # out/ directory ready for upload to any static host
 ```
 
diff --git a/next.config.mjs b/next.config.mjs
index 7f6a112..2ef92dd 100644
--- a/next.config.mjs
+++ b/next.config.mjs
@@ -1,8 +1,10 @@
 const isProd = process.env.NODE_ENV === "production";
 const isCodeserver = process.env.NEXT_DEV_PROFILE === "codeserver";
-// Cloudflare Pages injects CF_PAGES=1 during its build; avoid the GH Pages
-// /loto basePath there since CF serves the site at the root.
-const isCfPages = process.env.CF_PAGES === "1";
+
+// Build profiles select basePath for the deploy target:
+//   gh — GitHub Pages, served at tiennm99.github.io/loto
+//   cf — Cloudflare Pages, served at loto.miti99.com (custom domain, root)
+const buildProfile = process.env.BUILD_PROFILE;
 
 // In dev under code-server's reverse proxy, basePath/assetPrefix must match
 // the proxy URL so links, assets, and the HMR socket all resolve.
@@ -21,11 +23,23 @@ function codeserverConfig() {
 }
 
 const cs = isCodeserver ? codeserverConfig() : null;
-// NEXT_BASE_PATH wins so custom-domain / fork deploys don't have to edit code.
+
+// basePath resolution order (first non-null wins):
+//   1. NEXT_BASE_PATH — explicit override (escape hatch for forks / custom domains)
+//   2. codeserver dev profile
+//   3. BUILD_PROFILE=gh|cf — explicit deploy target
+//   4. NODE_ENV=production — legacy fallback (bare `npm run build` → GH Pages)
+//   5. local dev — empty
 const basePath =
   process.env.NEXT_BASE_PATH ??
   cs?.basePath ??
-  (isCfPages ? "" : isProd ? "/loto" : "");
+  (buildProfile === "gh"
+    ? "/loto"
+    : buildProfile === "cf"
+      ? ""
+      : isProd
+        ? "/loto"
+        : "");
 
 const nextConfig = {
   output: "export",
diff --git a/package.json b/package.json
index 7ad817e..905587e 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,8 @@
     "dev": "next dev",
     "dev:codeserver": "NEXT_DEV_PROFILE=codeserver next dev -H 0.0.0.0",
     "build": "next build",
+    "build:gh": "BUILD_PROFILE=gh next build",
+    "build:cf": "BUILD_PROFILE=cf next build",
     "start": "next start",
     "lint": "eslint"
   },