diff --git a/README.md b/README.md
index ee00d5cf..d485ac8b 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ Pretext serves 2 use cases:
 import { prepare, layout } from '@chenglou/pretext'
 
 const prepared = prepare('AGI 春天到了. بدأت الرحلة 🚀', '16px Inter')
-const { height, lineCount } = layout(prepared, textWidth, 20) // pure arithmetics. No DOM layout & reflow!
+const { height, lineCount } = layout(prepared, 320, 20) // pure arithmetics. No DOM layout & reflow!
 ```
 
 `prepare()` does the one-time work: normalize whitespace, segment the text, apply glue rules, measure the segments with canvas, and return an opaque handle. `layout()` is the cheap hot path after that: pure arithmetic over cached widths. Do not rerun `prepare()` for the same text and configs; that'd defeat its precomputation. For example, on resize, only rerun `layout()`.