attempt to make a concept

Author: davidsgrogan

css-fonts-5/Overview.bs

@@ -76,13 +76,19 @@ For readability they have not been repeated explicitly.
 <h2 id="text-scale-meta">
 Text-Scale <code class=html>&lt;meta&gt;</code> element</h2>
 
+The <dfn>text scale factor</dfn> is a multiplier
+used to calculate the computed value of the ''font-size/medium'' font size.
+The computed value of ''font-size/medium''
+is 16px
+multiplied by the [=text scale factor=].
+This factor consequently
+scales the computed size of the other <<absolute-size>> keywords.
+
 A document with a <{meta}> tag
 whose <{meta/name}> attribute
 is a <a>ASCII case-insensitive</a> match for
 <dfn lt=text-scale><code>"text-scale"</code></dfn>
-is recognized as setting the computed value
-of the ''font-size/medium'' font size
-and consequently scaling the computed size of the other <<absolute-size>> keywords.
+is recognized as controlling the [=text scale factor=].
 
 Issue(12475):
 
@@ -123,10 +129,8 @@ The recognized keywords in the [=text-scale=]
 <h3 id="legacy-keyword">The 'legacy' keyword</h3>
 
 When the value of the [=text-scale=] content attribute is
-[=text-scale/legacy=]
-the user agent must set the computed ''font-size/medium'' font size
-to 16px multiplied by
-the font scale factor
+[=text-scale/legacy=],
+the [=text scale factor=] is the font scale factor
 the user has chosen from any settings <i>provided by the user agent</i>.
 The ''preferred-text-scale'' environment variable value must be 1 on desktop platforms.
 On mobile:
@@ -151,12 +155,12 @@ The <dfn for="text-scale" export><code>scale</code></dfn> property is
 recognized in the [=text-scale=] content attribute value.
 
 When the value of the [=text-scale=] content attribute is
-<a for=text-scale>scale</a>
-computed ''font-size/medium'' font size must match the user's preferred paragraph text size as determined from a combination of OS and UA preferences.
+<a for=text-scale>scale</a>,
+the [=text scale factor=] matches the user's preferred paragraph text size
+(as determined from a combination of OS and UA preferences)
+divided by 16px.
 
-The ''env()/preferred-text-scale'' environment variable must return a number that,
-when multiplied by 16px,
-provides a <<length>> that matches that of the ''font-size/medium'' font size.
+The ''env()/preferred-text-scale'' environment variable must return the [=text scale factor=].
 
 Further, when the value of the [=text-scale=] content attribute is
 <a for=text-scale>scale</a>, the user agent should skip all font-sizing interventions it would otherwise perform in an attempt to automatically honor the user's preferences. E.g. text autosizing on mobile (See [[css-size-adjust#intro]]) and full-application zoom (<a href="https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/env-preferred-text-scale.md#windows-11">popular browsers do this on Windows)</a>.