use theme colors

Author: mbostock

docs/features/marks.md

@@ -363,12 +363,12 @@ Not all mark options can be expressed as channels. For example, **stroke** can b
 To vary the definition of a constant option with data, create multiple marks with your different constant options, and then filter the data for each mark to achieve the desired result.
 :::
 
-Some options can be either a channel or a constant depending on the provided value. For example, if you set the **fill** option to *steelblue*, Plot interprets it as a literal color.
+Some options can be either a channel or a constant depending on the provided value. For example, if you set the **fill** option to *purple*, Plot interprets it as a literal color.
 
 :::plot https://observablehq.com/@observablehq/plot-marks-have-channels
 ```js
 Plot
-  .barX(timeseries, {x: "population", y: "year", fill: "steelblue"})
+  .barX(timeseries, {x: "population", y: "year", fill: "purple"})
   .plot({y: {label: null, tickFormat: ""}})
 ```
 :::

docs/marks/density.md

@@ -37,8 +37,8 @@ The **density mark** shows the [estimated density](https://en.wikipedia.org/wiki
 Plot.plot({
   inset: 10,
   marks: [
-    Plot.density(faithful, {x: "waiting", y: "eruptions", stroke: "steelblue", strokeWidth: 0.25}),
-    Plot.density(faithful, {x: "waiting", y: "eruptions", stroke: "steelblue", thresholds: 4}),
+    Plot.density(faithful, {x: "waiting", y: "eruptions", stroke: "blue", strokeWidth: 0.25}),
+    Plot.density(faithful, {x: "waiting", y: "eruptions", stroke: "blue", thresholds: 4}),
     Plot.dot(faithful, {x: "waiting", y: "eruptions", fill: "currentColor", r: 1.5})
   ]
 })
@@ -97,8 +97,8 @@ Plot.plot({
   height: 100,
   inset: 10,
   marks: [
-    Plot.density(faithful, {x: "waiting", stroke: "steelblue", strokeWidth: 0.25, bandwidth: 10}),
-    Plot.density(faithful, {x: "waiting", stroke: "steelblue", thresholds: 4, bandwidth: 10}),
+    Plot.density(faithful, {x: "waiting", stroke: "blue", strokeWidth: 0.25, bandwidth: 10}),
+    Plot.density(faithful, {x: "waiting", stroke: "blue", thresholds: 4, bandwidth: 10}),
     Plot.dot(faithful, {x: "waiting", fill: "currentColor", r: 1.5})
   ]
 })

docs/why-plot.md

@@ -124,7 +124,7 @@ You can use this composite mark like any built-in mark:
 
 :::plot https://observablehq.com/@observablehq/plot-arealiney-custom-mark
 ```js
-arealineY(aapl, {x: "Date", y: "Close", color: "steelblue"}).plot()
+arealineY(aapl, {x: "Date", y: "Close", color: "blue"}).plot()
 ```
 :::