diff --git a/docs/public/specs/esm/line-multi-series.js b/docs/public/specs/esm/line-multi-series.js
index a3e404e9..9d23d973 100644
--- a/docs/public/specs/esm/line-multi-series.js
+++ b/docs/public/specs/esm/line-multi-series.js
@@ -15,8 +15,8 @@ export default vg.plot(
       y: "unemployment",
       z: "division",
       stroke: "steelblue",
-      curve: "monotone-x",
-      mixBlendMode: "multiply"
+      strokeOpacity: 0.9,
+      curve: "monotone-x"
     }
   ),
   vg.nearestX({channels: ["z"], as: $curr}),
diff --git a/docs/public/specs/esm/region-tests.js b/docs/public/specs/esm/region-tests.js
index 2aca05c1..e0f61776 100644
--- a/docs/public/specs/esm/region-tests.js
+++ b/docs/public/specs/esm/region-tests.js
@@ -22,8 +22,8 @@ export default vg.vconcat(
         y: "unemployment",
         z: "division",
         stroke: "steelblue",
-        curve: "monotone-x",
-        mixBlendMode: "multiply"
+        strokeOpacity: 0.9,
+        curve: "monotone-x"
       }
     ),
     vg.region({channels: ["z"], as: $series}),
diff --git a/docs/public/specs/json/line-multi-series.json b/docs/public/specs/json/line-multi-series.json
index b9f62040..2560ba5c 100644
--- a/docs/public/specs/json/line-multi-series.json
+++ b/docs/public/specs/json/line-multi-series.json
@@ -26,8 +26,8 @@
       "y": "unemployment",
       "z": "division",
       "stroke": "steelblue",
-      "curve": "monotone-x",
-      "mixBlendMode": "multiply"
+      "strokeOpacity": 0.9,
+      "curve": "monotone-x"
     },
     {
       "select": "nearestX",
diff --git a/docs/public/specs/json/region-tests.json b/docs/public/specs/json/region-tests.json
index 9454e75d..cf7432fb 100644
--- a/docs/public/specs/json/region-tests.json
+++ b/docs/public/specs/json/region-tests.json
@@ -52,8 +52,8 @@
           "y": "unemployment",
           "z": "division",
           "stroke": "steelblue",
-          "curve": "monotone-x",
-          "mixBlendMode": "multiply"
+          "strokeOpacity": 0.9,
+          "curve": "monotone-x"
         },
         {
           "select": "region",
diff --git a/docs/public/specs/yaml/line-multi-series.yaml b/docs/public/specs/yaml/line-multi-series.yaml
index 101be16f..4aca35a6 100644
--- a/docs/public/specs/yaml/line-multi-series.yaml
+++ b/docs/public/specs/yaml/line-multi-series.yaml
@@ -20,8 +20,8 @@ plot:
     y: unemployment
     z: division
     stroke: steelblue
+    strokeOpacity: 0.9
     curve: monotone-x
-    mixBlendMode: multiply
   - { select: nearestX, channels: ['z'], as: $curr }
   - { select: highlight, by: $curr }
   - mark: dot
diff --git a/docs/public/specs/yaml/region-tests.yaml b/docs/public/specs/yaml/region-tests.yaml
index f77e8c58..0dfebb04 100644
--- a/docs/public/specs/yaml/region-tests.yaml
+++ b/docs/public/specs/yaml/region-tests.yaml
@@ -30,8 +30,8 @@ vconcat:
     y: unemployment
     z: division
     stroke: steelblue
+    strokeOpacity: 0.9
     curve: monotone-x
-    mixBlendMode: multiply
   - select: region
     channels: [z]
     as: $series
diff --git a/specs/esm/line-multi-series.js b/specs/esm/line-multi-series.js
index a3e404e9..9d23d973 100644
--- a/specs/esm/line-multi-series.js
+++ b/specs/esm/line-multi-series.js
@@ -15,8 +15,8 @@ export default vg.plot(
       y: "unemployment",
       z: "division",
       stroke: "steelblue",
-      curve: "monotone-x",
-      mixBlendMode: "multiply"
+      strokeOpacity: 0.9,
+      curve: "monotone-x"
     }
   ),
   vg.nearestX({channels: ["z"], as: $curr}),
diff --git a/specs/esm/region-tests.js b/specs/esm/region-tests.js
index 2aca05c1..e0f61776 100644
--- a/specs/esm/region-tests.js
+++ b/specs/esm/region-tests.js
@@ -22,8 +22,8 @@ export default vg.vconcat(
         y: "unemployment",
         z: "division",
         stroke: "steelblue",
-        curve: "monotone-x",
-        mixBlendMode: "multiply"
+        strokeOpacity: 0.9,
+        curve: "monotone-x"
       }
     ),
     vg.region({channels: ["z"], as: $series}),
diff --git a/specs/json/line-multi-series.json b/specs/json/line-multi-series.json
index 7cc0db00..412d1160 100644
--- a/specs/json/line-multi-series.json
+++ b/specs/json/line-multi-series.json
@@ -32,8 +32,8 @@
       "y": "unemployment",
       "z": "division",
       "stroke": "steelblue",
-      "curve": "monotone-x",
-      "mixBlendMode": "multiply"
+      "strokeOpacity": 0.9,
+      "curve": "monotone-x"
     },
     {
       "select": "nearestX",
diff --git a/specs/json/region-tests.json b/specs/json/region-tests.json
index 7026e196..5939c7c4 100644
--- a/specs/json/region-tests.json
+++ b/specs/json/region-tests.json
@@ -53,8 +53,8 @@
           "y": "unemployment",
           "z": "division",
           "stroke": "steelblue",
-          "curve": "monotone-x",
-          "mixBlendMode": "multiply"
+          "strokeOpacity": 0.9,
+          "curve": "monotone-x"
         },
         {
           "select": "region",
diff --git a/specs/ts/line-multi-series.ts b/specs/ts/line-multi-series.ts
index 4c7b6118..db0bd9ce 100644
--- a/specs/ts/line-multi-series.ts
+++ b/specs/ts/line-multi-series.ts
@@ -28,8 +28,8 @@ export const spec : Spec = {
       "y": "unemployment",
       "z": "division",
       "stroke": "steelblue",
-      "curve": "monotone-x",
-      "mixBlendMode": "multiply"
+      "strokeOpacity": 0.9,
+      "curve": "monotone-x"
     },
     {
       "select": "nearestX",
diff --git a/specs/ts/region-tests.ts b/specs/ts/region-tests.ts
index 468e8e80..1776f5c4 100644
--- a/specs/ts/region-tests.ts
+++ b/specs/ts/region-tests.ts
@@ -54,8 +54,8 @@ export const spec : Spec = {
           "y": "unemployment",
           "z": "division",
           "stroke": "steelblue",
-          "curve": "monotone-x",
-          "mixBlendMode": "multiply"
+          "strokeOpacity": 0.9,
+          "curve": "monotone-x"
         },
         {
           "select": "region",
diff --git a/specs/yaml/line-multi-series.yaml b/specs/yaml/line-multi-series.yaml
index 101be16f..4aca35a6 100644
--- a/specs/yaml/line-multi-series.yaml
+++ b/specs/yaml/line-multi-series.yaml
@@ -20,8 +20,8 @@ plot:
     y: unemployment
     z: division
     stroke: steelblue
+    strokeOpacity: 0.9
     curve: monotone-x
-    mixBlendMode: multiply
   - { select: nearestX, channels: ['z'], as: $curr }
   - { select: highlight, by: $curr }
   - mark: dot
diff --git a/specs/yaml/region-tests.yaml b/specs/yaml/region-tests.yaml
index f77e8c58..0dfebb04 100644
--- a/specs/yaml/region-tests.yaml
+++ b/specs/yaml/region-tests.yaml
@@ -30,8 +30,8 @@ vconcat:
     y: unemployment
     z: division
     stroke: steelblue
+    strokeOpacity: 0.9
     curve: monotone-x
-    mixBlendMode: multiply
   - select: region
     channels: [z]
     as: $series