diff --git a/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties.rs b/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties.rs
index 4a46349585..e5f4835b0f 100644
--- a/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties.rs
+++ b/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties.rs
@@ -1,5 +1,7 @@
 use super::*;
 
+mod background;
+
 pub(in crate::native_bridge::element::styles) fn style_property_value_with_context(
     runtime: &JsContextHost,
     handle: DomHandle,
@@ -105,6 +107,9 @@ pub(super) fn computed_style_property_value_after_style_update(
     if property == "font-variant" {
         return computed_font_variant_shorthand_value(runtime, handle, resolution);
     }
+    if property == "background" {
+        return background::computed_shorthand(runtime, handle, resolution);
+    }
     if property == "mask" {
         return computed_mask_shorthand_value(runtime, handle, resolution);
     }
diff --git a/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties/background.rs b/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties/background.rs
new file mode 100644
index 0000000000..927af2f2e7
--- /dev/null
+++ b/moli-renderer-v8/src/native_bridge/element/styles/declaration/values/computed_properties/background.rs
@@ -0,0 +1,67 @@
+use super::*;
+
+/// CSSOM serializes the coordinated background layers, including initial
+/// components. Specified-value shorthand serialization would omit those parts.
+pub(super) fn computed_shorthand(
+    runtime: &JsContextHost,
+    handle: DomHandle,
+    resolution: StyleResolutionContext<'_>,
+) -> String {
+    let [
+        Some(images),
+        Some(repeats),
+        Some(attachments),
+        Some(positions_x),
+        Some(positions_y),
+        Some(sizes),
+        Some(origins),
+        Some(clips),
+    ] = [
+        "background-image",
+        "background-repeat",
+        "background-attachment",
+        "background-position-x",
+        "background-position-y",
+        "background-size",
+        "background-origin",
+        "background-clip",
+    ]
+    .map(|property| {
+        top_level_comma_separated_component_values(
+            &resolution.computed_property(runtime, handle, property),
+        )
+        .filter(|values| !values.is_empty())
+    })
+    else {
+        return String::new();
+    };
+    let color = resolution.computed_property(runtime, handle, "background-color");
+    images
+        .iter()
+        .enumerate()
+        .map(|(index, image)| {
+            // The image list controls the layer count. Other lists repeat or
+            // truncate to that count, and only the final layer carries color.
+            let color = if index + 1 == images.len() {
+                format!("{color} ")
+            } else {
+                String::new()
+            };
+            format!(
+                "{color}{image} {} {} {} {} / {} {} {}",
+                layer_value(&repeats, index),
+                layer_value(&attachments, index),
+                layer_value(&positions_x, index),
+                layer_value(&positions_y, index),
+                layer_value(&sizes, index),
+                layer_value(&origins, index),
+                layer_value(&clips, index),
+            )
+        })
+        .collect::<Vec<_>>()
+        .join(", ")
+}
+
+fn layer_value(values: &[String], index: usize) -> &str {
+    &values[index % values.len()]
+}
diff --git a/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style.rs b/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style.rs
index 854b983bdc..4d936e5573 100644
--- a/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style.rs
+++ b/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style.rs
@@ -58,6 +58,7 @@ mod advanced_style_values;
 mod computed_style_access;
 mod content_and_invalidation;
 mod cross_document_and_animations;
+mod css_computed_background;
 mod css_computed_map_enumeration;
 mod nested_document_invalidation;
 mod properties_and_selectors;
diff --git a/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style/css_computed_background.js b/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style/css_computed_background.js
new file mode 100644
index 0000000000..e1ad052488
--- /dev/null
+++ b/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style/css_computed_background.js
@@ -0,0 +1,33 @@
+(() => {
+    const check = (ok, message) => {if (!ok) throw new Error(message);};
+    const cases = [
+        ['', 'rgba(0, 0, 0, 0) none repeat scroll 0% 0% / auto padding-box border-box'],
+        ['background:blue', 'rgb(0, 0, 255) none repeat scroll 0% 0% / auto padding-box border-box'],
+        ['color:red;background:currentcolor', 'rgb(255, 0, 0) none repeat scroll 0% 0% / auto padding-box border-box'],
+        ['background:blue content-box', 'rgb(0, 0, 255) none repeat scroll 0% 0% / auto content-box content-box'],
+        ['background:blue;background-repeat:no-repeat,repeat', 'rgb(0, 0, 255) none no-repeat scroll 0% 0% / auto padding-box border-box'],
+        ['background-image:none,none;background-color:blue', 'none repeat scroll 0% 0% / auto padding-box border-box, rgb(0, 0, 255) none repeat scroll 0% 0% / auto padding-box border-box'],
+        ['background-image:none,none;background-size:10px,20px,30px', 'none repeat scroll 0% 0% / 10px auto padding-box border-box, rgba(0, 0, 0, 0) none repeat scroll 0% 0% / 20px auto padding-box border-box'],
+        ['background:blue;background-position-x:10%;background-position-y:20%', 'rgb(0, 0, 255) none repeat scroll 10% 20% / auto padding-box border-box'],
+        ['background-image:linear-gradient(red,blue),linear-gradient(black,white);background-repeat:no-repeat', 'linear-gradient(rgb(255, 0, 0), rgb(0, 0, 255)) no-repeat scroll 0% 0% / auto padding-box border-box, rgba(0, 0, 0, 0) linear-gradient(rgb(0, 0, 0), rgb(255, 255, 255)) no-repeat scroll 0% 0% / auto padding-box border-box'],
+    ];
+    for (const [text, expected] of cases) {
+        const element = document.createElement('div');
+        element.style.cssText = text;
+        document.body.append(element);
+        const style = getComputedStyle(element);
+        check(style.background === expected, text + ': ' + style.background);
+        element.remove();
+    }
+    const element = document.createElement('div');
+    element.style.background = 'blue'; document.body.append(element);
+    const computed = getComputedStyle(element);
+    const previous = computed.background;
+    element.style.backgroundColor = 'red';
+    check(String(previous).startsWith('rgb(0, 0, 255) '), 'retained value is immutable');
+    check(computed.background.startsWith('rgb(255, 0, 0) '), 'retained declaration observes mutations');
+    check(computed.backgroundImage === 'none', 'longhand value preserved');
+    element.remove();
+    check(computed.background === '', 'inactive owner is empty');
+    return true;
+})()
diff --git a/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style/css_computed_background.rs b/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style/css_computed_background.rs
new file mode 100644
index 0000000000..05b4c85aab
--- /dev/null
+++ b/moli-renderer-v8/src/script_vm/tests/dom_xhr/computed_style/css_computed_background.rs
@@ -0,0 +1,10 @@
+use super::*;
+
+#[test]
+fn css_computed_background_preserves_coordinated_layers() {
+    let mut vm = new_parsed_test_vm("https://computed-background.test/", "<!doctype html><body>");
+    assert_eq!(
+        vm.eval(include_str!("css_computed_background.js")).unwrap(),
+        "true"
+    );
+}