diff --git a/.isu/issues.json b/.isu/issues.json
index 1b3f32d..8d8736e 100644
--- a/.isu/issues.json
+++ b/.isu/issues.json
@@ -1,5 +1,5 @@
 {
-  "next_id": 405,
+  "next_id": 406,
   "issues": [
     {
       "id": 1,
@@ -4949,6 +4949,19 @@
       "author": "piefev",
       "state": "closed",
       "created_at": "2026-07-18T08:05:58Z"
+    },
+    {
+      "id": 405,
+      "repo": "we",
+      "title": "Track remaining opera.com hero and cookie panel parity gap",
+      "body": "Follow-up from isu issue 281 after fixing the mobile-header absolute-positioning offset. The opera.com real-web scenario still fails Chromium screenshot parity.\\n\\nRepro:\\n  cargo run -p we-e2e -- --scenario crates/e2e/scenarios/real-web/opera.com.we --out-dir crates/e2e/artifacts\\n\\nCurrent failures after the header fix:\\n  - Desktop L101: 64.68% match, 433885/1228500 px differ.\\n  - Mobile L113: 68.54% match, 103570/329160 px differ.\\n\\nArtifacts:\\n  - crates/e2e/artifacts/real-web/opera.com/desktop.png\\n  - crates/e2e/artifacts/real-web/opera.com/desktop.png.diff.png\\n  - crates/e2e/artifacts/real-web/opera.com/mobile.png\\n  - crates/e2e/artifacts/real-web/opera.com/mobile.png.diff.png\\n\\nObserved remaining gaps are concentrated in the hero/cookie-panel area: title/hero vertical placement, cookie panel text metrics/height, and lower hero image crop. The mobile header logo/menu now align with the committed Chromium golden, so this should be tracked independently of the flex absolute-positioning fix.",
+      "labels": [
+        "real-web"
+      ],
+      "assigned": [],
+      "author": "piefev",
+      "state": "open",
+      "created_at": "2026-07-18T09:10:52Z"
     }
   ]
 }
diff --git a/crates/e2e/scenarios/real-web/opera.com.we b/crates/e2e/scenarios/real-web/opera.com.we
index 9ae7e93..63aa4c1 100644
--- a/crates/e2e/scenarios/real-web/opera.com.we
+++ b/crates/e2e/scenarios/real-web/opera.com.we
@@ -88,7 +88,6 @@ cache_put opera https://cdn-production-opera-website.operacdn.com/staticfiles/as
 cache_put opera https://cdn-production-opera-website.operacdn.com/staticfiles/assets/images/main/home/opera__home--hero__mobile-android.0ce2e2d9de27.png ../../real-web/snapshots/opera.com/cdn-production-opera-website.operacdn.com/staticfiles/assets/images/main/home/opera__home--hero__mobile-android.0ce2e2d9de27.png image/png
 cache_put opera https://cdn-production-opera-website.operacdn.com/staticfiles/assets/images/main/home/opera__home--hero__mobile-android%402x.239d7c979096.png ../../real-web/snapshots/opera.com/cdn-production-opera-website.operacdn.com/staticfiles/assets/images/main/home/opera__home--hero__mobile-android%402x.239d7c979096.png image/png
 goto_as https://www.opera.com/ crates/e2e/real-web/snapshots/opera.com/index.html
-screenshot real-web/opera.com/desktop.png
 dump_dom real-web/opera.com/desktop_dom.txt
 dump_console real-web/opera.com/desktop_console.txt
 assert_dom_contains "Opera"
@@ -98,11 +97,11 @@ type [id=footer__lang-input-next] interactivity
 dump_dom real-web/opera.com/desktop_interaction_dom.txt
 assert_dom_contains https://www.opera.com/interactivity
 assert_dom_contains survey_container
+screenshot real-web/opera.com/desktop.png
 assert_screenshot_matches real-web/opera.com/desktop.png opera.com.desktop.chromium.expected.png
 
 viewport 390 844
 goto_as https://www.opera.com/ crates/e2e/real-web/snapshots/opera.com/index.html
-screenshot real-web/opera.com/mobile.png
 dump_dom real-web/opera.com/mobile_dom.txt
 dump_console real-web/opera.com/mobile_console.txt
 assert_dom_contains "Opera"
@@ -110,4 +109,5 @@ type [id=footer__lang-input-next] interactivity
 dump_dom real-web/opera.com/mobile_interaction_dom.txt
 assert_dom_contains https://www.opera.com/interactivity
 assert_dom_contains survey_container
+screenshot real-web/opera.com/mobile.png
 assert_screenshot_matches real-web/opera.com/mobile.png opera.com.mobile.chromium.expected.png
diff --git a/crates/layout/src/lib.rs b/crates/layout/src/lib.rs
index ca375e4..d5f941f 100644
--- a/crates/layout/src/lib.rs
+++ b/crates/layout/src/lib.rs
@@ -2633,6 +2633,29 @@ fn padding_box_rect(b: &LayoutBox) -> Rect {
     }
 }
 
+#[derive(Debug, Clone, Copy)]
+struct AbsposStaticContext {
+    rect: Rect,
+    display: Display,
+    flex_direction: FlexDirection,
+    align_items: AlignItems,
+    justify_content: JustifyContent,
+}
+
+fn abspos_static_context(parent: &LayoutBox) -> Option<AbsposStaticContext> {
+    if matches!(parent.display, Display::Flex | Display::InlineFlex) {
+        Some(AbsposStaticContext {
+            rect: parent.rect,
+            display: parent.display,
+            flex_direction: parent.flex_direction,
+            align_items: parent.align_items,
+            justify_content: parent.justify_content,
+        })
+    } else {
+        None
+    }
+}
+
 /// Lay out all absolutely and fixed positioned children of `parent`.
 ///
 /// `abs_cb` is the padding box of the nearest positioned ancestor passed from
@@ -2661,12 +2684,14 @@ fn layout_abspos_children(
     } else {
         abs_cb
     };
+    let static_context = abspos_static_context(parent);
 
     for i in 0..parent.children.len() {
         if parent.children[i].position == Position::Absolute {
             layout_absolute_child(
                 &mut parent.children[i],
                 new_abs_cb,
+                static_context,
                 viewport_width,
                 viewport_height,
                 font,
@@ -2677,6 +2702,54 @@ fn layout_abspos_children(
             layout_absolute_child(
                 &mut parent.children[i],
                 viewport_cb,
+                None,
+                viewport_width,
+                viewport_height,
+                font,
+                font_registry,
+                doc,
+            );
+        }
+    }
+}
+
+/// Recompute out-of-flow descendants after an in-flow subtree has been shifted
+/// from provisional measurement coordinates to its final position.
+///
+/// Flex and grid layout measure items at temporary origins and then offset the
+/// whole item subtree into place. Absolute/fixed descendants do not always use
+/// that item as their containing block, so a blind subtree offset can move them
+/// away from the positioned ancestor or viewport they should remain anchored to.
+fn relayout_out_of_flow_descendants(
+    parent: &mut LayoutBox,
+    inherited_abs_cb: Rect,
+    viewport_width: f32,
+    viewport_height: f32,
+    font: &Font,
+    font_registry: Option<&FontRegistry>,
+    doc: &Document,
+) {
+    layout_abspos_children(
+        parent,
+        inherited_abs_cb,
+        viewport_width,
+        viewport_height,
+        font,
+        font_registry,
+        doc,
+    );
+
+    let child_abs_cb = if parent.position != Position::Static {
+        padding_box_rect(parent)
+    } else {
+        inherited_abs_cb
+    };
+
+    for child in &mut parent.children {
+        if is_in_flow(child) {
+            relayout_out_of_flow_descendants(
+                child,
+                child_abs_cb,
                 viewport_width,
                 viewport_height,
                 font,
@@ -2691,9 +2764,11 @@ fn layout_abspos_children(
 ///
 /// `cb` is the containing block (padding box of nearest positioned ancestor
 /// for absolute, or the viewport for fixed).
+#[allow(clippy::too_many_arguments)]
 fn layout_absolute_child(
     child: &mut LayoutBox,
     cb: Rect,
+    static_context: Option<AbsposStaticContext>,
     viewport_width: f32,
     viewport_height: f32,
     font: &Font,
@@ -2966,8 +3041,9 @@ fn layout_absolute_child(
             - child.padding.bottom
             - child.rect.height
     } else {
-        // Static position: containing block origin.
-        cb.y + child.margin.top + child.border.top + child.padding.top
+        static_context
+            .and_then(|ctx| flex_abspos_static_y(child, ctx))
+            .unwrap_or(cb.y + child.margin.top + child.border.top + child.padding.top)
     };
 
     // Shift from temporary y to final y.
@@ -2996,6 +3072,53 @@ fn layout_absolute_child(
     );
 }
 
+fn flex_abspos_static_y(child: &LayoutBox, ctx: AbsposStaticContext) -> Option<f32> {
+    if !matches!(ctx.display, Display::Flex | Display::InlineFlex) {
+        return None;
+    }
+
+    let is_row = matches!(
+        ctx.flex_direction,
+        FlexDirection::Row | FlexDirection::RowReverse
+    );
+
+    if is_row {
+        let outer_cross = child.margin.top
+            + child.border.top
+            + child.padding.top
+            + child.rect.height
+            + child.padding.bottom
+            + child.border.bottom
+            + child.margin.bottom;
+        let align = match child.align_self {
+            AlignSelf::Auto => ctx.align_items,
+            AlignSelf::FlexStart => AlignItems::FlexStart,
+            AlignSelf::FlexEnd => AlignItems::FlexEnd,
+            AlignSelf::Center => AlignItems::Center,
+            AlignSelf::Baseline => AlignItems::Baseline,
+            AlignSelf::Stretch => AlignItems::Stretch,
+        };
+        let free = ctx.rect.height - outer_cross;
+        let offset = match align {
+            AlignItems::FlexEnd => free,
+            AlignItems::Center => free / 2.0,
+            AlignItems::FlexStart | AlignItems::Stretch | AlignItems::Baseline => 0.0,
+        };
+        Some(ctx.rect.y + offset + child.margin.top + child.border.top + child.padding.top)
+    } else {
+        let outer_main = child.margin.top
+            + child.border.top
+            + child.padding.top
+            + child.rect.height
+            + child.padding.bottom
+            + child.border.bottom
+            + child.margin.bottom;
+        let free = (ctx.rect.height - outer_main).max(0.0);
+        let (initial, _) = compute_content_distribution(ctx.justify_content, free, 1);
+        Some(ctx.rect.y + initial + child.margin.top + child.border.top + child.padding.top)
+    }
+}
+
 fn has_block_children(b: &LayoutBox) -> bool {
     b.children
         .iter()
@@ -5834,11 +5957,33 @@ fn layout_flex_children(
                 let dy = content_cross - child.rect.y;
                 offset_subtree(child, dx, dy);
                 child.rect.width = target_main;
+                if dx != 0.0 || dy != 0.0 {
+                    relayout_out_of_flow_descendants(
+                        child,
+                        abs_cb,
+                        viewport_width,
+                        viewport_height,
+                        font,
+                        font_registry,
+                        doc,
+                    );
+                }
             } else {
                 let dx = content_cross - child.rect.x;
                 let dy = content_main - child.rect.y;
                 offset_subtree(child, dx, dy);
                 child.rect.height = target_main;
+                if dx != 0.0 || dy != 0.0 {
+                    relayout_out_of_flow_descendants(
+                        child,
+                        abs_cb,
+                        viewport_width,
+                        viewport_height,
+                        font,
+                        font_registry,
+                        doc,
+                    );
+                }
             }
 
             if !is_reverse {
@@ -7687,6 +7832,7 @@ fn adjust_fieldset_legend(fieldset: &mut LayoutBox, doc: &Document) {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use we_css::parser::Parser;
     use we_dom::Document;
     use we_style::computed::{extract_stylesheets, resolve_styles};
 
@@ -7705,10 +7851,14 @@ mod tests {
     }
 
     fn layout_doc(doc: &Document) -> LayoutTree {
+        layout_doc_viewport(doc, 800.0, 600.0)
+    }
+
+    fn layout_doc_viewport(doc: &Document, width: f32, height: f32) -> LayoutTree {
         let font = test_font();
         let sheets = extract_stylesheets(doc);
-        let styled = resolve_styles(doc, &sheets, (800.0, 600.0)).unwrap();
-        layout(&styled, doc, 800.0, 600.0, &font, &HashMap::new())
+        let styled = resolve_styles(doc, &sheets, (width, height)).unwrap();
+        layout(&styled, doc, width, height, &font, &HashMap::new())
     }
 
     fn find_box(b: &LayoutBox, node: NodeId) -> Option<&LayoutBox> {
@@ -11294,6 +11444,193 @@ body { margin: 0; }
         assert_eq!(child.rect.y, 24.0);
     }
 
+    #[test]
+    fn absolute_auto_top_in_flex_container_uses_aligned_static_position() {
+        let mut doc = Document::new();
+        let (_, _, body) = make_html_body(&mut doc);
+        let bar = doc.create_element("div");
+        let brand = doc.create_element("a");
+        doc.append_child(body, bar);
+        doc.append_child(bar, brand);
+        doc.set_attribute(body, "style", "margin: 0;");
+        doc.set_attribute(
+            bar,
+            "style",
+            "box-sizing: border-box; display: flex; align-items: center; height: 72px; padding: 16px 20px; position: relative; width: 390px;",
+        );
+        doc.set_attribute(
+            brand,
+            "style",
+            "height: 30px; left: 18px; position: absolute; width: 82px;",
+        );
+        let tree = layout_doc(&doc);
+
+        let brand = find_box(&tree.root, brand).expect("brand box");
+
+        assert!((brand.rect.x - 18.0).abs() < 0.01);
+        assert!(
+            (brand.rect.y - 21.0).abs() < 0.01,
+            "auto top should use centered flex static position, got {}",
+            brand.rect.y
+        );
+    }
+
+    #[test]
+    fn nested_fixed_header_absolute_mobile_bar_stays_at_viewport_top() {
+        let mut doc = Document::new();
+        let (_, _, body) = make_html_body(&mut doc);
+        let fixed = doc.create_element("header");
+        let wrapper = doc.create_element("div");
+        let mobile = doc.create_element("div");
+        let brand = doc.create_element("a");
+        doc.append_child(body, fixed);
+        doc.append_child(fixed, wrapper);
+        doc.append_child(wrapper, mobile);
+        doc.append_child(mobile, brand);
+        doc.set_attribute(body, "style", "margin: 0;");
+        doc.set_attribute(
+            fixed,
+            "style",
+            "left: 0; min-height: 104px; position: fixed; top: 0; width: 390px;",
+        );
+        doc.set_attribute(
+            wrapper,
+            "style",
+            "box-sizing: border-box; display: flex; height: 72px; padding: 16px 0; position: relative; width: 390px;",
+        );
+        doc.set_attribute(
+            mobile,
+            "style",
+            "align-items: center; box-sizing: border-box; display: flex; height: 72px; left: 0; padding: 16px 20px; position: absolute; top: 0; width: 390px;",
+        );
+        doc.set_attribute(
+            brand,
+            "style",
+            "height: 30px; left: 18px; position: absolute; width: 82px;",
+        );
+        let tree = layout_doc(&doc);
+
+        let mobile = find_box(&tree.root, mobile).expect("mobile bar");
+        let brand = find_box(&tree.root, brand).expect("brand box");
+
+        assert!(
+            (mobile.rect.y - 16.0).abs() < 0.01,
+            "mobile bar content y should be its 16px top padding, got {}",
+            mobile.rect.y
+        );
+        assert!(
+            (brand.rect.y - 21.0).abs() < 0.01,
+            "brand should center in the viewport-top mobile bar, got {}",
+            brand.rect.y
+        );
+    }
+
+    #[test]
+    fn opera_mobile_header_ignores_unmatched_navigation_sibling_rule() {
+        let mut doc = Document::new();
+        let (_, _, body) = make_html_body(&mut doc);
+        let fixed = doc.create_element("header");
+        let nav = doc.create_element("div");
+        let wrapper = doc.create_element("div");
+        let desktop_brand = doc.create_element("a");
+        let menu = doc.create_element("div");
+        let mobile = doc.create_element("div");
+        let brand = doc.create_element("a");
+        let logo = doc.create_element("img");
+        doc.append_child(body, fixed);
+        doc.append_child(fixed, nav);
+        doc.append_child(nav, wrapper);
+        doc.append_child(wrapper, desktop_brand);
+        doc.append_child(wrapper, menu);
+        doc.append_child(wrapper, mobile);
+        doc.append_child(mobile, brand);
+        doc.append_child(brand, logo);
+        doc.set_attribute(body, "style", "margin: 0;");
+        doc.set_attribute(fixed, "class", "hf hf__header active");
+        doc.set_attribute(nav, "class", "header ");
+        doc.set_attribute(wrapper, "class", "header__wrapper container-fluid wrapper");
+        doc.set_attribute(desktop_brand, "class", "header__brand");
+        doc.set_attribute(menu, "class", "header__menu");
+        doc.set_attribute(mobile, "class", "header__mobile container-fluid");
+        doc.set_attribute(brand, "class", "header__mobile__brand");
+        doc.set_attribute(logo, "width", "274");
+        doc.set_attribute(logo, "height", "100");
+        doc.set_attribute(
+            logo,
+            "style",
+            "height: 30px; width: auto; aspect-ratio: 274/100;",
+        );
+        let css = r#"
+body { margin: 0; }
+header.hf__header {
+    left: 0;
+    min-height: 104px;
+    position: fixed;
+    top: 0;
+    width: 390px;
+}
+.header {
+    box-sizing: border-box;
+    display: flex;
+    height: 104px;
+    padding: 24px 0;
+    position: relative;
+}
+.header__wrapper {
+    align-items: center;
+    display: flex;
+    flex-direction: row;
+    flex-wrap: wrap;
+    width: 100%;
+}
+.header__mobile { display: none; }
+@media(max-width:1223px) {
+    .header { height: 72px; }
+    .header__mobile {
+        align-items: center;
+        box-sizing: border-box;
+        display: flex;
+        height: 72px;
+        left: 0;
+        padding: 16px 20px;
+        position: absolute;
+        top: 0;
+        width: 100vw;
+    }
+    .header__mobile__brand {
+        display: block;
+        left: 18px;
+        position: absolute;
+    }
+    .header__brand { display: none; }
+}
+.header__navigation-top~.header__mobile {
+    height: 100px;
+    padding-top: 44px;
+}
+"#;
+        let font = test_font();
+        let stylesheet = Parser::parse(css);
+        let styled = resolve_styles(&doc, &[stylesheet], (390.0, 844.0)).unwrap();
+        let mut image_sizes = HashMap::new();
+        image_sizes.insert(logo, ReplacedContent::Size(274.0, 100.0));
+        let tree = layout(&styled, &doc, 390.0, 844.0, &font, &image_sizes);
+
+        let mobile = find_box(&tree.root, mobile).expect("mobile bar");
+        let logo = find_box(&tree.root, logo).expect("mobile logo");
+
+        assert!(
+            (mobile.rect.y - 16.0).abs() < 0.01,
+            "unmatched sibling rule must not change header padding, got {}",
+            mobile.rect.y
+        );
+        assert!(
+            logo.rect.y < 24.0,
+            "logo should stay in the viewport-top mobile header, got {}",
+            logo.rect.y
+        );
+    }
+
     // -----------------------------------------------------------------------
     // Absolute positioning tests
     // -----------------------------------------------------------------------
diff --git a/crates/style/src/matching.rs b/crates/style/src/matching.rs
index 765e12e..3e7932f 100644
--- a/crates/style/src/matching.rs
+++ b/crates/style/src/matching.rs
@@ -982,6 +982,27 @@ mod tests {
 
         let sel2 = parse_first_selector("p.intro ~ a {}");
         assert!(matches_selector(&t.doc, t.a_link, &sel2));
+
+        let sel3 = parse_first_selector(".intro~a {}");
+        assert!(matches_selector(&t.doc, t.a_link, &sel3));
+
+        let sel4 = parse_first_selector(".missing~a {}");
+        assert!(!matches_selector(&t.doc, t.a_link, &sel4));
+    }
+
+    #[test]
+    fn general_sibling_class_selector_does_not_match_without_previous_sibling() {
+        let mut doc = Document::new();
+        let root = doc.root();
+        let parent = doc.create_element("div");
+        let mobile = doc.create_element("div");
+        doc.append_child(root, parent);
+        doc.append_child(parent, mobile);
+        doc.set_attribute(mobile, "class", "header__mobile container-fluid");
+
+        let sel = parse_first_selector(".header__navigation-top~.header__mobile {}");
+
+        assert!(!matches_selector(&doc, mobile, &sel));
     }
 
     // -----------------------------------------------------------------------