Merge pull request #1380 from huaninstratech/pr/io-locked-drawings

fix(io): open locked, shrinking and cloud-placeholder drawings without crashing

src/app/update/viewport.rs

@@ -5511,9 +5511,10 @@ properties={:.1}ms picked={}",
         }
         let eye_dir = r_ucs.transform_vector3(region.snap_direction());
 
-        // Faces snap to a canonical upright orientation (never upside
-        // down); edges/corners keep the current up-sense so they spin
-        // smoothly around the clicked feature.
+        // Faces and edges/corners all snap deterministically (world +Z
+        // horizon, north +Y for top/bottom) so a cube click is repeatable
+        // and matches the turntable orbit; snap_to_direction preserves an
+        // intentional upside-down sense by sign-flipping only.
         let is_face = matches!(region, scene::CubeRegion::Face(_));
         if self.tabs[i].scene.active_viewport.is_some() {
             if is_face {

src/io/mod.rs

@@ -319,10 +319,24 @@ async fn open_path_with_phase_attempt(
                     });
                     callback
                 };
-                std::fs::File::open(&path2).map_err(|error| OpenAttemptFailure {
-                    message: format!("failed to open drawing: {error}"),
-                    read_stats: None,
-                    recoverable: false,
+                std::fs::File::open(&path2).map_err(|error| {
+                    // 32 = ERROR_SHARING_VIOLATION, 33 = ERROR_LOCK_VIOLATION:
+                    // another program holds the drawing without read sharing,
+                    // so nothing on the machine can read the bytes until it
+                    // closes the file — not even read-only.
+                    let message = match error.raw_os_error() {
+                        Some(32) | Some(33) => format!(
+                            "\"{}\" is in use by another program. Close the file there and \
+                             reopen it here, or open a copy of the file.",
+                            path2.display()
+                        ),
+                        _ => format!("failed to open drawing: {error}"),
+                    };
+                    OpenAttemptFailure {
+                        message,
+                        read_stats: None,
+                        recoverable: false,
+                    }
                 })?;
                 let outcome = load_file_for_open(&path2, Some(parser_progress), &attempt)?;
                 let read_stats = outcome.stats;
@@ -1036,20 +1050,117 @@ fn read_dwg_path(
         DwgReadOptions::default()
     };
     #[cfg(not(target_arch = "wasm32"))]
-    let mut reader = {
-        let mut reader = DwgReader::from_mmap(path).map_err(ReaderFailure::from_reader)?;
-        reader.options = options;
+    {
+        // The memory-mapped read is the fast path, but a mapped file is read
+        // through the page-fault handler: a file that shrinks while mapped
+        // (a writer saving over it) or a cloud placeholder that cannot page
+        // in raises an in-page exception the process cannot catch. Both are
+        // ordinary I/O errors through plain reads, so anything that can
+        // fault — or refuses to open under a third-party lock — falls back
+        // to one in-memory snapshot read below.
+        if !cloud_placeholder(path) {
+            match DwgReader::from_mmap(path) {
+                Ok(mut reader) => {
+                    reader.options = options.clone();
+                    if let Some(progress) = &progress {
+                        reader.set_progress_callback(progress.clone());
+                    }
+                    match reader.read_with_stats() {
+                        Ok(outcome) => return Ok(outcome),
+                        // The file shrank or became unreadable mid-parse;
+                        // retry from a snapshot instead of reporting a bare
+                        // I/O error.
+                        Err(acadrust::DxfError::Io(_)) => {}
+                        Err(error) => return Err(ReaderFailure::from_reader(error)),
+                    }
+                }
+                // Locked or unmappable: the snapshot read surfaces the real
+                // error when the file genuinely cannot be read.
+                Err(_) => {}
+            }
+        }
+        let bytes = read_drawing_snapshot(path).map_err(|error| {
+            ReaderFailure::terminal(format!(
+                "failed to open drawing (is it in use by another program?): {error}"
+            ))
+        })?;
+        let mut reader = DwgReader::from_stream_with_options(std::io::Cursor::new(bytes), options);
+        if let Some(progress) = progress {
+            reader.set_progress_callback(progress);
+        }
         reader
-    };
+            .read_with_stats()
+            .map_err(ReaderFailure::from_reader)
+    }
     #[cfg(target_arch = "wasm32")]
-    let mut reader = DwgReader::from_file_with_options(path, options)
-        .map_err(ReaderFailure::from_reader)?;
-    if let Some(progress) = progress {
-        reader.set_progress_callback(progress);
+    {
+        let mut reader = DwgReader::from_file_with_options(path, options)
+            .map_err(ReaderFailure::from_reader)?;
+        if let Some(progress) = progress {
+            reader.set_progress_callback(progress);
+        }
+        reader
+            .read_with_stats()
+            .map_err(ReaderFailure::from_reader)
+    }
+}
+
+/// Windows cloud-placeholder files (OneDrive "Files On Demand" and similar)
+/// page their bytes in on demand; faulting a placeholder through a memory map
+/// can raise an in-page exception that kills the process. Plain reads hydrate
+/// the file instead. Checks `FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS`,
+/// `FILE_ATTRIBUTE_RECALL_ON_OPEN` and `FILE_ATTRIBUTE_OFFLINE`.
+#[cfg(all(not(target_arch = "wasm32"), target_os = "windows"))]
+fn cloud_placeholder(path: &Path) -> bool {
+    use std::os::windows::fs::MetadataExt;
+
+    const FILE_ATTRIBUTE_OFFLINE: u32 = 0x1000;
+    const FILE_ATTRIBUTE_RECALL_ON_OPEN: u32 = 0x0004_0000;
+    const FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS: u32 = 0x0040_0000;
+    std::fs::metadata(path)
+        .map(|meta| {
+            let attrs = meta.file_attributes();
+            attrs
+                & (FILE_ATTRIBUTE_OFFLINE
+                    | FILE_ATTRIBUTE_RECALL_ON_OPEN
+                    | FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS)
+                != 0
+        })
+        .unwrap_or(false)
+}
+
+#[cfg(all(not(target_arch = "wasm32"), not(target_os = "windows")))]
+fn cloud_placeholder(_path: &Path) -> bool {
+    false
+}
+
+/// Read the whole drawing through the most permissive share mode the platform
+/// offers. On Windows `std::fs::read` opens without `FILE_SHARE_DELETE`, so a
+/// concurrent atomic-save replace makes the read fail even though every byte
+/// was readable. A snapshot can never fault: a writer shrinking the file
+/// mid-read just ends the read early.
+#[cfg(not(target_arch = "wasm32"))]
+fn read_drawing_snapshot(path: &Path) -> std::io::Result<Vec<u8>> {
+    #[cfg(target_os = "windows")]
+    {
+        use std::io::Read;
+        use std::os::windows::fs::OpenOptionsExt;
+        use windows_sys::Win32::Storage::FileSystem::{
+            FILE_SHARE_DELETE, FILE_SHARE_READ, FILE_SHARE_WRITE,
+        };
+
+        let mut file = std::fs::OpenOptions::new()
+            .read(true)
+            .share_mode(FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE)
+            .open(path)?;
+        let mut bytes = Vec::new();
+        file.read_to_end(&mut bytes)?;
+        Ok(bytes)
+    }
+    #[cfg(not(target_os = "windows"))]
+    {
+        std::fs::read(path)
     }
-    reader
-        .read_with_stats()
-        .map_err(ReaderFailure::from_reader)
 }
 
 fn read_dxf_path(path: &Path, failsafe: bool) -> Result<acadrust::ReadOutcome, ReaderFailure> {

src/scene/pipeline/viewcube.rs

@@ -142,24 +142,39 @@ impl CubeRegion {
 
     /// Unit eye-direction vector (from target toward the camera) that
     /// looks straight at this region. Used by `Camera::snap_to_direction`
-    /// which derives the full orientation by re-using the current
-    /// camera's up vector, projected onto the plane perpendicular to
-    /// this direction — so clicking an edge spins the cube around the
-    /// edge without rolling the user's "up" sense.
+    /// / `snap_to_face` which derive a deterministic horizon (world +Z,
+    /// except top/bottom where north +Y is used) so every cube click
+    /// lands repeatably.
     pub fn snap_direction(self) -> glam::Vec3 {
         let c = region_centroids()[self.id()];
         glam::Vec3::new(c[0], c[1], c[2]).normalize_or(glam::Vec3::Z)
     }
 
     pub fn opposite(self) -> CubeRegion {
-        match self {
-            CubeRegion::Face(FACE_TOP) => CubeRegion::Face(FACE_BOTTOM),
-            CubeRegion::Face(FACE_BOTTOM) => CubeRegion::Face(FACE_TOP),
-            CubeRegion::Face(FACE_FRONT) => CubeRegion::Face(FACE_BACK),
-            CubeRegion::Face(FACE_BACK) => CubeRegion::Face(FACE_FRONT),
-            CubeRegion::Face(FACE_RIGHT) => CubeRegion::Face(FACE_LEFT),
-            CubeRegion::Face(FACE_LEFT) => CubeRegion::Face(FACE_RIGHT),
-            other => other,
+        // Generic opposite: the region whose centroid is nearest to -self.
+        // Covers faces, edges and corners so "already there → flip" works
+        // for every cube click, not just faces.
+        let centroids = region_centroids();
+        let c = centroids[self.id()];
+        let neg = [-c[0], -c[1], -c[2]];
+        let mut best = self.id();
+        let mut best_d = f32::MAX;
+        for (i, cc) in centroids.iter().enumerate() {
+            let dx = cc[0] - neg[0];
+            let dy = cc[1] - neg[1];
+            let dz = cc[2] - neg[2];
+            let d = dx * dx + dy * dy + dz * dz;
+            if d < best_d {
+                best_d = d;
+                best = i;
+            }
+        }
+        if best < 6 {
+            CubeRegion::Face(best)
+        } else if best < 18 {
+            CubeRegion::Edge(best)
+        } else {
+            CubeRegion::Corner(best)
         }
     }
 

src/scene/view/camera.rs

@@ -645,44 +645,29 @@ impl Camera {
     /// Snap to a canonical view direction (called by ViewCubeSnap).
     /// `eye_dir` is the unit vector from the target toward the camera.
     ///
-    /// Up vector resolution:
-    ///  1. Take the current up.
-    ///  2. Pick the world axis (±X, ±Y, ±Z) whose dot product with the
-    ///     current up is highest — skipping any axis (anti-)parallel to
-    ///     the new gaze direction.
-    ///  3. Project that axis onto the plane ⊥ `new_eye` and use that as
-    ///     the new up.
-    ///
-    /// Result: small tilts collapse onto the nearest world axis (so the
-    /// view always lands cleanly aligned), while genuine flips of the
-    /// up-sense (e.g. orbited upside-down) are preserved.
+    /// Deterministic horizon: when looking close to ±Z (top/bottom) the
+    /// up is north (+Y), otherwise world up (+Z), projected onto the
+    /// plane ⊥ `new_eye`. This matches the turntable `orbit` (which never
+    /// banks) so a cube corner always lands with the same roll and the
+    /// base never appears rotated. The sign is flipped only if the
+    /// current view is intentionally upside-down, preserving that sense.
     pub fn snap_to_direction(&mut self, eye_dir: Vec3, ucs: glam::Mat4) {
         let new_eye = eye_dir.normalize_or(Vec3::Z);
-        let cur_up = self.rotation * Vec3::Y;
-        // Candidate up axes are the UCS axes, not world X/Y/Z, so a face snap
-        // lands the view square to the user's coordinate system (in-plane roll
-        // included). Identity `ucs` reproduces the world-aligned snap.
-        let ux = ucs.transform_vector3(Vec3::X).normalize_or(Vec3::X);
         let uy = ucs.transform_vector3(Vec3::Y).normalize_or(Vec3::Y);
         let uz = ucs.transform_vector3(Vec3::Z).normalize_or(Vec3::Z);
-        let cardinals = [ux, -ux, uy, -uy, uz, -uz];
-        let mut best_score = f32::NEG_INFINITY;
-        let mut best_up = uz;
-        for axis in cardinals {
-            // Skip axes (nearly) collinear with the new gaze — they can't
-            // serve as up because the projection onto the plane would
-            // vanish.
-            if axis.dot(new_eye).abs() > 0.999 {
-                continue;
-            }
-            let score = axis.dot(cur_up);
-            if score > best_score {
-                best_score = score;
-                best_up = axis;
-            }
-        }
-        // Project the chosen axis onto the plane ⊥ new_eye and normalize.
-        let projected = best_up - new_eye * best_up.dot(new_eye);
+        // Deterministic horizon: top/bottom views (eye ≈ ±Z) use north (+Y)
+        // as up; every other direction uses world up (+Z). This keeps the
+        // cube's "Top Front Right" etc. repeatable and aligned with the
+        // turntable orbit (which never banks), and avoids the previous
+        // adaptive choice that picked the nearest cardinal to the current
+        // up — from a top view that was +Y, so an oblique top corner kept
+        // Y as up and tilted the base (roll) instead of keeping the horizon
+        // level. Preserve the sign only to keep an intentionally inverted
+        // (upside-down) view inverted.
+        let cur_up = self.rotation * Vec3::Y;
+        let raw_ref = if new_eye.dot(uz).abs() > 0.9 { uy } else { uz };
+        let up_ref = if cur_up.dot(raw_ref) < 0.0 { -raw_ref } else { raw_ref };
+        let projected = up_ref - new_eye * up_ref.dot(new_eye);
         let new_up = projected.normalize_or(if new_eye.dot(uz).abs() < 0.99 {
             (uz - new_eye * uz.dot(new_eye)).normalize()
         } else {

src/ui/theme_accessibility_tests.rs

@@ -9,6 +9,8 @@
 //! - Properties & Dock Panels (field labels, section headers, muted text)
 //! - Modals & Action Buttons (dialog body, Primary, Danger, Success buttons)
 //! - Dropdowns & Selection Overlays (visual style picker, item checkmarks)
+//! - Block Palette (card labels in normal/hover/pressed/placing states,
+//!   header icon buttons, empty-state muted text)
 
 use crate::ui::style::common::{accessible_accent, accessible_accent_threshold, wcag_contrast};
 use iced::{Color, Theme};
@@ -462,3 +464,174 @@ fn test_viewport_controls_toggle_buttons_contrast() {
     }
 }
 
+#[test]
+fn test_block_palette_contrast() {
+    use crate::ui::window::block_palette::{
+        block_card_border, block_card_colors, block_icon_button_text_color,
+    };
+    use iced::widget::button::Status as BtnStatus;
+
+    for theme in Theme::ALL {
+        let p = theme.palette();
+
+        // ── 1. Card label pairs resolve to the theme's own text colors ──
+        // Regression guard for the light-theme bug where labels were hardcoded
+        // to `Color::WHITE` (unreadable white-on-light). If anyone reintroduces
+        // a hardcoded foreground, these equality checks fail on every theme
+        // whose surface text is not pure white.
+        let (normal_bg, normal_fg) = block_card_colors(theme, false, BtnStatus::Active);
+        assert_eq!(
+            normal_bg, p.background.base.color,
+            "Theme {:?} block card normal background drifted from base pair",
+            theme
+        );
+        assert_eq!(
+            normal_fg, p.background.base.text,
+            "Theme {:?} block card normal label must use base text (was hardcoded WHITE)",
+            theme
+        );
+
+        let (_, hover_fg) = block_card_colors(theme, false, BtnStatus::Hovered);
+        assert_eq!(
+            hover_fg, p.background.strong.text,
+            "Theme {:?} block card hover label must use strong text (was hardcoded WHITE)",
+            theme
+        );
+
+        let (_, pressed_fg) = block_card_colors(theme, false, BtnStatus::Pressed);
+        assert_eq!(
+            pressed_fg, p.background.strong.text,
+            "Theme {:?} block card pressed label must use strong text (was hardcoded WHITE)",
+            theme
+        );
+
+        // Default-branch statuses (Active/Disabled/Focused/...) share the base pair.
+        let (_, disabled_fg) = block_card_colors(theme, false, BtnStatus::Disabled);
+        assert_eq!(
+            disabled_fg, p.background.base.text,
+            "Theme {:?} block card default-state label must use base text",
+            theme
+        );
+
+        // Placing (selected) cards always use the primary pair, regardless of
+        // hover — the background does not switch on hover while placing.
+        for status in [BtnStatus::Active, BtnStatus::Hovered, BtnStatus::Pressed] {
+            let (bg, fg) = block_card_colors(theme, true, status);
+            assert_eq!(bg, p.primary.base.color, "Theme {:?} placing card bg must be primary.base", theme);
+            assert_eq!(fg, p.primary.base.text, "Theme {:?} placing card label must be primary.base.text", theme);
+        }
+
+        // ── 2. Card label contrast: normal / hover / pressed ──
+        // 11px single-line labels are normal text → WCAG AA >= 4.5:1.
+        let normal_contrast = wcag_contrast(normal_fg, normal_bg);
+        assert!(
+            normal_contrast >= 4.5,
+            "Theme {:?} block card label ({:.2}:1) fails WCAG AA on card background",
+            theme, normal_contrast
+        );
+
+        let (hover_bg, hover_fg) = block_card_colors(theme, false, BtnStatus::Hovered);
+        let hover_contrast = wcag_contrast(hover_fg, hover_bg);
+        assert!(
+            hover_contrast >= 4.5,
+            "Theme {:?} block card hovered label ({:.2}:1) fails WCAG AA on hovered background",
+            theme, hover_contrast
+        );
+
+        let (pressed_bg, pressed_fg) = block_card_colors(theme, false, BtnStatus::Pressed);
+        let pressed_contrast = wcag_contrast(pressed_fg, pressed_bg);
+        assert!(
+            pressed_contrast >= 4.5,
+            "Theme {:?} block card pressed label ({:.2}:1) fails WCAG AA on pressed background",
+            theme, pressed_contrast
+        );
+
+        // ── 3. Placing card contrast ──
+        // Selected-card label on `primary.base`: UI button component threshold
+        // (>= 3.0:1 per WCAG 1.4.11, matching the Primary-button test above).
+        let (placing_bg, placing_fg) = block_card_colors(theme, true, BtnStatus::Active);
+        let placing_contrast = wcag_contrast(placing_fg, placing_bg);
+        assert!(
+            placing_contrast >= 3.0,
+            "Theme {:?} placing block card label ({:.2}:1) fails button threshold (>=3.0:1)",
+            theme, placing_contrast
+        );
+        // Placing + hover must not silently drop contrast (bg is sticky).
+        let (placing_hover_bg, placing_hover_fg) =
+            block_card_colors(theme, true, BtnStatus::Hovered);
+        let placing_hover_contrast = wcag_contrast(placing_hover_fg, placing_hover_bg);
+        assert!(
+            placing_hover_contrast >= 3.0,
+            "Theme {:?} placing+hover block card label ({:.2}:1) fails button threshold (>=3.0:1)",
+            theme, placing_hover_contrast
+        );
+
+        // ── 4. Card border is theme-driven (no invisible borders) ──
+        assert_eq!(
+            block_card_border(theme, false),
+            p.background.neutral.color,
+            "Theme {:?} block card border must use neutral color",
+            theme
+        );
+        assert_eq!(
+            block_card_border(theme, true),
+            p.primary.base.color,
+            "Theme {:?} placing block card border must use primary color",
+            theme
+        );
+
+        // ── 5. Header icon buttons (glyphs inherit button text_color) ──
+        // Resting buttons are transparent over the dock (`base`) background.
+        let icon_rest = block_icon_button_text_color(theme, BtnStatus::Active);
+        assert_eq!(icon_rest, p.background.base.text);
+        let icon_rest_contrast = wcag_contrast(icon_rest, p.background.base.color);
+        assert!(
+            icon_rest_contrast >= 4.5,
+            "Theme {:?} block palette icon button ({:.2}:1) fails WCAG AA on dock background",
+            theme, icon_rest_contrast
+        );
+        // Hovered/pressed buttons sit on the `strong` surface with its text.
+        for status in [BtnStatus::Hovered, BtnStatus::Pressed] {
+            let icon_fg = block_icon_button_text_color(theme, status);
+            assert_eq!(
+                icon_fg, p.background.strong.text,
+                "Theme {:?} hovered icon button must use strong text",
+                theme
+            );
+            let c = wcag_contrast(icon_fg, p.background.strong.color);
+            assert!(
+                c >= 4.5,
+                "Theme {:?} hovered icon button ({:.2}:1) fails WCAG AA on hovered background",
+                theme, c
+            );
+        }
+
+        // ── 6. Empty-state muted text ("No blocks in this drawing") ──
+        // Rendered as `base.text` at 0.72 alpha over the dock `base`
+        // background → secondary text threshold >= 3.0:1. (The old hardcoded
+        // 0.55-gray failed this on light themes.)
+        let empty_text = composite_over(p.background.base.text.scale_alpha(0.72), p.background.base.color);
+        let empty_contrast = wcag_contrast(empty_text, p.background.base.color);
+        assert!(
+            empty_contrast >= 3.0,
+            "Theme {:?} block palette empty-state text ({:.2}:1) fails secondary text threshold (>=3.0:1)",
+            theme, empty_contrast
+        );
+
+        // ── 7. Hardcoded-white regression probe ──
+        // The exact reported bug: pure white labels on the light card
+        // background. Every theme's card background must NOT be near-white
+        // with white text — i.e. white-on-card must fail while the real
+        // theme pair passes (proves the fix matters on light themes and the
+        // test would catch a WHITE hardcode).
+        let white_on_normal = wcag_contrast(Color::WHITE, normal_bg);
+        if white_on_normal < 4.5 {
+            assert!(
+                normal_contrast >= 4.5,
+                "Theme {:?} needs theme-aware labels: white-on-card is {:.2}:1 but theme pair is {:.2}:1",
+                theme, white_on_normal, normal_contrast
+            );
+        }
+    }
+}
+

src/ui/window/block_palette.rs

@@ -264,7 +264,20 @@ pub fn view(palette: &BlockPalette, width: f32, auto_collapse: bool) -> Element<
         } else {
             "No matches"
         };
-        container(text(crate::t!(msg)).size(12).color(iced::Color { r: 0.55, g: 0.55, b: 0.55, a: 1.0 }))
+        container(
+            text(crate::t!(msg))
+                .size(12)
+                .style(|theme: &Theme| iced::widget::text::Style {
+                    color: Some(
+                        theme
+                            .palette()
+                            .background
+                            .base
+                            .text
+                            .scale_alpha(0.72),
+                    ),
+                }),
+        )
             .center_x(Fill)
             .center_y(Fill)
             .width(Fill)
@@ -307,6 +320,56 @@ pub fn view(palette: &BlockPalette, width: f32, auto_collapse: bool) -> Element<
         .into()
 }
 
+/// Theme-aware foreground/background pair for a block card.
+///
+/// Centralizes the card's text/background mapping so the contrast suite can
+/// exercise the exact colors the UI renders (instead of re-implementing the
+/// match). Normal cards use the `base` pair, hovered/pressed cards use the
+/// `strong` pair, and the actively-placing card uses the `primary.base` pair.
+pub(crate) fn block_card_colors(
+    theme: &Theme,
+    is_placing: bool,
+    status: button::Status,
+) -> (Color, Color) {
+    let palette = theme.palette();
+    if is_placing {
+        (palette.primary.base.color, palette.primary.base.text)
+    } else {
+        match status {
+            button::Status::Hovered | button::Status::Pressed => {
+                (palette.background.strong.color, palette.background.strong.text)
+            }
+            _ => (
+                palette.background.base.color,
+                palette.background.base.text,
+            ),
+        }
+    }
+}
+
+/// Border color for a block card in a given state (exposed for contrast tests).
+pub(crate) fn block_card_border(theme: &Theme, is_placing: bool) -> Color {
+    let palette = theme.palette();
+    if is_placing {
+        palette.primary.base.color
+    } else {
+        palette.background.neutral.color
+    }
+}
+
+/// Theme-aware foreground for the palette's header icon buttons.
+///
+/// Transparent resting state composites over the dock (`base`) background;
+/// hovered/pressed state sits on the `strong` surface, so each state pairs
+/// with its own background's text color to preserve contrast.
+pub(crate) fn block_icon_button_text_color(theme: &Theme, status: button::Status) -> Color {
+    let palette = theme.palette();
+    match status {
+        button::Status::Hovered | button::Status::Pressed => palette.background.strong.text,
+        _ => palette.background.base.text,
+    }
+}
+
 fn block_card<'a>(palette: &'a BlockPalette, block: &'a BlockEntry) -> Element<'a, Message> {
     let is_placing = palette.placing.as_deref() == Some(block.name.as_str());
     let preview = canvas(BlockPreviewCanvas { wires: &block.wires })
@@ -315,9 +378,13 @@ fn block_card<'a>(palette: &'a BlockPalette, block: &'a BlockEntry) -> Element<'
     // Fixed height guarantees the label occupies exactly one line, so every
     // cell in a row keeps the same height even for long names (the elide budget
     // handles overflow, and this clips anything that still won't fit).
+    //
+    // NOTE: no explicit `.color(...)` here — the label inherits the button's
+    // `text_color` so normal/hover/placing states each get a theme-aware
+    // foreground with sufficient contrast on both light and dark themes.
+    // (A hardcoded `Color::WHITE` is unreadable on light themes.)
     let label = text(crate::ui::text_util::elide(&block.name, MAX_LABEL_CHARS))
         .size(11)
-        .color(Color::WHITE)
         .width(Fill)
         .height(Length::Fixed(LABEL_LINE_H))
         .center();
@@ -326,18 +393,8 @@ fn block_card<'a>(palette: &'a BlockPalette, block: &'a BlockEntry) -> Element<'
         .on_press(Message::BlockPalette(BlockPaletteMsg::Insert(block.name.clone())))
         .width(Fill)
         .style(move |theme: &Theme, status| {
-            let palette = theme.palette();
-            let neutral = palette.background.neutral.color;
-            let base = palette.background.base.color;
-            let strong = palette.background.strong.color;
-            let (bg, border) = if is_placing {
-                (palette.primary.base.color, palette.primary.base.color)
-            } else {
-                match status {
-                    button::Status::Hovered | button::Status::Pressed => (strong, neutral),
-                    _ => (base, neutral),
-                }
-            };
+            let (bg, fg) = block_card_colors(theme, is_placing, status);
+            let border = block_card_border(theme, is_placing);
             button::Style {
                 background: Some(Background::Color(bg)),
                 border: Border {
@@ -345,7 +402,7 @@ fn block_card<'a>(palette: &'a BlockPalette, block: &'a BlockEntry) -> Element<'
                     width: 1.0,
                     radius: 3.0.into(),
                 },
-                text_color: Color::WHITE,
+                text_color: fg,
                 ..Default::default()
             }
         })
@@ -354,7 +411,9 @@ fn block_card<'a>(palette: &'a BlockPalette, block: &'a BlockEntry) -> Element<'
 
 fn icon_button<'a>(icon: IconKind, msg: BlockPaletteMsg) -> Element<'a, Message> {
     let icon_el: Element<'_, Message> = match icon {
-        IconKind::Glyph(s) => text(s).size(15).color(Color::WHITE).into(),
+        // No explicit color — inherits the button's theme-aware `text_color`
+        // so glyphs stay legible on light themes.
+        IconKind::Glyph(s) => text(s).size(15).into(),
         IconKind::Svg(bytes) => crate::ui::icons::semantic(bytes, TOOL_H),
     };
     button(icon_el)
@@ -372,7 +431,7 @@ fn icon_button<'a>(icon: IconKind, msg: BlockPaletteMsg) -> Element<'a, Message>
                 radius: 3.0.into(),
                 ..Default::default()
             },
-            text_color: Color::WHITE,
+            text_color: block_icon_button_text_color(theme, status),
             ..Default::default()
         })
         .into()