diff --git a/src-tauri/bindings/types.ts b/src-tauri/bindings/types.ts
index 186d78f..d20caa7 100644
--- a/src-tauri/bindings/types.ts
+++ b/src-tauri/bindings/types.ts
@@ -12,7 +12,7 @@ export type ChatMessage = { role: string, content: string, };
 
 export type Deck = { v: number, theme: string, slides: Array<Slide>, chat_id: string | null, };
 
-export type ElementStyle = { font_size: number | null, color: string | null, align: string | null, bold: boolean | null, italic: boolean | null, anim: string | null, label: string | null, label_color: string | null, label_size: number | null, fit: string | null, shape_type: ShapeType | null, fill: string | null, gradient: boolean | null, opacity: number | null, radius: number | null, max: number | null, chart_type: ChartType | null, legend: boolean | null, stack: boolean | null, grid: boolean | null, header: boolean | null, lang: string | null, inline: boolean | null, icon: string | null, accent: string | null, };
+export type ElementStyle = { fontSize: number | null, color: string | null, align: string | null, bold: boolean | null, italic: boolean | null, anim: string | null, label: string | null, labelColor: string | null, labelSize: number | null, fit: string | null, shapeType: ShapeType | null, fill: string | null, gradient: boolean | null, opacity: number | null, radius: number | null, max: number | null, chartType: ChartType | null, legend: boolean | null, stack: boolean | null, grid: boolean | null, header: boolean | null, lang: string | null, inline: boolean | null, icon: string | null, accent: string | null, };
 
 export type ElementType = "title" | "text" | "list" | "stat" | "quote" | "image" | "shape" | "chart" | "card" | "table" | "code" | "formula";
 
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 7d01495..4d4794d 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -9,6 +9,7 @@
 
 mod color;
 mod model;
+mod op;
 
 /// IPC 验证命令
 #[tauri::command]
diff --git a/src-tauri/src/model.rs b/src-tauri/src/model.rs
index dbbf639..0c262ab 100644
--- a/src-tauri/src/model.rs
+++ b/src-tauri/src/model.rs
@@ -157,6 +157,7 @@ pub struct RichLine {
 
 #[derive(Debug, Clone, Default, Serialize, Deserialize, TS)]
 #[ts(export, export_to = "../bindings/types.ts")]
+#[serde(rename_all = "camelCase")]
 pub struct ElementStyle {
     pub font_size: Option<f64>,
     pub color: Option<String>,
diff --git a/src-tauri/src/op.rs b/src-tauri/src/op.rs
new file mode 100644
index 0000000..8a3bd78
--- /dev/null
+++ b/src-tauri/src/op.rs
@@ -0,0 +1,558 @@
+/* =====================================================================
+ * op.rs — Op Log reducer（对应 src/core/op.ts）
+ *
+ * 纯函数：apply_op(deck, op) → new deck，不 mutate 输入
+ * invert_op(deck, op) → 能撤销 op 的逆 op
+ *
+ * 所有 Op 通过 serde_json::Value 传递 payload，按 op_type 分发。
+ * ===================================================================== */
+use crate::model::{Deck, Slide, SlideElement};
+
+/* ---------- 工具 ---------- */
+
+fn clone_deck(deck: &Deck) -> Deck {
+    serde_json::from_str(&serde_json::to_string(deck).unwrap()).unwrap()
+}
+
+fn find_element(deck: &Deck, slide_idx: usize, el_id: &str) -> Option<usize> {
+    let slide = deck.slides.get(slide_idx)?;
+    slide.elements.iter().position(|e| e.id == el_id)
+}
+
+/* ---------- reducer ---------- */
+
+pub fn apply_op(input_deck: &Deck, op: &crate::model::Op) -> Deck {
+    let mut deck = clone_deck(input_deck);
+
+    match op.op_type.as_str() {
+        "add_slide" => {
+            if let Some(slide) = op.payload.get("slide").and_then(|v| v.as_object()) {
+                if let Ok(s) = serde_json::from_value(serde_json::Value::Object(slide.clone())) as Result<Slide, _> {
+                    let at_index = op.payload.get("atIndex")
+                        .or_else(|| op.payload.get("at_index"))
+                        .and_then(|v| v.as_f64())
+                        .map(|f| f as usize)
+                        .unwrap_or(deck.slides.len());
+                    let idx = at_index.min(deck.slides.len());
+                    deck.slides.insert(idx, s);
+                }
+            }
+        }
+
+        "del_slide" => {
+            if deck.slides.len() <= 1 {
+                return deck;
+            }
+            if let Some(index) = op.payload.get("index").and_then(|v| v.as_f64()).map(|f| f as usize) {
+                if index < deck.slides.len() {
+                    deck.slides.remove(index);
+                }
+            }
+        }
+
+        "move_slide" => {
+            let from = op.payload.get("from").and_then(|v| v.as_f64()).map(|f| f as usize);
+            let to = op.payload.get("to").and_then(|v| v.as_f64()).map(|f| f as usize);
+            if let (Some(from), Some(to)) = (from, to) {
+                if from != to && from < deck.slides.len() && to < deck.slides.len() {
+                    let item = deck.slides.remove(from);
+                    deck.slides.insert(to, item);
+                }
+            }
+        }
+
+        "replace_slide" => {
+            if let Some(slide_val) = op.payload.get("slide") {
+                if let Ok(mut s) = serde_json::from_value(slide_val.clone()) as Result<Slide, _> {
+                    if let Some(index) = op.payload.get("index").and_then(|v| v.as_f64()).map(|f| f as usize) {
+                        if let Some(existing) = deck.slides.get(index) {
+                            s.id = existing.id.clone(); // 保持 id 不变
+                        }
+                        if index < deck.slides.len() {
+                            deck.slides[index] = s;
+                        }
+                    }
+                }
+            }
+        }
+
+        "set_slide_bg" => {
+            if let Some(index) = op.payload.get("index").and_then(|v| v.as_f64()).map(|f| f as usize) {
+                if let Some(bg) = op.payload.get("bg").and_then(|v| v.as_str()) {
+                    if let Some(slide) = deck.slides.get_mut(index) {
+                        slide.background = bg.to_string();
+                    }
+                }
+            }
+        }
+
+        "add_element" => {
+            if let Some(el_val) = op.payload.get("element") {
+                if let Ok(el) = serde_json::from_value(el_val.clone()) as Result<SlideElement, _> {
+                    if let Some(slide_idx) = op.payload.get("slideIdx")
+                        .or_else(|| op.payload.get("slide_idx"))
+                        .and_then(|v| v.as_f64())
+                        .map(|f| f as usize)
+                    {
+                        if let Some(slide) = deck.slides.get_mut(slide_idx) {
+                            slide.elements.push(el);
+                        }
+                    }
+                }
+            }
+        }
+
+        "update_element" => {
+            let slide_idx = op.payload.get("slideIdx")
+                .or_else(|| op.payload.get("slide_idx"))
+                .and_then(|v| v.as_f64())
+                .map(|f| f as usize);
+            let element_id = op.payload.get("elementId")
+                .or_else(|| op.payload.get("element_id"))
+                .and_then(|v| v.as_str());
+            if let (Some(sidx), Some(eid)) = (slide_idx, element_id) {
+                if let Some(eidx) = find_element(&deck, sidx, eid) {
+                    let slide = &mut deck.slides[sidx];
+                    let el = &mut slide.elements[eidx];
+                    // 应用 patch
+                    if let Some(patch) = op.payload.get("patch").and_then(|v| v.as_object()) {
+                        if let Some(style_patch) = patch.get("style").and_then(|v| v.as_object()) {
+                            // 字段级 merge style
+                            let current_style_val = serde_json::to_value(&el.style).unwrap_or_default();
+                            if let Ok(mut current_style_map) = current_style_val.as_object().cloned().ok_or(()) {
+                                for (k, v) in style_patch {
+                                    current_style_map.insert(k.clone(), v.clone());
+                                }
+                                if let Ok(new_style) = serde_json::from_value(serde_json::Value::Object(current_style_map)) {
+                                    el.style = new_style;
+                                }
+                            }
+                        }
+                        // 非 style 字段
+                        let el_val = serde_json::to_value(&el.clone()).unwrap_or_default();
+                        if let Ok(mut el_map) = el_val.as_object().cloned().ok_or(()) {
+                            for (k, v) in patch {
+                                if k != "style" {
+                                    el_map.insert(k.clone(), v.clone());
+                                }
+                            }
+                            if let Ok(new_el) = serde_json::from_value(serde_json::Value::Object(el_map)) {
+                                *el = new_el;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        "del_element" => {
+            let slide_idx = op.payload.get("slideIdx")
+                .or_else(|| op.payload.get("slide_idx"))
+                .and_then(|v| v.as_f64())
+                .map(|f| f as usize);
+            let element_id = op.payload.get("elementId")
+                .or_else(|| op.payload.get("element_id"))
+                .and_then(|v| v.as_str());
+            if let (Some(sidx), Some(eid)) = (slide_idx, element_id) {
+                if let Some(slide) = deck.slides.get_mut(sidx) {
+                    slide.elements.retain(|e| e.id != eid);
+                }
+            }
+        }
+
+        "move_element_z" => {
+            let slide_idx = op.payload.get("slideIdx")
+                .or_else(|| op.payload.get("slide_idx"))
+                .and_then(|v| v.as_f64())
+                .map(|f| f as usize);
+            let element_id = op.payload.get("elementId")
+                .or_else(|| op.payload.get("element_id"))
+                .and_then(|v| v.as_str());
+            let dir = op.payload.get("dir").and_then(|v| v.as_f64()).map(|f| f as i64);
+            if let (Some(sidx), Some(eid), Some(dir)) = (slide_idx, element_id, dir) {
+                if let Some(eidx) = find_element(&deck, sidx, eid) {
+                    let j = if dir > 0 { eidx + 1 } else { eidx.saturating_sub(1) };
+                    if let Some(slide) = deck.slides.get_mut(sidx) {
+                        if j < slide.elements.len() {
+                            slide.elements.swap(eidx, j);
+                        }
+                    }
+                }
+            }
+        }
+
+        "set_theme" => {
+            if let Some(theme) = op.payload.get("theme").and_then(|v| v.as_str()) {
+                deck.theme = theme.to_string();
+            }
+        }
+
+        "replace_deck" => {
+            if let Some(new_deck) = op.payload.get("deck") {
+                if let Ok(mut d) = serde_json::from_value(new_deck.clone()) as Result<Deck, _> {
+                    d.v = deck.v; // 保持版本号
+                    return d;
+                }
+            }
+        }
+
+        _ => {} // 未知 Op，不修改
+    }
+
+    deck
+}
+
+/* ---------- 逆操作计算 ---------- */
+
+pub fn invert_op(input_deck: &Deck, op: &crate::model::Op) -> crate::model::Op {
+    use crate::model::Op;
+    use serde_json::json;
+
+    match op.op_type.as_str() {
+        "add_slide" => {
+            // 逆：删除加的那页
+            let slide_id = op.payload.get("slide").and_then(|v| v.get("id")).and_then(|v| v.as_str());
+            let idx = if let Some(sid) = slide_id {
+                input_deck.slides.iter().position(|s| s.id == sid)
+            } else {
+                op.payload.get("atIndex").and_then(|v| v.as_f64()).map(|f| f as usize)
+            };
+            Op {
+                op_type: "del_slide".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "index": idx.unwrap_or(input_deck.slides.len().saturating_sub(1)) }),
+            }
+        }
+
+        "del_slide" => {
+            // 逆：把删掉的页插回原位
+            let index = op.payload.get("index").and_then(|v| v.as_f64()).map(|f| f as usize);
+            if let Some(deleted) = op.payload.get("deletedSlide").or_else(|| op.payload.get("deleted_slide")) {
+                Op {
+                    op_type: "add_slide".into(),
+                    client_id: None,
+                    timestamp: None,
+                    payload: json!({ "atIndex": index, "slide": deleted }),
+                }
+            } else {
+                Op { op_type: "replace_deck".into(), client_id: None, timestamp: None, payload: json!({ "deck": clone_deck(input_deck) }) }
+            }
+        }
+
+        "move_slide" => {
+            let from = op.payload.get("from").cloned().unwrap_or_default();
+            let to = op.payload.get("to").cloned().unwrap_or_default();
+            Op {
+                op_type: "move_slide".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "from": to, "to": from }),
+            }
+        }
+
+        "replace_slide" => {
+            let index = op.payload.get("index").cloned().unwrap_or_default();
+            let old = op.payload.get("oldSlide").or_else(|| op.payload.get("old_slide")).cloned()
+                .unwrap_or_else(|| {
+                    let idx = index.as_f64().map(|f| f as usize).unwrap_or(0);
+                    serde_json::to_value(input_deck.slides.get(idx).cloned().unwrap_or_else(|| Slide { id: String::new(), background: "bg".into(), elements: vec![] })).unwrap_or_default()
+                });
+            Op {
+                op_type: "replace_slide".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "index": index, "slide": old }),
+            }
+        }
+
+        "set_slide_bg" => {
+            let index = op.payload.get("index").and_then(|v| v.as_f64()).map(|f| f as usize);
+            let old_bg = index.and_then(|i| input_deck.slides.get(i)).map(|s| s.background.clone()).unwrap_or_else(|| "bg".into());
+            Op {
+                op_type: "set_slide_bg".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "index": index, "bg": old_bg }),
+            }
+        }
+
+        "add_element" => {
+            let slide_idx = op.payload.get("slideIdx").or_else(|| op.payload.get("slide_idx")).cloned().unwrap_or_default();
+            let element_id = op.payload.get("element").and_then(|v| v.get("id")).cloned().unwrap_or_default();
+            Op {
+                op_type: "del_element".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "slideIdx": slide_idx, "elementId": element_id }),
+            }
+        }
+
+        "update_element" => {
+            // 构造反向 patch：取当前值
+            let slide_idx = op.payload.get("slideIdx").or_else(|| op.payload.get("slide_idx")).and_then(|v| v.as_f64()).map(|f| f as usize);
+            let element_id = op.payload.get("elementId").or_else(|| op.payload.get("element_id")).and_then(|v| v.as_str()).unwrap_or("").to_string();
+            let patch = op.payload.get("patch").cloned().unwrap_or_default();
+
+            if let Some(sidx) = slide_idx {
+                if let Some(eidx) = find_element(input_deck, sidx, &element_id) {
+                    let el = &input_deck.slides[sidx].elements[eidx];
+                    let el_val = serde_json::to_value(el).unwrap_or_default();
+                    let mut backward_patch = serde_json::Map::new();
+
+                    if let Some(patch_obj) = patch.as_object() {
+                        if let Some(style_patch) = patch_obj.get("style").and_then(|v| v.as_object()) {
+                            let current_style = &el.style;
+                            let style_val = serde_json::to_value(current_style).unwrap_or_default();
+                            let mut old_style = serde_json::Map::new();
+                            if let Some(style_map) = style_val.as_object() {
+                                for (k, _) in style_patch {
+                                    if let Some(v) = style_map.get(k) {
+                                        old_style.insert(k.clone(), v.clone());
+                                    }
+                                }
+                            }
+                            backward_patch.insert("style".into(), serde_json::Value::Object(old_style));
+                        }
+                        for (k, _) in patch_obj {
+                            if k != "style" {
+                                if let Some(v) = el_val.get(k) {
+                                    backward_patch.insert(k.clone(), v.clone());
+                                }
+                            }
+                        }
+                    }
+
+                    return Op {
+                        op_type: "update_element".into(),
+                        client_id: None,
+                        timestamp: None,
+                        payload: json!({ "slideIdx": sidx, "elementId": element_id, "patch": serde_json::Value::Object(backward_patch) }),
+                    };
+                }
+            }
+
+            Op { op_type: "replace_deck".into(), client_id: None, timestamp: None, payload: json!({ "deck": clone_deck(input_deck) }) }
+        }
+
+        "del_element" => {
+            let slide_idx = op.payload.get("slideIdx").or_else(|| op.payload.get("slide_idx")).and_then(|v| v.as_f64()).map(|f| f as usize);
+            let element_id = op.payload.get("elementId").or_else(|| op.payload.get("element_id")).and_then(|v| v.as_str()).unwrap_or("").to_string();
+            if let Some(deleted) = op.payload.get("deletedElement").or_else(|| op.payload.get("deleted_element")) {
+                Op {
+                    op_type: "add_element".into(),
+                    client_id: None,
+                    timestamp: None,
+                    payload: json!({ "slideIdx": slide_idx, "element": deleted }),
+                }
+            } else {
+                Op { op_type: "replace_deck".into(), client_id: None, timestamp: None, payload: json!({ "deck": clone_deck(input_deck) }) }
+            }
+        }
+
+        "move_element_z" => {
+            let slide_idx = op.payload.get("slideIdx").or_else(|| op.payload.get("slide_idx")).cloned().unwrap_or_default();
+            let element_id = op.payload.get("elementId").or_else(|| op.payload.get("element_id")).cloned().unwrap_or_default();
+            let dir = op.payload.get("dir").and_then(|v| v.as_f64()).unwrap_or(0.0);
+            Op {
+                op_type: "move_element_z".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "slideIdx": slide_idx, "elementId": element_id, "dir": -dir }),
+            }
+        }
+
+        "set_theme" => {
+            Op {
+                op_type: "set_theme".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "theme": input_deck.theme }),
+            }
+        }
+
+        "replace_deck" => {
+            Op {
+                op_type: "replace_deck".into(),
+                client_id: None,
+                timestamp: None,
+                payload: json!({ "deck": clone_deck(input_deck) }),
+            }
+        }
+
+        _ => Op {
+            op_type: "replace_deck".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "deck": clone_deck(input_deck) }),
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::model::*;
+    use serde_json::json;
+
+    fn make_test_deck() -> Deck {
+        Deck {
+            v: 3,
+            theme: "indigo".into(),
+            slides: vec![
+                Slide {
+                    id: "s1".into(),
+                    background: "bg".into(),
+                    elements: vec![
+                        SlideElement {
+                            id: "e1".into(),
+                            element_type: "title".into(),
+                            x: 10.0, y: 10.0, w: 80.0, h: 15.0,
+                            content: "Hello".into(),
+                            style: ElementStyle { font_size: Some(48.0), ..Default::default() },
+                            segments: None,
+                        },
+                    ],
+                },
+                Slide {
+                    id: "s2".into(),
+                    background: "panel".into(),
+                    elements: vec![],
+                },
+            ],
+            chat_id: None,
+        }
+    }
+
+    #[test]
+    fn test_add_slide() {
+        let deck = make_test_deck();
+        let new_slide = Slide { id: "s3".into(), background: "bg".into(), elements: vec![] };
+        let op = Op {
+            op_type: "add_slide".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "atIndex": 1, "slide": new_slide }),
+        };
+        let result = apply_op(&deck, &op);
+        assert_eq!(result.slides.len(), 3);
+        assert_eq!(result.slides[1].id, "s3");
+    }
+
+    #[test]
+    fn test_del_slide() {
+        let deck = make_test_deck();
+        let op = Op {
+            op_type: "del_slide".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "index": 1 }),
+        };
+        let result = apply_op(&deck, &op);
+        assert_eq!(result.slides.len(), 1);
+        assert_eq!(result.slides[0].id, "s1");
+    }
+
+    #[test]
+    fn test_set_theme() {
+        let deck = make_test_deck();
+        let op = Op {
+            op_type: "set_theme".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "theme": "rose" }),
+        };
+        let result = apply_op(&deck, &op);
+        assert_eq!(result.theme, "rose");
+    }
+
+    #[test]
+    fn test_update_element() {
+        let deck = make_test_deck();
+        let op = Op {
+            op_type: "update_element".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "slideIdx": 0, "elementId": "e1", "patch": { "style": { "fontSize": 56 } } }),
+        };
+        let result = apply_op(&deck, &op);
+        assert_eq!(result.slides[0].elements[0].style.font_size, Some(56.0));
+    }
+
+    #[test]
+    fn test_del_element() {
+        let deck = make_test_deck();
+        let op = Op {
+            op_type: "del_element".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "slideIdx": 0, "elementId": "e1" }),
+        };
+        let result = apply_op(&deck, &op);
+        assert_eq!(result.slides[0].elements.len(), 0);
+    }
+
+    #[test]
+    fn test_move_slide() {
+        let deck = make_test_deck();
+        let op = Op {
+            op_type: "move_slide".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "from": 0, "to": 1 }),
+        };
+        let result = apply_op(&deck, &op);
+        assert_eq!(result.slides[0].id, "s2");
+        assert_eq!(result.slides[1].id, "s1");
+    }
+
+    #[test]
+    fn test_undo_update() {
+        let deck = make_test_deck();
+        let op = Op {
+            op_type: "update_element".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "slideIdx": 0, "elementId": "e1", "patch": { "style": { "fontSize": 56 } } }),
+        };
+        let backward = invert_op(&deck, &op);
+        let applied = apply_op(&deck, &op);
+        let undone = apply_op(&applied, &backward);
+        assert_eq!(undone.slides[0].elements[0].style.font_size, Some(48.0));
+    }
+
+    #[test]
+    fn test_undo_add_slide() {
+        let deck = make_test_deck();
+        let new_slide = Slide { id: "s3".into(), background: "bg".into(), elements: vec![] };
+        let op = Op {
+            op_type: "add_slide".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "atIndex": 1, "slide": new_slide }),
+        };
+        let backward = invert_op(&deck, &op);
+        let applied = apply_op(&deck, &op);
+        assert_eq!(applied.slides.len(), 3);
+        let undone = apply_op(&applied, &backward);
+        assert_eq!(undone.slides.len(), 2);
+    }
+
+    #[test]
+    fn test_replace_deck_undo() {
+        let deck = make_test_deck();
+        let new_deck = Deck { v: 3, theme: "rose".into(), slides: vec![Slide { id: "s9".into(), background: "bg".into(), elements: vec![] }], chat_id: None };
+        let op = Op {
+            op_type: "replace_deck".into(),
+            client_id: None,
+            timestamp: None,
+            payload: json!({ "deck": new_deck }),
+        };
+        let backward = invert_op(&deck, &op);
+        let applied = apply_op(&deck, &op);
+        assert_eq!(applied.slides.len(), 1);
+        let undone = apply_op(&applied, &backward);
+        assert_eq!(undone.slides.len(), 2);
+        assert_eq!(undone.slides[0].id, "s1");
+    }
+}