diff --git a/CHANGELOG.md b/CHANGELOG.md
index a9ed6c3..1fe4886 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,10 +18,14 @@ Versioning: [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - "Scan image" button replaced with a floating action button at the bottom-right of the viewport, using a Material Symbols Outlined camera glyph (`photo_camera`) for consistent rendering across platforms (was a small text button in the input pane header).
 - Crop modal:
   - No default crop box. User drags on the image to draw the region; falls back to full image if they confirm without drawing.
-  - Rotate left / Rotate right / Reset / Use this buttons replaced with Material Symbols icons (`rotate_left`, `rotate_right`, `restart_alt`, `check`). Cancel kept as text.
+  - Buttons are now Material Symbols icons: `rotate_left`, `rotate_right`, `invert_colors` (new — see below), `check`. Cancel kept as text. The `check` (Use this) button is larger and more prominent. The Reset button was removed (rarely useful with no default box).
   - Inner padding bumped to 2 rem so cropperjs's corner handles never sit on the right/bottom edges where Android's edge-swipe back gesture fires. iOS safe-area insets honoured on the backdrop and FAB.
   - Header text is now a hint ("Drag on the image to select the text region") instead of a title.
 
+### Added
+- Camera viewfinder modal on mobile (via `navigator.mediaDevices.getUserMedia` with `facingMode: environment`) — replaces the `<input type=file capture>` flow. Tapping the shutter goes directly to the crop modal, skipping the OS-level "retake / use" confirm step. Falls back to the file picker if camera access is denied or unavailable; a "Pick from file" icon (`photo_library`) inside the camera modal also routes to the picker on demand.
+- Invert-colours toggle (`invert_colors`) in the crop modal. Tap to flip light-on-dark text into the dark-on-light polarity Tesseract expects. The grayscale buffer is inverted before adaptive thresholding so the binarised output is correct.
+
 ### Fixed
 - "Hot: …" status no longer claims "unloads in X" when the server's `keep_alive` is `-1` (Ollama returns an absurd year-4001 `expires_at`). Threshold: any expiry >7 days drops the suffix and just shows the model name.
 
diff --git a/static/index.html b/static/index.html
index 81b989d..cf3b714 100644
--- a/static/index.html
+++ b/static/index.html
@@ -269,13 +269,36 @@
     .modal-btn .material-symbols-outlined { font-size: 20px; }
     .modal-btn.icon { padding: 0.35rem 0.55rem; min-width: 2.4rem; }
     .modal-btn:hover { border-color: var(--accent); color: var(--fg); }
+    .modal-btn.active {
+      background: var(--accent);
+      color: #fff;
+      border-color: var(--accent);
+    }
     .modal-btn.primary {
       background: var(--accent);
       color: #fff;
       border-color: var(--accent);
     }
+    .modal-btn.primary.icon {
+      padding: 0.55rem 1.1rem;
+      min-width: 3.2rem;
+    }
+    .modal-btn.primary.icon .material-symbols-outlined { font-size: 24px; }
     .modal-btn.primary:hover { color: #fff; }
 
+    /* Camera viewfinder modal */
+    .cam-body {
+      display: flex;
+      align-items: center;
+      justify-content: center;
+      padding: 0 !important;
+    }
+    .cam-body video {
+      max-width: 100%;
+      max-height: 70vh;
+      display: block;
+    }
+
     /* CodeMirror editor host — matches .output styling so input & output align */
     .cm-editor {
       min-height: 180px;
@@ -330,7 +353,7 @@
       <div>
         <label for="input">Input</label>
         <div id="input"></div>
-        <input type="file" id="scan-input" accept="image/*" capture="environment" hidden>
+        <input type="file" id="scan-input" accept="image/*" hidden>
         <div id="scan-status" class="scan-status"></div>
       </div>
       <div>
@@ -443,7 +466,7 @@
             <div class="group">
               <button class="modal-btn icon" data-act="rotL" title="Rotate left"><span class="material-symbols-outlined">rotate_left</span></button>
               <button class="modal-btn icon" data-act="rotR" title="Rotate right"><span class="material-symbols-outlined">rotate_right</span></button>
-              <button class="modal-btn icon" data-act="reset" title="Reset"><span class="material-symbols-outlined">restart_alt</span></button>
+              <button class="modal-btn icon" data-act="invert" title="Invert colours (for light text on dark background)"><span class="material-symbols-outlined">invert_colors</span></button>
             </div>
             <div class="group">
               <button class="modal-btn" data-act="cancel">Cancel</button>
@@ -465,13 +488,15 @@
           checkOrientation: true,
         });
 
+        let invert = false;
+
         const cleanup = () => {
           cropper.destroy();
           URL.revokeObjectURL(url);
           backdrop.remove();
           document.removeEventListener("keydown", onKey);
         };
-        const finish = (blob) => { cleanup(); resolve(blob); };
+        const finish = (result) => { cleanup(); resolve(result); };
 
         const onKey = (e) => {
           if (e.key === "Escape") finish(null);
@@ -479,10 +504,13 @@
         };
         document.addEventListener("keydown", onKey);
 
-        function emit(act) {
+        function emit(act, btn) {
           if (act === "rotL")   cropper.rotate(-90);
           else if (act === "rotR")  cropper.rotate(90);
-          else if (act === "reset") cropper.reset();
+          else if (act === "invert") {
+            invert = !invert;
+            btn?.classList.toggle("active", invert);
+          }
           else if (act === "cancel") finish(null);
           else if (act === "use") {
             // With autoCrop:false, if the user never drew a region, force a
@@ -492,14 +520,14 @@
               maxWidth: OCR_MAX_DIM * 2,
               maxHeight: OCR_MAX_DIM * 2,
             });
-            if (canvas) canvas.toBlob(blob => finish(blob), "image/png");
+            if (canvas) canvas.toBlob(blob => finish({ blob, invert }), "image/png");
             else finish(null);
           }
         }
 
         modal.addEventListener("click", (e) => {
-          const act = e.target.closest("[data-act]")?.dataset.act;
-          if (act) emit(act);
+          const btn = e.target.closest("[data-act]");
+          if (btn) emit(btn.dataset.act, btn);
         });
         // Click on backdrop (outside the modal) = cancel
         backdrop.addEventListener("click", (e) => {
@@ -516,7 +544,7 @@
     const OCR_MAX_DIM = 1600;
     const OCR_CONFIDENCE_MIN = 60;  // word-level confidence (0-100)
 
-    async function preprocessForOCR(file) {
+    async function preprocessForOCR(file, { invert = false } = {}) {
       const bitmap = await createImageBitmap(file);
       const long = Math.max(bitmap.width, bitmap.height);
       const scale = Math.min(1, OCR_MAX_DIM / long);
@@ -530,7 +558,7 @@
       ctx.drawImage(bitmap, 0, 0, w, h);
       bitmap.close?.();
 
-      binarizeAdaptive(ctx, w, h);
+      binarizeAdaptive(ctx, w, h, { invert });
 
       // PNG, not JPEG — JPEG would re-blur the freshly-sharp B/W edges.
       const blob = await new Promise(resolve => canvas.toBlob(resolve, "image/png"));
@@ -540,7 +568,9 @@
     // Bradley/Roth adaptive threshold: compare each pixel against the
     // mean of a local window. Computed in O(N) total via an integral
     // image. Output is a 3-channel B/W image (R=G=B=0 or 255).
-    function binarizeAdaptive(ctx, w, h) {
+    // invert=true flips the grayscale before thresholding so white-on-dark
+    // text comes out as the expected black-on-white for Tesseract.
+    function binarizeAdaptive(ctx, w, h, { invert = false } = {}) {
       const imgData = ctx.getImageData(0, 0, w, h);
       const data = imgData.data;
 
@@ -549,6 +579,9 @@
       for (let i = 0, j = 0; i < data.length; i += 4, j++) {
         gray[j] = (data[i] * 0.299 + data[i + 1] * 0.587 + data[i + 2] * 0.114) | 0;
       }
+      if (invert) {
+        for (let i = 0; i < gray.length; i++) gray[i] = 255 - gray[i];
+      }
 
       // 2. Integral image (summed-area table)
       const integral = new Float64Array(w * h);
@@ -608,9 +641,9 @@
       scanBtn.disabled = true;
       setScanStatus("Loading crop editor…");
 
-      let cropped;
+      let cropResult;
       try {
-        cropped = await openCropper(file);
+        cropResult = await openCropper(file);
       } catch (e) {
         console.error(e);
         setScanStatus(`Crop editor failed: ${e.message || e}`, { error: true });
@@ -618,19 +651,20 @@
         scanInput.value = "";
         return;
       }
-      if (!cropped) {
+      if (!cropResult) {
         // User cancelled
         setScanStatus("");
         scanBtn.disabled = false;
         scanInput.value = "";
         return;
       }
+      const { blob: cropped, invert } = cropResult;
 
       setScanStatus("Preparing image…");
       const t0 = performance.now();
 
       try {
-        const { blob, w, h, scaled, origLong } = await preprocessForOCR(cropped);
+        const { blob, w, h, scaled, origLong } = await preprocessForOCR(cropped, { invert });
         if (scaled) {
           setScanStatus(`Preprocessed ${origLong}px → ${Math.max(w, h)}px (binarised)`);
         } else {
@@ -670,7 +704,93 @@
       }
     }
 
-    scanBtn.addEventListener("click", () => scanInput.click());
+    // Live camera capture via getUserMedia — bypasses the OS camera's
+    // "retake / use" confirm step that <input type=file capture> shows.
+    // Tap the shutter → frame is captured and crop modal opens immediately.
+    // Returns the captured Blob, "file" if the user wants the file picker,
+    // or null on cancel.
+    async function captureFromCamera() {
+      let stream;
+      try {
+        stream = await navigator.mediaDevices.getUserMedia({
+          video: { facingMode: { ideal: "environment" } },
+          audio: false,
+        });
+      } catch (e) {
+        console.warn("Camera unavailable:", e);
+        return "file";  // fall through to file picker
+      }
+      return new Promise((resolve) => {
+        const backdrop = document.createElement("div");
+        backdrop.className = "modal-backdrop";
+        const modal = document.createElement("div");
+        modal.className = "modal";
+        modal.innerHTML = `
+          <div class="modal-header">Aim at the text and tap the shutter</div>
+          <div class="modal-body cam-body"><video autoplay playsinline muted></video></div>
+          <div class="modal-footer">
+            <div class="group">
+              <button class="modal-btn icon" data-act="file" title="Pick from file instead"><span class="material-symbols-outlined">photo_library</span></button>
+            </div>
+            <div class="group">
+              <button class="modal-btn" data-act="cancel">Cancel</button>
+              <button class="modal-btn primary icon" data-act="shoot" title="Capture"><span class="material-symbols-outlined">photo_camera</span></button>
+            </div>
+          </div>
+        `;
+        backdrop.appendChild(modal);
+        document.body.appendChild(backdrop);
+
+        const video = modal.querySelector("video");
+        video.srcObject = stream;
+
+        const cleanup = () => {
+          stream.getTracks().forEach(t => t.stop());
+          video.srcObject = null;
+          backdrop.remove();
+          document.removeEventListener("keydown", onKey);
+        };
+        const finish = (r) => { cleanup(); resolve(r); };
+
+        const onKey = (e) => {
+          if (e.key === "Escape") finish(null);
+        };
+        document.addEventListener("keydown", onKey);
+
+        modal.addEventListener("click", (e) => {
+          const act = e.target.closest("[data-act]")?.dataset.act;
+          if (act === "cancel") finish(null);
+          else if (act === "file") finish("file");
+          else if (act === "shoot") {
+            const canvas = document.createElement("canvas");
+            canvas.width = video.videoWidth;
+            canvas.height = video.videoHeight;
+            canvas.getContext("2d").drawImage(video, 0, 0);
+            canvas.toBlob(blob => finish(blob), "image/jpeg", 0.92);
+          }
+        });
+        backdrop.addEventListener("click", (e) => {
+          if (e.target === backdrop) finish(null);
+        });
+      });
+    }
+
+    async function startScan() {
+      // On a touch device with getUserMedia, go straight to the live
+      // viewfinder. On desktop / no-camera, use the file picker.
+      if (isCoarsePointer && navigator.mediaDevices?.getUserMedia) {
+        const result = await captureFromCamera();
+        if (result === "file") {
+          scanInput.click();
+        } else if (result) {
+          runOCR(result);
+        }
+        return;
+      }
+      scanInput.click();
+    }
+
+    scanBtn.addEventListener("click", startScan);
     scanInput.addEventListener("change", (e) => {
       const file = e.target.files?.[0];
       if (file) runOCR(file);