samples/styles.css

@@ -1,14 +1,3 @@
-body {
-  color: #000;
-  background-color: #eee;
-}
-
-input, textarea {
-  color: #000;
-  background-color: #f5f5f5;
-  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
-}
-
 .my-block {
   max-width: 500px;
   margin: 0 auto;
@@ -24,6 +13,7 @@ input, textarea {
   border-radius: 10px;
   background-color: #f5f5f5;
   box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
+  line-height: 20px;
 }
 
 .ck-editor__editable {
@@ -62,22 +52,3 @@ input, textarea {
 .bes-status-icon.bes-status-mistakes {
   background-image: url('images/mistake-svgrepo-com.svg');
 }
-
-@media (prefers-color-scheme: dark) {
-  body {
-    color: #eee;
-    background-color: #444;
-    font-weight: bolder;
-  }
-
-  input, textarea {
-    color: #eee;
-    background-color: #222;
-    box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
-  }
-
-  .my-control {
-    background-color: #222;
-    box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
-  }
-}

service.js

@@ -1,5 +1,4 @@
 // TODO: Research if there is a way to disable languageTool & Grammarly extensions in CKEditor
-// TODO: Add mutation observer should any style of hostElement/textElement change and repaint markup (e.g. notice font-weight difference when toggling light/dark color-scheme)
 
 /**
  * Collection of all grammar checking services in the document
@@ -60,6 +59,7 @@ class BesService {
     this.hostElement.setAttribute('data-gramm', 'false')
     this.hostElement.setAttribute('data-gramm_editor', 'false')
     this.hostElement.setAttribute('data-enable-grammarly', 'false')
+    this.textFont = window.getComputedStyle(this.hostElement).fontFamily
 
     this.onScroll = this.onScroll.bind(this)
     this.hostElement.addEventListener('scroll', this.onScroll)
@@ -723,7 +723,7 @@ class BesService {
     this.ctx.stroke()
 
     if (comment) {
-      this.setCtxFont(scale, dpr)
+      this.ctx.font = `${12 * scale * dpr}px ${this.textFont}`
       this.ctx.textAlign = 'center'
       this.ctx.textBaseline = 'bottom'
       this.ctx.fillText('?', (x + 2 * scale) * dpr, (y - 6 * scale) * dpr)
@@ -807,7 +807,7 @@ class BesService {
     this.ctx.lineTo(x2 * dpr, (y2 + 6 * scale) * dpr)
     this.ctx.stroke()
 
-    this.setCtxFont(scale, dpr)
+    this.ctx.font = `${12 * scale * dpr}px ${this.textFont}`
     this.ctx.textAlign = 'left' // Thou we want the text to be centered, we align it manually to prevent it getting off canvas.
     this.ctx.textBaseline = 'bottom'
     const textMetrics = this.ctx.measureText(text)
@@ -842,7 +842,7 @@ class BesService {
     this.ctx.lineTo(x * dpr, (y2 + 6 * scale) * dpr)
     this.ctx.stroke()
 
-    this.setCtxFont(scale, dpr)
+    this.ctx.font = `${12 * scale * dpr}px ${this.textFont}`
     this.ctx.textAlign = 'left' // Thou we want the text to be centered, we align it manually to prevent it getting off canvas.
     this.ctx.textBaseline = 'bottom'
     const textMetrics = this.ctx.measureText(text)
@@ -880,18 +880,6 @@ class BesService {
     this.ctx.stroke()
   }
 
-  /**
-   * Sets markup font
-   *
-   * @param {Number} scale Sign scale
-   * @param {Number} dpr Device pixel ratio
-   */
-  setCtxFont(scale, dpr)
-  {
-    const styles = window.getComputedStyle(this.canvasPanel)
-    this.ctx.font = `${styles.fontStyle} ${styles.fontWeight} ${14 * scale * dpr}px ${styles.fontFamily}`
-  }
-
   /**
    * Calculates rectangles covering a given range and compensates for scroll offset
    *
@@ -1011,6 +999,8 @@ class BesService {
       this.scrollPanel.style.height = `${hostRect.height}px`
     }
 
+    this.textFont = styles.fontFamily
+
     // Resize canvas if needed.
     this.canvasPanel.style.width = `${this.hostElement.scrollWidth}px`
     this.canvasPanel.style.height = `${this.hostElement.scrollHeight}px`

styles.css

@@ -1,3 +1,5 @@
+/* TODO: Dark mode theme */
+
 /* Mistake types styles */
 .bes-spelling-mistake {
   border-bottom: 2px solid #ff7300;