diff --git a/public/css/admin.css b/public/css/admin.css
index 6be934e..9f3d97c 100644
--- a/public/css/admin.css
+++ b/public/css/admin.css
@@ -34,7 +34,7 @@
 	color: #fff;
 }
 #crop_editor input[type=number] {
-	width: 75px;
+	width: 85px;
 	background: #555;
 	color: #fff;
 }
@@ -44,6 +44,7 @@
 .crop_position {
 	background: rgba(0, 0, 0, 1.0);
 	border: none;
+	display: flex;
 	padding: 5px;
 	text-align: center;
 }
diff --git a/public/js/crop_editor.js b/public/js/crop_editor.js
index e1e3329..5aa64c6 100644
--- a/public/js/crop_editor.js
+++ b/public/js/crop_editor.js
@@ -16,6 +16,7 @@ class CropEditor {
 
 	initDOM() {
 		this.container = document.createElement("div");
+		this.container.className = 'container-fluid';
 		this.container.id = "crop_editor";
 
 		this.initPositionForm();
@@ -27,19 +28,30 @@ class CropEditor {
 
 	initPositionForm() {
 		this.position = document.createElement("fieldset");
-		this.position.className = "crop_position";
+		this.position.className = "crop_position flex-row justify-content-center";
 		this.container.appendChild(this.position);
 
 		const addNumericControl = (label, changeEvent) => {
-			const labelEl = document.createTextNode("div");
-			this.position.appendChild(labelEl);
+			const column = document.createElement('div');
+			column.className = 'col-auto';
+			this.position.appendChild(column);
+
+			const group = document.createElement('div');
+			group.className = 'input-group';
+			column.appendChild(group);
+
+			const labelEl = document.createElement("span");
+			labelEl.className = 'input-group-text';
+			labelEl.textContent = label;
+			group.appendChild(labelEl);
 
 			const control = document.createElement("input");
-			control.className = 'form-control d-inline';
+			control.className = 'form-control';
 			control.type = 'number';
 			control.addEventListener("change", changeEvent);
 			control.addEventListener("keyup", changeEvent);
-			this.position.appendChild(control);
+			group.appendChild(control);
+
 			return control;
 		};
 
@@ -48,28 +60,38 @@ class CropEditor {
 		this.crop_width = addNumericControl("Crop width:", this.positionBoundary);
 		this.crop_height = addNumericControl("Crop height:", this.positionBoundary);
 
-		this.crop_constrain_label = document.createElement("label");
-		this.position.appendChild(this.crop_constrain_label);
+		const otherColumn = document.createElement('div');
+		otherColumn.className = 'col-auto text-nowrap';
+		this.position.appendChild(otherColumn);
+
+		const constrainContainer = document.createElement("div");
+		constrainContainer.className = 'form-checkbox d-inline';
+		otherColumn.appendChild(constrainContainer);
 
 		this.crop_constrain = document.createElement("input");
 		this.crop_constrain.checked = true;
+		this.crop_constrain.className = 'form-check-input';
+		this.crop_constrain.id = 'check_constrain';
 		this.crop_constrain.type = 'checkbox';
-		this.crop_constrain_label.appendChild(this.crop_constrain);
+		constrainContainer.appendChild(this.crop_constrain);
 
-		this.crop_constrain_text = document.createTextNode('Constrain proportions');
-		this.crop_constrain_label.appendChild(this.crop_constrain_text);
+		this.crop_constrain_label = document.createElement("label");
+		this.crop_constrain_label.className = 'form-check-label';
+		this.crop_constrain_label.htmlFor = 'check_constrain';
+		this.crop_constrain_label.textContent = 'Constrain proportions';
+		constrainContainer.appendChild(this.crop_constrain_label);
 
 		this.save_button = document.createElement("span");
 		this.save_button.className = "btn btn-light";
 		this.save_button.textContent = "Save";
 		this.save_button.addEventListener('click', this.save.bind(this));
-		this.position.appendChild(this.save_button);
+		otherColumn.appendChild(this.save_button);
 
 		this.abort_button = document.createElement("span");
 		this.abort_button.className = "btn btn-danger";
 		this.abort_button.textContent = "Abort";
 		this.abort_button.addEventListener('click', this.hide.bind(this));
-		this.position.appendChild(this.abort_button);
+		otherColumn.appendChild(this.abort_button);
 	}
 
 	initImageContainer() {
@@ -153,7 +175,7 @@ class CropEditor {
 		this.source_x.max = source.naturalWidth - 1;
 		this.source_y.max = source.naturalHeight - 1;
 
-		this.crop_constrain_text.textContent = `Constrain proportions (${current.crop_width} × ${current.crop_height})`;
+		this.crop_constrain_label.textContent = `Constrain proportions (${current.crop_width} × ${current.crop_height})`;
 	}
 
 	showContainer() {