added icons and moved to the css directory

css/calculator.css

@@ -0,0 +1,39 @@
+@charset "UTF-8";
+
+i.icon.calculator {
+	position: relative;
+	width: 18px;
+	height: 22px;
+	box-sizing: border-box;
+	display: block;
+	border-radius: 2px;
+	border: 2px solid;
+
+	&::after,
+	&::before {
+		top: 2px;
+		left: 2px;
+		content: "";
+		position: absolute;
+		width: 10px;
+		height: 2px;
+		box-sizing: border-box;
+		display: block;
+		background-color: currentColor;
+	}
+
+	&::after {
+		top: 6px;
+		width: 2px;
+		box-shadow:
+			4px 0 0,
+			8px 0 0,
+			0 4px 0,
+			4px 4px 0,
+			8px 4px 0,
+			0 8px 0,
+			4px 8px 0,
+			8px 8px 0,
+			8px 6px 0;
+	}
+}