add calculation module and fix many bugs

assets/sass/_globalStyles.scss

@@ -11,8 +11,8 @@ body {
   }
 }
 
-p, a, span, b {
-  font-family: 'sahel';
+p, a, span, b, label, strong, small, li {
+  font-family: 'sahel', 'diodrum', sans-serif;
   color: rgba(0, 0, 0, 0.7);
   line-height: 1.6em;
 
@@ -67,6 +67,24 @@ section {
   padding: 0 0 100px;
 }
 
+.latin-digits {
+  p, a, span, b, label, strong, small, li, td, tr, th {
+    font-family: 'sahel-LD', 'diodrum', sans-serif;
+
+    &:lang(en) {
+      font-family: 'diodrum';
+    }
+  }
+
+  h1, h2, h3, h4, h5, h6 {
+    font-family: 'sahel-black-LD';
+
+    &:lang(en) {
+      font-family: 'diodrum-bold';
+    }
+  }
+}
+
 @keyframes loading {
   0% {
     @include transform(rotateZ(0));
@@ -168,6 +186,11 @@ section {
     display: flex;
     align-items: stretch;
     background: $darkGray;
+    direction: ltr;
+
+    &:lang(en) {
+      direction: rtl;
+    }
 
     .catalog-download {
       display: block;