Add new files for other syntax issues

Author: jacobcassidy

.dev-assets/syntax-issues/at-import.css

@@ -0,0 +1,4 @@
+@import url("green.css") layer supports(selector(&)) (min-width: calc(10px));
+
+/* layer as a function */
+@import url("green.css") layer(bar) supports(selector(&)) (min-width: calc(10px));

.dev-assets/syntax-issues/at-media-propertie.css

@@ -0,0 +1,6 @@
+/**
+ * AT MEDIA PROPERTY
+ */
+
+/* Missing token for `prefers-reduced-motion: reduce` */
+@media (prefers-reduced-motion: reduce) {}

.dev-assets/syntax-issues/of-not.css

@@ -0,0 +1,18 @@
+.item > div:nth-child(1 of :not(.hidden))  {
+  padding-left: var(--item_margin);
+}
+
+.item > div:nth-last-child(1 of :not(.hidden)) {
+  padding-right: var(--item_margin);
+}
+
+.item {
+  & > div {
+    &:nth-child(1 of :not(.hidden))  {
+      padding-left: var(--item_margin);
+    }
+    &:nth-last-child(1 of :not(.hidden)) {
+      padding-right: var(--item_margin);
+    }
+  }
+}