==============================
Import statements
==============================

@import url("fineprint.css") print;
@import url("bluish.css") speech;
@import 'custom.css';
@import url("chrome://communicator/skin/");
@import "common.css" screen;

---

(stylesheet
  (import_statement (call_expression (function_name) (arguments (string_value))) (keyword_query))
  (import_statement (call_expression (function_name) (arguments (string_value))) (keyword_query))
  (import_statement (string_value))
  (import_statement (call_expression (function_name) (arguments (string_value))))
  (import_statement (string_value) (keyword_query)))

==============================
Namespace statements
==============================

/* Default namespace */
@namespace url(XML-namespace-URL);
@namespace "XML-namespace-URL";
@namespace url(http://www.w3.org/1999/xhtml);
@namespace svg url(http://www.w3.org/2000/svg);

/* Prefixed namespace */
@namespace prefix url(XML-namespace-URL);
@namespace prefix "XML-namespace-URL";

---

(stylesheet
  (comment)
  (namespace_statement (call_expression (function_name) (arguments (plain_value))))
  (namespace_statement (string_value))
  (namespace_statement (call_expression (function_name) (arguments (plain_value))))
  (namespace_statement (namespace_name) (call_expression (function_name) (arguments (plain_value))))
  (comment)
  (namespace_statement (namespace_name) (call_expression (function_name) (arguments (plain_value))))
  (namespace_statement (namespace_name) (string_value)))

==============================
Media statements
==============================

@media screen and (min-width: 30em) and (orientation: landscape) {}
@media (min-height: 680px), screen and (orientation: portrait) {}
@media not all and (monochrome) {}

---

(stylesheet
  (media_statement
    (binary_query
      (binary_query
        (keyword_query)
        (feature_query (feature_name) (integer_value (unit))))
      (feature_query (feature_name) (plain_value)))
    (block))
  (media_statement
    (feature_query (feature_name) (integer_value (unit)))
    (binary_query (keyword_query) (feature_query (feature_name) (plain_value)))
    (block))
  (media_statement
    (binary_query (negated_query (keyword_query)) (parenthesized_query (keyword_query)))
    (block)))

==============================
Charset statements
==============================

@charset "utf-8";

---

(stylesheet
  (charset_statement (string_value)))

==============================
Other at-statements
==============================

@font-face {
  font-family: "Open Sans";
  src: url("/a") format("woff2"), url("/b/c") format("woff");
}

---

(stylesheet
  (at_rule
    (at_keyword)
    (block
      (declaration (property_name) (string_value))
      (declaration (property_name)
        (call_expression (function_name) (arguments (string_value)))
        (call_expression (function_name) (arguments (string_value)))
        (call_expression (function_name) (arguments (string_value)))
        (call_expression (function_name) (arguments (string_value)))))))