diff --git a/tests/css_less/__snapshots__/jsfmt.spec.js.snap b/tests/css_less/__snapshots__/jsfmt.spec.js.snap
new file mode 100644
index 000000000..86c4237a3
--- /dev/null
+++ b/tests/css_less/__snapshots__/jsfmt.spec.js.snap
@@ -0,0 +1,3189 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`less.css 1`] = `
+@nice-blue: #5B83AD;
+@light-blue: @nice-blue + #111;
+
+#header {
+  color: @light-blue;
+}
+
+
+#header {
+  color: #6c94be;
+}
+
+
+.bordered {
+  border-top: dotted 1px black;
+  border-bottom: solid 2px black;
+}
+
+
+#menu a {
+  color: #111;
+  .bordered;
+}
+
+.post a {
+  color: red;
+  .bordered;
+}
+
+
+#header {
+  color: black;
+}
+#header .navigation {
+  font-size: 12px;
+}
+#header .logo {
+  width: 300px;
+}
+
+
+#header {
+  color: black;
+  .navigation {
+    font-size: 12px;
+  }
+  .logo {
+    width: 300px;
+  }
+}
+
+
+.clearfix {
+  display: block;
+  zoom: 1;
+
+  &:after {
+    content: " ";
+    display: block;
+    font-size: 0;
+    height: 0;
+    clear: both;
+    visibility: hidden;
+  }
+}
+
+
+.screen-color {
+  @media screen {
+    color: green;
+    @media (min-width: 768px) {
+      color: red;
+    }
+  }
+  @media tv {
+    color: black;
+  }
+}
+
+
+@media screen {
+  .screen-color {
+    color: green;
+  }
+}
+@media screen and (min-width: 768px) {
+  .screen-color {
+    color: red;
+  }
+}
+@media tv {
+  .screen-color {
+    color: black;
+  }
+}
+
+
+#a {
+  color: blue;
+  @font-face {
+    src: made-up-url;
+  }
+  padding: 2 2 2 2;
+}
+
+
+#a {
+  color: blue;
+}
+@font-face {
+  src: made-up-url;
+}
+#a {
+  padding: 2 2 2 2;
+}
+
+
+// numbers are converted into the same units
+@conversion-1: 5cm + 10mm; // result is 6cm
+@conversion-2: 2 - 3cm - 5mm; // result is -1.5cm
+
+// conversion is impossible
+@incompatible-units: 2 + 5px - 3cm; // result is 4px
+
+// example with variables
+@base: 5%;
+@filler: @base * 2; // result is 10%
+@other: @base + @filler; // result is 15%
+
+
+@base: 2cm * 3mm; // result is 6cm
+
+
+@color: #224488 / 2; //results in #112244
+background-color: #112244 + #111; // result is #223355
+
+
+.weird-element {
+  content: ~"^//* some horrible but needed css hack";
+}
+
+
+@base: #f04615;
+@width: 0.5;
+
+.class {
+  width: percentage(@width); // returns \`50%\`
+  color: saturate(@base, 5%);
+  background-color: spin(lighten(@base, 25%), 8);
+}
+
+
+#bundle {
+  .button {
+    display: block;
+    border: 1px solid black;
+    background-color: grey;
+    &:hover {
+      background-color: white
+    }
+  }
+  .tab { /* ... */ }
+  .citation { /* ... */ }
+}
+
+
+#header a {
+  color: orange;
+  #bundle > .button;
+}
+
+
+@var: red;
+
+#page {
+  @var: white;
+  #header {
+    color: @var; // white
+  }
+}
+
+
+@var: red;
+
+#page {
+  #header {
+    color: @var; // white
+  }
+  @var: white;
+}
+
+
+/* One hell of a block
+style comment! */
+@var: red;
+
+// Get in line!
+@var: white;
+
+
+@import "library"; // library.less
+@import "typo.css";
+
+
+a,
+.link {
+  color: #428bca;
+}
+.widget {
+  color: #fff;
+  background: #428bca;
+}
+
+
+// Variables
+@link-color:        #428bca; // sea blue
+@link-color-hover:  darken(@link-color, 10%);
+
+// Usage
+a,
+.link {
+  color: @link-color;
+}
+a:hover {
+  color: @link-color-hover;
+}
+.widget {
+  color: #fff;
+  background: @link-color;
+}
+
+
+// Variables
+@my-selector: banner;
+
+// Usage
+.@{my-selector} {
+  font-weight: bold;
+  line-height: 40px;
+  margin: 0 auto;
+}
+
+
+.banner {
+  font-weight: bold;
+  line-height: 40px;
+  margin: 0 auto;
+}
+
+
+// Variables
+@images: "../img";
+
+// Usage
+body {
+  color: #444;
+  background: url("@{images}/white-sand.png");
+}
+
+
+// Variables
+@themes: "../../src/themes";
+
+// Usage
+@import "@{themes}/tidal-wave.less";
+
+
+@property: color;
+
+.widget {
+  @{property}: #0ee;
+  background-@{property}: #999;
+}
+
+
+.widget {
+  color: #0ee;
+  background-color: #999;
+}
+
+
+@fnord:  "I am fnord.";
+@var:    "fnord";
+content: @@var;
+
+
+content: "I am fnord.";
+
+
+.lazy-eval {
+  width: @var;
+}
+
+@var: @a;
+@a: 9%;
+
+
+.lazy-eval-scope {
+  width: @var;
+  @a: 9%;
+}
+
+@var: @a;
+@a: 100%;
+
+
+.lazy-eval-scope {
+  width: 9%;
+}
+
+
+@var: 0;
+.class {
+  @var: 1;
+  .brass {
+    @var: 2;
+    three: @var;
+    @var: 3;
+  }
+  one: @var;
+}
+
+
+.class {
+  one: 1;
+}
+.class .brass {
+  three: 3;
+}
+
+
+// library
+@base-color: green;
+@dark-color: darken(@base-color, 10%);
+
+// use of library
+@import "library.less";
+@base-color: red;
+
+
+nav ul {
+  &:extend(.inline);
+  background: blue;
+}
+
+
+nav ul {
+  &:extend(.inline);
+  background: blue;
+}
+.inline {
+  color: red;
+}
+
+
+nav ul {
+  background: blue;
+}
+.inline,
+nav ul {
+  color: red;
+}
+
+
+.a:extend(.b) {}
+
+// the above block does the same thing as the below block
+.a {
+  &:extend(.b);
+}
+
+
+.c:extend(.d all) {
+  // extends all instances of ".d" e.g. ".x.d" or ".d.x"
+}
+.c:extend(.d) {
+  // extends only instances where the selector will be output as just ".d"
+}
+
+
+.e:extend(.f) {}
+.e:extend(.g) {}
+
+// the above an the below do the same thing
+.e:extend(.f, .g) {}
+
+
+.big-division,
+.big-bag:extend(.bag),
+.big-bucket:extend(.bucket) {
+  // body
+}
+
+
+pre:hover,
+.some-class {
+  &:extend(div pre);
+}
+
+
+pre:hover:extend(div pre),
+.some-class:extend(div pre) {}
+
+
+.bucket {
+  tr { // nested ruleset with target selector
+    color: blue;
+  }
+}
+.some-class:extend(.bucket tr) {} // nested ruleset is recognized
+
+
+.bucket tr,
+.some-class {
+  color: blue;
+}
+
+
+.bucket {
+  tr & { // nested ruleset with target selector
+    color: blue;
+  }
+}
+.some-class:extend(tr .bucket) {} // nested ruleset is recognized
+
+
+tr .bucket,
+.some-class {
+  color: blue;
+}
+
+
+.a.class,
+.class.a,
+.class > .a {
+  color: blue;
+}
+.test:extend(.class) {} // this will NOT match the any selectors above
+
+
+*.class {
+  color: blue;
+}
+.noStar:extend(.class) {} // this will NOT match the *.class selector
+
+
+*.class {
+  color: blue;
+}
+
+
+link:hover:visited {
+  color: blue;
+}
+.selector:extend(link:visited:hover) {}
+
+
+link:hover:visited {
+  color: blue;
+}
+
+
+:nth-child(1n+3) {
+  color: blue;
+}
+.child:extend(:nth-child(n+3)) {}
+
+
+:nth-child(1n+3) {
+  color: blue;
+}
+
+
+[title=identifier] {
+  color: blue;
+}
+[title='identifier'] {
+  color: blue;
+}
+[title="identifier"] {
+  color: blue;
+}
+
+.noQuote:extend([title=identifier]) {}
+.singleQuote:extend([title='identifier']) {}
+.doubleQuote:extend([title="identifier"]) {}
+
+
+[title=identifier],
+.noQuote,
+.singleQuote,
+.doubleQuote {
+  color: blue;
+}
+
+[title='identifier'],
+.noQuote,
+.singleQuote,
+.doubleQuote {
+  color: blue;
+}
+
+[title="identifier"],
+.noQuote,
+.singleQuote,
+.doubleQuote {
+  color: blue;
+}
+
+
+.a.b.test,
+.test.c {
+  color: orange;
+}
+.test {
+  &:hover {
+    color: green;
+  }
+}
+
+.replacement:extend(.test all) {}
+
+
+.a.b.test,
+.test.c,
+.a.b.replacement,
+.replacement.c {
+  color: orange;
+}
+.test:hover,
+.replacement:hover {
+  color: green;
+}
+
+
+@variable: .bucket;
+@{variable} { // interpolated selector
+  color: blue;
+}
+.some-class:extend(.bucket) {} // does nothing, no match is found
+
+
+.bucket {
+  color: blue;
+}
+.some-class:extend(@{variable}) {} // interpolated selector matches nothing
+@variable: .bucket;
+
+
+.bucket {
+  color: blue;
+}
+
+
+.bucket {
+  color: blue;
+}
+@{variable}:extend(.bucket) {}
+@variable: .selector;
+
+
+.bucket, .selector {
+  color: blue;
+}
+
+
+@media print {
+  .screenClass:extend(.selector) {} // extend inside media
+  .selector { // this will be matched - it is in the same media
+    color: black;
+  }
+}
+.selector { // ruleset on top of style sheet - extend ignores it
+  color: red;
+}
+@media screen {
+  .selector {  // ruleset inside another media - extend ignores it
+    color: blue;
+  }
+}
+
+
+@media print {
+  .selector,
+  .screenClass { /*  ruleset inside the same media was extended */
+    color: black;
+  }
+}
+.selector { /* ruleset on top of style sheet was ignored */
+  color: red;
+}
+@media screen {
+  .selector { /* ruleset inside another media was ignored */
+    color: blue;
+  }
+}
+
+
+@media screen {
+  .screenClass:extend(.selector) {} // extend inside media
+  @media (min-width: 1023px) {
+    .selector {  // ruleset inside nested media - extend ignores it
+      color: blue;
+    }
+  }
+}
+
+
+@media screen and (min-width: 1023px) {
+  .selector { /* ruleset inside another nested media was ignored */
+    color: blue;
+  }
+}
+
+
+@media screen {
+  .selector {  /* ruleset inside nested media - top level extend works */
+    color: blue;
+  }
+  @media (min-width: 1023px) {
+    .selector {  /* ruleset inside nested media - top level extend works */
+      color: blue;
+    }
+  }
+}
+
+.topLevel:extend(.selector) {} /* top level extend matches everything */
+
+
+@media screen {
+  .selector,
+  .topLevel { /* ruleset inside media was extended */
+    color: blue;
+  }
+}
+@media screen and (min-width: 1023px) {
+  .selector,
+  .topLevel { /* ruleset inside nested media was extended */
+    color: blue;
+  }
+}
+
+
+.alert-info,
+.widget {
+  /* declarations */
+}
+
+.alert:extend(.alert-info, .widget) {}
+
+
+.alert-info,
+.widget,
+.alert,
+.alert {
+  /* declarations */
+}
+
+
+.animal {
+  background-color: black;
+  color: white;
+}
+
+
+.animal {
+  background-color: black;
+  color: white;
+}
+.bear {
+  background-color: brown;
+}
+
+.animal {
+  background-color: black;
+  color: white;
+}
+.bear {
+  &:extend(.animal);
+  background-color: brown;
+}
+
+
+.my-inline-block() {
+  display: inline-block;
+  font-size: 0;
+}
+.thing1 {
+  .my-inline-block;
+}
+.thing2 {
+  .my-inline-block;
+}
+
+
+.thing1 {
+  display: inline-block;
+  font-size: 0;
+}
+.thing2 {
+  display: inline-block;
+  font-size: 0;
+}
+
+
+.my-inline-block {
+  display: inline-block;
+  font-size: 0;
+}
+.thing1 {
+  &:extend(.my-inline-block);
+}
+.thing2 {
+  &:extend(.my-inline-block);
+}
+
+
+.my-inline-block,
+.thing1,
+.thing2 {
+  display: inline-block;
+  font-size: 0;
+}
+
+
+li.list > a {
+  // list styles
+}
+button.list-style {
+  &:extend(li.list > a); // use the same list styles
+}
+
+
+.a, #b {
+  color: red;
+}
+.mixin-class {
+  .a();
+}
+.mixin-id {
+  #b();
+}
+
+
+.a, #b {
+  color: red;
+}
+.mixin-class {
+  color: red;
+}
+.mixin-id {
+  color: red;
+}
+
+
+// these two statements do the same thing:
+.a();
+.a;
+
+
+.my-mixin {
+  color: black;
+}
+.my-other-mixin() {
+  background: white;
+}
+.class {
+  .my-mixin;
+  .my-other-mixin;
+}
+
+
+.my-mixin {
+  color: black;
+}
+.class {
+  color: black;
+  background: white;
+}
+
+
+.my-hover-mixin() {
+  &:hover {
+    border: 1px solid red;
+  }
+}
+button {
+  .my-hover-mixin();
+}
+
+
+button:hover {
+  border: 1px solid red;
+}
+
+
+#outer {
+  .inner {
+    color: red;
+  }
+}
+
+.c {
+  #outer > .inner;
+}
+
+
+// all do the same thing
+#outer > .inner;
+#outer > .inner();
+#outer .inner;
+#outer .inner();
+#outer.inner;
+#outer.inner();
+
+
+#my-library {
+  .my-mixin() {
+    color: black;
+  }
+}
+// which can be used like this
+.class {
+  #my-library > .my-mixin();
+}
+
+
+#namespace when (@mode=huge) {
+  .mixin() { /* */ }
+}
+
+#namespace {
+  .mixin() when (@mode=huge) { /* */ }
+}
+
+
+#sp_1 when (default()) {
+  #sp_2 when (default()) {
+    .mixin() when not(default()) { /* */ }
+  }
+}
+
+
+.foo (@bg: #f5f5f5, @color: #900) {
+  background: @bg;
+  color: @color;
+}
+.unimportant {
+  .foo();
+}
+.important {
+  .foo() !important;
+}
+
+
+.unimportant {
+  background: #f5f5f5;
+  color: #900;
+}
+.important {
+  background: #f5f5f5 !important;
+  color: #900 !important;
+}
+
+
+.border-radius(@radius) {
+  -webkit-border-radius: @radius;
+     -moz-border-radius: @radius;
+          border-radius: @radius;
+}
+
+
+#header {
+  .border-radius(4px);
+}
+.button {
+  .border-radius(6px);
+}
+
+
+.border-radius(@radius: 5px) {
+  -webkit-border-radius: @radius;
+     -moz-border-radius: @radius;
+          border-radius: @radius;
+}
+
+
+#header {
+  .border-radius;
+}
+
+
+.wrap() {
+  text-wrap: wrap;
+  white-space: -moz-pre-wrap;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+
+pre { .wrap }
+
+
+pre {
+  text-wrap: wrap;
+  white-space: -moz-pre-wrap;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+
+
+.mixin(@color) {
+  color-1: @color;
+}
+.mixin(@color; @padding: 2) {
+  color-2: @color;
+  padding-2: @padding;
+}
+.mixin(@color; @padding; @margin: 2) {
+  color-3: @color;
+  padding-3: @padding;
+  margin: @margin @margin @margin @margin;
+}
+.some .selector div {
+  .mixin(#008000);
+}
+
+
+.some .selector div {
+  color-1: #008000;
+  color-2: #008000;
+  padding-2: 2;
+}
+
+
+.mixin(@color: black; @margin: 10px; @padding: 20px) {
+  color: @color;
+  margin: @margin;
+  padding: @padding;
+}
+.class1 {
+  .mixin(@margin: 20px; @color: #33acfe);
+}
+.class2 {
+  .mixin(#efca44; @padding: 40px);
+}
+
+
+.class1 {
+  color: #33acfe;
+  margin: 20px;
+  padding: 20px;
+}
+.class2 {
+  color: #efca44;
+  margin: 10px;
+  padding: 40px;
+}
+
+
+.box-shadow(@x: 0; @y: 0; @blur: 1px; @color: #000) {
+  -webkit-box-shadow: @arguments;
+     -moz-box-shadow: @arguments;
+          box-shadow: @arguments;
+}
+.big-block {
+  .box-shadow(2px; 5px);
+}
+
+
+.big-block {
+  -webkit-box-shadow: 2px 5px 1px #000;
+     -moz-box-shadow: 2px 5px 1px #000;
+          box-shadow: 2px 5px 1px #000;
+}
+
+
+.mixin(/* ... */) {}        // matches 0-N arguments
+.mixin() {}           // matches exactly 0 arguments
+.mixin(@a: 1) {}      // matches 0-1 arguments
+.mixin(@a: 1; /* ... */) {} // matches 0-N arguments
+.mixin(@a; /* ... */) {}    // matches 1-N arguments
+
+
+.mixin(@a; @rest...) {
+   // @rest is bound to arguments after @a
+   // @arguments is bound to all arguments
+}
+
+
+.mixin(@s; @color) { /* ... */ }
+
+.class {
+  .mixin(@switch; #888);
+}
+
+
+.mixin(dark; @color) {
+  color: darken(@color, 10%);
+}
+.mixin(light; @color) {
+  color: lighten(@color, 10%);
+}
+.mixin(@_; @color) {
+  display: block;
+}
+
+
+@switch: light;
+
+.class {
+  .mixin(@switch; #888);
+}
+
+
+.class {
+  color: #a2a2a2;
+  display: block;
+}
+
+
+.mixin(@a) {
+  color: @a;
+}
+.mixin(@a; @b) {
+  color: fade(@a; @b);
+}
+
+
+.mixin() {
+  @width:  100%;
+  @height: 200px;
+}
+
+.caller {
+  .mixin();
+  width:  @width;
+  height: @height;
+}
+
+
+.caller {
+  width:  100%;
+  height: 200px;
+}
+
+
+.average(@x, @y) {
+  @average: ((@x + @y) / 2);
+}
+
+div {
+  .average(16px, 50px); // "call" the mixin
+  padding: @average;    // use its "return" value
+}
+
+
+div {
+  padding: 33px;
+}
+
+
+.mixin() {
+  @size: in-mixin;
+  @definedOnlyInMixin: in-mixin;
+}
+
+.class {
+  margin: @size @definedOnlyInMixin;
+  .mixin();
+}
+
+@size: globally-defined-value; // callers parent scope - no protection
+
+
+.class {
+  margin: in-mixin in-mixin;
+}
+
+
+.unlock(@value) { // outer mixin
+  .doSomething() { // nested mixin
+    declaration: @value;
+  }
+}
+
+#namespace {
+  .unlock(5); // unlock doSomething mixin
+  .doSomething(); //nested mixin was copied here and is usable
+}
+
+
+#namespace {
+  declaration: 5;
+}
+
+
+// declare detached ruleset
+@detached-ruleset: { background: red; };
+
+// use detached ruleset
+.top {
+    @detached-ruleset();
+}
+
+
+.top {
+  background: red;
+}
+
+
+.desktop-and-old-ie(@rules) {
+  @media screen and (min-width: 1200px) { @rules(); }
+  html.lt-ie9 &                         { @rules(); }
+}
+
+header {
+  background-color: blue;
+
+  .desktop-and-old-ie({
+    background-color: red;
+  });
+}
+
+
+header {
+  background-color: blue;
+}
+@media screen and (min-width: 1200px) {
+  header {
+    background-color: red;
+  }
+}
+html.lt-ie9 header {
+  background-color: red;
+}
+
+
+@my-ruleset: {
+    .my-selector {
+      background-color: black;
+    }
+  };
+
+
+@my-ruleset: {
+    .my-selector {
+      @media tv {
+        background-color: black;
+      }
+    }
+  };
+@media (orientation:portrait) {
+    @my-ruleset();
+}
+
+
+@media (orientation: portrait) and tv {
+  .my-selector {
+    background-color: black;
+  }
+}
+
+
+// detached ruleset with a mixin
+@detached-ruleset: {
+    .mixin() {
+        color:blue;
+    }
+};
+// call detached ruleset
+.caller {
+    @detached-ruleset();
+    .mixin();
+}
+
+
+.caller {
+  color: blue;
+}
+
+
+@detached-ruleset: {
+    @color:blue; // this variable is private
+};
+.caller {
+    color: @color; // syntax error
+}
+
+
+@detached-ruleset: {
+  caller-variable: @caller-variable; // variable is undefined here
+  .caller-mixin(); // mixin is undefined here
+};
+
+selector {
+  // use detached ruleset
+  @detached-ruleset();
+
+  // define variable and mixin needed inside the detached ruleset
+  @caller-variable: value;
+  .caller-mixin() {
+    variable: declaration;
+  }
+}
+
+
+selector {
+  caller-variable: value;
+  variable: declaration;
+}
+
+
+@variable: global;
+@detached-ruleset: {
+  // will use global variable, because it is accessible
+  // from detached-ruleset definition
+  variable: @variable;
+};
+
+selector {
+  @detached-ruleset();
+  @variable: value; // variable defined in caller - will be ignored
+}
+
+
+selector {
+  variable: global;
+}
+
+
+@detached-1: { scope-detached: @one @two; };
+.one {
+  @one: visible;
+  .two {
+    @detached-2: @detached-1; // copying/renaming ruleset
+    @two: visible; // ruleset can not see this variable
+  }
+}
+
+.use-place {
+  .one > .two();
+  @detached-2();
+}
+
+
+ERROR 1:32 The variable "@one" was not declared.
+
+
+#space {
+  .importer-1() {
+    @detached: { scope-detached: @variable; }; // define detached ruleset
+  }
+}
+
+.importer-2() {
+  @variable: value; // unlocked detached ruleset CAN see this variable
+  #space > .importer-1(); // unlock/import detached ruleset
+}
+
+.use-place {
+  .importer-2(); // unlock/import detached ruleset second time
+   @detached();
+}
+
+
+.use-place {
+  scope-detached: value;
+}
+
+
+.foo {
+  background: #900;
+}
+@import "this-is-valid.less";
+
+
+@import "foo";      // foo.less is imported
+@import "foo.less"; // foo.less is imported
+@import "foo.php";  // foo.php imported as a less file
+@import "foo.css";  // statement left in place, as-is
+
+
+.navbar:extend(.navbar all) {}
+
+
+@import (less) "foo.css";
+
+
+@import (css) "foo.less";
+
+
+@import "foo.less";
+
+
+@import (once) "foo.less";
+@import (once) "foo.less"; // this statement will be ignored
+
+
+// file: foo.less
+.a {
+  color: green;
+}
+// file: main.less
+@import (multiple) "foo.less";
+@import (multiple) "foo.less";
+
+
+.a {
+  color: green;
+}
+.a {
+  color: green;
+}
+
+
+.mixin (@a) when (lightness(@a) >= 50%) {
+  background-color: black;
+}
+.mixin (@a) when (lightness(@a) < 50%) {
+  background-color: white;
+}
+.mixin (@a) {
+  color: @a;
+}
+
+
+.class1 { .mixin(#ddd) }
+.class2 { .mixin(#555) }
+
+
+.class1 {
+  background-color: black;
+  color: #ddd;
+}
+.class2 {
+  background-color: white;
+  color: #555;
+}
+
+
+.truth (@a) when (@a) { /* ... */ }
+.truth (@a) when (@a = true) { /* ... */ }
+
+
+.class {
+  .truth(40); // Will not match any of the above definitions.
+}
+
+
+@media: mobile;
+
+.mixin (@a) when (@media = mobile) { /* ... */ }
+.mixin (@a) when (@media = desktop) { /* ... */ }
+
+.max (@a; @b) when (@a > @b) { width: @a }
+.max (@a; @b) when (@a < @b) { width: @b }
+
+
+.mixin (@a) when (isnumber(@a)) and (@a > 0) { /* ... */ }
+
+
+.mixin (@a) when (@a > 10), (@a < -10) { /* ... */ }
+
+
+.mixin (@b) when not (@b > 0) { /* ... */ }
+
+
+.mixin (@a; @b: 0) when (isnumber(@b)) { /* ... */ }
+.mixin (@a; @b: black) when (iscolor(@b)) { /* ... */ }
+
+
+.mixin (@a) when (@a > 0) { /* ... */  }
+.mixin (@a) when (default()) { /* ... */ } // matches only if first mixin does not, i.e. when @a <= 0
+
+
+.my-optional-style() when (@my-option = true) {
+  button {
+    color: white;
+  }
+}
+.my-optional-style();
+
+
+button when (@my-option = true) {
+  color: white;
+}
+
+
+& when (@my-option = true) {
+  button {
+    color: white;
+  }
+  a {
+    color: blue;
+  }
+}
+
+
+.loop(@counter) when (@counter > 0) {
+  .loop((@counter - 1));    // next iteration
+  width: (10px * @counter); // code for each iteration
+}
+
+div {
+  .loop(5); // launch the loop
+}
+
+
+div {
+  width: 10px;
+  width: 20px;
+  width: 30px;
+  width: 40px;
+  width: 50px;
+}
+
+
+.generate-columns(4);
+
+.generate-columns(@n, @i: 1) when (@i =< @n) {
+  .column-@{i} {
+    width: (@i * 100% / @n);
+  }
+  .generate-columns(@n, (@i + 1));
+}
+
+
+.column-1 {
+  width: 25%;
+}
+.column-2 {
+  width: 50%;
+}
+.column-3 {
+  width: 75%;
+}
+.column-4 {
+  width: 100%;
+}
+
+
+.mixin() {
+  box-shadow+: inset 0 0 10px #555;
+}
+.myclass {
+  .mixin();
+  box-shadow+: 0 0 20px black;
+}
+
+
+.myclass {
+  box-shadow: inset 0 0 10px #555, 0 0 20px black;
+}
+
+
+.mixin() {
+  transform+_: scale(2);
+}
+.myclass {
+  .mixin();
+  transform+_: rotate(15deg);
+}
+
+
+.myclass {
+  transform: scale(2) rotate(15deg);
+}
+
+
+a {
+  color: blue;
+  &:hover {
+    color: green;
+  }
+}
+
+
+a {
+  color: blue;
+}
+
+a:hover {
+  color: green;
+}
+
+
+.button {
+  &-ok {
+    background-image: url("ok.png");
+  }
+  &-cancel {
+    background-image: url("cancel.png");
+  }
+
+  &-custom {
+    background-image: url("custom.png");
+  }
+}
+
+
+.button-ok {
+  background-image: url("ok.png");
+}
+.button-cancel {
+  background-image: url("cancel.png");
+}
+.button-custom {
+  background-image: url("custom.png");
+}
+
+
+.link {
+  & + & {
+    color: red;
+  }
+
+  & & {
+    color: green;
+  }
+
+  && {
+    color: blue;
+  }
+
+  &, &ish {
+    color: cyan;
+  }
+}
+
+
+.link + .link {
+  color: red;
+}
+.link .link {
+  color: green;
+}
+.link.link {
+  color: blue;
+}
+.link, .linkish {
+  color: cyan;
+}
+
+
+.grand {
+  .parent {
+    & > & {
+      color: red;
+    }
+
+    & & {
+      color: green;
+    }
+
+    && {
+      color: blue;
+    }
+
+    &, &ish {
+      color: cyan;
+    }
+  }
+}
+
+
+.grand .parent > .grand .parent {
+  color: red;
+}
+.grand .parent .grand .parent {
+  color: green;
+}
+.grand .parent.grand .parent {
+  color: blue;
+}
+.grand .parent,
+.grand .parentish {
+  color: cyan;
+}
+
+
+.header {
+  .menu {
+    border-radius: 5px;
+    .no-borderradius & {
+      background-image: url('images/button-background.png');
+    }
+  }
+}
+
+
+.header .menu {
+  border-radius: 5px;
+}
+.no-borderradius .header .menu {
+  background-image: url('images/button-background.png');
+}
+
+
+p, a, ul, li {
+  border-top: 2px dotted #366;
+  & + & {
+    border-top: 0;
+  }
+}
+
+
+p,
+a,
+ul,
+li {
+  border-top: 2px dotted #366;
+}
+p + p,
+p + a,
+p + ul,
+p + li,
+a + p,
+a + a,
+a + ul,
+a + li,
+ul + p,
+ul + a,
+ul + ul,
+ul + li,
+li + p,
+li + a,
+li + ul,
+li + li {
+  border-top: 0;
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+@nice-blue: #5b83ad;
+@light-blue: @nice-blue + #111;
+
+#header {
+  color: @light-blue;
+}
+
+#header {
+  color: #6c94be;
+}
+
+.bordered {
+  border-top: dotted 1px black;
+  border-bottom: solid 2px black;
+}
+
+#menu a {
+  color: #111;
+  .bordered;
+}
+
+.post a {
+  color: red;
+  .bordered;
+}
+
+#header {
+  color: black;
+}
+#header .navigation {
+  font-size: 12px;
+}
+#header .logo {
+  width: 300px;
+}
+
+#header {
+  color: black;
+  .navigation {
+    font-size: 12px;
+  }
+  .logo {
+    width: 300px;
+  }
+}
+
+.clearfix {
+  display: block;
+  zoom: 1;
+
+  &:after {
+    content: " ";
+    display: block;
+    font-size: 0;
+    height: 0;
+    clear: both;
+    visibility: hidden;
+  }
+}
+
+.screen-color {
+  @media screen {
+    color: green;
+    @media (min-width: 768px) {
+      color: red;
+    }
+  }
+  @media tv {
+    color: black;
+  }
+}
+
+@media screen {
+  .screen-color {
+    color: green;
+  }
+}
+@media screen and (min-width: 768px) {
+  .screen-color {
+    color: red;
+  }
+}
+@media tv {
+  .screen-color {
+    color: black;
+  }
+}
+
+#a {
+  color: blue;
+  @font-face {
+    src: made-up-url;
+  }
+  padding: 2 2 2 2;
+}
+
+#a {
+  color: blue;
+}
+@font-face {
+  src: made-up-url;
+}
+#a {
+  padding: 2 2 2 2;
+}
+
+// numbers are converted into the same units
+@conversion-1: 5cm + 10mm; // result is 6cm
+@conversion-2: 2 - 3cm - 5mm; // result is -1.5cm
+
+// conversion is impossible
+@incompatible-units: 2 + 5px - 3cm; // result is 4px
+
+// example with variables
+@base: 5%;
+@filler: @base * 2; // result is 10%
+@other: @base + @filler; // result is 15%
+
+@base: 2cm * 3mm; // result is 6cm
+
+@color: #224488 / 2; //results in #112244
+background-color: #112244 + #111; // result is #223355
+
+.weird-element {
+  content: ~"^//* some horrible but needed css hack";
+}
+
+@base: #f04615;
+@width: 0.5;
+
+.class {
+  width: percentage(@width); // returns \`50%\`
+  color: saturate(@base, 5%);
+  background-color: spin(lighten(@base, 25%), 8);
+}
+
+#bundle {
+  .button {
+    display: block;
+    border: 1px solid black;
+    background-color: grey;
+    &:hover {
+      background-color: white;
+    }
+  }
+  .tab {
+    /* ... */
+  }
+  .citation {
+    /* ... */
+  }
+}
+
+#header a {
+  color: orange;
+  #bundle > .button;
+}
+
+@var: red;
+
+#page {
+  @var: white;
+  #header {
+    color: @var; // white
+  }
+}
+
+@var: red;
+
+#page {
+  #header {
+    color: @var; // white
+  }
+  @var: white;
+}
+
+/* One hell of a block
+style comment! */
+@var: red;
+
+// Get in line!
+@var: white;
+
+@import "library"; // library.less
+@import "typo.css";
+
+a,
+.link {
+  color: #428bca;
+}
+.widget {
+  color: #fff;
+  background: #428bca;
+}
+
+// Variables
+@link-color: #428bca; // sea blue
+@link-color-hover: darken(@link-color, 10%);
+
+// Usage
+a,
+.link {
+  color: @link-color;
+}
+a:hover {
+  color: @link-color-hover;
+}
+.widget {
+  color: #fff;
+  background: @link-color;
+}
+
+// Variables
+@my-selector: banner;
+
+// Usage
+.@{my-selector} {
+  font-weight: bold;
+  line-height: 40px;
+  margin: 0 auto;
+}
+
+.banner {
+  font-weight: bold;
+  line-height: 40px;
+  margin: 0 auto;
+}
+
+// Variables
+@images: "../img";
+
+// Usage
+body {
+  color: #444;
+  background: url("@{images}/white-sand.png");
+}
+
+// Variables
+@themes: "../../src/themes";
+
+// Usage
+@import "@{themes}/tidal-wave.less";
+
+@property: color;
+
+.widget {
+  @{property}: #0ee;
+  background-@{property}: #999;
+}
+
+.widget {
+  color: #0ee;
+  background-color: #999;
+}
+
+@fnord: "I am fnord.";
+@var: "fnord";
+content: @@var;
+
+content: "I am fnord.";
+
+.lazy-eval {
+  width: @var;
+}
+
+@var: @a;
+@a: 9%;
+
+.lazy-eval-scope {
+  width: @var;
+  @a: 9%;
+}
+
+@var: @a;
+@a: 100%;
+
+.lazy-eval-scope {
+  width: 9%;
+}
+
+@var: 0;
+.class {
+  @var: 1;
+  .brass {
+    @var: 2;
+    three: @var;
+    @var: 3;
+  }
+  one: @var;
+}
+
+.class {
+  one: 1;
+}
+.class .brass {
+  three: 3;
+}
+
+// library
+@base-color: green;
+@dark-color: darken(@base-color, 10%);
+
+// use of library
+@import "library.less";
+@base-color: red;
+
+nav ul {
+  &:extend(.inline);
+  background: blue;
+}
+
+nav ul {
+  &:extend(.inline);
+  background: blue;
+}
+.inline {
+  color: red;
+}
+
+nav ul {
+  background: blue;
+}
+.inline,
+nav ul {
+  color: red;
+}
+
+.a:extend(.b) {
+}
+
+// the above block does the same thing as the below block
+.a {
+  &:extend(.b);
+}
+
+.c:extend(.d all) {
+  // extends all instances of ".d" e.g. ".x.d" or ".d.x"
+}
+.c:extend(.d) {
+  // extends only instances where the selector will be output as just ".d"
+}
+
+.e:extend(.f) {
+}
+.e:extend(.g) {
+}
+
+// the above an the below do the same thing
+.e:extend(.f, .g) {
+}
+
+.big-division,
+.big-bag:extend(.bag),
+.big-bucket:extend(.bucket) {
+  // body
+}
+
+pre:hover,
+.some-class {
+  &:extend(div pre);
+}
+
+pre:hover:extend(div pre),
+.some-class:extend(div pre) {
+}
+
+.bucket {
+  tr {
+    // nested ruleset with target selector
+    color: blue;
+  }
+}
+.some-class:extend(.bucket tr) {
+} // nested ruleset is recognized
+
+.bucket tr,
+.some-class {
+  color: blue;
+}
+
+.bucket {
+  tr & {
+    // nested ruleset with target selector
+    color: blue;
+  }
+}
+.some-class:extend(tr .bucket) {
+} // nested ruleset is recognized
+
+tr .bucket,
+.some-class {
+  color: blue;
+}
+
+.a.class,
+.class.a,
+.class > .a {
+  color: blue;
+}
+.test:extend(.class) {
+} // this will NOT match the any selectors above
+
+*.class {
+  color: blue;
+}
+.noStar:extend(.class) {
+} // this will NOT match the *.class selector
+
+*.class {
+  color: blue;
+}
+
+link:hover:visited {
+  color: blue;
+}
+.selector:extend(link:visited:hover) {
+}
+
+link:hover:visited {
+  color: blue;
+}
+
+:nth-child(1n + 3) {
+  color: blue;
+}
+.child:extend(:nth-child(n + 3)) {
+}
+
+:nth-child(1n + 3) {
+  color: blue;
+}
+
+[title="identifier"] {
+  color: blue;
+}
+[title="identifier"] {
+  color: blue;
+}
+[title="identifier"] {
+  color: blue;
+}
+
+.noQuote:extend([title="identifier"]) {
+}
+.singleQuote:extend([title="identifier"]) {
+}
+.doubleQuote:extend([title="identifier"]) {
+}
+
+[title="identifier"],
+.noQuote,
+.singleQuote,
+.doubleQuote {
+  color: blue;
+}
+
+[title="identifier"],
+.noQuote,
+.singleQuote,
+.doubleQuote {
+  color: blue;
+}
+
+[title="identifier"],
+.noQuote,
+.singleQuote,
+.doubleQuote {
+  color: blue;
+}
+
+.a.b.test,
+.test.c {
+  color: orange;
+}
+.test {
+  &:hover {
+    color: green;
+  }
+}
+
+.replacement:extend(.test all) {
+}
+
+.a.b.test,
+.test.c,
+.a.b.replacement,
+.replacement.c {
+  color: orange;
+}
+.test:hover,
+.replacement:hover {
+  color: green;
+}
+
+@variable: .bucket;
+@{variable} {
+  // interpolated selector
+  color: blue;
+}
+.some-class:extend(.bucket) {
+} // does nothing, no match is found
+
+.bucket {
+  color: blue;
+}
+.some-class:extend(@{variable}) {
+} // interpolated selector matches nothing
+@variable: .bucket;
+
+.bucket {
+  color: blue;
+}
+
+.bucket {
+  color: blue;
+}
+@{variable}:extend(.bucket) {
+}
+@variable: .selector;
+
+.bucket,
+.selector {
+  color: blue;
+}
+
+@media print {
+  .screenClass:extend(.selector) {
+  } // extend inside media
+  .selector {
+    // this will be matched - it is in the same media
+    color: black;
+  }
+}
+.selector {
+  // ruleset on top of style sheet - extend ignores it
+  color: red;
+}
+@media screen {
+  .selector {
+    // ruleset inside another media - extend ignores it
+    color: blue;
+  }
+}
+
+@media print {
+  .selector,
+  .screenClass {
+    /*  ruleset inside the same media was extended */
+    color: black;
+  }
+}
+.selector {
+  /* ruleset on top of style sheet was ignored */
+  color: red;
+}
+@media screen {
+  .selector {
+    /* ruleset inside another media was ignored */
+    color: blue;
+  }
+}
+
+@media screen {
+  .screenClass:extend(.selector) {
+  } // extend inside media
+  @media (min-width: 1023px) {
+    .selector {
+      // ruleset inside nested media - extend ignores it
+      color: blue;
+    }
+  }
+}
+
+@media screen and (min-width: 1023px) {
+  .selector {
+    /* ruleset inside another nested media was ignored */
+    color: blue;
+  }
+}
+
+@media screen {
+  .selector {
+    /* ruleset inside nested media - top level extend works */
+    color: blue;
+  }
+  @media (min-width: 1023px) {
+    .selector {
+      /* ruleset inside nested media - top level extend works */
+      color: blue;
+    }
+  }
+}
+
+.topLevel:extend(.selector) {
+} /* top level extend matches everything */
+
+@media screen {
+  .selector,
+  .topLevel {
+    /* ruleset inside media was extended */
+    color: blue;
+  }
+}
+@media screen and (min-width: 1023px) {
+  .selector,
+  .topLevel {
+    /* ruleset inside nested media was extended */
+    color: blue;
+  }
+}
+
+.alert-info,
+.widget {
+  /* declarations */
+}
+
+.alert:extend(.alert-info, .widget) {
+}
+
+.alert-info,
+.widget,
+.alert,
+.alert {
+  /* declarations */
+}
+
+.animal {
+  background-color: black;
+  color: white;
+}
+
+.animal {
+  background-color: black;
+  color: white;
+}
+.bear {
+  background-color: brown;
+}
+
+.animal {
+  background-color: black;
+  color: white;
+}
+.bear {
+  &:extend(.animal);
+  background-color: brown;
+}
+
+.my-inline-block() {
+  display: inline-block;
+  font-size: 0;
+}
+.thing1 {
+  .my-inline-block;
+}
+.thing2 {
+  .my-inline-block;
+}
+
+.thing1 {
+  display: inline-block;
+  font-size: 0;
+}
+.thing2 {
+  display: inline-block;
+  font-size: 0;
+}
+
+.my-inline-block {
+  display: inline-block;
+  font-size: 0;
+}
+.thing1 {
+  &:extend(.my-inline-block);
+}
+.thing2 {
+  &:extend(.my-inline-block);
+}
+
+.my-inline-block,
+.thing1,
+.thing2 {
+  display: inline-block;
+  font-size: 0;
+}
+
+li.list > a {
+  // list styles
+}
+button.list-style {
+  &:extend(li.list > a); // use the same list styles
+}
+
+.a,
+#b {
+  color: red;
+}
+.mixin-class {
+  .a();
+}
+.mixin-id {
+  #b();
+}
+
+.a,
+#b {
+  color: red;
+}
+.mixin-class {
+  color: red;
+}
+.mixin-id {
+  color: red;
+}
+
+// these two statements do the same thing:
+.a();
+.a;
+
+.my-mixin {
+  color: black;
+}
+.my-other-mixin() {
+  background: white;
+}
+.class {
+  .my-mixin;
+  .my-other-mixin;
+}
+
+.my-mixin {
+  color: black;
+}
+.class {
+  color: black;
+  background: white;
+}
+
+.my-hover-mixin() {
+  &:hover {
+    border: 1px solid red;
+  }
+}
+button {
+  .my-hover-mixin();
+}
+
+button:hover {
+  border: 1px solid red;
+}
+
+#outer {
+  .inner {
+    color: red;
+  }
+}
+
+.c {
+  #outer > .inner;
+}
+
+// all do the same thing
+#outer > .inner;
+#outer > .inner();
+#outer .inner;
+#outer .inner();
+#outer.inner;
+#outer.inner();
+
+#my-library {
+  .my-mixin() {
+    color: black;
+  }
+}
+// which can be used like this
+.class {
+  #my-library > .my-mixin();
+}
+
+#namespace when (@mode=huge) {
+  .mixin() {
+    /* */
+  }
+}
+
+#namespace {
+  .mixin() when (@mode=huge) {
+    /* */
+  }
+}
+
+#sp_1 when (default()) {
+  #sp_2 when (default()) {
+    .mixin() when not(default()) {
+      /* */
+    }
+  }
+}
+
+.foo (@bg: #f5f5f5, @color: #900) {
+  background: @bg;
+  color: @color;
+}
+.unimportant {
+  .foo();
+}
+.important {
+  .foo() !important;
+}
+
+.unimportant {
+  background: #f5f5f5;
+  color: #900;
+}
+.important {
+  background: #f5f5f5 !important;
+  color: #900 !important;
+}
+
+.border-radius(@radius) {
+  -webkit-border-radius: @radius;
+  -moz-border-radius: @radius;
+  border-radius: @radius;
+}
+
+#header {
+  .border-radius(4px);
+}
+.button {
+  .border-radius(6px);
+}
+
+.border-radius(@radius: 5px) {
+  -webkit-border-radius: @radius;
+  -moz-border-radius: @radius;
+  border-radius: @radius;
+}
+
+#header {
+  .border-radius;
+}
+
+.wrap() {
+  text-wrap: wrap;
+  white-space: -moz-pre-wrap;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+
+pre {
+  .wrap;
+}
+
+pre {
+  text-wrap: wrap;
+  white-space: -moz-pre-wrap;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+
+.mixin(@color) {
+  color-1: @color;
+}
+.mixin(@color; @padding: 2) {
+  color-2: @color;
+  padding-2: @padding;
+}
+.mixin(@color; @padding; @margin: 2) {
+  color-3: @color;
+  padding-3: @padding;
+  margin: @margin @margin @margin @margin;
+}
+.some .selector div {
+  .mixin(#008000);
+}
+
+.some .selector div {
+  color-1: #008000;
+  color-2: #008000;
+  padding-2: 2;
+}
+
+.mixin(@color: black; @margin: 10px; @padding: 20px) {
+  color: @color;
+  margin: @margin;
+  padding: @padding;
+}
+.class1 {
+  .mixin(@margin: 20px; @color: #33acfe);
+}
+.class2 {
+  .mixin(#efca44; @padding: 40px);
+}
+
+.class1 {
+  color: #33acfe;
+  margin: 20px;
+  padding: 20px;
+}
+.class2 {
+  color: #efca44;
+  margin: 10px;
+  padding: 40px;
+}
+
+.box-shadow(@x: 0; @y: 0; @blur: 1px; @color: #000) {
+  -webkit-box-shadow: @arguments;
+  -moz-box-shadow: @arguments;
+  box-shadow: @arguments;
+}
+.big-block {
+  .box-shadow(2px; 5px);
+}
+
+.big-block {
+  -webkit-box-shadow: 2px 5px 1px #000;
+  -moz-box-shadow: 2px 5px 1px #000;
+  box-shadow: 2px 5px 1px #000;
+}
+
+.mixin(/* ... */) {
+} // matches 0-N arguments
+.mixin() {
+} // matches exactly 0 arguments
+.mixin(@a: 1) {
+} // matches 0-1 arguments
+.mixin(@a: 1; /* ... */) {
+} // matches 0-N arguments
+.mixin(@a; /* ... */) {
+} // matches 1-N arguments
+
+.mixin(@a; @rest...) {
+  // @rest is bound to arguments after @a
+  // @arguments is bound to all arguments
+}
+
+.mixin(@s; @color) {
+  /* ... */
+}
+
+.class {
+  .mixin(@switch; #888);
+}
+
+.mixin(dark; @color) {
+  color: darken(@color, 10%);
+}
+.mixin(light; @color) {
+  color: lighten(@color, 10%);
+}
+.mixin(@_; @color) {
+  display: block;
+}
+
+@switch: light;
+
+.class {
+  .mixin(@switch; #888);
+}
+
+.class {
+  color: #a2a2a2;
+  display: block;
+}
+
+.mixin(@a) {
+  color: @a;
+}
+.mixin(@a; @b) {
+  color: fade(@a; @b);
+}
+
+.mixin() {
+  @width: 100%;
+  @height: 200px;
+}
+
+.caller {
+  .mixin();
+  width: @width;
+  height: @height;
+}
+
+.caller {
+  width: 100%;
+  height: 200px;
+}
+
+.average(@x, @y) {
+  @average: ((@x + @y) / 2);
+}
+
+div {
+  .average(16px, 50px); // "call" the mixin
+  padding: @average; // use its "return" value
+}
+
+div {
+  padding: 33px;
+}
+
+.mixin() {
+  @size: in-mixin;
+  @definedOnlyInMixin: in-mixin;
+}
+
+.class {
+  margin: @size @definedOnlyInMixin;
+  .mixin();
+}
+
+@size: globally-defined-value; // callers parent scope - no protection
+
+.class {
+  margin: in-mixin in-mixin;
+}
+
+.unlock(@value) {
+  // outer mixin
+  .doSomething() {
+    // nested mixin
+    declaration: @value;
+  }
+}
+
+#namespace {
+  .unlock(5); // unlock doSomething mixin
+  .doSomething(); //nested mixin was copied here and is usable
+}
+
+#namespace {
+  declaration: 5;
+}
+
+// declare detached ruleset
+@detached-ruleset: {
+  background: red;
+}
+
+// use detached ruleset
+.top {
+  @detached-ruleset();
+}
+
+.top {
+  background: red;
+}
+
+.desktop-and-old-ie(@rules) {
+  @media screen and (min-width: 1200px) {
+    @rules();
+  }
+  html.lt-ie9 & {
+    @rules();
+  }
+}
+
+header {
+  background-color: blue;
+
+  .desktop-and-old-ie({
+    background-color: red;
+  });
+}
+
+header {
+  background-color: blue;
+}
+@media screen and (min-width: 1200px) {
+  header {
+    background-color: red;
+  }
+}
+html.lt-ie9 header {
+  background-color: red;
+}
+
+@my-ruleset: {
+  .my-selector {
+    background-color: black;
+  }
+}
+
+@my-ruleset: {
+  .my-selector {
+    @media tv {
+      background-color: black;
+    }
+  }
+}
+@media (orientation: portrait) {
+  @my-ruleset();
+}
+
+@media (orientation: portrait) and tv {
+  .my-selector {
+    background-color: black;
+  }
+}
+
+// detached ruleset with a mixin
+@detached-ruleset: {
+  .mixin() {
+    color: blue;
+  }
+}
+// call detached ruleset
+.caller {
+  @detached-ruleset();
+  .mixin();
+}
+
+.caller {
+  color: blue;
+}
+
+@detached-ruleset: {
+  @color: blue; // this variable is private
+}
+.caller {
+  color: @color; // syntax error
+}
+
+@detached-ruleset: {
+  caller-variable: @caller-variable; // variable is undefined here
+  .caller-mixin(); // mixin is undefined here
+}
+
+selector {
+  // use detached ruleset
+  @detached-ruleset();
+
+  // define variable and mixin needed inside the detached ruleset
+  @caller-variable: value;
+  .caller-mixin() {
+    variable: declaration;
+  }
+}
+
+selector {
+  caller-variable: value;
+  variable: declaration;
+}
+
+@variable: global;
+@detached-ruleset: {
+  // will use global variable, because it is accessible
+  // from detached-ruleset definition
+  variable: @variable;
+}
+
+selector {
+  @detached-ruleset();
+  @variable: value; // variable defined in caller - will be ignored
+}
+
+selector {
+  variable: global;
+}
+
+@detached-1: {
+  scope-detached: @one @two;
+}
+.one {
+  @one: visible;
+  .two {
+    @detached-2: @detached-1; // copying/renaming ruleset
+    @two: visible; // ruleset can not see this variable
+  }
+}
+
+.use-place {
+  .one > .two();
+  @detached-2();
+}
+
+ERROR 1:32 The variable "@one" was not declared. #space {
+  .importer-1() {
+    @detached: {
+      scope-detached: @variable;
+    } // define detached ruleset
+  }
+}
+
+.importer-2() {
+  @variable: value; // unlocked detached ruleset CAN see this variable
+  #space > .importer-1(); // unlock/import detached ruleset
+}
+
+.use-place {
+  .importer-2(); // unlock/import detached ruleset second time
+  @detached();
+}
+
+.use-place {
+  scope-detached: value;
+}
+
+.foo {
+  background: #900;
+}
+@import "this-is-valid.less";
+
+@import "foo"; // foo.less is imported
+@import "foo.less"; // foo.less is imported
+@import "foo.php"; // foo.php imported as a less file
+@import "foo.css"; // statement left in place, as-is
+
+.navbar:extend(.navbar all) {
+}
+
+@import (less) "foo.css";
+
+@import (css) "foo.less";
+
+@import "foo.less";
+
+@import (once) "foo.less";
+@import (once) "foo.less"; // this statement will be ignored
+
+// file: foo.less
+.a {
+  color: green;
+}
+// file: main.less
+@import (multiple) "foo.less";
+@import (multiple) "foo.less";
+
+.a {
+  color: green;
+}
+.a {
+  color: green;
+}
+
+.mixin (@a) when (lightness(@a) >= 50%) {
+  background-color: black;
+}
+.mixin (@a) when (lightness(@a) < 50%) {
+  background-color: white;
+}
+.mixin (@a) {
+  color: @a;
+}
+
+.class1 {
+  .mixin(#ddd);
+}
+.class2 {
+  .mixin(#555);
+}
+
+.class1 {
+  background-color: black;
+  color: #ddd;
+}
+.class2 {
+  background-color: white;
+  color: #555;
+}
+
+.truth (@a) when (@a) {
+  /* ... */
+}
+.truth (@a) when (@a = true) {
+  /* ... */
+}
+
+.class {
+  .truth(40); // Will not match any of the above definitions.
+}
+
+@media: mobile;
+
+.mixin (@a) when (@media = mobile) {
+  /* ... */
+}
+.mixin (@a) when (@media = desktop) {
+  /* ... */
+}
+
+.max (@a; @b) when (@a > @b) {
+  width: @a;
+}
+.max (@a; @b) when (@a < @b) {
+  width: @b;
+}
+
+.mixin (@a) when (isnumber(@a)) and (@a > 0) {
+  /* ... */
+}
+
+.mixin (@a) when (@a > 10), (@a < -10) {
+  /* ... */
+}
+
+.mixin (@b) when not (@b > 0) {
+  /* ... */
+}
+
+.mixin (@a; @b: 0) when (isnumber(@b)) {
+  /* ... */
+}
+.mixin (@a; @b: black) when (iscolor(@b)) {
+  /* ... */
+}
+
+.mixin (@a) when (@a > 0) {
+  /* ... */
+}
+.mixin (@a) when (default()) {
+  /* ... */
+} // matches only if first mixin does not, i.e. when @a <= 0
+
+.my-optional-style() when (@my-option = true) {
+  button {
+    color: white;
+  }
+}
+.my-optional-style();
+
+button when (@my-option = true) {
+  color: white;
+}
+
+& when (@my-option = true) {
+  button {
+    color: white;
+  }
+  a {
+    color: blue;
+  }
+}
+
+.loop(@counter) when (@counter > 0) {
+  .loop((@counter - 1)); // next iteration
+  width: (10px * @counter); // code for each iteration
+}
+
+div {
+  .loop(5); // launch the loop
+}
+
+div {
+  width: 10px;
+  width: 20px;
+  width: 30px;
+  width: 40px;
+  width: 50px;
+}
+
+.generate-columns(4);
+
+.generate-columns(@n, @i: 1) when (@i =< @n) {
+  .column-@{i} {
+    width: (@i * 100% / @n);
+  }
+  .generate-columns(@n, (@i + 1));
+}
+
+.column-1 {
+  width: 25%;
+}
+.column-2 {
+  width: 50%;
+}
+.column-3 {
+  width: 75%;
+}
+.column-4 {
+  width: 100%;
+}
+
+.mixin() {
+  box-shadow+: inset 0 0 10px #555;
+}
+.myclass {
+  .mixin();
+  box-shadow+: 0 0 20px black;
+}
+
+.myclass {
+  box-shadow: inset 0 0 10px #555, 0 0 20px black;
+}
+
+.mixin() {
+  transform+_: scale(2);
+}
+.myclass {
+  .mixin();
+  transform+_: rotate(15deg);
+}
+
+.myclass {
+  transform: scale(2) rotate(15deg);
+}
+
+a {
+  color: blue;
+  &:hover {
+    color: green;
+  }
+}
+
+a {
+  color: blue;
+}
+
+a:hover {
+  color: green;
+}
+
+.button {
+  &-ok {
+    background-image: url("ok.png");
+  }
+  &-cancel {
+    background-image: url("cancel.png");
+  }
+
+  &-custom {
+    background-image: url("custom.png");
+  }
+}
+
+.button-ok {
+  background-image: url("ok.png");
+}
+.button-cancel {
+  background-image: url("cancel.png");
+}
+.button-custom {
+  background-image: url("custom.png");
+}
+
+.link {
+  & + & {
+    color: red;
+  }
+
+  & & {
+    color: green;
+  }
+
+  && {
+    color: blue;
+  }
+
+  &,
+  &ish {
+    color: cyan;
+  }
+}
+
+.link + .link {
+  color: red;
+}
+.link .link {
+  color: green;
+}
+.link.link {
+  color: blue;
+}
+.link,
+.linkish {
+  color: cyan;
+}
+
+.grand {
+  .parent {
+    & > & {
+      color: red;
+    }
+
+    & & {
+      color: green;
+    }
+
+    && {
+      color: blue;
+    }
+
+    &,
+    &ish {
+      color: cyan;
+    }
+  }
+}
+
+.grand .parent > .grand .parent {
+  color: red;
+}
+.grand .parent .grand .parent {
+  color: green;
+}
+.grand .parent.grand .parent {
+  color: blue;
+}
+.grand .parent,
+.grand .parentish {
+  color: cyan;
+}
+
+.header {
+  .menu {
+    border-radius: 5px;
+    .no-borderradius & {
+      background-image: url("images/button-background.png");
+    }
+  }
+}
+
+.header .menu {
+  border-radius: 5px;
+}
+.no-borderradius .header .menu {
+  background-image: url("images/button-background.png");
+}
+
+p,
+a,
+ul,
+li {
+  border-top: 2px dotted #366;
+  & + & {
+    border-top: 0;
+  }
+}
+
+p,
+a,
+ul,
+li {
+  border-top: 2px dotted #366;
+}
+p + p,
+p + a,
+p + ul,
+p + li,
+a + p,
+a + a,
+a + ul,
+a + li,
+ul + p,
+ul + a,
+ul + ul,
+ul + li,
+li + p,
+li + a,
+li + ul,
+li + li {
+  border-top: 0;
+}
+
+`;
diff --git a/tests/css_less/jsfmt.spec.js b/tests/css_less/jsfmt.spec.js
new file mode 100644
index 000000000..7d3726c81
--- /dev/null
+++ b/tests/css_less/jsfmt.spec.js
@@ -0,0 +1 @@
+run_spec(__dirname, ["css"]);
diff --git a/tests/css_less_docs/less_docs.css b/tests/css_less/less.css
similarity index 96%
rename from tests/css_less_docs/less_docs.css
rename to tests/css_less/less.css
index 0229682bd..30f9d9311 100644
--- a/tests/css_less_docs/less_docs.css
+++ b/tests/css_less/less.css
@@ -159,8 +159,8 @@ background-color: #112244 + #111; // result is #223355
       background-color: white
     }
   }
-  .tab { ... }
-  .citation { ... }
+  .tab { /* ... */ }
+  .citation { /* ... */ }
 }
 
 
@@ -663,9 +663,6 @@ link:hover:visited {
 }
 
 
-<a class="animal bear">Bear</a>
-
-
 .animal {
   background-color: black;
   color: white;
@@ -674,10 +671,6 @@ link:hover:visited {
   background-color: brown;
 }
 
-
-<a class="bear">Bear</a>
-
-
 .animal {
   background-color: black;
   color: white;
@@ -981,11 +974,11 @@ pre {
 }
 
 
-.mixin(...) {}        // matches 0-N arguments
+.mixin(/* ... */) {}        // matches 0-N arguments
 .mixin() {}           // matches exactly 0 arguments
 .mixin(@a: 1) {}      // matches 0-1 arguments
-.mixin(@a: 1; ...) {} // matches 0-N arguments
-.mixin(@a; ...) {}    // matches 1-N arguments
+.mixin(@a: 1; /* ... */) {} // matches 0-N arguments
+.mixin(@a; /* ... */) {}    // matches 1-N arguments
 
 
 .mixin(@a; @rest...) {
@@ -994,7 +987,7 @@ pre {
 }
 
 
-.mixin(@s; @color) { ... }
+.mixin(@s; @color) { /* ... */ }
 
 .class {
   .mixin(@switch; #888);
@@ -1345,8 +1338,8 @@ ERROR 1:32 The variable "@one" was not declared.
 }
 
 
-.truth (@a) when (@a) { ... }
-.truth (@a) when (@a = true) { ... }
+.truth (@a) when (@a) { /* ... */ }
+.truth (@a) when (@a = true) { /* ... */ }
 
 
 .class {
@@ -1356,28 +1349,28 @@ ERROR 1:32 The variable "@one" was not declared.
 
 @media: mobile;
 
-.mixin (@a) when (@media = mobile) { ... }
-.mixin (@a) when (@media = desktop) { ... }
+.mixin (@a) when (@media = mobile) { /* ... */ }
+.mixin (@a) when (@media = desktop) { /* ... */ }
 
 .max (@a; @b) when (@a > @b) { width: @a }
 .max (@a; @b) when (@a < @b) { width: @b }
 
 
-.mixin (@a) when (isnumber(@a)) and (@a > 0) { ... }
+.mixin (@a) when (isnumber(@a)) and (@a > 0) { /* ... */ }
 
 
-.mixin (@a) when (@a > 10), (@a < -10) { ... }
+.mixin (@a) when (@a > 10), (@a < -10) { /* ... */ }
 
 
-.mixin (@b) when not (@b > 0) { ... }
+.mixin (@b) when not (@b > 0) { /* ... */ }
 
 
-.mixin (@a; @b: 0) when (isnumber(@b)) { ... }
-.mixin (@a; @b: black) when (iscolor(@b)) { ... }
+.mixin (@a; @b: 0) when (isnumber(@b)) { /* ... */ }
+.mixin (@a; @b: black) when (iscolor(@b)) { /* ... */ }
 
 
-.mixin (@a) when (@a > 0) { ...  }
-.mixin (@a) when (default()) { ... } // matches only if first mixin does not, i.e. when @a <= 0
+.mixin (@a) when (@a > 0) { /* ... */  }
+.mixin (@a) when (default()) { /* ... */ } // matches only if first mixin does not, i.e. when @a <= 0
 
 
 .my-optional-style() when (@my-option = true) {