Added some test files for manual inspection

test/case.css

+A.UPPER:Hover:not(:visiteD) {
+    Font-Weight: Bold;
+}

test/color.css

+p {
+    color: rgb(257, -2, 0);       /* red */
+    color: rgb(67%, 67.5%, 68%);  /* #abacad */
+    color: #aaffbb;               /* #afb */
+    color: white;                 /* #fff */
+}

test/combine.css

+a    { color: red; }
+.foo { font-size: 1em; }
+ul   { color: red; }
+.foo { color: blue; }
+li   { color: red; }
+
+/*
+a, ul { color: red; }
+.foo  { font-size: 1em; color: blue; }
+li    { color: red; }
+*/

test/duplicates.css

+a {
+    color: red;
+    color: blue;
+    /* color: blue */
+}
+
+a {
+    color: red !important;
+    color: blue;
+    /* color: red !important */
+}
+
+a {
+    color: red !important;
+    color: blue;
+    color: green !important;
+    color: black;
+    /* color: green !important */
+}
+
+li {
+    font-size: 13px;
+    font: 12px/14px normal;
+    /* font: 12px/14px normal */
+}
+
+li {
+    font-size: 11px !important;
+    font-size: 13px !important;
+    font-size: 14px;
+    font: 12px/15px normal;
+    /*
+    font-size: 13px !important;
+    font: 13px/15px normal;
+    */
+}

test/font.css

+a {
+    font-weight: bold;
+    /* font-weight: 700 */
+}
+a {
+    font: normal 12px sans-serif;
+    /* font: 400 12px sans-serif */
+}

test/keyframe.css

+div {
+  animation-name: diagonal-slide;
+  animation-duration: 5s;
+  animation-iteration-count: 10;
+}
+
+@keyframes   diagonal-slide {
+
+  from {
+    left: 0;
+    top: 0;
+  }
+
+  to {
+    left: 100px;
+    top: 100px;
+  }
+
+  100% {}
+}

test/numbers.css

+li {
+    margin: 0;          /* 0   */
+    opacity: 0.5;       /* .5  */
+    -moz-opacity: 1.5;  /* 1.5 */
+}

test/shorthand.css

+.dims-1 {
+    margin-top: 10px;
+    margin-right: 10px;
+    margin-bottom: 10px;
+    margin-left: 10px;
+    /* margin: 10px */
+}
+
+.dims-2 {
+    margin-top: 10px;
+    margin-right: 20px;
+    margin-bottom: 10px;
+    margin-left: 20px;
+    /* margin: 10px 20px */
+}
+
+.dims-3 {
+    padding-top: 10px;
+    padding-right: 20px;
+    padding-bottom: 30px;
+    padding-left: 20px;
+    /* padding: 10px 20px 30px */
+}
+
+.dims-4 {
+    padding-top: 10px;
+    padding-right: 20px;
+    padding-bottom: 30px;
+    padding-left: 40px;
+    /* padding: 10px 20px 30px 40px */
+}
+
+.use-last-declaration-unless-important {
+    font-family: sans-serif;
+    font-size: 10px;
+    font-size: 13px;
+    /* font: 13px sans-serif */
+
+    border-width: 1px;
+    border-style: solid !important;
+    border-style: dotted
+    /* border: 1px solid */
+}
+
+.unfold {
+    border: 1px solid red;
+    border-color: blue;
+    /* border: 1px solid blue */
+
+    background: transparent url(../img/cat.png) no-repeat scroll left center;
+    background-repeat: repeat-y;
+    /* background: transparent url(../img/cat.png) repeat-y scroll left center; */
+
+    font: bold 1em/1.1em 'Roboto Condensed', sans-serif;
+    line-height: 10px;
+    /* font: bold 1em/10px "Roboto Condensed", sans-serif */
+}
+
+.unfold-font-1 {
+    font: normal normal 1em sans-serif;
+    font-variant: small-caps;
+    /* font: small-caps normal 1em sans-serif */
+}
+
+.unfold-margin-1 {
+    margin: 10px;
+    margin-bottom: 20px;
+    /* margin: 10px 10px 20px */
+}

test/supports.css

+@supports (not (display: flexbox)) and ((a: b) or (b: c)) {
+  body { width: 100%; height: 100%; background: white; color: black; }
+  #navigation { width: 25%; }
+  #article { width: 75%; }
+}

test/syntax.css

+@charset "UTF-8";
+
+@import url("base.css");
+
+div[class ~= "foo"] > ul li {
+    font: normal 12px / 15px Arial, Tahoma, Verdana;
+    bordeR: 1px solid #fff;
+}
+
+@media all and (max-width: 699px) and (min-width: 520px), (min-width: 1151px) {
+    a {
+        font-weight: bold
+    }
+}
+
+.weird-shit-ie-1 {
+    filter: alpha(opacity=60);
+}
+.weird-shit-ie-2 {
+    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#80000000', endColorstr='#00000000', GradientType=1);
+}
+.weird-shit-webkit {
+    background-image: linear-gradient(to right, rgba(0, 0, 0, .0001) 0%, rgba(0, 0, 0, .5) 100%);
+}
+
+@-ms-viewport {
+    width: device-width;
+}
+
+@media all {
+    @-ms-viewport {
+        width: device-width;
+    }
+    a {
+        font-weight : bold;
+    }
+}

test/unfold.css

+.bg1  { background: transparent url(cat.png) no-repeat scroll left center; }
+.bg2  { background: url(cat.png) no-repeat scroll left center; }
+.bg3  { background: url(cat.png) scroll left center; }
+.bg4  { background: url(cat.png) repeat left center; }
+.bg5  { background: url(cat.png) left center; }
+.bg6  { background: url(cat.png) scroll; }
+.bg7  { background: url(cat.png) repeat-x; }
+.bg8  { background: url(cat.png) inherit; }
+.bg9  { background: url(cat.png); }
+.bg10 { background: #fff; }
+
+.list-style1 { list-style: circle outset url(cat.png) }
+.list-style2 { list-style: disk inset }
+.list-style3 { list-style: inset url(cat.png) }