tools/css: Trim whitespace around CSS values.

static/styles/informational-overlays.css

@@ -38,7 +38,7 @@
 }
 
 .informational-overlays .overlay-tabs .tab-switcher {
-    margin-left: 15px ;
+    margin-left: 15px;
 }
 
 .informational-overlays .overlay-tabs .exit {

static/styles/zulip.css

@@ -799,8 +799,8 @@ just a temporary hack.
 }
 
 @keyframes rotate {
-    from { transform:rotate(0deg); }
-    to { transform:rotate(359deg); }
+    from { transform: rotate(0deg); }
+    to { transform: rotate(359deg); }
 }
 
 .messagebox-bottom {

tools/lib/css_parser.py

@@ -366,7 +366,13 @@ class CssDeclaration(object):
         res += self.pre_fluff
         res += self.css_property
         res += ':'
-        res += self.css_value.text()
+        value_text = self.css_value.text()
+        if '\n' in value_text:
+            # gradient values can be multi-line
+            res += value_text.rstrip()
+        else:
+            res += ' '
+            res += value_text.strip()
         res += ';'
         res += self.post_fluff
         return res

tools/tests/test_css_parser.py

@@ -63,7 +63,7 @@ class ParserTestHappyPath(unittest.TestCase):
         '''
 
         reformatted_css = '''
-            p { color: red ;}
+            p { color: red;}
         '''
 
         res = parse(my_css)