fix little style errors

searx/static/css/definitions.less

 @color-settings-label-deny-background: #2ECC71;
 @color-settings-label-deny-font: @color-font;
 
+@color-settings-return-background: @color-base;
+@color-settings-return-font: #FFF;
 
 /// Other
 

searx/static/css/style.css

 html{font-family:sans-serif;font-size:.9em;-webkit-text-size-adjust:100%;-ms-text-size-adjust:100%;-moz-text-size-adjust:100%;text-size-adjust:100%;color:#444;padding:0;margin:0}
 body,#container{padding:0;margin:0}
 #container{width:100%;position:absolute;top:0}
-.row{max-width:800px;margin:auto;text-align:justify}.row h1{font-size:3em;margin-top:50px}
+.row{max-width:800px;margin:20px auto;text-align:justify}.row h1{font-size:3em;margin-top:50px}
 .row p{padding:0 10px;max-width:700px}
 .row h3,.row ul{margin:4px 8px}
 .hmarg{margin:0 20px;border:1px solid #3498db;padding:4px 10px}
 #preferences{top:10px;padding:0;border:0;background:url('/static/img/preference-icon.png') no-repeat;background-size:28px 28px;opacity:.8;width:28px;height:30px;display:block}#preferences *{display:none}
 #pagination{clear:both}
 #apis{margin-top:8px;clear:both}
-@media screen and (max-width:60em){#sidebar{position:static;max-width:50em;margin:0 0 2px 0;padding:0;float:none;border:none;width:auto} #suggestions span{display:inline;font-size:.8em} #suggestions form{display:inline} #suggestions input{padding:2px 6px;margin:2px 4px;font-size:.8em;display:inline-block;-webkit-border-radius:4px;-moz-border-radius:4px;border-radius:4px;border:0;cursor:pointer}}@media screen and (max-width:680px){#search_wrapper{width:90%;clear:both;overflow:hidden} .right{display:none;postion:fixed !important;top:100px;right:0} #apis{display:none} #categories{font-size:80%;clear:both}#categories .checkbox_container{margin-top:2px;margin:0 2px} .checkbox_container{display:block;width:100%;float:left}.checkbox_container label{border-bottom:0} .result{border-top:1px solid #e8e7e6;margin:7px 0 6px 0}.result img{max-width:90%;width:auto;height:auto}}.favicon{float:left;margin-right:4px;margin-top:2px}
+@media screen and (max-width:60em){#sidebar{position:static;max-width:50em;margin:0 0 2px 0;padding:0;float:none;border:none;width:auto} #suggestions span{display:inline;font-size:.8em} #suggestions form{display:inline} #suggestions input{padding:2px 6px;margin:2px 4px;font-size:.8em;display:inline-block;-webkit-border-radius:4px;-moz-border-radius:4px;border-radius:4px;border:0;cursor:pointer}}@media screen and (max-width:680px){#search_wrapper{width:90%;clear:both;overflow:hidden} .right{display:none;postion:fixed !important;top:100px;right:0} #apis{display:none} #categories{font-size:80%;clear:both}#categories .checkbox_container{margin-top:2px;margin:0 2px} .checkbox_container{display:block;width:100%}.checkbox_container label{border-bottom:0} .result{border-top:1px solid #e8e7e6;margin:7px 0 6px 0}.result img{max-width:90%;width:auto;height:auto}}.favicon{float:left;margin-right:4px;margin-top:2px}
+.preferences_back{background:none repeat scroll 0 0 #3498db;border:0 none;-webkit-border-radius:4px;-moz-border-radius:4px;border-radius:4px;cursor:pointer;display:inline-block;margin:2px 4px;padding:4px 6px}.preferences_back a{color:#fff}

searx/static/css/style.less

 
 .row {
 	max-width: 800px;
-	margin: auto;
+	margin: 20px auto;
 	text-align: justify;
 
 	h1 { 
 	.checkbox_container {
 		display: block;
 		width: 100%;
-		float: left;
+		//float: left;
 
 		label {
 			border-bottom: 0;
 	margin-right: 4px;
 	margin-top: 2px;
 }
+
+.preferences_back {
+	background: none repeat scroll 0 0 @color-settings-return-background;
+    border: 0 none;
+    .rounded-corners;
+    cursor: pointer;
+    display: inline-block;
+    margin: 2px 4px;
+    padding: 4px 6px;
+
+	a {
+		color: @color-settings-return-font;
+	}
+}

searx/templates/preferences.html

     </p>
 
     <input type="submit" value="{{ _('save') }}" />
-    </form>
-    <div class="right"><a href="{{ url_for('index') }}">{{ _('back') }}</a></div>
+	<div class="right preferences_back"><a href="{{ url_for('index') }}">{{ _('back') }}</a></div>
+    </form>    
 </div>
 {% endblock %}