[fix] visited link color change

searx/static/css/style.css

 .engine_checkbox input[type="checkbox"]:checked + label.allow { display: inline; }
 
 a { text-decoration: none; color: #1a11be; }
-a:visited { color: #7b11be; }
+a:visited { color: #8E44AD; }
 
 .result { margin: 19px 0 18px 0; padding: 0; max-width: 55em;  clear: both; }
 .result_title { margin-bottom: 0; }
 .result_title a { color: #1168CC; font-weight: normal; font-size: 1.1em; }
 .result_title a:hover { text-decoration: underline; }
+.result_title a:visited { color: #8E44AD }
 .result h3 { font-size: 1em; word-wrap:break-word; margin: 5px 0 1px 0; padding: 0 }
 .result .content { font-size: 0.8em; margin: 0; padding: 0; max-width: 54em; word-wrap:break-word; line-height: 1.24; }
 .result .url { font-size: 0.8em; margin: 3px 0 0 0; padding: 0; max-width: 54em; word-wrap:break-word; color: #C0392B; }