Hi,i'm an idiot new to Elgg

my question is: i would like to change the length of the input text box displayed in the group's profile page while using this plugin :

http://community.elgg.org/pg/plugins/release/114145/developer/webgalli/message-board-with-group-message-board-option (thank you Team Webgalli)

I suppose i should edit the css file where the input text box is described [i mean the graphic details] so i changed them,but when i refresh the page nothing changes(and the same thing happens if i disable/activate the plugin).

I'll paste the css file concerning the input text box,maybe it could help you:

<?php

    /**
     * Elgg Messageboard CSS extender
     *
     * @package ElggMessageBoard
     * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
     * @author Curverider Ltd <info@elgg.com>
     * @copyright Curverider Ltd 2008-2009
     * @link http://elgg.com/
     */

?>

/* input msg area */
#mb_input_wrapper {
    margin:0 10px 5px 10px;
    padding:5px;
    background: white;
    -webkit-border-radius: 8px;
    -moz-border-radius: 8px;
}

#mb_input_wrapper .input_textarea {
    width:675px;
}
.collapsable_box_content #mb_input_wrapper .input_textarea {
    width:259px;
}
.message_item_timestamp {
    font-size:90%;
    padding:10px 0 0 0;
}
p.message_item_timestamp {
    margin-bottom: 10px;
}
/* wraps each message */
.messageboard {
    margin:0 10px 5px 10px;
    padding:0;
    background: white;
    -webkit-border-radius: 8px;
    -moz-border-radius: 8px;
}
.messageboard .message_sender {
    float:left;
    margin: 5px 10px 0 5px;
}
/* IE6 */
* html .messageboard { width: 280px; }
* html #two_column_left_sidebar_maincontent .messageboard { width: 667px; }
* html .messageboard .message_sender { margin: 5px 10px 0 2px; }
* html #mb_input_wrapper .input_textarea { width:645px; }
/* IE7 */
*:first-child+html .messageboard { width: 280px; }
*:first-child+html #two_column_left_sidebar_maincontent .messageboard { width: 698px; }
*:first-child+html .messageboard .message_sender { margin: 5px 10px 0 2px; }

.messageboard .message p {
    line-height: 1.2em;
    background:#dedede;
    margin:0 6px 4px 6px;
    padding:4px;
    -webkit-border-radius: 4px;
    -moz-border-radius: 4px;
    overflow-y:hidden;
    overflow-x:auto;
    color:#333333;
}

.message_buttons {
    padding:0 0 3px 4px;
    margin:0;
    font-size: 90%;
    color:#666666;
}

.messageboard .delete_message a {
    display:block;
    float:right;
    cursor: pointer;
    width:14px;
    height:14px;
    margin:0 3px 3px 0;
    background: url("<?php echo $vars['url']; ?>_graphics/icon_customise_remove.png") no-repeat 0 0;
    text-indent: -9000px;
}
.messageboard .delete_message a:hover {
    background-position: 0 -16px;
}



/* ***************************************
  GROUP MESSAGE BOARD
*************************************** */
/* input msg area */
#mb_input_wrapper_group {
    margin:0 0px 5px 0px;
    padding:5px;
    min-height:60px;
    display:block;
    background: white;
    -webkit-border-radius: 8px;
    -moz-border-radius: 8px;
}

#mb_input_wrapper_group .input_textarea {
    width:300px;
}


/* IE6 */
* html .messageboard { width: 280px; }
* html #two_column_left_sidebar_maincontent .messageboard { width: 667px; }
* html .messageboard .message_sender { margin: 5px 10px 0 2px; }
* html #mb_input_wrapper_group .input_textarea { width:645px; }
/* IE7 */
*:first-child+html .messageboard { width: 280px; }
*:first-child+html #two_column_left_sidebar_maincontent .messageboard { width: 698px; }
*:first-child+html .messageboard .message_sender { margin: 5px 10px 0 2px; }


.river_group_messageboard {
    background: url(<?php echo $vars['url']; ?>_graphics/river_icons/river_icon_comment.gif) no-repeat left -1px;   
}