How to modify wordpress plugin css

Please check this link: http://ift.tt/1YdKiSq

<div id="aq-block-1076-2" class="aq-block aq-block-aq_text_block aq_span4 aq-first clearfix">
<div class="cp-calc-widget" data-calcid="2424" data-anchor="2">
    <form class="widgetForm cleanslate" id="widgetForm" method="post" 
        style="width: 260px !important; background-color: #378CAF !important; 
        border-color: #006395 !important; color: #ffffff !important; font-size: 16px !important;">           

            <input name="numFields" type="hidden" value="1">           
            <input name="calcId" type="hidden" value="2424">
            <input name="answer_format" type="hidden" value="function">

            <div class="widgetTitle">Water Intake Calculator</div>           
            <hr style="color: #006395 !important; background-color: #006395 !important;">           
            <div class="form_area"><div class="field">Weight:<div class="buffer">
                <input class="inputArea" name="input0" value="">
            </div>
            </div>
            <input type="submit" id="widgetSubmit" class="widgetSubmit calc_button" value="Calculate" 
            style="color: #ffffff !important; background-image: -moz-linear-gradient(top, #378CAF, #006395) !important; 
            background-image: -webkit-gradient(linear,left top,left bottom,color-stop(0, #378CAF),color-stop(1, #006395)) !important; 
            filter:  progid:DXImageTransform.Microsoft.Gradient(startColorStr=#378CAF, endColorStr=#006395, GradientType=0 ); 
            border-color: #006395 !important;">           
            </div>           

            <div class="answer_area hidden_class">             
            <div class="loading">loading...</div>             
            <div class="actual_answer hidden_class">               
            <span class="pre_answer"></span>               
            <div class="answer">
                <span class="return_answer"></span></div>             
            </div>             
            <div>
                <input type="button" id="backButton" class="backButton calc_button" value="< back" 
                style="color: #ffffff !important; background-image: -moz-linear-gradient(top, #378CAF, #006395) !important; 
                background-image: -webkit-gradient(linear,left top,left bottom,color-stop(0, #378CAF),color-stop(1, #006395)) !important; 
                filter:  progid:DXImageTransform.Microsoft.Gradient(startColorStr=#378CAF, endColorStr=#006395, GradientType=0 ); 
                border-color: #006395 !important;">
            </div>           
            </div>
            </div>
        </form>
    </div>

I have embedded wordpress plugin pro-calculator and want to change its:

1. Background Color
2. Button Color
3. Want to write lbs in Front of "Weight" as "Weight (lbs)"

Please advise

via Chebli Mohamed