How to replace fixed values in resposible form css

[cyclone]

Resposible form is created using code below.If window is resized, it resizes itself automatically, captions and input elements stay aligned.It contains fixed values 210px, 75px, 100px, 120 px is css below.Is it reasonable and if yes, how to remove/replace those fixed values with something otherlike percents or em's ?input, select elements and jquery-ui autocomplete with dropdown button are used.\[code\]<form class='ui-widget-content form-document'><div class='form-field'><label class='form-label' for='nimi'>Customer name</label><span class='form-fullwidth'><input class='ui-widget-content ui-corner-all form-autocomplete' name='nimi' value='http://stackoverflow.com/questions/14047195/Karu Org AS' ></input><button type='button' class='form-combobutton' tabindex=-1 ></button></span></div><div class='form-field'><label class='form-label' for='Number'>Number</label><input class='ui-widget-content ui-corner-all form-fullwidth' name='Number' /></div><div class='form-field'><label class='form-label' for='payterm'>Pay term</label><span id='span_Maksetin1_tingimus' class='form-fullwidth'><select class='ui-widget-content ui-corner-all form-fullwidth' name='payterm'><option value='' selected='selected'></option><option value='http://stackoverflow.com/questions/14047195/0'>0 days</option></select></span></div>... lot of similar form-field divs</form>\[/code\]css:\[code\].form-document{ padding: 0.5%;}.form-field{ display: inline-block; margin: 2px; width: 210px; /* label width + input field width */}.form-label{ padding-left: 5px; padding-right: 5px; font-family: Arial, Helvetica, sans-serif; font-size: smaller; display: inline-block; text-align: right; width: 75px; /* determine by max caption width */}.form-fullwidth{ width: 120px; /* 210-5-75 */}.form-autocomplete{ width: 100px; /* 210-5-75-combobutton width*/}.form-combobutton{ height: 1.09em; margin: 0 0 0px; padding: 0; margin-left: -6px; vertical-align: middle; width: 1em !important;}\[/code\]