Marketo Form Normalizer--making things actually responsive.

NormalizeMktoForms.css

.mktoForm, .mktoForm .mktoFieldWrap, .mktoForm .mktoHtmlText, .mktoForm input, .mktoLogicalField .mktoCheckboxList {width:100% !important;}
@media only screen and (min-width:480px) {
.mktoFormCol:first-child:nth-last-child(2), .mktoFormCol:first-child:nth-last-child(2) ~ .mktoFormCol {width: 100% !important;}
.mktoFormCol:first-child:nth-last-child(3), .mktoFormCol:first-child:nth-last-child(3) ~ .mktoFormCol {width: 50% !important;}
.mktoFormCol:first-child:nth-last-child(4), .mktoFormCol:first-child:nth-last-child(4) ~ .mktoFormCol {width: 33.3333% !important;}
.mktoFormCol:first-child:nth-last-child(3) ~ .mktoFormCol {padding-left: 0.3em !important;}
}
@media only screen and (max-width:480px) {.mktoFormCol {width:100% !important;}}
.mktoAsterix{display:none !important;}
.mktoForm .mktoGutter {display:none !important;}
.mktoButtonWrap {margin-left:0 !important;}
.mktoForm input[type=text], .mktoForm input[type=url], .mktoForm input[type=email], .mktoForm input[type=tel], .mktoForm input[type=number], .mktoForm input[type=date], .mktoForm textarea.mktoField, .mktoForm select.mktoField {padding: 0.3em; width: 100% !important;}
.mktoForm {clear: both; margin-bottom: 0.3em;}
.mktoForm .mktoRadioList, .mktoForm .mktoCheckboxList {float: left !important; width: auto !important;}
.mktoForm .mktoRadioList > label, .mktoForm .mktoCheckboxList > label {display: inherit !important;}
.mktoForm input[type="radio"], .mktoForm input[type="checkbox"] {width: auto !important;}
.mktoForm fieldset legend {margin: inherit !important;}