form {
font-family: "Open Sans", verdana, arial;
font-size:22px; 
font-style:normal; 
font-weight:normal; 
text-decoration:none; 
color:#000;
padding-top: 10px; 
width: 100%;
border: 0px solid #e7e7e7;  
}



label {
font-family: "Open Sans", verdana, arial;
font-size:12px; 
  float: left;
  min-width: 180px;
  padding-top: 12px; 
}



label.input { 
  text-align: left;
  line-height: 1.0;
  padding-top: 5px; 

}

<?php if (isset($_POST['senden'])) { echo"input:invalid {
	border: 1px solid red; 
}
"; } ?>

label.input::after {
  content: ": ";
}



input[type=text]{


border:1px solid #c4c4c4;

}


input[type="checkbox"] {
    color:#f2f2f2;
    width:19px;
    height:19px;
    display:inline-block;
} 

input[type="radio"] {
    color:#f2f2f2;
    width:19px;
    height:19px;

} 

input:readonly {
  background-color: #EAF0F0;
  }
  input:readonly[value] {
    color: #000;
  }

input[type=checkbox] {
  transform: scale(1.2);
}


textarea { 
    resize: none;
    overflow: auto;
}


    select {
      -moz-appearance: none;
      -webkit-appearance: none;
      appearance: none;
      border: none;
    }

    select::-ms-expand {
      display: none;
    }

    select {
      box-shadow: 0 0px 0px 0 rgba(0,0,0,0.2);
      background-color:white;
      background-position: right;
      background-repeat: no-repeat;
      height: 20px;
      min-width: 10px;
      padding-left: 10px;
      border:1px solid #c4c4c4;   
      color: #000;
      font-size: 12px;
      text-indent: 0px;
    }

    select option {
      color: #000;

    }

select:hover {
  box-shadow: 0 1px 1px 0 rgba(0,0,0,0.1);
}


.selectToCart {
  position: relative;  
  width: 150px;

}
 

.selectToCartIn {
  position: relative;  
  width: 80px;

}

select::-ms-expand {
     display: none;
}

 
.selectToCart:after {
  content: '<>';
  font: 13px "Consolas", monospace;
  color: #333;
  -webkit-transform: rotate(90deg);
  -moz-transform: rotate(90deg);
  -ms-transform: rotate(90deg);
  transform: rotate(90deg);
  right: 1px;
  /*Adjust for position however you want*/
  
  top: 10px;
  padding: 0 0 2px;
  border-bottom: 1px solid #999;
  /*left line */
  
  position: absolute;
  pointer-events: none;
}
 
.selectToCart select {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  
  display: block;
  width: 100%;
 
  height: 30px;
  float: left;
  margin: 5px 0px;
  paddinng: 0px 4px;
  font-size: 14px;
  line-height: 1.75;
  color: #333;
  background-color: #ffffff;
  background-image: none;
  border: 1px solid #cccccc;
  -ms-word-break: normal;
  word-break: normal;
 
  bottom: 0;
  padding: 0 1em;
  background: #F6F6F6;

}



.selectToCart:hover::after {
  color: #f39c12;
}

.selectToCart::after {
  -webkit-transition: .25s all ease;
  -o-transition: .25s all ease;
  transition: .25s all ease;
}




.selectToCheckOut select {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  
  display: block;
  width: 100%;
 
  height: 30px;
  float: left;
  margin: 5px 0px;
  padding: 0px 4px;
  font-size: 14px;
  line-height: 1.75;
  color: #333;
  background-color: #ffffff;
  background-image: none;
  border: none;
  border-bottom: 1px solid #cccccc;
  -ms-word-break: normal;
  word-break: normal;
 
  bottom: 0;
  padding: 0 1em;
  background: #FFF;

}



.selectToCheckOut:hover::after {
  color: #f39c12;
}

.selectToCheckOut::after {
  -webkit-transition: .25s all ease;
  -o-transition: .25s all ease;
  transition: .25s all ease;
}