I used this:
.hikashop_checkout_page .hikashop_cart_input_button{
background: #9dd53a;
background: -moz-linear-gradient(top, #9dd53a 0%, #a1d54f 37%, #80c217 63%, #7cbc0a 100%);
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#9dd53a), color-stop(37%,#a1d54f), color-stop(63%,#80c217), color-stop(100%,#7cbc0a));
background: -webkit-linear-gradient(top, #9dd53a 0%,#a1d54f 37%,#80c217 63%,#7cbc0a 100%);
background: -o-linear-gradient(top, #9dd53a 0%,#a1d54f 37%,#80c217 63%,#7cbc0a 100%);
background: -ms-linear-gradient(top, #9dd53a 0%,#a1d54f 37%,#80c217 63%,#7cbc0a 100%);
background: linear-gradient(to bottom, #9dd53a 0%,#a1d54f 37%,#80c217 63%,#7cbc0a 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#9dd53a', endColorstr='#7cbc0a',GradientType=0 );
}
.hikashop_notice_box_content input{
background: #e6f0a3;
background: -moz-linear-gradient(top, #e6f0a3 0%, #d2e638 50%, #c3d825 51%, #dbf043 100%);
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#e6f0a3), color-stop(50%,#d2e638), color-stop(51%,#c3d825), color-stop(100%,#dbf043));
background: -webkit-linear-gradient(top, #e6f0a3 0%,#d2e638 50%,#c3d825 51%,#dbf043 100%);
background: -o-linear-gradient(top, #e6f0a3 0%,#d2e638 50%,#c3d825 51%,#dbf043 100%);
background: -ms-linear-gradient(top, #e6f0a3 0%,#d2e638 50%,#c3d825 51%,#dbf043 100%);
background: linear-gradient(to bottom, #e6f0a3 0%,#d2e638 50%,#c3d825 51%,#dbf043 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#e6f0a3', endColorstr='#dbf043',GradientType=0 );
}