For the submit button try this. You can change the colors as you please.
.age-gate-submit {
background: #fff; /* button background */
padding: 10px 20px; /* top, right */
font-size: 20px;
margin: 5px 10px 0; /* top, right, bottom */
transition: all 0.2s ease;
-moz-appearance: none;
-webkit-appearance: none;
border-color: white;
border-radius: 40% 1%; /* makes the button curve */
min-width: 75px;
}
.age-gate-submit:hover {
opacity: 0.6;
}
.age-gate-submit:hover {background-color: #000; /* button background color – or your choice of color */
color: #fff; /* text or your choice of color */
}`
