<form>
<input type="email" name="email" />
<button type="submit">submit</button>
</form>
body {
background: #5B909F;
}
form {
display: flex;
}
input {
flex-grow: 1;
border: none;
outline: none;
}
button {
background: #B8E7AF;
border: 1px solid #B8E7AF;
font-size: 30px
}