If you want to change the colors of the Direct Posts-button, you need to add the CSS code snippets below to your custom CSS box under Settings > Design 👇
Changing the background color:
This snippet changes the background color to orange:
#createPostButton {
background-color: #fbbc56;
}
#createPostButton:hover {
background-color: #fbbc56;
box-shadow: 0 0 0 2px orange;
}
Changing the text color:
This snippet changes the text color to back:
#createPostButton {
color: #000000;
} 
Changing the size of the button:
This snippet doubles the size of the button. You can experiment with your own preferred values for width & height!
.desktop #createPostButton canvas {
height: 180px !important;
width: 180px !important;
}
.desktop #createPostButton {
max-width: 200px !important;
width: 200px !important;
}
In case you have further questions, don't hesitate to contact the support team via chat or support@walls.io!