public/custom.css
@import url('//maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css');
.flash_success, .flash_warning, .flash_error {
padding: 12px;
}
.flash_success {
color: #4F8A10;
background-color: #DFF2BF;
}
.flash_warning {
color: #9F6000;
background-color: #FEEFB3;
}
.flash_error {
color: #D8000C;
background-color: #FFD2D2;
}
.flash_success i, .flash_warning i, .flash_error i {
margin: 10px 30px;
font-size: 2em;
vertical-align: middle;
}