bootstrap border collapse class code example
Example: disable border toggle bootstrap
.navbar-toggler:focus,
.navbar-toggler:active,
.navbar-toggler-icon:focus {
outline: none;
box-shadow: none;
}
.navbar-toggler:focus,
.navbar-toggler:active,
.navbar-toggler-icon:focus {
outline: none;
box-shadow: none;
}