NbTabsetComponent: Tabset overflow-x should scroll

[braydoncbell]

Issue:

When using an NbTabsetComponent, the <ul> inside the tabset should scroll horizontally to improve UX, especially on small screens or when there are many tabs.

The responsive input parameter does not work well when tab titles contain arbitrary text and cannot be expressed by an icon.

Manually setting overflow-x: auto in the parent component's stylesheet causes the .tab.active .tab-link::before element inside nb-tabset to be mostly hidden.

Workaround:

To resolve this issue, I removed the border from the <ul> and created a custom border using the ::after pseudo-element. This allows margin or padding to be applied to <nb-tabset>, ensuring that the .tab.active .tab-link::before element is not clipped, preventing a vertical scrollbar.

nb-tabset .tabset {
    border-bottom: none;
    position: relative;
    overflow-x: auto;
    padding-bottom: 4px;
}

nb-tabset .tabset::after {
    content: "";
    position: absolute;
    bottom: 2px;
    left: 0;
    width: 100%;
    height: var(--tabset-divider-width);
    background: var(--tabset-divider-color);
}

nb-tabset .tab.active .tab-link::before {
    z-index: 1;
}

This approach ensures proper scrolling behavior while maintaining the visual integrity of the active tab indicator.