Changelog

All notable changes to this project are documented here. The format follows Keep a Changelog, and the project adheres to Semantic Versioning.

Unreleased

App-shell layout (LanternUI.Components.Layout) — the core Fluxon-style navigation chrome: sidebar_layout (fixed sidebar + main + optional topbar), sidebar_header (logo corner), sidebar_nav / nav_group / nav_item (grouped nav with icons + active state), and sidebar_toggle (collapse to an icon rail, persisted per-id in localStorage via the new LanternSidebar hook). Collapses to a horizontal strip on narrow viewports.
Icons: bars-3, squares-2x2, chart-bar, circle-stack, cloud.

CSS split into two artifacts (per the embeddable-core architecture): lantern_ui.css is now the always-required component styles, and the optional default theme (tokens, light/dark, density) moved to lantern_ui_theme.css. Standalone hosts import both; Fluxon/token-bearing hosts import only the component styles and bridge --lantern-* onto their own tokens (example in the file header). Migration: add lantern_ui_theme.css next to your existing lantern_ui.css import.

Modal (modal/1 + LanternUI.open_dialog/1,2 / close_dialog/1,2) — Fluxon-compatible dialog on the shared overlay runtime: focus trap, Escape/outside dismissal, prevent_closing, placement, token-driven fade.
Dropdown menu (dropdown/1 + dropdown_header/separator/link/button/custom) — Fluxon-compatible family with WAI-ARIA menu keyboard navigation.
Checkbox (checkbox/1) — Fluxon-compatible, FormField-aware, hidden unchecked-value input, label/description/error states.
Breadcrumb (breadcrumb/1) — path navigation for file/tree UIs (lantern-ui extension).
Empty state (empty_state/1) — quiet zero states with icon, title, description, and action slot (lantern-ui extension).
Icons: folder, folder-open, document, arrow-up-tray, arrow-down-tray, arrow-path, trash.
Hooks: LanternModal, LanternDropdown.

Picker panel now carries the popover chrome itself (background, border, shadow) — the time pane and footer no longer float transparent below the calendar's box.
Open panels follow their anchor during scroll/resize instead of staying pinned to the viewport.
The panel time pane no longer shows its own ∅ clear glyph (the footer's Clear covers it).

Explicit .light token block, so a subtree can force light mode under a dark OS (mirror of .dark).

date_time_picker panel now includes a time pane — a non-submitting segmented time field under the calendar, kept in two-way sync with the trigger (new lantern:set-time event on the field hook). Picking a time with no date yet defaults the date to today.

Segmented field no longer wraps onto multiple lines in narrow hosts (explicit flex-wrap: nowrap + overflow guards on .lui-dtf).

date_picker / date_time_picker / time_picker now accept a form attribute and forward it to the hidden value input, so the pickers work as editors rendered outside their <form> element (e.g. lantern's table cell editors, which submit via form="...").

Component system foundation: full design-token set in priv/static/lantern_ui.css (semantic colors, shadcn-density scale — 32px controls / 13px text — monochrome primary + coral accent, light/dark, data-lantern-density modes), the use LanternUI importer with Fluxon-compatible :only/:except, LanternUI.Class helpers, and a dependency-free JS runtime core (position, trapFocus, onDismiss, LanternOverlay).
Primitives (Fluxon-compatible API, lui-* namespaced CSS, zero build step): button/button_group, icon (curated inline Heroicons-outline set), form.input/label/error, calendar (WAI-ARIA month grid + LanternCalendar hook with the full APG keyboard model), and the segmented datetime_field (typeable/steppable segments to millisecond precision, hidden canonical input, clear-to-null) with the LanternDatetimeField hook.
Pickers: date_picker, date_time_picker (calendar popover with Today/Now · Clear · Done), and time_picker (segments-only). Canonical values YYYY-MM-DD / HH:MM:SS.mmm / YYYY-MM-DDTHH:MM:SS.mmm; empty = null. Accepts Date/Time/NaiveDateTime/DateTime structs or strings.

line_chart crosshair tooltip: size the box to the longest label + value so long series names (e.g. Kubernetes pod names) no longer collide with the right-aligned value.

LanternUI.Charts.line_chart/1 — multi-series time-series line chart with a legend and a shared crosshair tooltip (LineHover hook). Accepts %{label, color, points: [{datetime, number}]} series; 0-based y axis; built for resource/monitoring metrics.
Initial chart set as native Phoenix LiveView function components under LanternUI.Charts: area_chart/1, sparkline/1, bar_chart/1.
LanternUI.Charts.Geometry — pure scaling, "nice" tick, and SVG path helpers.
ChartHover LiveView JS hook (priv/static/lantern_ui_hooks.js) for the crosshair + tooltip on area_chart.
Optional standalone theme (priv/static/lantern_ui.css); components otherwise inherit host CSS variables (Fluxon-compatible).