/* ==========================================================================
   Layout: Three-Panel
   Reusable 3-panel grid: nav (tree) + main (editor) + aside (preview).
   Single source of truth for Experience Editor, Org Browser, etc.

   Three responsive modes:
     Wide  (≥1200px) — All 3 panels visible. Nav + Main capped at phone width.
     Mid   (768–1199px) — Nav + Main side-by-side (equal width), Aside via tab.
     Narrow (<768px) — Single panel + 3-tab bar.

   Tab bar HTML includes both combined and separate tabs:
     .panel-layout__tab--combined  — visible in mid mode only ("Editor" = nav+main)
     .panel-layout__tab--separate  — visible in narrow mode only ("Tree" / "Editor")
     (aside tab is always visible when tab bar is shown)

   Usage:
     <div class="panel-layout" data-controller="panel-layout">
       <aside class="panel-layout__nav">...</aside>
       <div class="panel-layout__main">...</div>
       <aside class="panel-layout__aside">...</aside>
       <nav class="panel-layout__tab-bar">
         <button class="panel-layout__tab panel-layout__tab--combined panel-layout__tab--active"
                 data-panel-layout-target="tab"
                 data-action="panel-layout#show"
                 data-panel-layout-panel-param="nav-main">
           <span class="material-symbols-rounded">edit</span><span>Editor</span>
         </button>
         <button class="panel-layout__tab panel-layout__tab--separate panel-layout__tab--active"
                 data-panel-layout-target="tab"
                 data-action="panel-layout#show"
                 data-panel-layout-panel-param="nav">
           <span class="material-symbols-rounded">account_tree</span><span>Tree</span>
         </button>
         <button class="panel-layout__tab panel-layout__tab--separate"
                 data-panel-layout-target="tab"
                 data-action="panel-layout#show"
                 data-panel-layout-panel-param="main">
           <span class="material-symbols-rounded">edit</span><span>Editor</span>
         </button>
         <button class="panel-layout__tab"
                 data-panel-layout-target="tab"
                 data-action="panel-layout#show"
                 data-panel-layout-panel-param="aside">
           <span class="material-symbols-rounded">preview</span><span>Preview</span>
         </button>
       </nav>
     </div>
   ========================================================================== */

/* ── Tokens ── */
.panel-layout {
  --panel-max-width: 390px;
  --panel-header-height: 52px;
  --panel-border: var(--border-subtle);
  --panel-border-subtle: var(--border-subtle);
}

/* ── Viewport containment ──
   panel-layout is a viewport-contained layout: each panel owns its own
   scroll. For that to work, the panel-layout's `height: 100%` (wide/mid
   modes) must resolve to the available viewport track. The app-shell's
   default content slot is `flex: 1 0 auto` (content-sized), and the
   workspace defaults to `overflow-y: auto` (page-level scroll for
   long-form pages). When panel-layout is the workspace's content, neither
   default is correct — panel-layout's height: 100% would collapse to
   content height, the workspace would scroll the whole stack, and the
   user would see "all three panels scrolling together".

   Fix at the DS level: when the workspace contains a panel-layout, clamp
   the workspace's overflow and let the content slot shrink to its flex
   track. Selector uses :has() (broadly supported since 2023). */
.app-shell__workspace:has(> .app-shell__content > .panel-layout) {
  overflow: hidden;
}
.app-shell__workspace:has(> .app-shell__content > .panel-layout) > .app-shell__content {
  flex: 1 1 0;
  min-height: 0;
}

/* ══════════════════════════════════════════════════════════════════════════
   PANEL BASE STYLES (all modes)
   ══════════════════════════════════════════════════════════════════════════ */

.panel-layout__nav {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-right: 1px solid var(--panel-border);
  background: var(--surface-base);
  min-width: 0;
}

.panel-layout__main {
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  overflow-y: auto;
  background: var(--surface-base);
  min-width: 0;
}

.panel-layout__aside {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-left: 1px solid var(--panel-border);
  background: var(--surface-neutral);
  padding: var(--space-4);
  min-width: 0;
}

/* ── Turbo frames: stretch within flex panels ── */
.panel-layout__main > turbo-frame {
  padding-bottom: var(--topbar-height);
}
.panel-layout__aside > turbo-frame {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
}
.panel-layout__aside > turbo-frame {
  overflow: hidden;
}

/* ── Panel empty states ── */
.panel-layout .empty-state {
  flex: 1;
  max-width: none;
  padding: var(--space-8);
}

/* ── Panel headers (shared sub-element) ── */
.panel-layout__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--panel-header-height);
  padding: 0 var(--space-3);
  border-bottom: 1px solid var(--panel-border-subtle);
  flex-shrink: 0;
}
.panel-layout__title {
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}
.panel-layout__actions {
  display: flex;
  gap: var(--space-1);
}

/* ── Panel scrollable body ── */
.panel-layout__body {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-2) 0;
}




/* ══════════════════════════════════════════════════════════════════════════
   TAB BAR BASE STYLES
   Must come BEFORE responsive media queries so breakpoints can override.
   ══════════════════════════════════════════════════════════════════════════ */
.panel-layout__tab-bar {
  display: flex;
  border-top: 1px solid var(--panel-border);
  background-color: var(--surface-page-translucent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  flex-shrink: 0;
  z-index: var(--z-sticky);
}

.panel-layout__tab {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: var(--space-2) var(--space-1);
  border: none;
  background: none;
  color: var(--text-tertiary);
  font-size: 10px;
  font-weight: 500;
  cursor: pointer;
  transition: color var(--duration-fast) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}
.panel-layout__tab .material-symbols-rounded {
  font-size: 22px;
}
.panel-layout__tab--active {
  color: var(--accent-primary);
}
.panel-layout__tab:active {
  background: var(--surface-hover);
}

/* Combined + separate tabs: hidden by default.
   Shown only by the correct breakpoint media query below. */
.panel-layout__tab--combined,
.panel-layout__tab--separate {
  display: none;
}

/* ══════════════════════════════════════════════════════════════════════════
   WIDE (≥1200px): 3-column grid
   Nav and Main capped at phone width, always equal.
   Aside fills remaining space. All columns can shrink (minmax(0, ...)).
   ══════════════════════════════════════════════════════════════════════════ */
@media (min-width: 1200px) {
  .panel-layout {
    display: grid;
    grid-template-columns:
      minmax(0, var(--panel-max-width))
      minmax(0, var(--panel-max-width))
      minmax(0, 1fr);
    grid-template-rows: 1fr;
    height: 100%;
    overflow: hidden;
  }

  .panel-layout__tab-bar { display: none; }
}

/* Wide desktop bump */
@media (min-width: 1600px) {
  .panel-layout {
    --panel-max-width: 420px;
  }
}

/* ══════════════════════════════════════════════════════════════════════════
   MID (768px–1199px): Nav + Main side-by-side, Aside via tab
   Both columns always equal width (1fr 1fr). Tab bar shows 2 tabs:
   combined "Editor" (nav+main) and "Preview" (aside full-width).
   ══════════════════════════════════════════════════════════════════════════ */
@media (min-width: 768px) and (max-width: 1199px) {
  .panel-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: 1fr auto;
    height: 100%;
    overflow: hidden;
  }

  /* Mid mode: panels fill their 1fr tracks (no max-width cap).
     The phone-width cap only applies in wide mode where aside needs space. */

  /* Aside hidden by default — shown via tab */
  .panel-layout__aside {
    display: none;
    grid-column: 1 / -1;
    grid-row: 1;
    border-left: none;
  }

  /* Tab bar spans both columns */
  .panel-layout__tab-bar {
    grid-column: 1 / -1;
    grid-row: 2;
  }

  /* When aside tab is active: hide nav+main, show aside full-width */
  .panel-layout[data-active-panel="aside"] .panel-layout__nav,
  .panel-layout[data-active-panel="aside"] .panel-layout__main {
    display: none;
  }
  .panel-layout[data-active-panel="aside"] .panel-layout__aside {
    display: flex;
  }

  /* Tab visibility: show combined, hide separate */
  .panel-layout__tab--separate { display: none; }
  .panel-layout__tab--combined { display: flex; }
}

/* ══════════════════════════════════════════════════════════════════════════
   NARROW (<768px): Single panel + 3-tab bar
   One panel visible at a time. All panels stay loaded.
   ══════════════════════════════════════════════════════════════════════════ */
@media (max-width: 767px) {
  .panel-layout {
    display: flex;
    flex-direction: column;
    height: 100%;
    overflow: hidden;
  }

  /* Hide all panels by default */
  .panel-layout__nav,
  .panel-layout__main,
  .panel-layout__aside {
    display: none;
    flex: 1;
    overflow-y: auto;
    border: none;
  }

  /* Show the active panel */
  .panel-layout[data-active-panel="nav"] .panel-layout__nav,
  .panel-layout[data-active-panel="nav-main"] .panel-layout__nav,
  .panel-layout[data-active-panel="main"] .panel-layout__main,
  .panel-layout[data-active-panel="aside"] .panel-layout__aside {
    display: flex;
  }

  /* Default: show nav on load */
  .panel-layout:not([data-active-panel]) .panel-layout__nav {
    display: flex;
  }

  /* Tab visibility: show separate, hide combined */
  .panel-layout__tab--combined { display: none; }
  .panel-layout__tab--separate { display: flex; }
}