/* ── Layout ──────────────────────────────────────────────────────────────── */

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    overflow: hidden;
    font-family: var(--font);
    color: var(--text);
    background-color: var(--bg);
}

#appMain {
    position: relative;
    height: calc(100vh - 2.65rem); /* clear .app-header */
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.browse-root {
    display: flex;
    flex-direction: column;
    flex: 1;
    height: 100%;
    overflow: hidden;
    background: var(--bg);
}

/* ── Toolbar ─────────────────────────────────────────────────────────────── */

.browse-toolbar {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.4rem 1rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}

.view-mode-toggle {
    display: inline-flex;
    gap: 0;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.view-mode-toggle .btn {
    border-radius: 0;
    border: none;
    border-right: 1px solid var(--border);
}

.view-mode-toggle .btn:last-child {
    border-right: none;
}

.view-mode-toggle .btn[aria-selected="true"] {
    background: var(--primary);
    color: var(--text-light);
}

/* Breadcrumbs */
.breadcrumbs {
    flex: 1;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.15rem 0.4rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    min-width: 0;
}

.breadcrumbs a,
.breadcrumbs button {
    color: var(--text-muted);
    background: none;
    border: 0;
    padding: 0.1rem 0.3rem;
    border-radius: var(--radius);
    cursor: pointer;
    text-decoration: none;
    font: inherit;
}

.breadcrumbs a:hover,
.breadcrumbs button:hover {
    color: var(--text);
    background: var(--bg-hover);
}

.breadcrumbs .bc-sep {
    color: var(--text-muted);
    user-select: none;
}

.breadcrumbs .bc-current {
    color: var(--text);
    font-weight: 600;
    padding: 0.1rem 0.3rem;
}

.bc-home-icon {
    width: 1em;
    height: 1em;
    vertical-align: -0.15em;
}

.toolbar__count {
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
}

/* ── Two-pane browse view ────────────────────────────────────────────────── */

.browse-view {
    display: flex;
    flex: 1;
    overflow: hidden;
    min-height: 0;
}

.pane {
    overflow: hidden;
    background: var(--bg);
    display: flex;
    flex-direction: column;
}

.tree-pane {
    width: 360px;
    min-width: 200px;
    max-width: 60%;
    border-right: 1px solid var(--border);
    flex-shrink: 0;
}

.tree-pane__body {
    flex: 1;
    overflow: auto;
    padding: 0.25rem 0;
    font-size: 0.875rem;
}

/* Pane resizer — 4px grab handle between tree and preview */
.pane-resizer {
    width: 4px;
    background: transparent;
    cursor: col-resize;
    flex-shrink: 0;
    position: relative;
    z-index: 1;
}

.pane-resizer:hover,
.pane-resizer.is-dragging {
    background: var(--primary);
}

.preview-pane {
    flex: 1;
    min-width: 0;
}

.preview-pane__header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 0.75rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
    min-height: 2.1rem;
}

.preview-pane__title {
    flex: 1;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    min-width: 0;
}

.preview-pane__meta {
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
}

.preview-pane__body {
    flex: 1;
    overflow: auto;
    display: flex;
    flex-direction: column;
    background: var(--bg);
}

/* The body's children fill the available space. Plugins inject
   different content here — img, iframe, pre, custom markdown editor. */
.preview-pane__body > * {
    flex: 1;
    min-height: 0;
}

.preview-empty {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 0.95rem;
    padding: 2rem;
    text-align: center;
}

.preview-pane__body img.preview-image {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    margin: auto;
    display: block;
    flex: none; /* avoid flex sizing interfering with object-fit */
}

.preview-pane__body iframe.preview-iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.preview-pane__body pre.preview-text {
    padding: 1rem;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    white-space: pre-wrap;
    word-wrap: break-word;
    margin: 0;
    overflow: auto;
    background: var(--bg);
    color: var(--text);
}

/* ── Tree (vertical, file-explorer style) ───────────────────────────────── */

.tree-row {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.15rem 0.5rem;
    cursor: pointer;
    user-select: none;
    border-radius: 0;
    color: var(--text);
}

.tree-row:hover {
    background: var(--bg-hover);
}

.tree-row.is-selected {
    background: var(--bg-selected);
    color: var(--text);
}

.tree-row.is-selected .tree-name__label {
    color: var(--text);
}

.tree-name__chevron {
    display: inline-block;
    width: 1rem;
    text-align: center;
    color: var(--text-muted);
    flex-shrink: 0;
    font-family: monospace;
    font-size: 0.65rem;
}

.tree-row[data-isdir="true"] .tree-name__chevron::before,
.tree-row[data-iszip="true"] .tree-name__chevron::before {
    content: "▸";
}

.tree-row[data-isdir="true"].expanded .tree-name__chevron::before,
.tree-row[data-iszip="true"].expanded .tree-name__chevron::before {
    content: "▾";
}

.tree-name__chevron--leaf::before {
    content: "";
}

.tree-name__icon {
    flex-shrink: 0;
    font-size: 0.95rem;
}

.tree-name__label {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: var(--text);
}

.tree-row[data-isdir="true"] .tree-name__label,
.tree-row[data-iszip="true"] .tree-name__label {
    font-weight: 500;
}

/* ── Drag-drop upload overlay ─────────────────────────────────────────────── */
/* Shown only while a drag is active over the page AND the current scope
   accepts uploads. Pointer-events:none below dragover so the underlying
   drop event still reaches the document handlers. */
.upload-overlay {
    position: fixed;
    inset: 0;
    z-index: 50;
    pointer-events: none;
    background: rgba(42, 90, 138, 0.18);
    backdrop-filter: blur(2px);
    -webkit-backdrop-filter: blur(2px);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.12s ease;
}
.upload-overlay.is-active {
    opacity: 1;
}
.upload-overlay__panel {
    background: var(--bg);
    border: 2px dashed var(--primary);
    border-radius: var(--radius);
    padding: 1.5rem 2.25rem;
    text-align: center;
    box-shadow: 0 6px 24px rgba(0, 0, 0, 0.18);
    pointer-events: none;
    color: var(--text);
    max-width: 80vw;
}
.upload-overlay__icon {
    font-size: 2.5rem;
    line-height: 1;
    color: var(--primary);
}
.upload-overlay__title {
    font-family: var(--font-display);
    font-size: 1.15rem;
    font-weight: 600;
    margin-top: 0.5rem;
}
.upload-overlay__path {
    margin-top: 0.35rem;
    font-family: var(--font-mono);
    font-size: 0.82rem;
    color: var(--text-muted);
    word-break: break-all;
}

/* Virtual rows: synthesized client-side for folders that aren't on
   disk yet (canonical project folders). Rendered muted so the user
   reads them as "available but empty" rather than ordinary entries.
   Hover/select states still apply; the hint sits to the right of the
   label. */
.tree-row--virtual .tree-name__icon,
.tree-row--virtual .tree-name__label {
    opacity: 0.65;
}
.tree-name__hint {
    margin-left: 0.5rem;
    font-size: 0.78rem;
    color: var(--text-muted);
    font-style: italic;
}

/* ── Grid view (Phase C) ─────────────────────────────────────────────────── */

.grid-view {
    flex: 1;
    overflow: auto;
    background: var(--bg);
    padding: 0;
}

.grid-empty {
    padding: 3rem;
    text-align: center;
    color: var(--text-muted);
}

/* ── Status bar ──────────────────────────────────────────────────────────── */

.status-bar {
    padding: 0.4rem 1rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    font-size: 0.8rem;
    color: var(--text-muted);
    min-height: 1.6rem;
    flex-shrink: 0;
}

.status-bar.is-error { color: var(--danger); }
.status-bar.is-info  { color: var(--text); }

/* ── Markdown plugin (right-pane internals when a .md is selected) ──────── */
/* CSS-Grid shell mirroring mdedit's layout: sidebar on the LEFT
   (front matter top + TOC bottom), content on the RIGHT (informational
   header above the Toast UI editor). The grid gives every cell a
   definite size, which Toast UI needs to compute its scroll regions
   correctly. */
.md-shell {
    display: grid;
    grid-template-rows: 1fr;
    grid-template-columns: 280px 1fr;        /* JS overrides on resize */
    grid-template-areas: "sidebar content";
    height: 100%;
    min-height: 0;
    background: var(--bg);
    overflow: hidden;
}

/* Sidebar (col 1): two stacked sections — Front matter (top, fixed
   default 180 px, drag-resizable) and TOC (bottom, takes the rest). */
.md-shell__sidebar {
    grid-area: sidebar;
    display: grid;
    grid-template-rows: 180px 1fr;            /* JS overrides on resize */
    min-height: 0;
    overflow: hidden;
    border-right: 1px solid var(--border);
    background: var(--bg);
    position: relative;
}

/* Vertical sidebar/content resizer. Sits absolutely on the column
   boundary so it doesn't occupy a grid track. */
.md-shell__resizer {
    grid-area: sidebar;
    align-self: stretch;
    justify-self: end;
    width: 6px;
    margin-right: -3px;
    cursor: col-resize;
    background: transparent;
    z-index: 2;
    transition: background 0.12s;
}
.md-shell__resizer:hover,
.md-shell__resizer.is-dragging,
.md-shell__resizer:focus-visible {
    background: var(--primary);
    outline: none;
}

/* Horizontal resizer between front-matter and TOC inside the sidebar.
   Spans both rows by placement, then absolutely positioned to overlay
   the grid-row boundary. */
.md-shell__fmresizer {
    grid-column: 1;
    grid-row: 1;
    align-self: end;
    justify-self: stretch;
    height: 6px;
    margin-bottom: -3px;
    cursor: row-resize;
    background: transparent;
    z-index: 2;
    transition: background 0.12s;
}
.md-shell__fmresizer:hover,
.md-shell__fmresizer.is-dragging,
.md-shell__fmresizer:focus-visible {
    background: var(--primary);
    outline: none;
}

/* Content (col 2): informational header above the Toast UI editor. */
.md-shell__content {
    grid-area: content;
    display: grid;
    grid-template-rows: auto 1fr;
    min-width: 0;
    min-height: 0;
    overflow: hidden;
}

/* Informational header above the editor: file name on the left, then
   dirty marker, status, source hint, save button. Reads as a header
   for the content panel — file metadata at a glance. */
.md-shell__infohdr {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 0.75rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    font-size: 0.85rem;
}
.md-shell__title {
    flex: 1;
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    min-width: 0;
}
.md-shell__dirty {
    color: var(--text-muted);
    font-size: 0.85rem;
    min-width: 5.5rem;
    text-align: right;
}
.md-shell__status {
    color: var(--text-muted);
    font-size: 0.85rem;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    max-width: 14rem;
}
.md-shell__source {
    color: var(--text-muted);
    font-size: 0.75rem;
    font-style: italic;
    padding: 0.15rem 0.4rem;
    border-radius: var(--radius);
    background: var(--bg);
    border: 1px solid var(--border);
}
.md-shell__download {
    /* Slightly tighter than the Save button so a row of three doesn't
       crowd the title. The base .btn styles still drive padding/color. */
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.02em;
}
.md-shell__download[disabled] {
    opacity: 0.55;
    cursor: progress;
}

/* Editor host: a single grid cell with overflow:hidden so Toast UI's
   internal scrollers handle the content. */
.md-shell__editor {
    min-width: 0;
    min-height: 0;
    overflow: hidden;
}

.md-side {
    display: grid;
    grid-template-rows: auto 1fr;
    min-height: 0;
    overflow: hidden;
}
.md-side--toc {
    border-top: 1px solid var(--border);
}
.md-side__header {
    padding: 0.35rem 0.75rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-muted);
}
.md-side__body {
    overflow-y: auto;
    min-height: 0;
    padding: 0.3rem 0;
    font-size: 0.85rem;
    line-height: 1.45;
}

/* ── Outline list ───────────────────────────────────────────────────────── */
.md-toc__empty {
    color: var(--text-muted);
    font-style: italic;
    padding: 0.5rem 0.75rem;
    margin: 0;
    font-size: 0.82rem;
}
.md-toc__list {
    list-style: none;
    margin: 0;
    padding: 0;
}
.md-toc__item {
    margin: 0;
    padding: 0.22rem 0.75rem;
    color: var(--text);
    cursor: pointer;
    border-left: 2px solid transparent;
    transition: background 0.1s, border-color 0.1s, color 0.1s;
    /* Truncate long headings rather than wrap; the title attribute
       carries the full text. */
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.md-toc__item:hover {
    background: var(--bg-secondary);
    border-left-color: var(--primary);
}
.md-toc__item:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: -2px;
}
.md-toc__item--l1 { padding-left: 0.75rem; font-weight: 600; }
.md-toc__item--l2 { padding-left: 1.4rem; }
.md-toc__item--l3 { padding-left: 2.05rem; font-size: 0.82rem; }
.md-toc__item--l4 { padding-left: 2.7rem;  font-size: 0.8rem;  color: var(--text-muted); }
.md-toc__item--l5 { padding-left: 3.35rem; font-size: 0.78rem; color: var(--text-muted); }
.md-toc__item--l6 { padding-left: 4rem;    font-size: 0.78rem; color: var(--text-muted); }

/* Flash on click — applied to the heading element in the editor pane.
   The class is scoped to .md-toc__flash so it doesn't paint outside
   this plugin. */
.md-toc__flash {
    background-color: rgba(95, 168, 224, 0.25) !important;
    transition: background-color 0.3s ease;
}

/* ── Front matter editor ────────────────────────────────────────────────── */
.md-fm__body {
    /* Body cell owns the textarea; sized by the sidebar's grid row. */
    padding: 0;
    display: block;
    overflow: hidden;
}
.md-fm__textarea {
    width: 100%;
    height: 100%;
    box-sizing: border-box;
    margin: 0;
    padding: 0.4rem 0.6rem;
    border: 0;
    background: transparent;
    color: var(--text);
    font-family: var(--font-mono, ui-monospace, SFMono-Regular, Consolas, monospace);
    font-size: 0.8rem;
    line-height: 1.45;
    resize: none;
    outline: none;
    white-space: pre;
    overflow: auto;
    tab-size: 2;
}
.md-fm__textarea::placeholder {
    color: var(--text-muted);
    font-style: italic;
}
.md-fm__textarea:focus {
    background: var(--surface-2, rgba(0, 0, 0, 0.025));
}
.md-fm__textarea[readonly] {
    color: var(--text-muted);
    cursor: not-allowed;
}

/* ── Sort control ────────────────────────────────────────────────────────── */
.sort-control {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
}

.sort-control__label {
    user-select: none;
}

.sort-control__select {
    font-family: var(--font);
    font-size: 0.8rem;
    padding: 0.2rem 0.4rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg);
    color: var(--text);
    cursor: pointer;
}

.sort-control__select:focus {
    outline: 2px solid var(--primary);
    outline-offset: -1px;
}

.sort-control__checkbox {
    /* Pair with the "Show hidden" label as a unified control. The
       parent .sort-control already does horizontal flex + gap, so the
       checkbox just needs sensible vertical alignment + a clickable
       hit target. */
    margin: 0;
    cursor: pointer;
}

/* Older .md-fm-section / .fm-list / .md-toc-resizer rules were replaced
   by the .md-shell BEM block above. */