/* ═══════════════════════════════════════════════════════════
   JSON Lint — Main Stylesheet
   CSS variables → light/dark theme → layout → components
   ═══════════════════════════════════════════════════════════ */

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }
button, select, input, textarea { font-family: inherit; font-size: inherit; }
button { cursor: pointer; border: none; background: none; }
ul { list-style: none; }
a { color: inherit; }

/* ── CSS Variables : Light Theme ── */
:root {
  /* Surfaces */
  --bg-app:           #f0f2f5;
  --bg-toolbar:       #1a1b2e;
  --bg-pane:          #ffffff;
  --bg-editor:        #fafafa;
  --bg-output:        #ffffff;
  --bg-pane-header:   #f7f8fa;
  --bg-error:         #fff5f5;
  --bg-stat:          #f0f4ff;
  --bg-hover:         rgba(0,0,0,.04);
  --bg-history:       #ffffff;
  --bg-drop:          rgba(99,102,241,.08);

  /* Text */
  --text-primary:     #111827;
  --text-secondary:   #6b7280;
  --text-toolbar:     #e8eaf6;
  --text-placeholder: #9ca3af;
  --text-error:       #dc2626;
  --text-success:     #16a34a;
  --text-warning:     #d97706;
  --text-link:        #6366f1;

  /* Syntax tokens */
  --tok-key:          #0f766e;
  --tok-string:       #b45309;
  --tok-number:       #1d4ed8;
  --tok-boolean:      #7c3aed;
  --tok-null:         #9ca3af;
  --tok-punct:        #374151;

  /* Borders */
  --border:           #e5e7eb;
  --border-pane:      #e5e7eb;
  --border-focus:     #6366f1;
  --border-drop:      #6366f1;

  /* Shadows */
  --shadow-sm:        0 1px 2px rgba(0,0,0,.06);
  --shadow-md:        0 4px 16px rgba(0,0,0,.12);

  /* Sizing */
  --toolbar-h:        52px;
  --pane-header-h:    38px;
  --status-h:         26px;
  --footer-h:         30px;
  --mobile-bar-h:     56px;
  --gutter-w:         44px;

  /* Type */
  --font-mono:        'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
  --font-ui:          system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-sz-editor:   13px;
  --font-sz-ui:       13px;
  --font-sz-sm:       11.5px;

  /* Misc */
  --radius:           6px;
  --radius-sm:        4px;
  --transition:       0.15s ease;

  /* Buttons */
  --btn-tool-bg:      rgba(255,255,255,.08);
  --btn-tool-hover:   rgba(255,255,255,.16);
  --btn-tool-active:  rgba(255,255,255,.22);
  --btn-primary-bg:   #6366f1;
  --btn-primary-hover:#4f46e5;

  /* Tab */
  --tab-active-bg:    #6366f1;
  --tab-active-color: #ffffff;
  --tab-hover-bg:     rgba(99,102,241,.1);

  /* Error panel */
  --error-border:     #fca5a5;

  /* Diff */
  --diff-added-bg:    #f0fdf4;
  --diff-removed-bg:  #fef2f2;
  --diff-changed-bg:  #fffbeb;
  --diff-added-color: #15803d;
  --diff-removed-color:#b91c1c;
  --diff-changed-color:#92400e;
}

/* ── CSS Variables : Dark Theme ── */
[data-theme="dark"] {
  --bg-app:           #0d0d1a;
  --bg-toolbar:       #0a0a15;
  --bg-pane:          #141424;
  --bg-editor:        #0f0f1e;
  --bg-output:        #0f0f1e;
  --bg-pane-header:   #1a1a2e;
  --bg-error:         #1c0f0f;
  --bg-stat:          #1a1f3a;
  --bg-hover:         rgba(255,255,255,.04);
  --bg-history:       #1a1a2e;
  --bg-drop:          rgba(99,102,241,.15);

  --text-primary:     #e2e8f0;
  --text-secondary:   #94a3b8;
  --text-toolbar:     #c7d2fe;
  --text-placeholder: #475569;
  --text-error:       #f87171;
  --text-success:     #4ade80;
  --text-warning:     #fbbf24;
  --text-link:        #818cf8;

  --tok-key:          #2dd4bf;
  --tok-string:       #fbbf24;
  --tok-number:       #60a5fa;
  --tok-boolean:      #a78bfa;
  --tok-null:         #64748b;
  --tok-punct:        #94a3b8;

  --border:           #2d2d4e;
  --border-pane:      #1e1e3a;
  --border-focus:     #818cf8;
  --border-drop:      #818cf8;

  --shadow-sm:        0 1px 2px rgba(0,0,0,.3);
  --shadow-md:        0 4px 16px rgba(0,0,0,.5);

  --btn-tool-bg:      rgba(255,255,255,.06);
  --btn-tool-hover:   rgba(255,255,255,.1);
  --btn-tool-active:  rgba(255,255,255,.14);

  --tab-active-bg:    #6366f1;
  --tab-hover-bg:     rgba(99,102,241,.15);

  --error-border:     #7f1d1d;

  --diff-added-bg:    #0a2318;
  --diff-removed-bg:  #2a0f0f;
  --diff-changed-bg:  #241c05;
  --diff-added-color: #4ade80;
  --diff-removed-color:#f87171;
  --diff-changed-color:#fbbf24;
}

/* ── Base ── */
html { height: 100%; }
body {
  height: 100%;
  font-family: var(--font-ui);
  font-size: var(--font-sz-ui);
  background: var(--bg-app);
  color: var(--text-primary);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ── App Shell ── */
#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

/* ══════════════════════════════════
   TOOLBAR
   ══════════════════════════════════ */
#toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 12px;
  height: var(--toolbar-h);
  background: var(--bg-toolbar);
  border-bottom: 1px solid rgba(255,255,255,.06);
  flex-shrink: 0;
  z-index: 100;
  user-select: none;
}

#brand {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-toolbar);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -.01em;
  flex-shrink: 0;
  margin-right: 4px;
}

#brand svg {
  width: 22px;
  height: 22px;
  opacity: .85;
}

#toolbar-actions {
  display: flex;
  align-items: center;
  gap: 2px;
  flex: 1;
  overflow-x: auto;
  scrollbar-width: none;
}
#toolbar-actions::-webkit-scrollbar { display: none; }

.btn-tool {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 5px 9px;
  border-radius: var(--radius-sm);
  color: var(--text-toolbar);
  background: var(--btn-tool-bg);
  font-size: var(--font-sz-sm);
  font-weight: 500;
  white-space: nowrap;
  transition: background var(--transition), color var(--transition);
  flex-shrink: 0;
}
.btn-tool:hover { background: var(--btn-tool-hover); }
.btn-tool:active { background: var(--btn-tool-active); transform: scale(.97); }
.btn-tool svg { width: 14px; height: 14px; stroke-width: 2.2; }

.btn-icon-only { padding: 5px 7px; }

.toolbar-sep {
  width: 1px;
  height: 20px;
  background: rgba(255,255,255,.12);
  flex-shrink: 0;
  margin: 0 4px;
}

#indent-picker {
  background: var(--btn-tool-bg);
  color: var(--text-toolbar);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: var(--radius-sm);
  padding: 4px 7px;
  font-size: var(--font-sz-sm);
  cursor: pointer;
  transition: background var(--transition);
  flex-shrink: 0;
}
#indent-picker:hover { background: var(--btn-tool-hover); }
#indent-picker option { background: #1a1b2e; color: #e2e8f0; }

/* ══════════════════════════════════
   MAIN — two-pane grid
   ══════════════════════════════════ */
#main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  overflow: hidden;
  min-height: 0;
}

/* ══════════════════════════════════
   PANE (shared)
   ══════════════════════════════════ */
#pane-input,
#pane-output {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-height: 0;
  background: var(--bg-pane);
}

#pane-input { border-right: 1px solid var(--border-pane); }

.pane-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 12px;
  height: var(--pane-header-h);
  background: var(--bg-pane-header);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  gap: 8px;
}

.pane-title {
  font-size: var(--font-sz-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-secondary);
}

.pane-actions {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ── Toggle label (auto-format checkbox) ── */
.toggle-label {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: var(--font-sz-sm);
  color: var(--text-secondary);
  cursor: pointer;
  user-select: none;
}
.toggle-label input[type="checkbox"] {
  accent-color: var(--border-focus);
  cursor: pointer;
}

/* ── Small buttons ── */
.btn-sm {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  background: transparent;
  transition: background var(--transition), color var(--transition);
}
.btn-sm:hover { background: var(--bg-hover); color: var(--text-primary); }
.btn-sm svg { width: 14px; height: 14px; stroke-width: 2; }

/* ── Link buttons ── */
.btn-link {
  background: none;
  border: none;
  color: var(--text-link);
  font-size: var(--font-sz-sm);
  font-weight: 500;
  padding: 2px 4px;
  border-radius: var(--radius-sm);
  transition: opacity var(--transition);
  cursor: pointer;
}
.btn-link:hover { opacity: .75; }

.btn-link-danger {
  background: none;
  border: none;
  color: var(--text-error);
  font-size: var(--font-sz-sm);
  font-weight: 500;
  cursor: pointer;
}
.btn-link-danger:hover { opacity: .75; }

.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 3px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  transition: background var(--transition);
}
.btn-icon:hover { background: var(--bg-hover); }
.btn-icon svg { width: 13px; height: 13px; }

/* Primary button */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  background: var(--btn-primary-bg);
  color: #fff;
  border-radius: var(--radius);
  font-size: var(--font-sz-ui);
  font-weight: 600;
  transition: background var(--transition), transform var(--transition);
}
.btn-primary:hover { background: var(--btn-primary-hover); }
.btn-primary:active { transform: scale(.97); }
.btn-primary svg { width: 15px; height: 15px; stroke-width: 2.2; }

/* ══════════════════════════════════
   EDITOR (input pane body)
   ══════════════════════════════════ */
.editor-wrapper {
  position: relative;
  flex: 1;
  display: flex;
  overflow: hidden;
  min-height: 0;
  background: var(--bg-editor);
}

#line-numbers {
  display: flex;
  flex-direction: column;
  padding: 10px 0;
  width: var(--gutter-w);
  min-width: var(--gutter-w);
  text-align: right;
  padding-right: 10px;
  font-family: var(--font-mono);
  font-size: var(--font-sz-editor);
  line-height: 1.6;
  color: var(--text-placeholder);
  background: var(--bg-editor);
  border-right: 1px solid var(--border);
  overflow: hidden;
  user-select: none;
  flex-shrink: 0;
}
#line-numbers span { display: block; }

#editor-input {
  flex: 1;
  padding: 10px 12px;
  border: none;
  outline: none;
  resize: none;
  background: var(--bg-editor);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: var(--font-sz-editor);
  line-height: 1.6;
  tab-size: 2;
  white-space: pre;
  overflow-wrap: normal;
  overflow-x: auto;
  overflow-y: auto;
  caret-color: var(--border-focus);
}
#editor-input::placeholder {
  color: var(--text-placeholder);
  font-family: var(--font-ui);
  white-space: pre-line;
  line-height: 2;
}
#editor-input:focus { outline: none; }

/* Drop overlay */
#drop-overlay {
  display: none;
  position: absolute;
  inset: 0;
  background: var(--bg-drop);
  border: 2px dashed var(--border-drop);
  border-radius: var(--radius);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: var(--border-drop);
  font-size: 15px;
  font-weight: 600;
  pointer-events: none;
  z-index: 20;
}
#drop-overlay svg { width: 36px; height: 36px; stroke-width: 1.5; }
.editor-wrapper.drag-over #drop-overlay { display: flex; }

/* ── Status bar ── */
#status-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 12px;
  height: var(--status-h);
  background: var(--bg-pane-header);
  border-top: 1px solid var(--border);
  flex-shrink: 0;
  font-size: var(--font-sz-sm);
  overflow: hidden;
}

#status-badge {
  font-weight: 600;
  font-size: var(--font-sz-sm);
  flex-shrink: 0;
}
.status-valid  { color: var(--text-success); }
.status-error  { color: var(--text-error); }
.status-warning{ color: var(--text-warning); }

#status-info {
  color: var(--text-secondary);
  flex-shrink: 0;
}

#path-display {
  margin-left: auto;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: var(--font-sz-sm);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 60%;
}

/* ══════════════════════════════════
   OUTPUT PANE
   ══════════════════════════════════ */

/* Output tabs */
#output-tabs {
  display: flex;
  gap: 2px;
}
.tab-btn {
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: var(--font-sz-sm);
  font-weight: 500;
  color: var(--text-secondary);
  background: transparent;
  transition: background var(--transition), color var(--transition);
}
.tab-btn:hover { background: var(--tab-hover-bg); color: var(--text-primary); }
.tab-btn.active {
  background: var(--tab-active-bg);
  color: var(--tab-active-color);
}

/* Output content area */
#output-content {
  flex: 1;
  overflow: hidden;
  min-height: 0;
  position: relative;
}

.tab-view {
  position: absolute;
  inset: 0;
  overflow-y: auto;
  overflow-x: auto;
  background: var(--bg-output);
  display: flex;
  flex-direction: column;
}

/* Formatted view */
#pre-output {
  margin: 0;
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: var(--font-sz-editor);
  line-height: 1.6;
  background: transparent;
  white-space: pre;
  overflow: visible;
  tab-size: 2;
  flex: 1;
}

#code-output {
  font-family: var(--font-mono);
  background: transparent !important;
  display: block;
}

/* Prism token overrides (use our CSS vars) */
.token.property          { color: var(--tok-key); }
.token.string            { color: var(--tok-string); }
.token.number            { color: var(--tok-number); }
.token.boolean           { color: var(--tok-boolean); }
.token.null              { color: var(--tok-null); }
.token.punctuation       { color: var(--tok-punct); }
.token.operator          { color: var(--tok-punct); }
code[class*="language-"] { background: transparent !important; text-shadow: none !important; }
pre[class*="language-"]  { background: transparent !important; text-shadow: none !important; }

/* Empty state */
#empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  position: absolute;
  inset: 0;
  color: var(--text-placeholder);
  text-align: center;
  padding: 40px;
  pointer-events: none;
}
#empty-state.hidden { display: none; }
.empty-icon { width: 48px; height: 48px; stroke-width: 1.2; opacity: .4; }
.empty-hint { font-size: var(--font-sz-sm); opacity: .7; }
.empty-hint kbd {
  background: var(--border);
  padding: 1px 5px;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 11px;
}

/* ── Stats panel ── */
#stats-panel {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding: 6px 12px;
  border-top: 1px solid var(--border);
  background: var(--bg-pane-header);
  flex-shrink: 0;
}

.stat-chip {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 3px 9px;
  background: var(--bg-stat);
  border-radius: 99px;
  font-size: var(--font-sz-sm);
}
.stat-label { color: var(--text-secondary); }
.stat-value { color: var(--text-primary); font-weight: 700; }

/* ── Error panel ── */
#error-panel {
  max-height: 0;
  overflow: hidden;
  background: var(--bg-error);
  border-top: 1px solid transparent;
  transition: max-height 0.25s ease, border-color 0.25s ease;
  flex-shrink: 0;
}
#error-panel.error-panel-open {
  max-height: 200px;
  border-color: var(--error-border);
  overflow-y: auto;
}

#error-header {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 7px 12px;
  position: sticky;
  top: 0;
  background: var(--bg-error);
  z-index: 1;
}
#error-header svg { width: 14px; height: 14px; color: var(--text-error); flex-shrink: 0; }
#error-count-label { font-weight: 600; color: var(--text-error); font-size: var(--font-sz-sm); }
#btn-close-errors { margin-left: auto; }

#error-list { padding: 0 12px 8px; }
#error-list li {
  display: flex;
  gap: 8px;
  padding: 4px 0;
  font-size: var(--font-sz-sm);
  border-bottom: 1px solid var(--error-border);
  cursor: pointer;
  transition: opacity var(--transition);
  align-items: flex-start;
}
#error-list li:last-child { border-bottom: none; }
#error-list li:hover { opacity: .75; }
.err-loc { color: var(--text-error); font-weight: 600; font-family: var(--font-mono); flex-shrink: 0; }
.err-msg { color: var(--text-secondary); word-break: break-word; }

/* ══════════════════════════════════
   DIFF TAB
   ══════════════════════════════════ */
#view-diff {
  padding: 12px;
  gap: 10px;
  overflow-y: auto;
}

#diff-inputs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  flex-shrink: 0;
}

.diff-col { display: flex; flex-direction: column; gap: 6px; }
.diff-col-header {
  font-size: var(--font-sz-sm);
  font-weight: 600;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

#diff-input-a, #diff-input-b {
  height: 140px;
  resize: vertical;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-editor);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: var(--font-sz-editor);
  line-height: 1.5;
  outline: none;
  transition: border-color var(--transition);
}
#diff-input-a:focus, #diff-input-b:focus { border-color: var(--border-focus); }

#diff-toolbar {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}
#diff-summary { font-size: var(--font-sz-sm); color: var(--text-secondary); }

#diff-result { flex: 1; overflow: auto; }

.diff-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-sz-sm);
}
.diff-table th {
  text-align: left;
  padding: 6px 10px;
  background: var(--bg-pane-header);
  border-bottom: 2px solid var(--border);
  color: var(--text-secondary);
  font-weight: 600;
  position: sticky;
  top: 0;
  z-index: 1;
}
.diff-table td { padding: 6px 10px; border-bottom: 1px solid var(--border); vertical-align: top; }
.diff-row.diff-added    td { background: var(--diff-added-bg); }
.diff-row.diff-removed  td { background: var(--diff-removed-bg); }
.diff-row.diff-changed  td { background: var(--diff-changed-bg); }
.diff-path { font-family: var(--font-mono); font-size: 11px; }
.diff-val code { font-family: var(--font-mono); font-size: 11px; white-space: pre-wrap; }
.diff-nil { color: var(--text-placeholder); }
.diff-string  { color: var(--tok-string); font-family: var(--font-mono); }
.diff-primitive{ font-family: var(--font-mono); color: var(--tok-number); }

.diff-empty {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 20px;
  color: var(--text-success);
  font-weight: 600;
}
.diff-empty svg { width: 18px; height: 18px; }

/* Badges */
.badge {
  display: inline-block;
  padding: 1px 7px;
  border-radius: 99px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .04em;
}
.badge-red   { background: #fee2e2; color: #991b1b; }
.badge-green { background: #dcfce7; color: #166534; }
[data-theme="dark"] .badge-red   { background: #3b0a0a; color: #f87171; }
[data-theme="dark"] .badge-green { background: #052e16; color: #4ade80; }

.diff-badge {
  padding: 1px 6px;
  border-radius: 3px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
}
.diff-badge.diff-added   { background: #dcfce7; color: #166534; }
.diff-badge.diff-removed { background: #fee2e2; color: #991b1b; }
.diff-badge.diff-changed { background: #fef9c3; color: #854d0e; }
[data-theme="dark"] .diff-badge.diff-added   { background: #052e16; color: #4ade80; }
[data-theme="dark"] .diff-badge.diff-removed { background: #3b0a0a; color: #f87171; }
[data-theme="dark"] .diff-badge.diff-changed { background: #1c1500; color: #fbbf24; }

/* ══════════════════════════════════
   TREE EMPTY STATE
   ══════════════════════════════════ */
.tree-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 100%;
  color: var(--text-placeholder);
  text-align: center;
  padding: 40px;
}
.tree-empty svg { width: 36px; height: 36px; opacity: .4; stroke-width: 1.5; }

/* ══════════════════════════════════
   HISTORY PANEL
   ══════════════════════════════════ */
#history-panel {
  position: fixed;
  top: var(--toolbar-h);
  right: 12px;
  width: 340px;
  max-height: 380px;
  background: var(--bg-history);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  z-index: 200;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#history-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  font-weight: 600;
  font-size: var(--font-sz-sm);
  flex-shrink: 0;
}

#history-list { overflow-y: auto; flex: 1; }

.history-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 9px 14px;
  cursor: pointer;
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}
.history-item:hover { background: var(--bg-hover); }
.history-item:last-child { border-bottom: none; }

.history-preview {
  font-family: var(--font-mono);
  font-size: var(--font-sz-sm);
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.history-time {
  font-size: 10px;
  color: var(--text-placeholder);
}

#history-empty { padding: 20px; text-align: center; color: var(--text-placeholder); font-size: var(--font-sz-sm); }

/* ══════════════════════════════════
   FOOTER
   ══════════════════════════════════ */
#footer {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 14px;
  height: var(--footer-h);
  background: var(--bg-pane-header);
  border-top: 1px solid var(--border);
  font-size: var(--font-sz-sm);
  color: var(--text-secondary);
  flex-shrink: 0;
  user-select: none;
  overflow-x: auto;
  scrollbar-width: none;
}
#footer::-webkit-scrollbar { display: none; }
.footer-right { margin-left: auto; white-space: nowrap; }

kbd {
  background: var(--bg-hover);
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  padding: 1px 5px;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-secondary);
}

/* ══════════════════════════════════
   MOBILE BOTTOM TAB BAR
   ══════════════════════════════════ */
#mobile-tab-bar {
  display: none;
  height: var(--mobile-bar-h);
  background: var(--bg-toolbar);
  border-top: 1px solid rgba(255,255,255,.06);
  flex-shrink: 0;
}

.mobile-tab {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  color: rgba(255,255,255,.5);
  font-size: 11px;
  font-weight: 500;
  transition: color var(--transition);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}
.mobile-tab svg { width: 20px; height: 20px; stroke-width: 2; }
.mobile-tab.active { color: #818cf8; }
.mobile-tab.active svg { stroke: #818cf8; }

/* ══════════════════════════════════
   TOAST NOTIFICATIONS
   ══════════════════════════════════ */
#toast-container {
  position: fixed;
  bottom: calc(var(--footer-h) + 12px);
  right: 14px;
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: flex-end;
  pointer-events: none;
}

.toast {
  padding: 9px 14px;
  border-radius: var(--radius);
  font-size: var(--font-sz-sm);
  font-weight: 500;
  max-width: 280px;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity .25s ease, transform .25s ease;
  box-shadow: var(--shadow-md);
  pointer-events: auto;
}
.toast-show { opacity: 1; transform: translateY(0); }
.toast-success { background: #14532d; color: #86efac; }
.toast-error   { background: #450a0a; color: #fca5a5; }
.toast-info    { background: #1e1b4b; color: #a5b4fc; }
[data-theme="light"] .toast-success { background: #f0fdf4; color: #15803d; border: 1px solid #86efac; }
[data-theme="light"] .toast-error   { background: #fef2f2; color: #b91c1c; border: 1px solid #fca5a5; }
[data-theme="light"] .toast-info    { background: #eef2ff; color: #4338ca; border: 1px solid #a5b4fc; }

/* ══════════════════════════════════
   RESPONSIVE — MOBILE (≤ 599px)
   ══════════════════════════════════ */
@media (max-width: 599px) {
  /* Show mobile tab bar */
  #mobile-tab-bar { display: flex; }

  /* Hide desktop footer */
  #footer { display: none; }

  /* Single-column main — only active pane shows */
  #main { display: block; position: relative; overflow: hidden; }

  #pane-input,
  #pane-output {
    position: absolute;
    inset: 0;
    display: none;
  }
  #pane-input.mobile-active,
  #pane-output.mobile-active { display: flex; }

  /* Larger touch targets */
  .btn-tool { padding: 8px 10px; }
  .btn-sm   { padding: 6px; }
  .btn-sm svg, .btn-tool svg { width: 16px; height: 16px; }

  /* Hide text labels on small toolbar to save space */
  .btn-label { display: none; }
  #brand span { display: none; }

  /* Diff inputs stack vertically */
  #diff-inputs { grid-template-columns: 1fr; }
  #diff-input-a, #diff-input-b { height: 100px; }

  /* History panel full-width */
  #history-panel { right: 0; left: 0; width: auto; border-radius: 0; }

  /* Toast above mobile bar */
  #toast-container { bottom: calc(var(--mobile-bar-h) + 10px + env(safe-area-inset-bottom, 0px)); }

  /* Larger editor font */
  #editor-input { font-size: 14px; }
  #pre-output   { font-size: 14px; }

  /* Stats panel wrap */
  #stats-panel { gap: 4px; padding: 5px 10px; }
  .stat-chip { font-size: 11px; padding: 2px 7px; }
}

/* ══════════════════════════════════
   RESPONSIVE — TABLET (600–899px)
   ══════════════════════════════════ */
@media (min-width: 600px) and (max-width: 899px) {
  .btn-label { display: none; }
  #main { grid-template-columns: 1fr 1fr; }
}

/* ══════════════════════════════════
   SCROLL BARS (chromium)
   ══════════════════════════════════ */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-placeholder); }