/* =========================================================
   Notebook — Local-first note taking
   ========================================================= */

:root {
  --nb-sidebar-w: 280px;
  --nb-topbar-h: 56px;
  --nb-mobile-bar-h: 52px;
  --nb-radius: 12px;
  --nb-radius-sm: 8px;
  --nb-easing: 220ms cubic-bezier(0.2, 0.7, 0.2, 1);

  --nb-accent: var(--purple);
  --nb-warm: var(--warm, #e8a87c);
  --nb-teal: var(--teal, #5cc9b5);
}

* { box-sizing: border-box; }

/* Make the `hidden` HTML attribute actually win against our class rules.
   Without this, `.nb-sheet[hidden]` still shows because `.nb-sheet`
   sets `display: flex` and the user-agent `[hidden]` rule loses. */
.nb-body [hidden],
.nb-body .nb-sheet[hidden],
.nb-body .nb-palette[hidden],
.nb-body .nb-slash-menu[hidden],
.nb-body .nb-emoji-picker[hidden],
.nb-body .nb-mobile-bar[hidden],
.nb-body .nb-toast[hidden],
.nb-body .nb-empty[hidden],
.nb-body .nb-editor[hidden] {
  display: none !important;
}

html, body {
  height: 100%;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overscroll-behavior-y: none; /* prevent pull-to-refresh, but allow horizontal swipe-back */
}

.nb-body {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

/* ── Topbar ──────────────────────────────────────────── */
.nb-topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  height: var(--nb-topbar-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(140%) blur(14px);
  -webkit-backdrop-filter: saturate(140%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.nb-topbar-left, .nb-topbar-right {
  display: flex;
  align-items: center;
  gap: 8px;
}
.nb-topbar-center {
  flex: 1;
  display: flex;
  justify-content: center;
  padding: 0 16px;
}
.nb-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: -0.01em;
}
.nb-logo-icon {
  color: var(--purple);
  font-size: 1.1rem;
}
.nb-logo-sep { color: var(--text-muted); font-weight: 400; }
.nb-logo-section { color: var(--text-dim); font-weight: 500; }

.nb-search-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  max-width: 380px;
  padding: 7px 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--nb-radius);
  color: var(--text-muted);
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
  transition: var(--nb-easing);
}
.nb-search-btn:hover {
  border-color: var(--border-hover);
  color: var(--text-dim);
}
.nb-search-btn svg { width: 14px; height: 14px; flex-shrink: 0; }
.nb-search-btn span { flex: 1; text-align: left; }
.nb-search-btn kbd {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 2px 6px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-muted);
}

.nb-icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 8px;
  color: var(--text-dim);
  cursor: pointer;
  transition: var(--nb-easing);
}
.nb-icon-btn:hover {
  background: var(--bg-elevated);
  border-color: var(--border);
  color: var(--text);
}
.nb-icon-btn svg { width: 18px; height: 18px; }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 8px;
  color: var(--text-dim);
  cursor: pointer;
  transition: var(--nb-easing);
}
.theme-toggle:hover {
  background: var(--bg-elevated);
  border-color: var(--border);
  color: var(--text);
}
.theme-toggle svg { width: 16px; height: 16px; }
.theme-toggle .icon-moon { display: none; }
[data-theme="light"] .theme-toggle .icon-sun { display: none; }
[data-theme="light"] .theme-toggle .icon-moon { display: inline; }

.nb-save-indicator {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  padding: 0 6px;
  transition: var(--nb-easing);
}
.nb-save-indicator.saving { color: var(--orange); }
.nb-save-indicator.saved { color: var(--green); }

.nb-sidebar-toggle { display: none; }

/* ── Shell ──────────────────────────────────────────── */
.nb-shell {
  display: grid;
  grid-template-columns: var(--nb-sidebar-w) 1fr;
  flex: 1;
  min-height: 0;
}

/* ── Sidebar ──────────────────────────────────────── */
.nb-sidebar {
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--border);
  background: var(--bg);
  height: calc(100dvh - var(--nb-topbar-h));
  position: sticky;
  top: var(--nb-topbar-h);
  overflow: hidden;
}
.nb-sidebar-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 16px 8px;
}
.nb-sidebar-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
}
.nb-new-btn {
  width: 28px;
  height: 28px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
}
.nb-new-btn:hover {
  background: var(--purple);
  border-color: var(--purple);
  color: white;
}
.nb-new-btn svg { width: 14px; height: 14px; }

.nb-quick-actions {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 0 8px 8px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}
.nb-quick-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 10px;
  background: transparent;
  border: none;
  border-radius: 6px;
  color: var(--text-dim);
  font: inherit;
  font-size: 0.82rem;
  text-align: left;
  cursor: pointer;
  transition: var(--nb-easing);
}
.nb-quick-btn:hover {
  background: var(--bg-elevated);
  color: var(--text);
}
.nb-quick-emoji { font-size: 1rem; }

.nb-sidebar-list {
  flex: 1;
  overflow-y: auto;
  padding: 0 8px 16px;
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.nb-list-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--nb-easing);
  position: relative;
  min-height: 36px;
}
.nb-list-item:hover {
  background: var(--bg-elevated);
}
.nb-list-item.active {
  background: var(--bg-card);
}
.nb-list-item.active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 2px;
  border-radius: 2px;
  background: var(--purple);
}
.nb-list-emoji { font-size: 1rem; flex-shrink: 0; }
.nb-list-text {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.nb-list-title {
  font-size: 0.86rem;
  font-weight: 500;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nb-list-sub {
  font-size: 0.7rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nb-list-menu {
  opacity: 0;
  background: transparent;
  border: none;
  width: 22px;
  height: 22px;
  border-radius: 4px;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--nb-easing);
}
.nb-list-menu:hover { background: var(--border); color: var(--text); }
.nb-list-item:hover .nb-list-menu { opacity: 1; }
.nb-list-menu svg { width: 14px; height: 14px; }

.nb-sidebar-foot {
  padding: 12px 12px 16px;
  border-top: 1px solid var(--border);
}
.nb-text-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  border: none;
  font: inherit;
  font-size: 0.78rem;
  color: var(--text-muted);
  padding: 4px 6px;
  border-radius: 5px;
  cursor: pointer;
  transition: var(--nb-easing);
}
.nb-text-btn:hover { color: var(--text-dim); background: var(--bg-elevated); }
.nb-text-btn svg { width: 14px; height: 14px; }

.nb-sidebar-overlay {
  display: none;
}

/* ── Main / Editor ──────────────────────────────── */
.nb-main {
  overflow-y: auto;
  height: calc(100dvh - var(--nb-topbar-h));
  scroll-behavior: smooth;
}

/* Empty state */
.nb-empty {
  max-width: 520px;
  margin: 0 auto;
  padding: 12vh 24px 24px;
  text-align: center;
}
.nb-empty-glyph {
  font-size: 4rem;
  margin-bottom: 1rem;
  filter: drop-shadow(0 8px 24px rgba(176, 122, 255, 0.3));
}
.nb-empty-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin: 0 0 0.75rem;
  color: var(--text);
}
.nb-empty-sub {
  color: var(--text-dim);
  line-height: 1.7;
  margin: 0 0 2rem;
}
.nb-empty-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
}
.nb-btn-primary {
  background: var(--purple);
  color: white;
  border: none;
  padding: 11px 20px;
  border-radius: var(--nb-radius);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--nb-easing);
  box-shadow: 0 4px 14px rgba(176, 122, 255, 0.35);
}
.nb-btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(176, 122, 255, 0.45);
}
.nb-btn-ghost {
  background: transparent;
  color: var(--text-dim);
  border: 1px solid var(--border);
  padding: 11px 20px;
  border-radius: var(--nb-radius);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--nb-easing);
}
.nb-btn-ghost:hover { border-color: var(--border-hover); color: var(--text); }

.nb-empty-hints {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.nb-hint kbd {
  display: inline-block;
  padding: 2px 7px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 5px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-right: 4px;
}

/* Editor */
.nb-editor {
  max-width: 760px;
  margin: 0 auto;
  padding: 32px 64px 30vh;
}

.nb-cover {
  margin-bottom: 24px;
  padding-top: 24px;
}
.nb-cover-emoji {
  font-size: 3.4rem;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 4px 8px;
  margin: 0 0 8px -8px;
  border-radius: var(--nb-radius);
  transition: var(--nb-easing);
  line-height: 1;
}
.nb-cover-emoji:hover { background: var(--bg-elevated); }
.nb-cover-title {
  font-size: 2.4rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.15;
  color: var(--text);
  margin: 0;
  outline: none;
  word-break: break-word;
}
.nb-cover-title:empty::before {
  content: attr(data-placeholder);
  color: var(--text-muted);
  pointer-events: none;
}
.nb-cover-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-top: 10px;
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}
.nb-cover-source {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-dim);
  text-decoration: none;
  padding: 3px 8px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 6px;
  transition: var(--nb-easing);
}
.nb-cover-source:hover { border-color: var(--purple); color: var(--text); }
.nb-cover-source::before {
  content: '↗';
  color: var(--purple);
}

/* Chapter tabs */
.nb-chapter-tabs {
  display: flex;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 24px;
  overflow-x: auto;
  scrollbar-width: thin;
  padding-bottom: 1px;
}
.nb-chapter-tabs::-webkit-scrollbar { height: 4px; }
.nb-chapter-tabs::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }
.nb-chapter-tab {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 14px;
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-muted);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--nb-easing);
  white-space: nowrap;
  margin-bottom: -1px;
  border-radius: 6px 6px 0 0;
}
.nb-chapter-tab:hover { color: var(--text-dim); background: var(--bg-elevated); }
.nb-chapter-tab.active {
  color: var(--text);
  border-bottom-color: var(--purple);
}
.nb-chapter-tab-name {
  outline: none;
  min-width: 1ch;
  pointer-events: none; /* clicks pass through to the tab button */
}
.nb-chapter-tab-close {
  width: 16px;
  height: 16px;
  border-radius: 3px;
  background: transparent;
  border: none;
  color: inherit;
  opacity: 0;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: var(--nb-easing);
}
.nb-chapter-tab:hover .nb-chapter-tab-close,
.nb-chapter-tab.active .nb-chapter-tab-close { opacity: 0.6; }
.nb-chapter-tab-close:hover { opacity: 1 !important; background: var(--border); }
.nb-add-chapter-btn {
  padding: 9px 12px;
  background: transparent;
  border: none;
  color: var(--text-muted);
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
  border-radius: 6px;
}
.nb-add-chapter-btn:hover { color: var(--text); background: var(--bg-elevated); }

/* Chapter body */
.nb-chapter { min-height: 50vh; }

/* Blocks */
.nb-block {
  position: relative;
  margin: 2px 0;
  padding: 3px 0;
  display: flex;
  gap: 6px;
  align-items: flex-start;
}
.nb-block-handle {
  flex-shrink: 0;
  width: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  cursor: grab;
  color: var(--text-muted);
  align-self: stretch;
  padding-top: 5px;
  transition: opacity var(--nb-easing);
  user-select: none;
}
.nb-block-handle::before {
  content: '⋮⋮';
  font-size: 0.8rem;
  line-height: 1;
  letter-spacing: -2px;
}
.nb-block:hover .nb-block-handle { opacity: 0.8; }
.nb-block-handle:hover { color: var(--text); }
.nb-block-handle:active { cursor: grabbing; }

.nb-block-add {
  position: absolute;
  left: -28px;
  top: 5px;
  width: 22px;
  height: 22px;
  border-radius: 4px;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  opacity: 0;
  transition: var(--nb-easing);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}
.nb-block:hover .nb-block-add { opacity: 0.8; }
.nb-block-add:hover { background: var(--bg-elevated); color: var(--text); opacity: 1; }

.nb-block-content {
  flex: 1;
  min-width: 0;
}
.nb-block-content[contenteditable="true"] {
  outline: none;
  word-break: break-word;
  line-height: 1.7;
}
.nb-block-content[contenteditable="true"]:empty::before {
  content: attr(data-placeholder);
  color: var(--text-muted);
  pointer-events: none;
}

/* Block types */
.nb-block.h1 .nb-block-content {
  font-size: 1.85rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-top: 18px;
  margin-bottom: 4px;
}
.nb-block.h2 .nb-block-content {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.3;
  margin-top: 16px;
  margin-bottom: 2px;
}
.nb-block.h3 .nb-block-content {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.4;
  margin-top: 10px;
}
.nb-block.p .nb-block-content {
  font-size: 0.95rem;
  color: var(--text);
}

.nb-block.bullet, .nb-block.numbered, .nb-block.todo {
  padding-left: 0;
}
/* Indented list items — each level adds a chunk of left padding so the
   item visibly nests under its parent. Marker glyph changes per level. */
.nb-block[data-indent="1"] { padding-left: 28px; }
.nb-block[data-indent="2"] { padding-left: 56px; }
.nb-block[data-indent="3"] { padding-left: 84px; }
.nb-block[data-indent="4"] { padding-left: 112px; }
@media (max-width: 720px) {
  .nb-block[data-indent="1"] { padding-left: 20px; }
  .nb-block[data-indent="2"] { padding-left: 40px; }
  .nb-block[data-indent="3"] { padding-left: 60px; }
  .nb-block[data-indent="4"] { padding-left: 80px; }
}
.nb-block.bullet[data-indent="1"] .nb-block-marker::before,
.nb-block.bullet[data-indent="3"] .nb-block-marker::before { content: '◦'; }
.nb-block.bullet[data-indent="2"] .nb-block-marker::before,
.nb-block.bullet[data-indent="4"] .nb-block-marker::before { content: '▪'; }

/* Flash highlight on a block — used to give immediate visual feedback
   after indent/outdent so users on phones can see the move even though
   the keyboard is up. */
@keyframes nbFlash {
  0%   { background: rgba(176, 122, 255, 0.22); }
  100% { background: transparent; }
}
.nb-block.nb-flash {
  animation: nbFlash 600ms ease-out;
  border-radius: 6px;
}
.nb-block-marker {
  flex-shrink: 0;
  min-width: 18px;
  height: 1.7em;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-dim);
  font-size: 1rem;
  user-select: none;
}
.nb-block.bullet .nb-block-marker::before {
  content: '•';
  font-size: 1.3rem;
  line-height: 1;
}
.nb-block.numbered .nb-block-marker {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  min-width: 22px;
}

.nb-todo-check {
  width: 17px;
  height: 17px;
  border-radius: 5px;
  border: 1.5px solid var(--border-hover);
  background: transparent;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 3px;
  transition: var(--nb-easing);
  flex-shrink: 0;
}
.nb-todo-check:hover { border-color: var(--purple); }
.nb-todo-check.checked {
  background: var(--purple);
  border-color: var(--purple);
}
.nb-todo-check.checked::after {
  content: '✓';
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
}
.nb-block.todo.done .nb-block-content {
  color: var(--text-muted);
  text-decoration: line-through;
}

.nb-block.quote .nb-block-content {
  border-left: 3px solid var(--purple);
  padding: 6px 0 6px 16px;
  font-style: italic;
  color: var(--text-dim);
  font-size: 1.05rem;
  line-height: 1.7;
}

.nb-block.code {
  margin: 12px 0;
}
.nb-block.code .nb-block-content {
  flex: 1;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--nb-radius);
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 0.83rem;
  color: var(--text);
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
  position: relative;
}
.nb-block.code .nb-block-content::before {
  content: attr(data-lang);
  position: absolute;
  top: 6px;
  right: 10px;
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-family: var(--font-mono);
}

.nb-block.math .nb-block-content {
  background: rgba(16, 185, 129, 0.06);
  border: 1px solid rgba(16, 185, 129, 0.2);
  border-radius: var(--nb-radius);
  padding: 14px 18px;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--green);
  text-align: center;
}

.nb-block.callout {
  margin: 12px 0;
}
.nb-callout-wrap {
  flex: 1;
  display: flex;
  gap: 10px;
  background: rgba(176, 122, 255, 0.06);
  border: 1px solid rgba(176, 122, 255, 0.22);
  border-radius: var(--nb-radius);
  padding: 14px 16px;
}
.nb-callout-emoji {
  font-size: 1.2rem;
  line-height: 1.5;
  flex-shrink: 0;
  cursor: pointer;
  user-select: none;
}
.nb-callout-wrap .nb-block-content {
  font-size: 0.92rem;
  line-height: 1.65;
  color: var(--text-dim);
}
.nb-block.callout[data-variant="warn"] .nb-callout-wrap {
  background: rgba(245, 158, 11, 0.07);
  border-color: rgba(245, 158, 11, 0.25);
}
.nb-block.callout[data-variant="check"] .nb-callout-wrap {
  background: rgba(16, 185, 129, 0.07);
  border-color: rgba(16, 185, 129, 0.25);
}
.nb-block.callout[data-variant="info"] .nb-callout-wrap {
  background: rgba(59, 130, 246, 0.07);
  border-color: rgba(59, 130, 246, 0.25);
}

.nb-block.divider {
  padding: 16px 0;
}
.nb-block.divider .nb-block-content {
  height: 1px;
  background: var(--border);
  flex: 1;
  pointer-events: none;
}

/* Image block */
.nb-block.image {
  margin: 12px 0;
}
.nb-image-wrap {
  flex: 1;
  position: relative;
  border-radius: var(--nb-radius);
  overflow: hidden;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
}
.nb-image-wrap img {
  width: 100%;
  height: auto;
  display: block;
}
.nb-image-caption {
  padding: 8px 12px;
  font-size: 0.78rem;
  color: var(--text-muted);
  text-align: center;
  outline: none;
  border-top: 1px solid var(--border);
}
.nb-image-caption:empty::before {
  content: 'Add caption…';
  color: var(--text-muted);
  opacity: 0.5;
}

/* Canvas / drawing block */
.nb-block.canvas {
  margin: 12px 0;
}
.nb-canvas-wrap {
  flex: 1;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--nb-radius);
  overflow: hidden;
  position: relative;
}
.nb-canvas-toolbar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.nb-canvas-tool {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-dim);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: var(--nb-easing);
  font-size: 0.85rem;
}
.nb-canvas-tool:hover { background: var(--bg-card); }
.nb-canvas-tool.active {
  background: var(--bg-card);
  border-color: var(--purple);
  color: var(--text);
}
.nb-canvas-tool svg { width: 14px; height: 14px; }
.nb-canvas-color {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: var(--nb-easing);
  margin: 0 2px;
}
.nb-canvas-color.active {
  border-color: var(--text);
  transform: scale(1.15);
}
.nb-canvas-sep { width: 1px; height: 20px; background: var(--border); margin: 0 4px; }
.nb-canvas-size {
  appearance: none;
  -webkit-appearance: none;
  width: 70px;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  outline: none;
}
.nb-canvas-size::-webkit-slider-thumb {
  appearance: none;
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--purple);
  cursor: pointer;
}
.nb-canvas-size::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--purple);
  cursor: pointer;
  border: none;
}
.nb-draw-canvas {
  display: block;
  width: 100%;
  height: 320px;
  cursor: crosshair;
  touch-action: none;
  background: #ffffff;
  background-image:
    linear-gradient(rgba(176, 122, 255, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(176, 122, 255, 0.06) 1px, transparent 1px);
  background-size: 24px 24px;
}
[data-theme="light"] .nb-draw-canvas { background-color: #fdfdff; }

/* Shared media action bar (image + canvas) — always visible so
   touch users can replace / delete / continue below. */
.nb-media-actions {
  display: flex;
  gap: 6px;
  align-items: center;
  padding: 8px 10px;
  border-top: 1px solid var(--border);
  background: var(--bg);
  flex-wrap: wrap;
}
.nb-media-act {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  font: inherit;
  font-size: 0.78rem;
  padding: 6px 11px;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--nb-easing);
}
.nb-media-act:hover {
  background: var(--bg-elevated);
  color: var(--text);
  border-color: var(--border-hover);
}
.nb-media-act.danger:hover {
  color: var(--red);
  border-color: rgba(239, 68, 68, 0.5);
  background: rgba(239, 68, 68, 0.08);
}
.nb-media-act.primary {
  color: var(--text);
  border-color: var(--purple);
  background: rgba(176, 122, 255, 0.1);
}
.nb-media-act.primary:hover {
  background: var(--purple);
  color: white;
}
@media (max-width: 880px) {
  .nb-media-act { font-size: 14px; padding: 8px 12px; }
}

/* Block delete */
.nb-block-delete {
  position: absolute;
  right: -28px;
  top: 4px;
  width: 22px;
  height: 22px;
  border-radius: 4px;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  opacity: 0;
  transition: var(--nb-easing);
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
}
.nb-block:hover .nb-block-delete { opacity: 0.6; }
.nb-block-delete:hover { background: rgba(239, 68, 68, 0.15); color: var(--red); opacity: 1; }

/* Slash menu */
.nb-slash-menu {
  position: fixed;
  z-index: 50;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--nb-radius);
  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.55), 0 2px 8px rgba(0,0,0,0.3);
  width: 280px;
  max-height: 360px;
  overflow-y: auto;
  padding: 6px;
}
.nb-slash-cat {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  padding: 8px 10px 4px;
}
.nb-slash-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  transition: background 100ms;
}
.nb-slash-item:hover, .nb-slash-item.active {
  background: var(--bg-card);
}
.nb-slash-icon {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 1rem;
  flex-shrink: 0;
}
.nb-slash-item:hover .nb-slash-icon,
.nb-slash-item.active .nb-slash-icon {
  background: var(--bg);
  border-color: var(--border-hover);
}
.nb-slash-text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}
.nb-slash-title {
  font-size: 0.85rem;
  color: var(--text);
  font-weight: 500;
}
.nb-slash-desc {
  font-size: 0.72rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nb-slash-empty {
  padding: 24px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Mobile slash menu: top-anchored sheet, always visible regardless
   of where the cursor was. CSS wins over the inline coords used on
   desktop because of !important. */
.nb-slash-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 49;
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}
.nb-slash-backdrop[hidden] { display: none !important; }
.nb-slash-menu.nb-slash-mobile {
  position: fixed !important;
  top: calc(var(--nb-topbar-h) + 6px) !important;
  left: 8px !important;
  right: 8px !important;
  bottom: auto !important;
  width: auto !important;
  max-width: none !important;
  max-height: 42vh !important;
  z-index: 51 !important;
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.55) !important;
}

/* Palette */
.nb-palette {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 12vh 16px 16px;
}
.nb-palette-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}
.nb-palette-box {
  position: relative;
  width: min(620px, 100%);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.55);
  overflow: hidden;
  animation: nbPop 200ms ease;
}
@keyframes nbPop {
  from { transform: translateY(-10px); opacity: 0; }
  to   { transform: translateY(0); opacity: 1; }
}
.nb-palette-input {
  width: 100%;
  padding: 18px 22px;
  background: transparent;
  border: none;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  font: inherit;
  font-size: 1.05rem;
  outline: none;
}
.nb-palette-input::placeholder { color: var(--text-muted); }
.nb-palette-results {
  max-height: 52vh;
  overflow-y: auto;
  padding: 6px;
}
.nb-palette-result {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 100ms;
}
.nb-palette-result:hover, .nb-palette-result.active {
  background: var(--bg-card);
}
.nb-palette-result-emoji { font-size: 1.2rem; flex-shrink: 0; }
.nb-palette-result-text { flex: 1; min-width: 0; }
.nb-palette-result-title {
  font-size: 0.9rem;
  color: var(--text);
  font-weight: 500;
  margin-bottom: 2px;
}
.nb-palette-result-snippet {
  font-size: 0.78rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nb-palette-result-snippet mark {
  background: rgba(176, 122, 255, 0.25);
  color: var(--text);
  padding: 0 2px;
  border-radius: 2px;
}
.nb-palette-empty {
  padding: 24px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}
.nb-palette-foot {
  display: flex;
  gap: 16px;
  padding: 10px 16px;
  border-top: 1px solid var(--border);
  font-size: 0.7rem;
  color: var(--text-muted);
  background: var(--bg);
}
.nb-palette-foot kbd {
  display: inline-block;
  padding: 1px 6px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  margin-right: 4px;
  color: var(--text-dim);
}

/* Emoji picker */
.nb-emoji-picker {
  position: fixed;
  z-index: 55;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--nb-radius);
  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.55);
  padding: 12px;
  width: 280px;
  max-height: 340px;
  overflow-y: auto;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 2px;
}
.nb-emoji-btn {
  background: transparent;
  border: none;
  font-size: 1.2rem;
  padding: 6px;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--nb-easing);
  line-height: 1;
}
.nb-emoji-btn:hover { background: var(--bg-card); transform: scale(1.15); }

/* Export sheet */
.nb-sheet {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px 16px;
}
.nb-sheet-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
.nb-sheet-box {
  position: relative;
  width: min(560px, 100%);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.55);
  padding: 20px 22px 22px;
  animation: nbPop 200ms ease;
}
.nb-sheet-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
}
.nb-sheet-head h2 {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
}
.nb-export-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}
.nb-export-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--nb-radius);
  padding: 16px 14px;
  text-align: left;
  cursor: pointer;
  transition: var(--nb-easing);
  font: inherit;
}
.nb-export-card:hover {
  border-color: var(--purple);
  transform: translateY(-2px);
  box-shadow: 0 8px 22px rgba(0, 0, 0, 0.35);
}
.nb-export-icon { font-size: 1.5rem; margin-bottom: 8px; }
.nb-export-title { font-weight: 600; color: var(--text); font-size: 0.92rem; margin-bottom: 2px; }
.nb-export-desc { font-size: 0.74rem; color: var(--text-muted); }

/* Mobile bar — JS sets the `bottom` dynamically using visualViewport so
   it stays above the on-screen keyboard. */
.nb-mobile-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--nb-mobile-bar-h);
  background: color-mix(in srgb, var(--bg-elevated) 96%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-top: 1px solid var(--border);
  display: flex;
  gap: 6px;
  padding: 8px 10px;
  padding-bottom: calc(8px + env(safe-area-inset-bottom, 0px));
  overflow-x: auto;
  z-index: 25;
  scrollbar-width: none;
  transition: bottom 120ms ease;
}
.nb-mobile-bar::-webkit-scrollbar { display: none; }
.nb-mobile-bar button {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text);
  font: inherit;
  font-size: 0.78rem;
  padding: 6px 12px;
  border-radius: 18px;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
}
.nb-mobile-bar button:active { transform: scale(0.96); }

/* Cards preview modal */
.nb-cards-modal {
  position: fixed;
  inset: 0;
  z-index: 70;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.nb-cards-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
.nb-cards-box {
  position: relative;
  width: min(960px, 100%);
  max-height: 88vh;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.6);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  animation: nbPop 220ms ease;
}
.nb-cards-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
}
.nb-cards-title { font-size: 1.05rem; font-weight: 700; color: var(--text); }
.nb-cards-sub { font-size: 0.78rem; color: var(--text-muted); margin-top: 2px; }
.nb-cards-grid {
  flex: 1;
  overflow-y: auto;
  padding: 18px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}
.nb-card-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
.nb-card-item img {
  width: 100%;
  height: auto;
  display: block;
  background: #0e0e18;
}
.nb-card-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px 12px;
  border-top: 1px solid var(--border);
}
.nb-card-name {
  font-size: 0.8rem;
  color: var(--text-dim);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nb-card-save {
  padding: 5px 12px !important;
  font-size: 0.76rem !important;
  flex-shrink: 0;
}
@media (max-width: 720px) {
  .nb-cards-grid {
    grid-template-columns: 1fr;
    padding: 12px;
    gap: 12px;
  }
  .nb-cards-box { max-height: 92vh; }
}

/* Toast */
.nb-toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 80;
  padding: 10px 18px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text);
  font-size: 0.85rem;
  box-shadow: 0 12px 36px rgba(0,0,0,0.45);
  animation: nbToast 220ms ease;
}
@keyframes nbToast {
  from { opacity: 0; transform: translate(-50%, 10px); }
  to   { opacity: 1; transform: translate(-50%, 0); }
}

/* Drag-over indicator */
.nb-block.drag-over::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--purple);
  border-radius: 2px;
}
.nb-block.dragging { opacity: 0.4; }

/* Selection */
.nb-block.selected {
  background: rgba(176, 122, 255, 0.07);
  border-radius: 4px;
}

/* ── Floating "Take Notes" button (injected into every page) ── */
.nb-floating-btn {
  position: fixed;
  z-index: 9999;
  bottom: 20px;
  right: 20px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--purple, #b07aff);
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 24px rgba(176, 122, 255, 0.45), 0 2px 8px rgba(0, 0, 0, 0.2);
  transition: transform 200ms ease, box-shadow 200ms ease;
}
.nb-floating-btn:hover {
  transform: translateY(-2px) scale(1.04);
  box-shadow: 0 12px 32px rgba(176, 122, 255, 0.55), 0 4px 12px rgba(0, 0, 0, 0.25);
}
.nb-floating-btn svg { width: 20px; height: 20px; }
.nb-floating-btn .nb-fb-label {
  position: absolute;
  right: calc(100% + 10px);
  background: rgba(0, 0, 0, 0.85);
  color: white;
  padding: 5px 10px;
  border-radius: 6px;
  font-size: 0.78rem;
  white-space: nowrap;
  opacity: 0;
  transform: translateX(8px);
  transition: var(--nb-easing);
  pointer-events: none;
}
.nb-floating-btn:hover .nb-fb-label {
  opacity: 1;
  transform: translateX(0);
}
@media (max-width: 720px) {
  .nb-floating-btn { width: 44px; height: 44px; bottom: 16px; right: 16px; }
  .nb-floating-btn .nb-fb-label { display: none; }
}

/* ── iOS: prevent zoom-on-tap & focus zoom ──────────────── */
/* iOS Safari zooms in whenever a contenteditable / input has
   font-size < 16px. Force every editable element to 16px on touch
   devices, and use touch-action: manipulation to kill the 300ms
   double-tap-to-zoom delay. */
.nb-editor, .nb-block, .nb-block-content,
.nb-image-caption, .nb-chapter-tab-name,
.nb-cover-title, .nb-canvas-wrap,
.nb-palette-input, .nb-mobile-bar button,
input, textarea, button {
  touch-action: manipulation;
}
@media (max-width: 880px), (pointer: coarse) {
  .nb-block-content,
  .nb-block.p .nb-block-content,
  .nb-block.bullet .nb-block-content,
  .nb-block.numbered .nb-block-content,
  .nb-block.todo .nb-block-content,
  .nb-block.quote .nb-block-content,
  .nb-block.callout .nb-callout-wrap .nb-block-content,
  .nb-block.code .nb-block-content,
  .nb-block.math .nb-block-content,
  .nb-image-caption,
  .nb-chapter-tab-name,
  .nb-palette-input,
  input, textarea {
    font-size: 16px !important;
  }
  .nb-block.h3 .nb-block-content { font-size: 18px !important; }
}

/* ── Mobile ──────────────────────────────────────── */
@media (max-width: 880px) {
  .nb-shell {
    grid-template-columns: 1fr;
  }
  .nb-sidebar {
    position: fixed;
    top: var(--nb-topbar-h);
    left: 0;
    bottom: 0;
    width: min(86vw, 320px);
    z-index: 40;
    transform: translateX(-105%);
    transition: transform var(--nb-easing);
    background: var(--bg-elevated);
    border-right: 1px solid var(--border);
  }
  .nb-sidebar.open { transform: translateX(0); }
  .nb-sidebar-overlay {
    display: block;
    position: fixed;
    inset: var(--nb-topbar-h) 0 0 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: 35;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--nb-easing);
  }
  .nb-sidebar-overlay.open { opacity: 1; pointer-events: auto; }

  .nb-sidebar-toggle { display: inline-flex; }
  .nb-search-btn span, .nb-search-btn kbd { display: none; }
  .nb-search-btn {
    width: 38px;
    height: 38px;
    padding: 0;
    justify-content: center;
  }
  .nb-search-btn svg { width: 16px; height: 16px; }
  .nb-logo-text { display: none; }
  .nb-logo-sep { display: none; }
  .nb-save-indicator { display: none; }

  .nb-editor {
    padding: 20px 18px calc(20px + var(--nb-mobile-bar-h) + env(safe-area-inset-bottom));
  }
  .nb-cover-title { font-size: 1.8rem; }
  .nb-cover-emoji { font-size: 2.6rem; }

  .nb-block-add { display: none; }
  .nb-block-delete { display: none; }
  .nb-block-handle { display: none; }

  .nb-mobile-bar { display: flex; }

  .nb-block.h1 .nb-block-content { font-size: 1.55rem; }
  .nb-block.h2 .nb-block-content { font-size: 1.25rem; }
}

@media (min-width: 881px) {
  .nb-mobile-bar { display: none !important; }
}

/* Scrollbars */
.nb-main::-webkit-scrollbar,
.nb-sidebar-list::-webkit-scrollbar {
  width: 6px;
}
.nb-main::-webkit-scrollbar-thumb,
.nb-sidebar-list::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}
.nb-main::-webkit-scrollbar-thumb:hover,
.nb-sidebar-list::-webkit-scrollbar-thumb:hover {
  background: var(--border-hover);
}

/* Light theme tweaks */
[data-theme="light"] .nb-draw-canvas {
  background-color: #ffffff;
  background-image:
    linear-gradient(rgba(109, 40, 217, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(109, 40, 217, 0.07) 1px, transparent 1px);
}
[data-theme="light"] .nb-block.code .nb-block-content {
  background: #1e1e2e;
  color: #d6d6e8;
}
[data-theme="light"] .nb-callout-wrap .nb-block-content { color: var(--text); }
[data-theme="light"] .nb-empty-glyph { filter: drop-shadow(0 6px 20px rgba(109, 40, 217, 0.25)); }

/* Print styles for PDF export */
@media print {
  .nb-topbar, .nb-sidebar, .nb-sidebar-overlay, .nb-mobile-bar,
  .nb-floating-btn, .nb-block-add, .nb-block-handle, .nb-block-delete,
  .nb-chapter-tab-close, .nb-add-chapter-btn { display: none !important; }
  .nb-shell { display: block; }
  .nb-main { height: auto; overflow: visible; }
  .nb-editor { padding: 0; max-width: none; }
  .nb-chapter-tabs { border-bottom: 2px solid #000; margin-bottom: 12px; }
  .nb-chapter-tab { color: #000 !important; opacity: 1 !important; border: none !important; padding: 4px 10px; page-break-after: avoid; }
  body { background: white; color: black; }
  .nb-cover-title, .nb-block-content { color: black !important; }
  .nb-block.code .nb-block-content { background: #f4f4f8 !important; color: black !important; border: 1px solid #ccc; }
}