/* Course builder — #page-course-builder (course-builder/course-builder.js).
   Chat on the left, the draft course's graph (or one concept's editor) on
   the right, a draggable divider between, and a full-screen mode for the
   right half.

   The look is a drafting table: the chat is the app's panel, the graph sits
   on a faint dot grid like drafting paper, labels are small caps. Tokens
   only (styles/variables.css), so every theme restyles it. */

#page-course-builder {
  display: flex;
  flex-direction: column;
  min-height: 420px;
  padding: 0;
}

#page-course-builder.hidden {
  display: none;
}

.cb-shell {
  --cb-left: 40%;
  --cb-grid: color-mix(in srgb, var(--text) 9%, transparent);
  display: flex;
  flex-direction: column;
  flex: 1 1 auto;
  min-height: 0;
}

/* ---- top strip -------------------------------------------------------- */
.cb-top {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 10px 18px;
  border-bottom: 1px solid var(--border);
}

.cb-top-title {
  display: flex;
  flex-direction: column;
  gap: 1px;
  margin-right: auto;
}

/* The course's name, edited in place: reads as a heading until focused. */
.cb-title-input {
  width: min(420px, 100%);
  margin: 0 0 0 -6px;
  padding: 2px 6px;
  color: var(--white);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  font: inherit;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.cb-title-input::placeholder {
  color: var(--muted);
  font-weight: 600;
}

.cb-title-input:hover {
  border-color: var(--border);
}

.cb-title-input:focus {
  outline: none;
  border-color: var(--accent);
  background: var(--input-bg);
}

.cb-eyebrow {
  color: var(--muted);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.cb-back {
  padding: 6px 4px;
  color: var(--muted);
  background: none;
  border: 0;
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.cb-back:hover {
  color: var(--text);
}

.cb-top-tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* ---- buttons ---------------------------------------------------------- */
.cb-btn,
.cb-icon-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 11px;
  color: var(--text);
  background: transparent;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  font: inherit;
  font-size: 12.5px;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
}

.cb-btn:hover:not(:disabled),
.cb-icon-btn:hover:not(:disabled) {
  border-color: var(--accent);
}

.cb-btn:disabled,
.cb-icon-btn:disabled {
  opacity: 0.55;
  cursor: default;
}

.cb-btn-solid {
  color: var(--on-accent);
  background: var(--accent);
  border-color: transparent;
}

.cb-btn-solid:hover:not(:disabled) {
  border-color: transparent;
  filter: brightness(1.08);
}

.cb-icon-btn {
  padding: 5px 9px;
  background: color-mix(in srgb, var(--panel) 85%, transparent);
  backdrop-filter: blur(6px);
}

/* ---- the split -------------------------------------------------------- */
.cb-split {
  display: grid;
  grid-template-columns: var(--cb-left) 10px minmax(0, 1fr);
  flex: 1 1 auto;
  min-height: 0;
}

.cb-chat-pane {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  background: var(--panel-deep);
}

.cb-chat-root {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
}

.cb-chat-root > deep-chat {
  flex: 1 1 auto;
  width: 100% !important;
  height: 100% !important;
}

/* Attached files and concepts, above the thread. Always shown: it holds
   the Attach button. Dropping files anywhere on the pane rings it. */
.cb-chat-pane.is-dropping {
  outline: 2px dashed var(--accent);
  outline-offset: -6px;
}

.cb-tray {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
}

.cb-tray[hidden] {
  display: none;
}

.cb-tray-label {
  margin-right: 2px;
  color: var(--muted);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.cb-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  max-width: 240px;
  padding: 3px 4px 3px 9px;
  color: var(--text);
  background: var(--card);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  animation: cb-chip-in 0.2s ease-out;
}

@keyframes cb-chip-in {
  from { opacity: 0; transform: scale(0.92); }
  to { opacity: 1; transform: none; }
}

.cb-chip-dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

.cb-chip-text {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.cb-chip-x {
  flex: none;
  width: 18px;
  height: 18px;
  padding: 0;
  color: var(--muted);
  background: none;
  border: 0;
  border-radius: 50%;
  font-size: 14px;
  line-height: 1;
  cursor: pointer;
}

.cb-chip-x:hover {
  color: var(--text);
  background: var(--input-bg);
}

/* ---- divider ---------------------------------------------------------- */
.cb-divider {
  position: relative;
  display: grid;
  place-items: center;
  background: var(--border);
  cursor: col-resize;
  touch-action: none;
}

.cb-divider-grip {
  width: 4px;
  height: 44px;
  border-radius: 4px;
  background: var(--muted-dim);
  transition: background-color 0.15s ease, height 0.15s ease;
}

.cb-divider:hover .cb-divider-grip,
.cb-divider:focus-visible .cb-divider-grip,
.cb-shell.is-dragging .cb-divider-grip {
  height: 72px;
  background: var(--accent);
}

.cb-divider:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

/* Mid-drag: no text selection, and the chat's iframe-like shadow DOM
   cannot swallow the pointer. */
.cb-shell.is-dragging {
  cursor: col-resize;
  user-select: none;
}

.cb-shell.is-dragging .cb-chat-pane,
.cb-shell.is-dragging .cb-view-pane {
  pointer-events: none;
}

/* ---- right half ------------------------------------------------------- */
.cb-view-pane {
  container-type: inline-size;
  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  background-color: var(--canvas-bg);
  background-image: radial-gradient(var(--cb-grid) 1px, transparent 1.2px);
  background-size: 22px 22px;
}

.cb-view-bar {
  position: absolute;
  z-index: 5;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  pointer-events: none;
}

.cb-view-bar > * {
  pointer-events: auto;
}

.cb-crumb {
  display: flex;
  align-items: baseline;
  gap: 10px;
  min-width: 0;
}

.cb-crumb-name {
  overflow: hidden;
  color: var(--white);
  font-size: 15px;
  font-weight: 700;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.cb-crumb-count {
  color: var(--muted);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.cb-crumb .cb-eyebrow {
  white-space: nowrap;
}

/* A narrow graph pane (divider dragged right): drop the words the bar can
   live without before the course name starts truncating. */
@container (max-width: 560px) {
  .cb-crumb-graph .cb-eyebrow,
  .cb-crumb-count,
  .cb-full-label {
    display: none;
  }
}

.cb-crumb-lesson {
  align-items: center;
}

.cb-view-pane[data-view="graph"] .cb-crumb-lesson,
.cb-view-pane[data-view="edit"] .cb-crumb-graph,
.cb-view-pane[data-view="edit"] .cb-view-tools {
  display: none;
}

.cb-view-tools {
  display: flex;
  gap: 6px;
  flex: none;
}

.cb-full-off,
.cb-shell.is-full .cb-full-on {
  display: none;
}

.cb-shell.is-full .cb-full-off {
  display: inline;
}

.cb-full-on,
.cb-full-off {
  font-size: 14px;
  line-height: 1;
}

/* Full screen: the right half takes the whole page. */
.cb-shell.is-full .cb-split {
  grid-template-columns: 0 0 minmax(0, 1fr);
}

.cb-shell.is-full .cb-chat-pane,
.cb-shell.is-full .cb-divider {
  visibility: hidden;
  overflow: hidden;
}

.cb-graph-host {
  position: relative;
  flex: 1 1 auto;
  min-height: 0;
  color: var(--text);
  outline: none;
}

.cb-graph-host[hidden] {
  display: none;
}

.cb-graph-canvas {
  position: absolute;
  inset: 0;
}

.cb-status {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

/* ---- node card -------------------------------------------------------- */
.cb-card {
  position: absolute;
  z-index: 10;
  width: 272px;
  padding: 14px 14px 12px;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  box-shadow: 0 14px 40px var(--shadow-strong);
  animation: cb-card-in 0.16s ease-out;
}

.cb-card[hidden] {
  display: none;
}

@keyframes cb-card-in {
  from { opacity: 0; transform: translateY(4px) scale(0.98); }
  to { opacity: 1; transform: none; }
}

.cb-card-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 8px;
}

.cb-card-title {
  color: var(--white);
  font-size: 14.5px;
  font-weight: 700;
  line-height: 1.3;
}

.cb-card-x {
  flex: none;
  width: 22px;
  height: 22px;
  padding: 0;
  color: var(--muted);
  background: none;
  border: 0;
  border-radius: 6px;
  font-size: 17px;
  line-height: 1;
  cursor: pointer;
}

.cb-card-x:hover {
  color: var(--text);
  background: var(--input-bg);
}

.cb-card-id {
  display: block;
  margin-top: 3px;
  overflow: hidden;
  color: var(--muted);
  font-size: 11px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.cb-card-summary {
  margin: 10px 0;
  font-size: 13px;
  line-height: 1.45;
}

.cb-card-stats {
  display: grid;
  gap: 5px;
  margin: 0 0 12px;
  font-size: 12.5px;
}

.cb-card-stats > div {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 8px;
}

.cb-card-stats dt {
  color: var(--muted);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.07em;
  line-height: 1.75;
  text-transform: uppercase;
}

.cb-card-stats dd {
  margin: 0;
}

.cb-card-dim {
  color: var(--muted);
}

.cb-card-actions {
  display: flex;
  gap: 6px;
}

.cb-card-actions .cb-btn {
  flex: 1 1 0;
  justify-content: center;
}

/* ---- concept editor (the right pane's second view) -------------------- */
.cb-lesson-host {
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  padding: 64px max(24px, 6%) 40px;
  background: var(--bg);
  color: var(--text);
}

.cb-lesson-host[hidden] {
  display: none;
}

.cb-lesson-host > * {
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
}

.cb-view-pane[data-view="edit"] .cb-view-bar {
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--border);
  pointer-events: auto;
}

/* ---- narrow: stack, chat above graph --------------------------------- */
@media (max-width: 820px) {
  .cb-top {
    flex-wrap: wrap;
  }
  /* The divider leaves the grid (display:none), so two rows, not three —
     a third, zero-height row would be where the graph pane lands. */
  .cb-split,
  .cb-shell.is-full .cb-split {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(260px, 45%) minmax(0, 1fr);
  }
  .cb-divider {
    display: none;
  }
  .cb-shell.is-full .cb-split {
    grid-template-rows: 0 minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .cb-chip,
  .cb-card {
    animation: none;
  }
}