/* ==========================================================================
   Mai-Reads: Study Notebooks Stylesheet (Conforming to MAI-READS-UI-SPEC.md Section 5)
   Minimal, calm 2-column layout with color dots, segmented details, and modal.
   ========================================================================== */

:root {
  --bg: #F6F5F1;
  --surface: #FFFFFF;
  --surface-2: #F1EFE8;
  --paper: #FDFCF9;
  --paper-ink: #26241E;
  --ink: #15140F;
  --ink-2: #4F4D45;
  --muted: #6B685E;
  --line: #E3E0D6;
  --line-strong: #DAD7CC;
  --hl: #F3D56B;
  --danger: #A23B2B;
  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 20px;
  --radius-xl: 24px;
  --radius-pill: 999px;
  --shadow-float: 0 12px 32px rgba(21, 20, 15, 0.12);
  --font-ui: 'Geist', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-serif: 'Fraunces', 'Newsreader', Georgia, serif;
  --font-display: 'Fraunces', 'Newsreader', Georgia, serif;
  --accent: #B5792F;
  --accent-soft: rgba(181, 121, 47, 0.12);
  --sat: env(safe-area-inset-top, 0px);
  --sab: env(safe-area-inset-bottom, 0px);
  --sal: env(safe-area-inset-left, 0px);
  --sar: env(safe-area-inset-right, 0px);
}

:root[data-resolved-theme="dark"] {
  --bg: #111111;
  --surface: #181818;
  --surface-2: #242424;
  --paper: #161616;
  --paper-ink: #ECECEC;
  --ink: #F5F5F7;
  --ink-2: #A1A1A6;
  --muted: #737378;
  --line: #262626;
  --line-strong: #383838;
  --shadow-float: 0 12px 32px rgba(0, 0, 0, 0.6);
}

body.notebook-page {
  min-height: 100dvh;
  background-color: var(--bg);
  color: var(--ink);
  font-family: var(--font-ui);
  display: flex;
  flex-direction: column;
}

/* ── Top Header Navigation ─────────────────────────────────────────────────── */
.nb-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg);
  border-bottom: 1px solid var(--line);
  padding-top: var(--sat);
  padding-left: var(--sal);
  padding-right: var(--sar);
}

.nb-nav-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 16px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nb-nav-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nb-back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--ink);
  font-size: 14px;
  font-weight: 500;
  min-height: 44px;
  padding: 0 8px;
  border-radius: var(--radius-sm);
  transition: color 160ms;
}

.nb-back-link:hover {
  color: var(--muted);
}

.nb-nav-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* ── Container Layout (2 Columns that Wrap) ────────────────────────────────── */
.nb-container {
  max-width: 1280px;
  width: 100%;
  margin: 0 auto;
  padding: 32px 32px calc(var(--sab) + 64px);
  display: flex;
  flex-direction: column;
  gap: 28px;
}

/* Title block */
.nb-title-block {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.nb-title-text h1 {
  font-family: var(--font-serif);
  font-size: 48px;
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--ink);
  margin-bottom: 6px;
}

.nb-title-text p {
  font-size: 15px;
  color: var(--ink-2);
}

.nb-title-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Two Columns Area */
.nb-columns-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  width: 100%;
}

.nb-list-column {
  flex: 999 1 560px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.nb-detail-column {
  flex: 1 1 380px;
  max-width: 420px;
}

/* ── 2-Column Notebook Grid ───────────────────────────────────────────────── */
.nb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(260px, 100%), 1fr));
  gap: 16px;
}

/* Notebook Card */
.nb-card {
  min-height: 164px;
  background-color: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 22px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 12px;
  cursor: pointer;
  transition: border-color 160ms cubic-bezier(0.16, 1, 0.3, 1), box-shadow 160ms cubic-bezier(0.16, 1, 0.3, 1);
  text-align: left;
}

.nb-card:hover {
  border-color: var(--line-strong);
}

.nb-card.selected {
  border: 1.5px solid var(--ink);
}

/* Card Header: Color Dot + Color Name */
.nb-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nb-card-dot-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nb-color-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* 5 Swatches defined in spec */
.dot-amber   { background-color: #B8893A; }
.dot-emerald { background-color: #4B7A5E; }
.dot-indigo  { background-color: #5560A8; }
.dot-rose    { background-color: #B45C6B; }
.dot-slate   { background-color: #5C6670; }

.nb-card-dot-name {
  font-size: 12px;
  color: var(--muted);
  text-transform: capitalize;
}

/* Card Body */
.nb-card-title {
  font-family: var(--font-serif);
  font-size: 24px;
  font-weight: 500;
  line-height: 1.25;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.nb-card-desc {
  font-size: 14px;
  color: var(--ink-2);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  line-height: 1.45;
}

/* Card Footer */
.nb-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: var(--muted);
  padding-top: 6px;
}

/* Create Notebook Tile (final tile) */
.nb-create-tile {
  min-height: 164px;
  border: 1.5px dashed #CFCBBE;
  border-radius: var(--radius-lg);
  background: transparent;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--ink-2);
  cursor: pointer;
  transition: border-color 160ms, color 160ms;
}

.nb-create-tile:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.nb-create-tile-text {
  font-size: 14px;
  font-weight: 500;
}

/* ── Detail Pane (White Card, radius 24) ─────────────────────────────────── */
.nb-detail-pane {
  background-color: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.nb-detail-header {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.nb-detail-kicker {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.nb-detail-title {
  font-family: var(--font-serif);
  font-size: 28px;
  font-weight: 500;
  line-height: 1.2;
  color: var(--ink);
}

.nb-detail-tabs {
  margin: 4px 0;
}

/* Document rows inside detail pane */
.nb-doc-rows {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.nb-doc-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  background-color: var(--surface-2);
  font-size: 13.5px;
}

.nb-doc-row-interactive {
  text-decoration: none;
  color: var(--ink);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 160ms cubic-bezier(0.16, 1, 0.3, 1);
}

.nb-doc-row-interactive:hover {
  background-color: var(--surface);
  border-color: var(--line-strong);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.nb-doc-row-name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-weight: 500;
}

.nb-doc-row-progress {
  font-size: 12px;
  color: var(--muted);
}

.nb-doc-row-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  transition: transform 160ms, color 160ms;
}

.nb-doc-row-interactive:hover .nb-doc-row-action {
  color: var(--ink);
  transform: translateX(2px);
}

.nb-detail-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 8px;
}

.nb-detail-helper {
  font-size: 12px;
  color: var(--muted);
  text-align: center;
}

/* ── Modals (Create Notebook & Import/Export) ─────────────────────────────── */
.nb-modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(8, 8, 6, 0.35);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 180ms cubic-bezier(0.16, 1, 0.3, 1);
}

.nb-modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.nb-modal {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  padding: 28px;
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  box-shadow: var(--shadow-float);
}

.nb-modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nb-modal-title {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 500;
  color: var(--ink);
}

.nb-modal-body {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.nb-form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.nb-form-label {
  font-size: 13px;
  font-weight: 500;
  color: var(--ink);
}

.nb-input,
.nb-textarea {
  min-height: 48px;
  padding: 0 14px;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  border: 1px solid var(--line-strong);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 16px; /* 16px prevents iOS Safari automatic viewport zoom */
  outline: none;
  transition: border-color 160ms;
}

.nb-textarea {
  min-height: 80px;
  padding: 12px 14px;
  resize: vertical;
}

.nb-input:focus,
.nb-textarea:focus {
  border-color: var(--ink);
  background: var(--surface);
}

/* Swatch Picker (5 dots) */
.nb-color-choice-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nb-swatch-btn {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform 160ms;
}

.nb-swatch-btn.selected {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
}

.nb-modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
}

/* Full-Width Artistic Empty State */
.nb-empty {
  display: flex;
  flex-direction: column;
  gap: 32px;
  width: 100%;
  max-width: 980px;
  margin: 0 auto;
}

.nb-empty.hidden {
  display: none !important;
}

.nb-empty-card {
  background-color: var(--surface);
  border: 1px solid var(--line);
  border-radius: 28px;
  padding: 48px 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 20px;
  box-shadow: 0 4px 20px rgba(35, 30, 20, 0.04);
}

:root[data-resolved-theme="dark"] .nb-empty-card {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
}

.nb-empty-illustration {
  width: 80px;
  height: 80px;
  border-radius: 24px;
  background-color: var(--surface-2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.05);
}

.nb-empty-headings {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 600px;
}

.nb-empty-headings h2 {
  font-family: var(--font-display);
  font-size: clamp(28px, 4.5vw, 36px);
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.02em;
}

.nb-empty-headings p {
  font-size: 15.5px;
  line-height: 1.6;
  color: var(--ink-2);
}

.nb-empty-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 6px;
}

/* Starter Templates Section */
.nb-templates-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.nb-templates-title {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  text-align: left;
}

.nb-templates-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.nb-template-card {
  background-color: var(--surface);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 22px 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  text-align: left;
  transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
  box-shadow: 0 2px 8px rgba(35, 30, 20, 0.03);
  cursor: pointer;
}

.nb-template-card:hover {
  transform: translateY(-2px);
  border-color: var(--line-strong);
  box-shadow: 0 8px 20px rgba(35, 30, 20, 0.06);
}

:root[data-resolved-theme="dark"] .nb-template-card {
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

:root[data-resolved-theme="dark"] .nb-template-card:hover {
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.5);
}

.nb-template-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nb-template-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
}

.nb-template-title {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.015em;
}

.nb-template-desc {
  font-size: 13px;
  line-height: 1.5;
  color: var(--ink-2);
}

.nb-template-btn {
  margin-top: auto;
  align-self: flex-start;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--accent);
  background: transparent;
  border: none;
  padding: 0;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* Mobile Responsiveness */
@media (max-width: 900px) {
  .nb-detail-column {
    max-width: 100%;
    flex: 1 1 100%;
  }
}

@media (max-width: 640px) {
  .nb-nav-inner {
    padding: 12px 16px;
  }

  .nb-container {
    padding: 20px 16px calc(var(--sab) + 40px);
  }

  .nb-title-text h1 {
    font-size: clamp(28px, 7.5vw, 36px);
  }

  .nb-title-block {
    flex-direction: column;
    align-items: stretch;
    gap: 16px;
  }

  .nb-title-actions {
    width: 100%;
    flex-direction: column;
  }

  .nb-title-actions .btn-primary,
  .nb-title-actions .btn-secondary {
    width: 100%;
    min-height: 48px;
    justify-content: center;
  }

  .nb-modal {
    padding: 20px;
    max-width: calc(100vw - 24px);
  }
}

/* Ultra-Compact (< 380px) */
@media (max-width: 380px) {
  .nb-container {
    padding: 16px 12px calc(var(--sab) + 32px);
  }

  .nb-title-text h1 {
    font-size: 26px;
  }

  .nb-card {
    padding: 16px;
    min-height: 140px;
  }

  .nb-card-title {
    font-size: 17px;
  }
}

/* Mobile Landscape (< 520px Height) */
@media (max-height: 520px) and (orientation: landscape) {
  .nb-nav-inner {
    padding: 8px 24px;
  }

  .nb-container {
    padding: 16px calc(20px + var(--sar)) calc(var(--sab) + 24px) calc(20px + var(--sal));
  }

  .nb-title-block {
    margin-bottom: 20px;
  }

  .nb-title-text h1 {
    font-size: 28px;
  }
}

/* Hover Guard: Prevent sticky hover on mobile touchscreens */
@media (hover: hover) and (pointer: fine) {
  .nb-card:hover {
    border-color: var(--line-strong);
    transform: translateY(-1px);
  }

  .nb-swatch-btn:hover {
    transform: scale(1.15);
  }
}