/* ─────────────────────────────────────────────────────────────────────────────
   BOOKSTRACKER — Design System
   Industrial/utilitarian dashboard aesthetic
   Fonts: JetBrains Mono (data) + DM Sans (UI)
   ───────────────────────────────────────────────────────────────────────────── */

@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ── CSS Variables: Dark Mode (default) ─────────────────────────────────────── */
:root {
  /* Surfaces */
  --bg-base:       #0a0a0f;
  --bg-surface:    #111118;
  --bg-elevated:   #1a1a24;
  --bg-overlay:    #22222e;

  /* Borders */
  --border:        #2a2a38;
  --border-subtle: #1e1e2a;
  --border-focus:  #6366f1;

  /* Text */
  --text-primary:  #f0f0f5;
  --text-secondary:#9090aa;
  --text-muted:    #5a5a72;
  --text-inverse:  #0a0a0f;

  /* Accent — electric indigo */
  --accent:        #6366f1;
  --accent-dim:    rgba(99, 102, 241, 0.15);
  --accent-hover:  #7577f3;
  --accent-active: #5254d4;

  /* Semantic */
  --success:       #22c55e;
  --success-dim:   rgba(34, 197, 94, 0.12);
  --warning:       #f59e0b;
  --warning-dim:   rgba(245, 158, 11, 0.12);
  --danger:        #ef4444;
  --danger-dim:    rgba(239, 68, 68, 0.12);
  --info:          #38bdf8;
  --info-dim:      rgba(56, 189, 248, 0.12);

  /* Level colors */
  --level-beginner:     #22c55e;
  --level-intermediate: #f59e0b;
  --level-advanced:     #ef4444;

  /* Sidebar */
  --sidebar-w:     240px;
  --header-h:      48px;

  /* Typography */
  --font-ui:    'DM Sans', system-ui, sans-serif;
  --font-mono:  'JetBrains Mono', 'Courier New', monospace;

  /* Shadows */
  --shadow-sm:  0 1px 3px rgba(0,0,0,0.4);
  --shadow-md:  0 4px 12px rgba(0,0,0,0.5);
  --shadow-lg:  0 8px 32px rgba(0,0,0,0.6);

  /* Transitions */
  --t-fast:  80ms ease;
  --t-base:  150ms ease;
  --t-slow:  250ms ease;

  /* Grid texture overlay */
  --grid-texture: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 0h40v1H0zM0 0v40h1V0z' fill='%236366f1' fill-opacity='0.03'/%3E%3C/svg%3E");
}

/* ── Light Mode Overrides ────────────────────────────────────────────────────── */
[data-theme="light"] {
  --bg-base:       #f4f4f8;
  --bg-surface:    #ffffff;
  --bg-elevated:   #f0f0f6;
  --bg-overlay:    #e8e8f0;

  --border:        #d4d4e0;
  --border-subtle: #e4e4ee;
  --border-focus:  #6366f1;

  --text-primary:  #0f0f1a;
  --text-secondary:#4a4a62;
  --text-muted:    #8888a0;
  --text-inverse:  #ffffff;

  --shadow-sm:  0 1px 3px rgba(0,0,0,0.08);
  --shadow-md:  0 4px 12px rgba(0,0,0,0.10);
  --shadow-lg:  0 8px 32px rgba(0,0,0,0.12);

  --grid-texture: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 0h40v1H0zM0 0v40h1V0z' fill='%236366f1' fill-opacity='0.05'/%3E%3C/svg%3E");
}

/* ── Reset ───────────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 14px; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font-ui);
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  background-image: var(--grid-texture);
  transition: background var(--t-slow), color var(--t-slow);
}
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }
img { max-width: 100%; display: block; }
button, input, select, textarea { font-family: inherit; }

/* ── Layout Shell ────────────────────────────────────────────────────────────── */
.app-shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  grid-template-rows: var(--header-h) 1fr;
  min-height: 100vh;
}

/* ── Header ──────────────────────────────────────────────────────────────────── */
.app-header {
  grid-column: 1 / -1;
  grid-row: 1;
  height: var(--header-h);
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 1rem;
  gap: 1rem;
  position: sticky;
  top: 0;
  z-index: 100;
}
.app-header .brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: var(--sidebar-w);
  flex-shrink: 0;
  padding-left: 0.25rem;
}
.app-header .brand-name {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  text-transform: uppercase;
}
.app-header .brand-dot {
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
  flex-shrink: 0;
}
.header-breadcrumb {
  flex: 1;
  font-size: 0.8rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.header-breadcrumb .sep { color: var(--border); }
.header-breadcrumb .current { color: var(--text-secondary); }
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
}
.header-user {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  border: 1px solid var(--border-subtle);
}
.header-user .avatar {
  width: 24px; height: 24px;
  background: var(--accent-dim);
  border: 1px solid var(--accent);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
}

/* ── Sidebar ─────────────────────────────────────────────────────────────────── */
.app-sidebar {
  grid-column: 1;
  grid-row: 2;
  background: var(--bg-surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  position: sticky;
  top: var(--header-h);
  height: calc(100vh - var(--header-h));
  padding: 0.75rem 0;
}
.sidebar-section {
  padding: 0 0.5rem;
  margin-bottom: 0.5rem;
}
.sidebar-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  text-transform: uppercase;
  padding: 0.5rem 0.75rem 0.25rem;
}
.sidebar-link {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.45rem 0.75rem;
  border-radius: 4px;
  font-size: 0.82rem;
  color: var(--text-secondary);
  transition: background var(--t-fast), color var(--t-fast);
  position: relative;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.sidebar-link:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
}
.sidebar-link.active {
  background: var(--accent-dim);
  color: var(--accent);
  font-weight: 500;
}
.sidebar-link.active::before {
  content: '';
  position: absolute;
  left: 0; top: 20%; bottom: 20%;
  width: 2px;
  background: var(--accent);
  border-radius: 0 2px 2px 0;
}
.sidebar-link .icon {
  width: 16px; height: 16px;
  opacity: 0.7;
  flex-shrink: 0;
}
.sidebar-link.active .icon { opacity: 1; }
.sidebar-count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-muted);
  background: var(--bg-elevated);
  padding: 1px 5px;
  border-radius: 3px;
  flex-shrink: 0;
}
.sidebar-divider {
  height: 1px;
  background: var(--border-subtle);
  margin: 0.5rem 0.75rem;
}

/* ── Main content ────────────────────────────────────────────────────────────── */
.app-main {
  grid-column: 2;
  grid-row: 2;
  padding: 1.5rem;
  overflow-x: hidden;
}

/* ── Page header ─────────────────────────────────────────────────────────────── */
.page-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}
.page-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
}
.page-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
  font-family: var(--font-mono);
}
.page-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

/* ── Stat cards ──────────────────────────────────────────────────────────────── */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 1.5rem;
}
.stat-card {
  background: var(--bg-surface);
  padding: 1rem;
  position: relative;
}
.stat-card:hover { background: var(--bg-elevated); }
.stat-label {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.4rem;
}
.stat-value {
  font-size: 1.6rem;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1;
}
.stat-value.accent { color: var(--accent); }
.stat-value.success { color: var(--success); }
.stat-value.warning { color: var(--warning); }
.stat-value.danger  { color: var(--danger); }
.stat-meta {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 0.3rem;
}

/* ── Cards ───────────────────────────────────────────────────────────────────── */
.card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}
.card-header {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}
.card-title {
  font-size: 0.8rem;
  font-weight: 600;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}
.card-body { padding: 1rem; }

/* ── Book cards grid ─────────────────────────────────────────────────────────── */
.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}
.book-card {
  background: var(--bg-surface);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  cursor: pointer;
  transition: background var(--t-fast);
  text-decoration: none;
  color: inherit;
  position: relative;
}
.book-card:hover { background: var(--bg-elevated); }
.book-cover {
  aspect-ratio: 2/3;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 3px;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 0.25rem;
  position: relative;
}
.book-cover img { object-fit: cover; width: 100%; height: 100%; }
.book-cover-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  width: 100%; height: 100%;
}
.book-cover-ext {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background: var(--bg-overlay);
  padding: 2px 6px;
  border-radius: 3px;
}
.book-title {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-primary);
  line-height: 1.3;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.book-author {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}
.book-meta {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-top: auto;
}

/* ── Table ───────────────────────────────────────────────────────────────────── */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}
.data-table th {
  padding: 0.5rem 0.75rem;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  background: var(--bg-elevated);
  white-space: nowrap;
}
.data-table td {
  padding: 0.6rem 0.75rem;
  border-bottom: 1px solid var(--border-subtle);
  vertical-align: middle;
  color: var(--text-secondary);
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tbody tr:hover td { background: var(--bg-elevated); color: var(--text-primary); }
.data-table .mono { font-family: var(--font-mono); font-size: 0.78rem; }

/* ── Buttons ─────────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.4rem 0.85rem;
  font-family: var(--font-ui);
  font-size: 0.8rem;
  font-weight: 500;
  border-radius: 4px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--t-fast), border-color var(--t-fast), color var(--t-fast), box-shadow var(--t-fast);
  white-space: nowrap;
  text-decoration: none;
  line-height: 1;
}
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn-primary:hover:not(:disabled) { background: var(--accent-hover); border-color: var(--accent-hover); color: #fff; }
.btn-primary:active:not(:disabled) { background: var(--accent-active); }

.btn-secondary {
  background: transparent;
  border-color: var(--border);
  color: var(--text-secondary);
}
.btn-secondary:hover:not(:disabled) { border-color: var(--text-muted); color: var(--text-primary); background: var(--bg-elevated); }

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover:not(:disabled) { background: var(--bg-elevated); color: var(--text-primary); }

.btn-danger {
  background: transparent;
  border-color: var(--danger);
  color: var(--danger);
}
.btn-danger:hover:not(:disabled) { background: var(--danger-dim); }

.btn-success {
  background: transparent;
  border-color: var(--success);
  color: var(--success);
}
.btn-success:hover:not(:disabled) { background: var(--success-dim); }

.btn-sm { padding: 0.25rem 0.6rem; font-size: 0.75rem; }
.btn-lg { padding: 0.6rem 1.25rem; font-size: 0.9rem; }
.btn-icon { padding: 0.35rem; width: 28px; height: 28px; }

/* ── Badges ──────────────────────────────────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 2px 7px;
  border-radius: 3px;
  font-size: 0.68rem;
  font-family: var(--font-mono);
  font-weight: 500;
  letter-spacing: 0.03em;
  white-space: nowrap;
  border: 1px solid transparent;
}
.badge-accent   { background: var(--accent-dim);   color: var(--accent);   border-color: rgba(99,102,241,0.25); }
.badge-success  { background: var(--success-dim);  color: var(--success);  border-color: rgba(34,197,94,0.25); }
.badge-warning  { background: var(--warning-dim);  color: var(--warning);  border-color: rgba(245,158,11,0.25); }
.badge-danger   { background: var(--danger-dim);   color: var(--danger);   border-color: rgba(239,68,68,0.25); }
.badge-info     { background: var(--info-dim);     color: var(--info);     border-color: rgba(56,189,248,0.25); }
.badge-neutral  { background: var(--bg-elevated);  color: var(--text-muted); border-color: var(--border); }

/* Level badges */
.badge-beginner     { background: var(--success-dim);  color: var(--success);  border-color: rgba(34,197,94,0.25); }
.badge-intermediate { background: var(--warning-dim);  color: var(--warning);  border-color: rgba(245,158,11,0.25); }
.badge-advanced     { background: var(--danger-dim);   color: var(--danger);   border-color: rgba(239,68,68,0.25); }

/* Extension badge */
.badge-ext {
  background: var(--bg-overlay);
  color: var(--text-muted);
  border-color: var(--border);
  font-weight: 600;
  text-transform: uppercase;
}

/* ── Forms ───────────────────────────────────────────────────────────────────── */
.form-group { margin-bottom: 1rem; }
.form-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.35rem;
  font-family: var(--font-mono);
  letter-spacing: 0.03em;
}
.form-label .required { color: var(--danger); margin-left: 2px; }
.form-control {
  display: block;
  width: 100%;
  padding: 0.5rem 0.75rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-primary);
  font-size: 0.82rem;
  font-family: var(--font-ui);
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
  appearance: none;
}
.form-control::placeholder { color: var(--text-muted); }
.form-control:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-dim);
}
.form-control.is-invalid { border-color: var(--danger); }
.form-control.is-invalid:focus { box-shadow: 0 0 0 3px var(--danger-dim); }
.form-hint   { font-size: 0.72rem; color: var(--text-muted); margin-top: 0.3rem; }
.form-error  { font-size: 0.72rem; color: var(--danger);     margin-top: 0.3rem; }
textarea.form-control { resize: vertical; min-height: 90px; }
select.form-control { cursor: pointer; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-row.cols-3 { grid-template-columns: 1fr 1fr 1fr; }

/* ── Toolbar (filter bar above book list) ────────────────────────────────────── */
.toolbar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}
.toolbar-search {
  flex: 1;
  min-width: 180px;
  position: relative;
}
.toolbar-search input {
  width: 100%;
  padding: 0.35rem 0.75rem 0.35rem 2rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-primary);
  font-size: 0.8rem;
}
.toolbar-search input:focus { border-color: var(--border-focus); outline: none; box-shadow: 0 0 0 3px var(--accent-dim); }
.toolbar-search .search-icon {
  position: absolute;
  left: 0.6rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}
.toolbar select {
  padding: 0.35rem 0.6rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-secondary);
  font-size: 0.8rem;
  cursor: pointer;
}
.toolbar select:focus { border-color: var(--border-focus); outline: none; }
.toolbar-sep { width: 1px; height: 20px; background: var(--border); flex-shrink: 0; }
.view-toggle { display: flex; border: 1px solid var(--border); border-radius: 4px; overflow: hidden; }
.view-toggle button {
  padding: 0.3rem 0.5rem;
  background: var(--bg-elevated);
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: background var(--t-fast), color var(--t-fast);
}
.view-toggle button.active { background: var(--accent-dim); color: var(--accent); }

/* ── Pagination ──────────────────────────────────────────────────────────────── */
.pagination {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-top: 1.25rem;
  flex-wrap: wrap;
}
.pagination a, .pagination span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 28px;
  height: 28px;
  padding: 0 0.4rem;
  border-radius: 4px;
  font-size: 0.78rem;
  font-family: var(--font-mono);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  transition: background var(--t-fast), color var(--t-fast);
}
.pagination a:hover { background: var(--bg-elevated); color: var(--text-primary); }
.pagination .active { background: var(--accent-dim); border-color: var(--accent); color: var(--accent); font-weight: 600; }
.pagination .disabled { opacity: 0.35; pointer-events: none; }
.pagination-info { font-size: 0.75rem; color: var(--text-muted); font-family: var(--font-mono); margin-left: 0.5rem; }

/* ── Alerts / Flashes ────────────────────────────────────────────────────────── */
.alert {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  padding: 0.65rem 0.85rem;
  border-radius: 4px;
  font-size: 0.8rem;
  border: 1px solid transparent;
  margin-bottom: 1rem;
}
.alert-success { background: var(--success-dim); border-color: rgba(34,197,94,.3); color: var(--success); }
.alert-error   { background: var(--danger-dim);  border-color: rgba(239,68,68,.3); color: var(--danger); }
.alert-warning { background: var(--warning-dim); border-color: rgba(245,158,11,.3); color: var(--warning); }
.alert-info    { background: var(--info-dim);    border-color: rgba(56,189,248,.3); color: var(--info); }
.alert .alert-close {
  margin-left: auto;
  background: none;
  border: none;
  color: inherit;
  cursor: pointer;
  opacity: 0.6;
  line-height: 1;
  padding: 0;
  font-size: 1rem;
}
.alert .alert-close:hover { opacity: 1; }

/* ── Modal ───────────────────────────────────────────────────────────────────── */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(2px);
}
.modal-overlay.open { display: flex; }
.modal {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 100%;
  max-width: 480px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  animation: modal-in 150ms ease;
}
@keyframes modal-in {
  from { opacity: 0; transform: translateY(-8px) scale(0.98); }
  to   { opacity: 1; transform: translateY(0)    scale(1); }
}
.modal-header {
  padding: 1rem 1.25rem 0.75rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.modal-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}
.modal-close {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.25rem;
  border-radius: 3px;
  font-size: 1.1rem;
  line-height: 1;
  transition: color var(--t-fast), background var(--t-fast);
}
.modal-close:hover { color: var(--text-primary); background: var(--bg-elevated); }
.modal-body { padding: 1.25rem; }
.modal-footer {
  padding: 0.75rem 1.25rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
}

/* ── Color swatch picker ─────────────────────────────────────────────────────── */
.color-swatches {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.5rem;
}
.color-swatch {
  width: 22px; height: 22px;
  border-radius: 3px;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform var(--t-fast), border-color var(--t-fast);
}
.color-swatch:hover { transform: scale(1.15); }
.color-swatch.selected { border-color: var(--text-primary); }

/* ── Theme toggle ────────────────────────────────────────────────────────────── */
.theme-toggle {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.3rem;
  cursor: pointer;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  transition: background var(--t-fast), color var(--t-fast);
}
.theme-toggle:hover { background: var(--bg-overlay); color: var(--text-primary); }

/* ── Empty state ─────────────────────────────────────────────────────────────── */
.empty-state {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--text-muted);
}
.empty-state .empty-icon { font-size: 2rem; margin-bottom: 0.75rem; opacity: 0.4; }
.empty-state .empty-title { font-size: 0.9rem; font-weight: 500; color: var(--text-secondary); margin-bottom: 0.4rem; }
.empty-state .empty-msg   { font-size: 0.8rem; }

/* ── Tag chip ────────────────────────────────────────────────────────────────── */
.tag-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 2px 8px;
  border-radius: 3px;
  font-size: 0.7rem;
  font-family: var(--font-mono);
  font-weight: 500;
  border: 1px solid transparent;
  white-space: nowrap;
}
.tag-chip .tag-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ── Utility ─────────────────────────────────────────────────────────────────── */
.mono    { font-family: var(--font-mono); }
.text-muted   { color: var(--text-muted); }
.text-secondary { color: var(--text-secondary); }
.text-accent  { color: var(--accent); }
.text-success { color: var(--success); }
.text-warning { color: var(--warning); }
.text-danger  { color: var(--danger); }
.text-sm  { font-size: 0.78rem; }
.text-xs  { font-size: 0.7rem; }
.fw-500   { font-weight: 500; }
.fw-600   { font-weight: 600; }
.d-flex   { display: flex; }
.align-center   { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-1    { gap: 0.25rem; }
.gap-2    { gap: 0.5rem; }
.gap-3    { gap: 0.75rem; }
.gap-4    { gap: 1rem; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 0.75rem; }
.mt-4 { margin-top: 1rem; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 0.75rem; }
.mb-4 { margin-bottom: 1rem; }
.w-100 { width: 100%; }
.truncate { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* ── Auth pages ──────────────────────────────────────────────────────────────── */
.auth-shell {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  background: var(--bg-base);
  background-image: var(--grid-texture);
}
.auth-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2.5rem;
  width: 100%;
  max-width: 380px;
  box-shadow: var(--shadow-lg);
}
.auth-brand {
  text-align: center;
  margin-bottom: 1.75rem;
}
.auth-brand-name {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-primary);
}
.auth-brand-dot {
  display: inline-block;
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
  margin-right: 0.4rem;
  vertical-align: middle;
}
.auth-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}
.auth-subtitle {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

/* ── Scrollbar ───────────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ── Responsive ──────────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
  .app-shell {
    grid-template-columns: 1fr;
    grid-template-rows: var(--header-h) auto 1fr;
  }
  .app-sidebar {
    grid-column: 1;
    grid-row: 2;
    position: static;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .app-main { grid-column: 1; grid-row: 3; padding: 1rem; }
  .app-header .brand { width: auto; }
  .form-row { grid-template-columns: 1fr; }
  .book-grid { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); }
  .stat-grid { grid-template-columns: repeat(2, 1fr); }
}