/* =====================================================================
   AI Notebook  —  components.css  (2026 Premium Design System)
   ---------------------------------------------------------------------
   One consistent, reusable component library used across every page:
   buttons · cards · inputs · selects · toggles · segmented controls ·
   chips/badges · tooltips · modals · dropdowns · tabs · progress ·
   skeletons · alerts · notifications · breadcrumbs · empty states.
   ===================================================================== */

/* =====================================================================
   SURFACES
   ===================================================================== */
.surface,
.card-premium {
  background: var(--surface-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base),
              box-shadow var(--transition-base),
              border-color var(--transition-base);
}

/* Upgrade legacy .glass to the refined look */
.glass {
  background: var(--surface-glass) !important;
  border: 1px solid var(--border) !important;
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  box-shadow: var(--shadow-md);
}

.card-hover:hover,
.card-premium:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-ring);
}

/* Subtle top sheen used on premium cards */
.card-premium { position: relative; overflow: hidden; }
.card-premium::before {
  content: '';
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-strong), transparent);
  opacity: 0.7;
}

/* =====================================================================
   BUTTONS  (extends legacy .btn, adds variants)
   ===================================================================== */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  padding: 0.7rem 1.25rem;
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: var(--fs-sm);
  line-height: 1;
  cursor: pointer;
  color: #fff;
  background: var(--grad);
  box-shadow: var(--shadow-accent);
  transition: transform var(--dur-base) var(--ease-spring),
              box-shadow var(--dur-base) var(--ease-smooth),
              filter var(--dur-base) var(--ease-smooth),
              background var(--dur-base) var(--ease-smooth);
  overflow: hidden;
  isolation: isolate;
  white-space: nowrap;
  -webkit-tap-highlight-color: transparent;
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-glow); filter: brightness(1.04); }
.btn:active { transform: translateY(0) scale(0.97); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; transform: none; box-shadow: none; }

.btn.primary { background: var(--grad); }
.btn.ghost,
.btn.secondary {
  background: var(--glass-2);
  border: 1px solid var(--border);
  color: var(--text);
  box-shadow: none;
  backdrop-filter: blur(12px);
}
.btn.ghost:hover,
.btn.secondary:hover { background: var(--glass-strong); border-color: var(--accent-ring); box-shadow: var(--shadow-sm); }

.btn.subtle {
  background: var(--accent-soft);
  color: var(--accent);
  box-shadow: none;
  border: 1px solid transparent;
}
.btn.subtle:hover { background: var(--accent-soft); filter: brightness(1.15); box-shadow: var(--shadow-sm); }

.btn.outline {
  background: transparent;
  border: 1px solid var(--border-strong);
  color: var(--text);
  box-shadow: none;
}
.btn.outline:hover { border-color: var(--accent); color: var(--accent); }

.btn.danger { background: linear-gradient(135deg, #f43f5e, #fb7185); box-shadow: 0 10px 24px rgba(244, 63, 94, 0.3); }
.btn.danger:hover { box-shadow: 0 14px 32px rgba(244, 63, 94, 0.45); }
.btn.danger.ghost { background: rgba(244, 63, 94, 0.08); color: var(--danger); border-color: rgba(244, 63, 94, 0.3); }

.btn.small { padding: 0.5rem 0.95rem; font-size: var(--fs-xs); }
.btn.large { padding: 0.95rem 1.7rem; font-size: var(--fs-base); }
.btn.block { width: 100%; }
.btn.icon-only { padding: 0.6rem; width: 40px; height: 40px; border-radius: var(--radius-md); }

/* Ripple (injected by motion.js) */
.btn .ripple,
.ripple-host .ripple {
  position: absolute;
  border-radius: 50%;
  transform: scale(0);
  background: rgba(255, 255, 255, 0.4);
  pointer-events: none;
  z-index: 0;
  animation: rippleExpand 0.6s var(--ease-out);
}
@keyframes rippleExpand { to { transform: scale(3.2); opacity: 0; } }

/* =====================================================================
   ICON BUTTON  (topbar / toolbars)
   ===================================================================== */
.icon-btn {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  background: var(--glass-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  cursor: pointer;
  font-size: 1rem;
  transition: all var(--dur-base) var(--ease-smooth);
  position: relative;
}
.icon-btn:hover { color: var(--text); background: var(--glass-strong); border-color: var(--accent-ring); transform: translateY(-2px); }
.icon-btn:active { transform: scale(0.94); }
.icon-btn .dot {
  position: absolute; top: 8px; right: 9px;
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--danger); border: 2px solid var(--bg-1);
}

/* =====================================================================
   FORM CONTROLS
   ===================================================================== */
.input,
.field-input,
input.ui-input,
textarea.ui-input,
select.ui-input {
  width: 100%;
  padding: 0.75rem 0.95rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--glass);
  color: var(--text);
  font-size: var(--fs-sm);
  font-family: inherit;
  transition: border-color var(--dur-base) var(--ease-smooth),
              box-shadow var(--dur-base) var(--ease-smooth),
              background var(--dur-base) var(--ease-smooth);
}
.input::placeholder, .ui-input::placeholder { color: var(--text-muted); }
.input:focus,
.ui-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
  background: var(--glass-2);
}

/* Input with leading icon */
.input-group { position: relative; }
.input-group .lead-icon {
  position: absolute; left: 0.9rem; top: 50%; transform: translateY(-50%);
  color: var(--text-muted); pointer-events: none; font-size: 0.95rem;
}
.input-group .input.with-icon,
.input-group input.with-icon { padding-left: 2.6rem; }

/* =====================================================================
   TOGGLE SWITCH  (premium, animated)
   ===================================================================== */
.toggle-switch,
.switch {
  position: relative;
  width: 50px;
  height: 28px;
  background: var(--border-strong);
  border-radius: var(--radius-full);
  cursor: pointer;
  border: none;
  padding: 0;
  flex-shrink: 0;
  transition: background var(--dur-base) var(--ease-smooth);
}
.toggle-switch::after,
.switch::after {
  content: '';
  position: absolute;
  width: 22px; height: 22px;
  background: #fff;
  border-radius: 50%;
  top: 3px; left: 3px;
  box-shadow: var(--shadow-sm);
  transition: left var(--dur-base) var(--ease-spring), width var(--dur-fast) var(--ease-smooth);
}
.toggle-switch.active,
.switch.active { background: var(--accent); }
.toggle-switch.active::after,
.switch.active::after { left: 25px; }
.toggle-switch:active::after,
.switch:active::after { width: 26px; }

/* =====================================================================
   SEGMENTED CONTROL
   ===================================================================== */
.segmented {
  display: inline-flex;
  padding: 4px;
  gap: 2px;
  background: var(--glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  position: relative;
}
.segmented .seg {
  position: relative;
  z-index: 1;
  border: none;
  background: transparent;
  color: var(--text-dim);
  font-weight: 600;
  font-size: var(--fs-xs);
  padding: 0.5rem 0.9rem;
  border-radius: calc(var(--radius-md) - 4px);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: color var(--dur-base) var(--ease-smooth);
}
.segmented .seg.active { color: #fff; }
.segmented .seg:not(.active):hover { color: var(--text); }
/* sliding pill highlight */
.segmented .seg-pill {
  position: absolute;
  z-index: 0;
  top: 4px; bottom: 4px;
  border-radius: calc(var(--radius-md) - 4px);
  background: var(--grad);
  box-shadow: var(--shadow-accent);
  transition: left var(--dur-base) var(--ease-spring), width var(--dur-base) var(--ease-spring);
}

/* =====================================================================
   CHIPS / BADGES
   ===================================================================== */
.chip,
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.32rem 0.7rem;
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  font-weight: 600;
  background: var(--glass-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  transition: all var(--dur-base) var(--ease-smooth);
}
.chip.active,
.chip[aria-pressed='true'] { background: var(--accent-soft); color: var(--accent); border-color: var(--accent-ring); }
.chip.clickable { cursor: pointer; }
.chip.clickable:hover { color: var(--text); border-color: var(--accent-ring); transform: translateY(-1px); }
.badge.success { color: var(--success); border-color: rgba(56, 211, 159, 0.3); background: rgba(56, 211, 159, 0.1); }
.badge.warning { color: var(--warning); border-color: rgba(251, 191, 36, 0.3); background: rgba(251, 191, 36, 0.1); }
.badge.danger  { color: var(--danger);  border-color: rgba(251, 113, 133, 0.3); background: rgba(251, 113, 133, 0.1); }
.badge.dot::before { content: ''; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }

/* =====================================================================
   TOOLTIP  (CSS-only, data-tooltip attribute)
   ===================================================================== */
[data-tooltip] { position: relative; }
[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  left: 50%; bottom: calc(100% + 8px);
  transform: translateX(-50%) translateY(4px);
  background: var(--menu-bg);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius-sm);
  font-size: var(--fs-xs);
  font-weight: 500;
  white-space: nowrap;
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(12px);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-fast) var(--ease-smooth), transform var(--dur-fast) var(--ease-smooth);
  z-index: 9999;
}
[data-tooltip]:hover::after { opacity: 1; transform: translateX(-50%) translateY(0); }
[data-tooltip-pos='right']::after { left: calc(100% + 8px); bottom: 50%; transform: translateY(50%) translateX(-4px); }
[data-tooltip-pos='right']:hover::after { transform: translateY(50%) translateX(0); }

/* =====================================================================
   DROPDOWN MENU
   ===================================================================== */
.dropdown { position: relative; }
.dropdown-menu {
  position: absolute;
  min-width: 220px;
  background: var(--menu-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(24px) saturate(150%);
  padding: 0.4rem;
  z-index: 1200;
  opacity: 0;
  transform: translateY(-8px) scale(0.97);
  transform-origin: top right;
  pointer-events: none;
  transition: opacity var(--dur-base) var(--ease-smooth), transform var(--dur-base) var(--ease-spring);
}
.dropdown-menu.open { opacity: 1; transform: translateY(0) scale(1); pointer-events: auto; }
.dropdown-item {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  width: 100%;
  padding: 0.6rem 0.7rem;
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  background: none;
  border: none;
  font: inherit;
  font-size: var(--fs-sm);
  text-align: left;
  cursor: pointer;
  transition: background var(--dur-fast), color var(--dur-fast);
}
.dropdown-item i { width: 18px; text-align: center; }
.dropdown-item:hover { background: var(--accent-soft); color: var(--text); }
.dropdown-item.danger:hover { background: rgba(244, 63, 94, 0.12); color: var(--danger); }
.dropdown-sep { height: 1px; background: var(--border); margin: 0.35rem 0.2rem; }

/* =====================================================================
   MODAL / DIALOG
   ===================================================================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 4000;
  display: grid;
  place-items: center;
  padding: 1.2rem;
  background: rgba(4, 6, 16, 0.55);
  backdrop-filter: blur(8px);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--dur-base) var(--ease-smooth), visibility var(--dur-base);
}
.modal-overlay.open { opacity: 1; visibility: visible; }
.modal {
  width: min(520px, 100%);
  background: var(--menu-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  backdrop-filter: blur(24px);
  padding: 1.7rem;
  transform: translateY(16px) scale(0.96);
  opacity: 0;
  transition: transform var(--dur-slow) var(--ease-spring), opacity var(--dur-base) var(--ease-smooth);
}
.modal-overlay.open .modal { transform: translateY(0) scale(1); opacity: 1; }
.modal h3 { font-size: var(--fs-xl); margin-bottom: 0.5rem; display: flex; align-items: center; gap: 0.6rem; }
.modal p { color: var(--text-dim); font-size: var(--fs-sm); margin-bottom: 1.3rem; }
.modal-actions { display: flex; gap: 0.7rem; justify-content: flex-end; }

/* =====================================================================
   PROGRESS BAR / RING
   ===================================================================== */
.progress {
  width: 100%;
  height: 8px;
  border-radius: var(--radius-full);
  background: var(--glass-strong);
  overflow: hidden;
}
.progress > span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--grad);
  width: 0;
  transition: width 1s var(--ease-out);
  box-shadow: 0 0 14px var(--accent-ring);
}

/* =====================================================================
   SKELETON LOADER
   ===================================================================== */
.skeleton {
  position: relative;
  overflow: hidden;
  background: var(--glass-strong);
  border-radius: var(--radius-sm);
  display: block;
}
.skeleton::after {
  content: '';
  position: absolute;
  inset: 0;
  transform: translateX(-100%);
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.12), transparent);
  animation: skeletonSweep 1.5s infinite;
}
@keyframes skeletonSweep { 100% { transform: translateX(100%); } }

/* =====================================================================
   ALERTS / INLINE MESSAGES
   ===================================================================== */
.alert {
  display: flex;
  gap: 0.8rem;
  align-items: flex-start;
  padding: 0.9rem 1.1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: var(--glass-2);
  font-size: var(--fs-sm);
}
.alert i { margin-top: 2px; }
.alert.success { border-color: rgba(56, 211, 159, 0.3); background: rgba(56, 211, 159, 0.08); }
.alert.success i { color: var(--success); }
.alert.warning { border-color: rgba(251, 191, 36, 0.3); background: rgba(251, 191, 36, 0.08); }
.alert.warning i { color: var(--warning); }
.alert.danger { border-color: rgba(251, 113, 133, 0.3); background: rgba(251, 113, 133, 0.08); }
.alert.danger i { color: var(--danger); }
.alert.info i { color: var(--info); }

/* =====================================================================
   TOAST (premium upgrade of legacy .toast)
   ===================================================================== */
#toast-wrap {
  position: fixed;
  top: 1.2rem; right: 1.2rem;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  max-width: min(360px, 92vw);
}
.toast {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.85rem 1.1rem;
  border-radius: var(--radius-md);
  background: var(--menu-bg);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: var(--fs-sm);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(18px);
  animation: toastSlideIn 0.42s var(--ease-spring);
  border-left: 3px solid var(--accent);
}
.toast i { font-size: 1.05rem; }
.toast.success { border-left-color: var(--success); }
.toast.success i { color: var(--success); }
.toast.error { border-left-color: var(--danger); }
.toast.error i { color: var(--danger); }
@keyframes toastSlideIn {
  from { opacity: 0; transform: translateX(120%) scale(0.9); }
  to { opacity: 1; transform: translateX(0) scale(1); }
}

/* =====================================================================
   TABS (generic underline tabs)
   ===================================================================== */
.tabs {
  display: flex;
  gap: 0.3rem;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
  scrollbar-width: none;
}
.tabs::-webkit-scrollbar { display: none; }
.tabs .tab {
  position: relative;
  padding: 0.8rem 1.05rem;
  background: none;
  border: none;
  color: var(--text-dim);
  font-weight: 600;
  font-size: var(--fs-sm);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
  transition: color var(--dur-base) var(--ease-smooth);
}
.tabs .tab::after {
  content: '';
  position: absolute;
  left: 0.6rem; right: 0.6rem; bottom: -1px;
  height: 2px;
  border-radius: 2px;
  background: var(--grad);
  transform: scaleX(0);
  transition: transform var(--dur-base) var(--ease-spring);
}
.tabs .tab:hover { color: var(--text); }
.tabs .tab.active { color: var(--accent); }
.tabs .tab.active::after { transform: scaleX(1); }

/* =====================================================================
   BREADCRUMBS
   ===================================================================== */
.breadcrumbs { display: flex; align-items: center; gap: 0.45rem; font-size: var(--fs-xs); color: var(--text-muted); }
.breadcrumbs a { color: var(--text-dim); transition: color var(--dur-fast); }
.breadcrumbs a:hover { color: var(--accent); }
.breadcrumbs .sep { opacity: 0.5; }

/* =====================================================================
   EMPTY STATE
   ===================================================================== */
.empty-state {
  text-align: center;
  padding: 2.5rem 1.5rem;
  color: var(--text-dim);
}
.empty-state .empty-icon {
  width: 72px; height: 72px;
  margin: 0 auto 1rem;
  display: grid; place-items: center;
  border-radius: var(--radius-xl);
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 1.9rem;
}
.empty-state h4 { color: var(--text); margin-bottom: 0.35rem; font-size: var(--fs-lg); }
.empty-state p { font-size: var(--fs-sm); margin-bottom: 1.1rem; }

/* =====================================================================
   SETTINGS ROW (label + control)  — reused on settings page
   ===================================================================== */
.set-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: var(--density-pad) 0;
  border-bottom: 1px solid var(--border-light);
}
.set-row:last-child { border-bottom: none; }
.set-row .set-label { display: flex; flex-direction: column; gap: 0.15rem; min-width: 0; }
.set-row .set-label b { font-weight: 600; font-size: var(--fs-sm); }
.set-row .set-label span { color: var(--text-muted); font-size: var(--fs-xs); }
.set-row .set-control { flex-shrink: 0; }

/* =====================================================================
   SCROLL-REVEAL  (driven by motion.js IntersectionObserver)
   ===================================================================== */
[data-reveal] {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
  will-change: opacity, transform;
}
[data-reveal].in-view { opacity: 1; transform: none; }
[data-reveal='left'] { transform: translateX(-26px); }
[data-reveal='right'] { transform: translateX(26px); }
[data-reveal='scale'] { transform: scale(0.94); }
[data-reveal].in-view { transform: none; }

/* Staggered children */
[data-stagger] > * { opacity: 0; transform: translateY(16px); }
[data-stagger].in-view > * {
  opacity: 1; transform: none;
  transition: opacity 0.5s var(--ease-out), transform 0.5s var(--ease-out);
}
[data-stagger].in-view > *:nth-child(1) { transition-delay: 0.04s; }
[data-stagger].in-view > *:nth-child(2) { transition-delay: 0.09s; }
[data-stagger].in-view > *:nth-child(3) { transition-delay: 0.14s; }
[data-stagger].in-view > *:nth-child(4) { transition-delay: 0.19s; }
[data-stagger].in-view > *:nth-child(5) { transition-delay: 0.24s; }
[data-stagger].in-view > *:nth-child(6) { transition-delay: 0.29s; }
[data-stagger].in-view > *:nth-child(7) { transition-delay: 0.34s; }
[data-stagger].in-view > *:nth-child(8) { transition-delay: 0.39s; }
[data-stagger].in-view > *:nth-child(n+9) { transition-delay: 0.44s; }

:root[data-motion='reduced'] [data-reveal],
:root[data-motion='reduced'] [data-stagger] > * { opacity: 1 !important; transform: none !important; }


/* Shared surface defaults use theme tokens; page sheets may refine them. */
:root {
  --site-bg: var(--bg-0);
  --site-panel: var(--surface);
  --site-panel-2: var(--surface-raised);
  --site-line: var(--border);
  --site-accent: var(--accent);
}
body { background: var(--page-bg); color: var(--text); }
.app-shell, .page-shell, .tools-shell, .topic-shell, .settings-wrapper { background: var(--page-bg); }
.panel, .glass, .settings-card, .tool-card, .topic-card, .learn-launcher, .dash-ai, .ach-card, .settings-panel {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--glass);
  box-shadow: var(--shadow-sm);
}
.panel:hover, .settings-card:hover, .tool-card:hover, .topic-card:hover, .ach-card:hover {
  border-color: var(--accent-ring);
  box-shadow: var(--shadow-md);
}
.topbar, .topbar-inner, .settings-tabs {
  border-color: var(--border);
  background: var(--nav-bg);
  backdrop-filter: blur(18px);
}
.section-title h2, .panel-head h3, .settings-card h3, .tool-card h3 {
  font-family: var(--font-family-ui);
  letter-spacing: -0.02em;
}
.search-trigger, input, textarea, select {
  border-radius: var(--radius-md);
  border-color: var(--border);
  background: var(--glass);
}
.search-trigger:focus-within, input:focus, textarea:focus, select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-ring);
}
.btn { border-radius: var(--radius-md); background: var(--grad); box-shadow: var(--shadow-accent); }
.btn.ghost, .btn.secondary, .btn.outline {
  background: var(--glass);
  border-color: var(--border);
  box-shadow: none;
}
.chip, .badge, .model-badge, .tag { border-radius: var(--radius-sm); }
.progress, .progress-track { height: 6px; border-radius: var(--radius-full); background: var(--glass-strong); }
.progress span, .progress-track span { border-radius: inherit; background: linear-gradient(90deg, var(--accent), var(--success)); }
@media (max-width: 700px) {
  .panel, .glass, .settings-card, .tool-card, .topic-card { border-radius: var(--radius-md); }
}


/* Install CTA is intentionally removed from the web product. */
#pwaInstallBtn, .pwa-install-btn { display: none !important; }