/* ============================================================
   XRP Blocks IDE — Design System & Layout
   Target audience: children 8–14, especially underrepresented
   groups in STEM. Light, friendly, encouraging.
   ============================================================ */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

/* --- Design Tokens --- */
:root {
  /* Typography */
  --font-ui: 'Nunito', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Cascadia Code', 'Consolas', monospace;

  /* Core palette — warm, welcoming light theme */
  --color-bg: #F8F9FC;
  --color-bg-warm: #FEFEFE;
  --color-surface: #FFFFFF;
  --color-surface-raised: #FFFFFF;
  --color-surface-hover: #F0F2F8;
  --color-border: #E2E6EF;
  --color-border-light: #EEF0F6;

  /* Text */
  --color-text: #2D3142;
  --color-text-secondary: #5C6378;
  --color-text-muted: #9CA3B8;
  --color-text-on-accent: #FFFFFF;

  /* Pastel category colors */
  --color-drive: #7CB9F0;
  --color-drive-dark: #5A9FDE;
  --color-motors: #B39DDB;
  --color-motors-dark: #9575CD;
  --color-servo: #FFB74D;
  --color-servo-dark: #FFA726;
  --color-sensors: #81C784;
  --color-sensors-dark: #66BB6A;
  --color-board: #FFD54F;
  --color-board-dark: #FFCA28;

  --color-events: #FFCA28;
  --color-events-dark: #FFB300;

  /* Standard Blockly category colors (pastel) */
  --color-logic: #82B1FF;
  --color-loops: #80CBC4;
  --color-math: #EF9A9A;
  --color-text-cat: #CE93D8;
  --color-variables: #FFAB91;
  --color-functions: #A5D6A7;

  /* Accent / action colors */
  --color-primary: #6C63FF;
  --color-primary-hover: #5A52E0;
  --color-success: #4CAF50;
  --color-success-hover: #43A047;
  --color-danger: #EF5350;
  --color-danger-hover: #E53935;
  --color-warning: #FFA726;

  /* Connection status */
  --color-connected: #4CAF50;
  --color-disconnected: #BDBDBD;
  --color-bt: #2196F3;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(45, 49, 66, 0.06);
  --shadow-md: 0 4px 12px rgba(45, 49, 66, 0.08);
  --shadow-lg: 0 8px 24px rgba(45, 49, 66, 0.10);
  --shadow-toolbar: 0 2px 8px rgba(45, 49, 66, 0.06);

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;
  --space-2xl: 32px;

  /* Toolbar */
  --toolbar-height: 56px;

  /* Bottom panel */
  --panel-height: 220px;
  --panel-tab-height: 38px;

  /* Transitions */
  --transition-fast: 120ms ease;
  --transition-normal: 200ms ease;
  --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  width: 100%;
  overflow: hidden;
  font-family: var(--font-ui);
  font-size: 14px;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

button {
  font-family: var(--font-ui);
  cursor: pointer;
  border: none;
  background: none;
  font-size: inherit;
  color: inherit;
}

/* --- App Layout --- */
#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  width: 100vw;
}

/* --- Toolbar --- */
.toolbar {
  display: flex;
  align-items: center;
  height: var(--toolbar-height);
  padding: 0 var(--space-lg);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-toolbar);
  z-index: 100;
  gap: var(--space-md);
  flex-shrink: 0;
}

.toolbar__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-right: var(--space-lg);
  text-decoration: none;
  color: var(--color-text);
}

.toolbar__logo-text {
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.3px;
}

.toolbar__divider {
  width: 1px;
  height: 28px;
  background: var(--color-border);
  margin: 0 var(--space-sm);
}

.toolbar__select {
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 13px;
  padding: 6px 12px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-full);
  background: var(--color-surface);
  color: var(--color-text);
  outline: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.toolbar__select:hover {
  border-color: var(--color-primary);
  background: var(--color-surface-hover);
}

/* Toolbar buttons */
.toolbar__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.2px;
  transition: all var(--transition-normal);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.toolbar__btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.toolbar__btn:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

.toolbar__btn--connect {
  background: var(--color-primary);
  color: var(--color-text-on-accent);
}

.toolbar__btn--connect:hover {
  background: var(--color-primary-hover);
}

.toolbar__btn--connect.connected {
  background: var(--color-success);
}

.toolbar__btn--connect.connected:hover {
  background: var(--color-success-hover);
}

.toolbar__btn--run {
  background: var(--color-success);
  color: var(--color-text-on-accent);
}

.toolbar__btn--run:hover {
  background: var(--color-success-hover);
}

.toolbar__btn--run:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* Deploy button — amber, signals a persistent "save to board" action */
.toolbar__btn--deploy {
  background: var(--color-warning);
  color: var(--color-text-on-accent);
}

.toolbar__btn--deploy:hover {
  background: #F57C00;
}

.toolbar__btn--deploy:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.toolbar__btn--deploy.deploying {
  opacity: 0.75;
  cursor: wait;
  animation: deploy-pulse 1s ease-in-out infinite alternate;
}

@keyframes deploy-pulse {
  from { opacity: 0.6; }
  to   { opacity: 1;   }
}

.toolbar__btn--stop {
  background: var(--color-danger);
  color: var(--color-text-on-accent);
  display: none;
}

.toolbar__btn--stop:hover {
  background: var(--color-danger-hover);
}

.toolbar__btn--stop.visible {
  display: inline-flex;
}

.toolbar__btn--secondary {
  background: var(--color-surface-hover);
  color: var(--color-text);
}

.toolbar__btn--secondary:hover {
  background: var(--color-border);
}

.toolbar__btn svg,
.toolbar__btn .btn-icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* Connection status indicator */
.connection-status {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 12px;
  font-weight: 600;
  color: var(--color-text-secondary);
}

.connection-status__dot {
  width: 8px;
  height: 8px;
  border-radius: var(--radius-full);
  background: var(--color-disconnected);
  transition: background var(--transition-normal);
}

.connection-status__dot.connected {
  background: var(--color-connected);
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {

  0%,
  100% {
    box-shadow: 0 0 0 0 rgba(76, 175, 80, 0.4);
  }

  50% {
    box-shadow: 0 0 0 6px rgba(76, 175, 80, 0);
  }
}

.toolbar__spacer {
  flex: 1;
}

/* --- Main Workspace Area --- */
.workspace-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  position: relative;
}

/* Blockly container */
#blocklyDiv {
  flex: 1;
  min-height: 0;
  width: 100%;
  position: relative;
}

/* --- Blockly Overrides --- */
/* Category toolbox styling */
.blocklyToolboxDiv {
  background: var(--color-surface) !important;
  border-right: 1px solid var(--color-border) !important;
  box-shadow: 4px 0 16px rgba(45, 49, 66, 0.05) !important;
  padding-top: var(--space-md) !important;
  padding-bottom: var(--space-md) !important;
  z-index: 10 !important;
}

.blocklyToolboxCategory {
  height: initial !important;
  padding: 4px 16px !important;
  margin: 0;
}

.blocklyToolboxCategoryLabel {
  font: 16px var(--font-ui);
}

.blocklyTreeRow {
  display: flex !important;
  align-items: center !important;
  flex-wrap: nowrap !important;
  padding: 6px 12px !important;
  margin: 6px var(--space-sm) !important;
  border-radius: 8px !important;
  /* hardcoded to avoid any variable issues */
  min-height: 40px !important;
  transition: transform var(--transition-fast) !important;
  border: 2px solid transparent !important;
  /* Prevent layout shift */
  cursor: pointer !important;
}

.blocklyTreeRow:hover {
  transform: translateX(2px) !important;
}

.blocklyTreeSelected {
  border-color: var(--color-text) !important;
  box-shadow: var(--shadow-sm) !important;
  transform: translateX(4px) !important;
}

.blocklyTreeSelected:hover {
  transform: translateX(4px) !important;
}

.blocklyTreeLabel {
  font-family: var(--font-ui) !important;
  font-size: 14px !important;
  font-weight: 800 !important;
  color: var(--color-text) !important;
  white-space: nowrap !important;
  margin-left: 6px !important;
}

.blocklyTreeIcon {
  display: none !important;
  /* Hide Blockly's default folder/arrow icons */
}

.blocklyTreeRowContentContainer {
  display: flex;
  align-items: center;
}

.cat-icon {
  position: relative !important;
  display: inline-flex !important;
  align-items: center !important;
  justify-content: center !important;
  width: 28px !important;
  height: 28px !important;
  border-radius: 50% !important;
  /* Perfect circle container */
  margin-right: 4px !important;
  flex-shrink: 0 !important;
}

.cat-icon::before {
  content: '';
  width: 16px;
  height: 16px;
  background-color: white !important;
  /* White icon symbol */
  mask-size: contain;
  mask-repeat: no-repeat;
  mask-position: center;
  -webkit-mask-size: contain;
  -webkit-mask-repeat: no-repeat;
  -webkit-mask-position: center;
}

/* XRP Category Icon Masks */
.cat-icon-events::before {
  mask-image: url('../images/icons/events.svg');
  -webkit-mask-image: url('../images/icons/events.svg');
}

.cat-icon-drive::before {
  mask-image: url('../images/icons/drive.svg');
  -webkit-mask-image: url('../images/icons/drive.svg');
}

.cat-icon-motors::before {
  mask-image: url('../images/icons/motors.svg');
  -webkit-mask-image: url('../images/icons/motors.svg');
}

.cat-icon-servo::before {
  mask-image: url('../images/icons/servo.svg');
  -webkit-mask-image: url('../images/icons/servo.svg');
}

.cat-icon-sensors::before {
  mask-image: url('../images/icons/sensors.svg');
  -webkit-mask-image: url('../images/icons/sensors.svg');
}

.cat-icon-board::before {
  mask-image: url('../images/icons/board.svg');
  -webkit-mask-image: url('../images/icons/board.svg');
}

/* Standard Category Icon Masks */
.cat-icon-logic::before {
  mask-image: url('../images/icons/logic.svg');
  -webkit-mask-image: url('../images/icons/logic.svg');
}

.cat-icon-loops::before {
  mask-image: url('../images/icons/loops.svg');
  -webkit-mask-image: url('../images/icons/loops.svg');
}

.cat-icon-math::before {
  mask-image: url('../images/icons/math.svg');
  -webkit-mask-image: url('../images/icons/math.svg');
}

.cat-icon-text::before {
  mask-image: url('../images/icons/text.svg');
  -webkit-mask-image: url('../images/icons/text.svg');
}

.cat-icon-variables::before {
  mask-image: url('../images/icons/variables.svg');
  -webkit-mask-image: url('../images/icons/variables.svg');
}

.cat-icon-functions::before {
  mask-image: url('../images/icons/functions.svg');
  -webkit-mask-image: url('../images/icons/functions.svg');
}

.blocklyFlyoutBackground {
  fill: var(--color-surface) !important;
  fill-opacity: 0.98 !important;
  stroke: var(--color-border) !important;
  stroke-width: 1px !important;
  filter: drop-shadow(4px 0 12px rgba(45, 49, 66, 0.06));
}

.blocklyMainBackground {
  fill: var(--color-bg) !important;
}

.blocklyScrollbarHandle {
  fill: var(--color-border) !important;
  rx: 4;
  ry: 4;
}

.blocklyScrollbarBackground {
  fill: transparent !important;
}

/* Zoom controls */
.blocklyZoom>image {
  opacity: 0.5;
  transition: opacity var(--transition-fast);
}

.blocklyZoom>image:hover {
  opacity: 0.8;
}

/* Trash can */
.blocklyTrash {
  opacity: 0.4;
  transition: opacity var(--transition-fast);
}

.blocklyTrash:hover {
  opacity: 0.7;
}

/* --- Bottom Panel --- */
.bottom-panel {
  height: var(--panel-height);
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  transition: height var(--transition-smooth);
  z-index: 50;
}

.bottom-panel.collapsed {
  height: var(--panel-tab-height);
}

/* Panel resize handle */
.bottom-panel__resize {
  height: 4px;
  cursor: ns-resize;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.bottom-panel__resize::after {
  content: '';
  width: 40px;
  height: 3px;
  border-radius: var(--radius-full);
  background: var(--color-border);
  transition: background var(--transition-fast);
}

.bottom-panel__resize:hover::after {
  background: var(--color-text-muted);
}

/* Panel tabs */
.bottom-panel__tabs {
  display: flex;
  align-items: center;
  gap: 0;
  padding: 0 var(--space-md);
  border-bottom: 1px solid var(--color-border-light);
  flex-shrink: 0;
  height: var(--panel-tab-height);
}

.bottom-panel__tab {
  padding: var(--space-sm) var(--space-lg);
  font-size: 12px;
  font-weight: 700;
  color: var(--color-text-muted);
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  cursor: pointer;
  background: none;
  border-top: none;
  border-left: none;
  border-right: none;
}

.bottom-panel__tab:hover {
  color: var(--color-text-secondary);
}

.bottom-panel__tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.bottom-panel__actions {
  margin-left: auto;
  display: flex;
  gap: var(--space-xs);
  align-items: center;
}

.bottom-panel__action-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  transition: all var(--transition-fast);
}

.bottom-panel__action-btn svg {
  width: 14px;
  height: 14px;
  transition: transform var(--transition-normal);
}

.bottom-panel:not(.collapsed) .bottom-panel__action-btn[id^="btn-collapse-panel"] svg {
  transform: rotate(180deg);
}

.bottom-panel__action-btn:hover {
  background: var(--color-surface-hover);
  color: var(--color-text);
}

/* Active/toggled state (e.g. console auto-scroll on) */
.bottom-panel__action-btn.is-active {
  background: rgba(108, 99, 255, 0.12);
  color: var(--color-primary);
}

.bottom-panel__action-btn.is-active:hover {
  background: rgba(108, 99, 255, 0.2);
  color: var(--color-primary);
}

.bottom-panel__action-btn svg {
  width: 14px;
  height: 14px;
}

/* Panel content */
.bottom-panel__content {
  flex: 1;
  overflow: hidden;
  position: relative;
  min-height: 0;
}

.panel-view {
  display: none;
  height: 100%;
  overflow: auto;
}

.panel-view.active {
  display: block;
}

/* Python preview */
.python-preview {
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-text);
  white-space: pre-wrap;
  word-wrap: break-word;
  background: var(--color-bg);
  min-height: 100%;
}

/* Python syntax highlighting (light theme) */
.python-preview .keyword {
  color: #7C4DFF;
  font-weight: 500;
}

.python-preview .string {
  color: #2E7D32;
}

.python-preview .number {
  color: #E65100;
}

.python-preview .comment {
  color: #9CA3B8;
  font-style: italic;
}

.python-preview .function {
  color: #1565C0;
}

.python-preview .builtin {
  color: #6A1B9A;
}

/* Console */
.console-output {
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-text);
  background: #1E1E2E;
  color: #CDD6F4;
  min-height: 100%;
}

.console-output .console-sent {
  color: var(--color-drive);
}

.console-output .console-received {
  color: #CDD6F4;
}

.console-output .console-error {
  color: var(--color-danger);
}

.console-output .console-system {
  color: var(--color-text-muted);
  font-style: italic;
}

/* --- Empty State --- */
.empty-state {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  pointer-events: none;
  z-index: 0;
  opacity: 0.6;
}

.empty-state__icon {
  width: 80px;
  height: 80px;
  margin-bottom: var(--space-lg);
  opacity: 0.3;
}

.empty-state__text {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.empty-state__subtext {
  font-size: 13px;
  color: var(--color-text-muted);
}

/* --- Tooltips --- */
[data-tooltip] {
  position: relative;
}

[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) scale(0.95);
  padding: var(--space-xs) var(--space-sm);
  background: var(--color-text);
  color: var(--color-text-on-accent);
  font-size: 11px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: all var(--transition-fast);
  z-index: 1000;
}

[data-tooltip]:hover::after {
  opacity: 1;
  transform: translateX(-50%) scale(1);
}

/* Panel action buttons sit flush against the right edge of the screen, so a
   centered tooltip overflows the viewport. Anchor those to the button's right
   edge instead, so the tooltip grows leftward (into the page) and stays visible. */
.bottom-panel__actions [data-tooltip]::after {
  left: auto;
  right: 0;
  transform: translateX(0) scale(0.95);
}

.bottom-panel__actions [data-tooltip]:hover::after {
  transform: translateX(0) scale(1);
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .toolbar {
    padding: 0 var(--space-md);
    gap: var(--space-sm);
  }

  .toolbar__btn {
    padding: var(--space-sm) var(--space-md);
    font-size: 12px;
  }

  .toolbar__btn .btn-label {
    display: none;
  }

  .toolbar__logo-text {
    font-size: 15px;
  }

  .bottom-panel {
    --panel-height: 180px;
  }
}

/* --- Utility --- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* --- Notification toast --- */
.toast {
  position: fixed;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  padding: var(--space-md) var(--space-xl);
  background: var(--color-text);
  color: var(--color-text-on-accent);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 13px;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: all var(--transition-smooth);
  z-index: 9999;
  pointer-events: none;
}

.toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast.toast--success {
  background: var(--color-success);
}

.toast.toast--error {
  background: var(--color-danger);
}

/* ============================================================
   Lesson / Tutorial Panel
   ============================================================ */

/* Toolbar: Lesson button */
.toolbar__btn--lesson {
  background: linear-gradient(135deg, #7C4DFF, #6C63FF);
  color: #fff;
  border: none;
}

.toolbar__btn--lesson:hover {
  background: linear-gradient(135deg, #6C3FE8, #5A52E0);
}

/* Lesson panel container */
.lesson-panel {
  background: linear-gradient(135deg, #f5f3ff 0%, #eef2ff 100%);
  border-bottom: 2px solid #c4b5fd;
  box-shadow: 0 4px 16px rgba(108, 99, 255, 0.10);
  flex-shrink: 0;
  overflow: hidden;
  /* Slide transition */
  max-height: 220px;
  opacity: 1;
  transition:
    max-height 300ms cubic-bezier(0.4, 0, 0.2, 1),
    opacity 300ms cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
}

.lesson-panel--hidden {
  max-height: 0 !important;
  opacity: 0 !important;
  border-bottom-width: 0;
  pointer-events: none;
}

/* Header row: title + step count + close */
.lesson-panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px 4px 16px;
  gap: var(--space-md);
}

.lesson-panel__title-row {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
}

.lesson-panel__book-icon {
  width: 18px;
  height: 18px;
  color: #7C4DFF;
  flex-shrink: 0;
}

.lesson-panel__title {
  font-weight: 800;
  font-size: 14px;
  color: #3d2c8d;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.lesson-panel__header-right {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.lesson-panel__step-count {
  font-size: 12px;
  font-weight: 700;
  color: #7C4DFF;
  background: rgba(124, 77, 255, 0.10);
  padding: 3px 10px;
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.lesson-panel__close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  background: rgba(124, 77, 255, 0.10);
  color: #7C4DFF;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.lesson-panel__close:hover {
  background: rgba(124, 77, 255, 0.22);
  transform: scale(1.1);
}

.lesson-panel__close svg {
  width: 14px;
  height: 14px;
}

/* Progress bar */
.lesson-panel__progress {
  height: 4px;
  background: rgba(124, 77, 255, 0.15);
  margin: 6px 16px 0 16px;
  border-radius: var(--radius-full);
  overflow: hidden;
}

.lesson-panel__progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #7C4DFF, #a78bfa);
  border-radius: var(--radius-full);
  transition: width 350ms cubic-bezier(0.4, 0, 0.2, 1);
  width: 0%;
}

/* Step text area */
.lesson-panel__step-text {
  flex: 1;
  padding: 10px 18px 6px 18px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.55;
  color: #2D3142;
  overflow-y: auto;
  /* Fade-in animation on step change */
  opacity: 1;
  transform: translateY(0);
  transition: opacity 180ms ease, transform 180ms ease;
}

.lesson-panel__step-text.lesson-step--animating {
  animation: stepFadeIn 220ms ease forwards;
}

@keyframes stepFadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Navigation buttons */
.lesson-panel__nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 16px 10px 16px;
  gap: var(--space-md);
}

.lesson-panel__btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 18px;
  border-radius: var(--radius-full);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 13px;
  border: none;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.lesson-panel__btn svg {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}

.lesson-panel__btn--prev {
  background: rgba(124, 77, 255, 0.10);
  color: #7C4DFF;
}

.lesson-panel__btn--prev:hover:not(:disabled) {
  background: rgba(124, 77, 255, 0.20);
  transform: translateX(-2px);
}

.lesson-panel__btn--prev:disabled {
  opacity: 0.35;
  cursor: not-allowed;
  transform: none;
}

.lesson-panel__btn--next {
  background: linear-gradient(135deg, #7C4DFF, #6C63FF);
  color: #fff;
  box-shadow: 0 2px 8px rgba(108, 99, 255, 0.30);
}

.lesson-panel__btn--next:hover {
  background: linear-gradient(135deg, #6C3FE8, #5A52E0);
  transform: translateX(2px);
  box-shadow: 0 4px 12px rgba(108, 99, 255, 0.40);
}

/* "Finish" variant for the last step */
.lesson-panel__btn--finish {
  background: linear-gradient(135deg, #4CAF50, #43A047) !important;
  box-shadow: 0 2px 8px rgba(76, 175, 80, 0.30) !important;
}

.lesson-panel__btn--finish:hover {
  background: linear-gradient(135deg, #43A047, #388E3C) !important;
  box-shadow: 0 4px 12px rgba(76, 175, 80, 0.40) !important;
  transform: translateX(2px);
}

/* ============================================================
   Lesson Exit Confirmation Dialog
   ============================================================ */

/* Backdrop overlay */
.lesson-confirm-overlay {
  position: fixed;
  inset: 0;
  background: rgba(45, 49, 66, 0.45);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9998;
  opacity: 0;
  pointer-events: none;
  transition: opacity 200ms ease;
}

.lesson-confirm-overlay--visible {
  opacity: 1;
  pointer-events: auto;
}

/* Dialog card */
.lesson-confirm-dialog {
  background: #fff;
  border-radius: 20px;
  box-shadow: 0 24px 64px rgba(45, 49, 66, 0.20), 0 4px 16px rgba(45, 49, 66, 0.10);
  padding: 32px 32px 24px;
  max-width: 380px;
  width: calc(100vw - 48px);
  text-align: center;
  transform: translateY(12px) scale(0.97);
  transition: transform 220ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.lesson-confirm-overlay--visible .lesson-confirm-dialog {
  transform: translateY(0) scale(1);
}

/* Warning icon */
.lesson-confirm-icon {
  width: 52px;
  height: 52px;
  margin: 0 auto 16px;
  border-radius: 50%;
  background: linear-gradient(135deg, #fff3cd, #ffe082);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(255, 160, 0, 0.25);
}

.lesson-confirm-icon svg {
  width: 26px;
  height: 26px;
  color: #e65100;
  stroke: #e65100;
}

/* Title */
.lesson-confirm-title {
  font-family: var(--font-ui);
  font-weight: 800;
  font-size: 18px;
  color: #2D3142;
  margin: 0 0 10px;
}

/* Body text */
.lesson-confirm-body {
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 500;
  color: #5C6378;
  line-height: 1.55;
  margin: 0 0 24px;
}

/* Action buttons row */
.lesson-confirm-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
}

.lesson-confirm-btn {
  flex: 1;
  padding: 10px 16px;
  border-radius: var(--radius-full);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 14px;
  border: none;
  cursor: pointer;
  transition: all var(--transition-normal);
}

/* "Keep going" — secondary */
.lesson-confirm-btn--no {
  background: #f0f2f8;
  color: #2D3142;
}

.lesson-confirm-btn--no:hover {
  background: #e2e6ef;
}

.lesson-confirm-btn--no:focus-visible {
  outline: 2px solid #6C63FF;
  outline-offset: 2px;
}

/* "Exit lesson" — danger */
.lesson-confirm-btn--yes {
  background: linear-gradient(135deg, #EF5350, #E53935);
  color: #fff;
  box-shadow: 0 2px 8px rgba(239, 83, 80, 0.30);
}

.lesson-confirm-btn--yes:hover {
  background: linear-gradient(135deg, #E53935, #C62828);
  box-shadow: 0 4px 12px rgba(239, 83, 80, 0.40);
  transform: translateY(-1px);
}

.lesson-confirm-btn--yes:focus-visible {
  outline: 2px solid #EF5350;
  outline-offset: 2px;
}
/* -------------------------------------------------------
   Connection Picker Modal
   ------------------------------------------------------- */

/* Overlay */
.connection-modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 9000;
  background: rgba(45, 49, 66, 0.45);
  backdrop-filter: blur(4px);
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
}

.connection-modal.visible {
  display: flex;
  animation: modal-fade-in 0.2s ease;
}

@keyframes modal-fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* Panel */
.connection-modal__panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  width: min(480px, 96vw);
  box-shadow: var(--shadow-lg);
  animation: panel-slide-in 0.25s cubic-bezier(0.34,1.56,0.64,1);
}

@keyframes panel-slide-in {
  from { transform: translateY(24px) scale(0.97); opacity: 0; }
  to   { transform: translateY(0)    scale(1);    opacity: 1; }
}

/* Header */
.connection-modal__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.75rem;
}

.connection-modal__title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: -0.01em;
  margin: 0;
}

.connection-modal__close {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  padding: 0;
}

.connection-modal__close svg {
  width: 14px;
  height: 14px;
}

.connection-modal__close:hover {
  background: var(--color-danger);
  border-color: var(--color-danger);
  color: var(--color-text-on-accent);
}

/* Options grid */
.connection-modal__options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

/* Option card */
.conn-opt {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.65rem;
  padding: 1.75rem 1rem 1.5rem;
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1.5px solid var(--color-border);
  cursor: pointer;
  transition:
    background var(--transition-normal),
    border-color var(--transition-normal),
    transform var(--transition-normal),
    box-shadow var(--transition-normal);
  text-align: center;
  overflow: hidden;
}

.conn-opt:hover:not(:disabled) {
  background: var(--color-surface-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.conn-opt:active:not(:disabled) {
  transform: translateY(0);
}

/* USB option accent */
.conn-opt--usb:hover:not(:disabled) {
  border-color: var(--color-primary);
  box-shadow: 0 8px 24px rgba(108,99,255,0.18);
}

/* Bluetooth option accent */
.conn-opt--bt:hover:not(:disabled) {
  border-color: var(--color-bt, #2196F3);
  box-shadow: 0 8px 24px rgba(33,150,243,0.18);
}

/* Icons */
.conn-opt__icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-lg);
  background: rgba(108,99,255,0.12);
  border: 1.5px solid rgba(108,99,255,0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-normal), border-color var(--transition-normal);
  color: var(--color-primary);
}

.conn-opt__icon svg {
  width: 32px;
  height: 32px;
}

.conn-opt__icon--bt {
  background: rgba(33,150,243,0.12);
  border-color: rgba(33,150,243,0.25);
  color: var(--color-bt, #2196F3);
}

.conn-opt--usb:hover:not(:disabled) .conn-opt__icon {
  background: rgba(108,99,255,0.2);
  border-color: rgba(108,99,255,0.5);
}

.conn-opt--bt:hover:not(:disabled) .conn-opt__icon--bt {
  background: rgba(33,150,243,0.2);
  border-color: rgba(33,150,243,0.5);
}

/* Label and description */
.conn-opt__label {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
}

.conn-opt__desc {
  font-size: 0.72rem;
  color: var(--color-text-secondary);
  line-height: 1.3;
}

/* Not-supported state */
.conn-opt--unsupported {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
}

/* "Not supported" badge */
.conn-opt__badge {
  display: none; /* shown via JS when unsupported */
  position: absolute;
  top: 8px;
  right: 8px;
  align-items: center;
  gap: 3px;
  background: rgba(239,83,80,0.12);
  border: 1px solid rgba(239,83,80,0.3);
  border-radius: var(--radius-sm);
  padding: 2px 6px;
  font-size: 0.62rem;
  font-weight: 700;
  color: var(--color-danger);
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.conn-opt__badge svg {
  width: 10px;
  height: 10px;
}

/* Status dot � Bluetooth variant */
.connection-status__dot.connected-bt {
  background: #2196F3;
  box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.25);
}

/* ── Unsupported-browser modal ──────────────────────────────────────────── */
.unsupported-modal__body {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-lg);
}

.unsupported-modal__icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,167,38,0.12);
  border: 1.5px solid rgba(255,167,38,0.3);
  color: var(--color-warning);
}

.unsupported-modal__icon svg {
  width: 32px;
  height: 32px;
}

.unsupported-modal__text {
  margin: 0;
  max-width: 38ch;
  font-size: 0.9rem;
  line-height: 1.5;
  color: var(--color-text-secondary);
}

.unsupported-modal__hint {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  background: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-text);
}

.unsupported-modal__hint svg {
  width: 18px;
  height: 18px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.unsupported-modal__btn {
  margin-top: var(--space-xs);
  padding: var(--space-sm) var(--space-xl);
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: var(--color-text-on-accent);
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.2px;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.unsupported-modal__btn:hover {
  background: var(--color-primary-hover);
}

/* Body scroll lock when modal open */
body.modal-open {
  overflow: hidden;
}