/**
 * WORKSHOP.CSS - The Workshop: Interactive Image Manipulation Tool
 * ================================================================
 * Renaissance-minimalist aesthetic for discoveringdavinci.com
 * Requires foundation.css custom properties (--color-*, --font-*, --space-*, etc.)
 */

/* ============================================================
   BASE LAYOUT
   ============================================================ */

.workshop {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--color-background);
  color: var(--color-text-primary);
  font-family: var(--font-ui);
  line-height: 1.5;
  overflow-x: hidden;
}

.workshop *,
.workshop *::before,
.workshop *::after {
  box-sizing: border-box;
}

/* ============================================================
   STICKY NAV BAR
   ============================================================ */

.workshop-nav {
  position: sticky;
  top: 0;
  z-index: var(--z-menu, 100);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  min-height: 52px;
}

.workshop-nav__back {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--color-accent-primary);
  text-decoration: none;
  font-family: var(--font-ui);
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

.workshop-nav__back:hover {
  color: var(--color-text-primary);
}

.workshop-nav__title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0;
  white-space: nowrap;
  letter-spacing: 0.02em;
}

.workshop-nav__tools {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* Small toolbar buttons */
.workshop-nav__btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-sm);
  background-color: transparent;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.workshop-nav__btn:hover {
  background-color: var(--color-surface-elevated);
  color: var(--color-text-primary);
  border-color: var(--color-accent-primary);
}

.workshop-nav__btn--active {
  background-color: var(--color-accent-primary);
  color: var(--color-background);
  border-color: var(--color-accent-primary);
}

.workshop-nav__btn--active:hover {
  background-color: var(--color-accent-secondary);
  border-color: var(--color-accent-secondary);
}

/* ============================================================
   MAIN BODY: SIDEBAR + WORKSPACE
   ============================================================ */

.workshop-body {
  display: grid;
  grid-template-columns: 240px 1fr;
  flex: 1;
  min-height: 0;
}

/* ============================================================
   TIER SIDEBAR
   ============================================================ */

.workshop-sidebar {
  background-color: var(--color-surface);
  border-right: 1px solid var(--color-border);
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-sm) 0;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}

.workshop-sidebar::-webkit-scrollbar {
  width: 6px;
}

.workshop-sidebar::-webkit-scrollbar-track {
  background: transparent;
}

.workshop-sidebar::-webkit-scrollbar-thumb {
  background-color: var(--color-border);
  border-radius: 3px;
}

/* Tier group */
.tier-group {
  margin-bottom: var(--space-xs);
}

.tier-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-md);
  background: none;
  border: none;
  width: 100%;
  color: var(--color-text-tertiary);
  font-family: var(--font-display);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: color var(--transition-fast);
  user-select: none;
}

.tier-header:hover {
  color: var(--color-accent-primary);
}

.tier-header__icon {
  font-family: var(--font-display);
  color: var(--color-accent-tertiary);
  font-size: 0.625rem;
  margin-right: var(--space-sm);
}

.tier-header__chevron {
  font-size: 0.5rem;
  transition: transform var(--transition-fast);
}

.tier-group--collapsed .tier-header__chevron {
  transform: rotate(-90deg);
}

.tier-list {
  list-style: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
}

.tier-group--collapsed .tier-list {
  display: none;
}

/* Technique sidebar items */
.tier-item {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  padding-left: var(--space-lg);
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  color: var(--color-text-secondary);
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 400;
  cursor: pointer;
  border-left: 3px solid transparent;
  transition: all var(--transition-fast);
  user-select: none;
}

.tier-item:hover {
  background-color: var(--color-surface-elevated);
  color: var(--color-text-primary);
}

/* Active / selected technique */
.tier-item--active {
  border-left-color: var(--color-accent-primary);
  color: var(--color-text-primary);
  background-color: rgba(212, 175, 55, 0.06);
  font-weight: 500;
}

/* Locked technique */
.tier-item--locked {
  opacity: 0.5;
  pointer-events: none;
  cursor: default;
}

.tier-item--locked::before {
  content: "\1F512";
  font-size: 0.625rem;
  position: absolute;
  right: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
}

.tier-item--locked[title]::after {
  /* Tooltip handled via title attribute; this reserves space */
  content: none;
}

.tier-item__icon {
  flex-shrink: 0;
  width: 1.25rem;
  text-align: center;
  font-size: 0.875rem;
  line-height: 1;
}

.tier-item__name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ============================================================
   WORKSPACE
   ============================================================ */

.workshop-workspace {
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-lg);
  gap: var(--space-lg);
}

/* ============================================================
   IMAGE VIEWPORT
   ============================================================ */

.workshop-viewport {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  min-height: 400px;
  overflow: hidden;
  box-shadow: inset 0 2px 12px rgba(0, 0, 0, 0.4);
}

.workshop-viewport__canvas-wrap {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
}

.workshop-viewport canvas {
  display: block;
  max-width: 100%;
  max-height: 70vh;
  object-fit: contain;
}

/* Placeholder when no image loaded */
.workshop-viewport__placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  padding: var(--space-3xl);
  color: var(--color-text-tertiary);
  text-align: center;
}

.workshop-viewport__placeholder-icon {
  font-size: 3rem;
  opacity: 0.4;
}

.workshop-viewport__placeholder-text {
  font-family: var(--font-ui);
  font-size: 0.9375rem;
}

.workshop-viewport__placeholder-hint {
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  color: var(--color-text-disabled, #666);
}

/* ============================================================
   SPLIT-VIEW DIVIDER
   ============================================================ */

.split-divider {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 3px;
  background-color: var(--color-accent-primary);
  cursor: col-resize;
  z-index: 10;
  touch-action: none;
}

.split-divider::before {
  /* Wider invisible hit target */
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: -8px;
  right: -8px;
}

.split-divider__handle {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 12px;
  height: 40px;
  background-color: var(--color-accent-primary);
  border-radius: 6px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.5);
  transition: background-color var(--transition-fast);
}

.split-divider:hover .split-divider__handle,
.split-divider--dragging .split-divider__handle {
  background-color: var(--color-text-primary);
}

/* Grip dots inside handle */
.split-divider__handle::before,
.split-divider__handle::after {
  content: "";
  position: absolute;
  left: 50%;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: var(--color-background);
  transform: translateX(-50%);
}

.split-divider__handle::before {
  top: 12px;
}

.split-divider__handle::after {
  bottom: 12px;
}

/* Preview canvas (right side of split) */
.workshop-viewport__preview {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
  pointer-events: none;
}

.workshop-viewport__preview canvas {
  position: absolute;
  top: 0;
  right: 0;
}

/* ============================================================
   TECHNIQUE PANEL
   ============================================================ */

.technique-panel {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: 12px;
  overflow: hidden;
}

/* Technique header */
.technique-panel__header {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--color-border-subtle);
}

.technique-panel__icon {
  flex-shrink: 0;
  width: 2.5rem;
  height: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 1.125rem;
  color: var(--color-accent-primary);
}

.technique-panel__info {
  flex: 1;
  min-width: 0;
}

.technique-panel__name {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0 0 var(--space-xs);
  line-height: 1.3;
}

.technique-panel__desc {
  font-family: var(--font-body);
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  margin: 0;
  line-height: 1.5;
}

.technique-panel__tier-badge {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  padding: var(--space-xs) var(--space-sm);
  background-color: rgba(212, 175, 55, 0.1);
  border: 1px solid rgba(212, 175, 55, 0.25);
  border-radius: 4px;
  font-family: var(--font-display);
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--color-accent-primary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* Controls area */
.technique-panel__controls {
  padding: var(--space-lg) var(--space-xl);
}

.technique-panel__controls:empty {
  display: none;
}

/* Individual control row */
.control-row {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-sm) 0;
}

.control-row + .control-row {
  margin-top: var(--space-sm);
}

.control-row__label {
  flex-shrink: 0;
  min-width: 100px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.control-row__input {
  flex: 1;
  min-width: 0;
}

.control-row__value {
  flex-shrink: 0;
  min-width: 48px;
  text-align: right;
  font-family: var(--font-code);
  font-size: 0.8125rem;
  color: var(--color-accent-primary);
}

/* ============================================================
   RANGE SLIDERS
   ============================================================ */

input[type="range"].workshop-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
  transition: background var(--transition-fast);
}

/* Filled track portion via JS-set CSS variable --fill */
input[type="range"].workshop-slider {
  background: linear-gradient(
    to right,
    var(--color-accent-primary) 0%,
    var(--color-accent-primary) var(--fill, 50%),
    var(--color-border) var(--fill, 50%),
    var(--color-border) 100%
  );
}

/* Thumb: WebKit */
input[type="range"].workshop-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background-color: var(--color-accent-primary);
  border: 2px solid var(--color-background);
  cursor: pointer;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

input[type="range"].workshop-slider::-webkit-slider-thumb:hover {
  transform: scale(1.1);
  box-shadow: 0 0 0 4px rgba(212, 175, 55, 0.2);
}

input[type="range"].workshop-slider:focus::-webkit-slider-thumb {
  box-shadow: 0 0 0 4px rgba(212, 175, 55, 0.35);
}

/* Thumb: Firefox */
input[type="range"].workshop-slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background-color: var(--color-accent-primary);
  border: 2px solid var(--color-background);
  cursor: pointer;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

input[type="range"].workshop-slider::-moz-range-thumb:hover {
  transform: scale(1.1);
  box-shadow: 0 0 0 4px rgba(212, 175, 55, 0.2);
}

input[type="range"].workshop-slider:focus::-moz-range-thumb {
  box-shadow: 0 0 0 4px rgba(212, 175, 55, 0.35);
}

/* Track: Firefox */
input[type="range"].workshop-slider::-moz-range-track {
  height: 4px;
  background: transparent;
  border: none;
  border-radius: 2px;
}

input[type="range"].workshop-slider::-moz-range-progress {
  height: 4px;
  background-color: var(--color-accent-primary);
  border-radius: 2px 0 0 2px;
}

/* ============================================================
   ACTION BUTTONS ROW
   ============================================================ */

.technique-panel__actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  border-top: 1px solid var(--color-border-subtle);
}

/* Primary button (gold) */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-accent-primary);
  color: var(--color-background);
  border: 1px solid var(--color-accent-primary);
  border-radius: 6px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.btn-primary:hover {
  background-color: var(--color-accent-secondary);
  border-color: var(--color-accent-secondary);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

/* Secondary button (outline) */
.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-lg);
  background-color: transparent;
  color: var(--color-accent-primary);
  border: 1px solid var(--color-accent-primary);
  border-radius: 6px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.btn-secondary:hover {
  background-color: rgba(212, 175, 55, 0.1);
  color: var(--color-text-primary);
  border-color: var(--color-accent-primary);
}

.btn-secondary:active {
  background-color: rgba(212, 175, 55, 0.18);
}

/* Ghost / subtle button */
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background-color: transparent;
  color: var(--color-text-tertiary);
  border: 1px solid transparent;
  border-radius: 6px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.btn-ghost:hover {
  background-color: var(--color-surface-elevated);
  color: var(--color-text-primary);
  border-color: var(--color-border);
}

/* Push last action button to the right */
.technique-panel__actions .btn-push-right {
  margin-left: auto;
}

/* ============================================================
   EDUCATIONAL DETAILS (collapsible)
   ============================================================ */

.technique-educational {
  border-top: 1px solid var(--color-border-subtle);
}

.technique-educational summary {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-family: var(--font-body);
  font-size: 0.9375rem;
  font-style: italic;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: color var(--transition-fast), background-color var(--transition-fast);
  list-style: none;
  user-select: none;
}

.technique-educational summary::-webkit-details-marker {
  display: none;
}

.technique-educational summary::before {
  content: "\25B6";
  font-size: 0.5rem;
  font-style: normal;
  color: var(--color-accent-primary);
  transition: transform var(--transition-fast);
}

.technique-educational[open] summary::before {
  transform: rotate(90deg);
}

.technique-educational summary:hover {
  color: var(--color-text-primary);
  background-color: var(--color-surface-elevated);
}

.technique-educational__content {
  padding: var(--space-md) var(--space-xl) var(--space-xl);
  background-color: var(--color-surface-elevated);
}

.technique-educational__text {
  font-family: var(--font-body);
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
  margin: 0 0 var(--space-md);
}

.technique-educational__text:last-child {
  margin-bottom: 0;
}

/* Leonardo connection highlight */
.technique-educational__leonardo {
  margin-top: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border-left: 3px solid var(--color-accent-primary);
  background-color: rgba(212, 175, 55, 0.04);
  border-radius: 0 8px 8px 0;
}

.technique-educational__leonardo-label {
  display: block;
  font-family: var(--font-display);
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--color-accent-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-xs);
}

.technique-educational__leonardo p {
  font-family: var(--font-body);
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
  margin: 0;
}

/* ============================================================
   HELP MODAL
   ============================================================ */

.help-overlay {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal, 110);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl);
  background-color: rgba(0, 0, 0, 0.75);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-medium), visibility var(--transition-medium);
}

.help-overlay--visible {
  opacity: 1;
  visibility: visible;
}

.help-modal {
  position: relative;
  width: 100%;
  max-width: 600px;
  max-height: 80vh;
  overflow-y: auto;
  background-color: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--space-2xl);
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
  transform: translateY(12px);
  transition: transform var(--transition-medium);
}

.help-overlay--visible .help-modal {
  transform: translateY(0);
}

.help-modal::-webkit-scrollbar {
  width: 6px;
}

.help-modal::-webkit-scrollbar-track {
  background: transparent;
}

.help-modal::-webkit-scrollbar-thumb {
  background-color: var(--color-border);
  border-radius: 3px;
}

.help-modal__close {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: none;
  border: 1px solid transparent;
  border-radius: 6px;
  color: var(--color-text-tertiary);
  font-size: 1.25rem;
  line-height: 1;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.help-modal__close:hover {
  color: var(--color-text-primary);
  background-color: var(--color-hover);
  border-color: var(--color-border);
}

.help-modal__title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-accent-primary);
  margin: 0 0 var(--space-lg);
}

.help-modal__section {
  margin-bottom: var(--space-xl);
}

.help-modal__section:last-child {
  margin-bottom: 0;
}

.help-modal__section h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 0 0 var(--space-sm);
}

.help-modal__section p {
  font-family: var(--font-body);
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin: 0 0 var(--space-sm);
}

/* Keyboard shortcuts table */
.shortcuts-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
}

.shortcuts-table th {
  text-align: left;
  padding: var(--space-sm) var(--space-md);
  color: var(--color-text-tertiary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 0.6875rem;
  border-bottom: 1px solid var(--color-border);
}

.shortcuts-table td {
  padding: var(--space-sm) var(--space-md);
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-border-subtle);
}

.shortcuts-table tr:last-child td {
  border-bottom: none;
}

.shortcuts-table kbd {
  display: inline-block;
  padding: 2px 6px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-family: var(--font-code);
  font-size: 0.75rem;
  color: var(--color-text-primary);
  white-space: nowrap;
}

/* ============================================================
   FULLSCREEN MODE
   ============================================================ */

.workshop--fullscreen {
  position: fixed;
  inset: 0;
  z-index: 9999;
}

.workshop--fullscreen .workshop-viewport {
  flex: 1;
  min-height: 0;
  border-radius: 0;
  border: none;
}

/* ============================================================
   LOADING / PROCESSING STATE
   ============================================================ */

.workshop-viewport--processing::after {
  content: "";
  position: absolute;
  inset: 0;
  background-color: rgba(10, 10, 10, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  z-index: 5;
}

.workshop-viewport__spinner {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 6;
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent-primary);
  border-radius: 50%;
  animation: workshop-spin 0.8s linear infinite;
}

@keyframes workshop-spin {
  to {
    transform: translate(-50%, -50%) rotate(360deg);
  }
}

/* ============================================================
   DROPZONE (for drag-and-drop image upload)
   ============================================================ */

.workshop-viewport--dropzone {
  border-color: var(--color-accent-primary);
  border-style: dashed;
  border-width: 2px;
  background-color: rgba(212, 175, 55, 0.04);
}

/* ============================================================
   NOTIFICATION / TOAST
   ============================================================ */

.workshop-toast {
  position: fixed;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%) translateY(120%);
  z-index: var(--z-modal, 110);
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  color: var(--color-text-primary);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
  opacity: 0;
  transition: transform var(--transition-medium), opacity var(--transition-medium);
  pointer-events: none;
  white-space: nowrap;
}

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

.workshop-toast--success {
  border-color: var(--color-accent-primary);
}

.workshop-toast--error {
  border-color: #c0392b;
}

/* ============================================================
   SELECT DROPDOWNS
   ============================================================ */

select.workshop-select {
  appearance: none;
  -webkit-appearance: none;
  padding: var(--space-sm) var(--space-xl) var(--space-sm) var(--space-md);
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M3 5l3 3 3-3' stroke='%23999' stroke-width='1.5' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-sm) center;
  transition: border-color var(--transition-fast);
}

select.workshop-select:hover {
  border-color: var(--color-accent-primary);
}

select.workshop-select:focus {
  border-color: var(--color-accent-primary);
  outline: 2px solid var(--color-accent-primary);
  outline-offset: 2px;
}

/* ============================================================
   CHECKBOX / TOGGLE
   ============================================================ */

.workshop-toggle {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  cursor: pointer;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  user-select: none;
}

.workshop-toggle input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.workshop-toggle__track {
  position: relative;
  width: 36px;
  height: 20px;
  background-color: var(--color-border);
  border-radius: 10px;
  transition: background-color var(--transition-fast);
}

.workshop-toggle input:checked + .workshop-toggle__track {
  background-color: var(--color-accent-primary);
}

.workshop-toggle__track::after {
  content: "";
  position: absolute;
  top: 2px;
  left: 2px;
  width: 16px;
  height: 16px;
  background-color: var(--color-text-primary);
  border-radius: 50%;
  transition: transform var(--transition-fast);
}

.workshop-toggle input:checked + .workshop-toggle__track::after {
  transform: translateX(16px);
}

.workshop-toggle input:focus-visible + .workshop-toggle__track {
  outline: 2px solid var(--color-accent-primary);
  outline-offset: 2px;
}

/* ============================================================
   IMAGE SELECTOR / FILE INPUT
   ============================================================ */

.image-selector {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-xl);
  border-bottom: 1px solid var(--color-border-subtle);
  background-color: var(--color-surface);
}

.image-selector__label {
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-tertiary);
  white-space: nowrap;
}

.image-selector__filename {
  flex: 1;
  font-family: var(--font-code);
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ============================================================
   ZOOM CONTROLS
   ============================================================ */

.zoom-controls {
  position: absolute;
  bottom: var(--space-md);
  right: var(--space-md);
  display: flex;
  align-items: center;
  gap: 2px;
  background-color: rgba(17, 17, 17, 0.9);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 2px;
  z-index: 5;
}

.zoom-controls__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: none;
  border: none;
  border-radius: 4px;
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.zoom-controls__btn:hover {
  background-color: var(--color-surface-elevated);
  color: var(--color-text-primary);
}

.zoom-controls__level {
  min-width: 40px;
  text-align: center;
  font-family: var(--font-code);
  font-size: 0.6875rem;
  color: var(--color-text-tertiary);
}

/* ============================================================
   ACCESSIBILITY
   ============================================================ */

/* Focus outlines for all interactive elements */
.workshop button:focus-visible,
.workshop a:focus-visible,
.workshop select:focus-visible,
.workshop input:focus-visible,
.workshop summary:focus-visible,
.workshop [tabindex]:focus-visible {
  outline: 2px solid var(--color-accent-primary);
  outline-offset: 2px;
}

/* Override the overly aggressive foundation/accessibility focus style for workshop */
.workshop button:focus:not(:focus-visible),
.workshop a:focus:not(:focus-visible) {
  outline: none;
  background-color: unset;
  color: unset;
  text-decoration: unset;
}

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

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  .workshop,
  .workshop *,
  .workshop *::before,
  .workshop *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .help-modal {
    transform: none !important;
  }

  .workshop-toast {
    transition: none !important;
  }
}

/* High contrast mode */
@media (prefers-contrast: high) {
  .workshop {
    --color-background: #000000;
    --color-surface: #000000;
    --color-surface-elevated: #111111;
    --color-border: #ffffff;
    --color-border-subtle: #cccccc;
    --color-text-primary: #ffffff;
    --color-text-secondary: #ffffff;
    --color-text-tertiary: #ffffff;
    --color-accent-primary: #ffff00;
    --color-accent-secondary: #ffff00;
  }

  .tier-item--active {
    border-left-color: #ffff00;
    background-color: rgba(255, 255, 0, 0.15);
  }

  .technique-educational__leonardo {
    border-left-color: #ffff00;
    background-color: rgba(255, 255, 0, 0.1);
  }

  input[type="range"].workshop-slider {
    background: linear-gradient(
      to right,
      #ffff00 0%,
      #ffff00 var(--fill, 50%),
      #ffffff var(--fill, 50%),
      #ffffff 100%
    );
  }

  input[type="range"].workshop-slider::-webkit-slider-thumb {
    background-color: #ffff00;
    border-color: #000000;
  }

  input[type="range"].workshop-slider::-moz-range-thumb {
    background-color: #ffff00;
    border-color: #000000;
  }
}

/* ============================================================
   RESPONSIVE: TABLET (768px - 1024px)
   ============================================================ */

@media (max-width: 1024px) {
  .workshop-body {
    grid-template-columns: 200px 1fr;
  }

  .tier-item {
    font-size: 0.75rem;
    padding-left: var(--space-md);
  }

  .technique-panel__header {
    padding: var(--space-md) var(--space-lg);
  }

  .technique-panel__controls {
    padding: var(--space-md) var(--space-lg);
  }

  .technique-panel__actions {
    padding: var(--space-sm) var(--space-lg);
  }

  .technique-educational summary {
    padding: var(--space-sm) var(--space-lg);
  }

  .technique-educational__content {
    padding: var(--space-sm) var(--space-lg) var(--space-lg);
  }
}

/* ============================================================
   RESPONSIVE: MOBILE (<768px)
   ============================================================ */

@media (max-width: 767px) {
  .workshop-body {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
  }

  /* Sidebar becomes horizontal scrollable tab bar */
  .workshop-sidebar {
    display: flex;
    flex-direction: row;
    overflow-x: auto;
    overflow-y: hidden;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
    padding: 0;
    gap: 0;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .workshop-sidebar::-webkit-scrollbar {
    display: none;
  }

  /* Tier groups become inline */
  .tier-group {
    display: flex;
    flex-shrink: 0;
    align-items: center;
    margin-bottom: 0;
  }

  .tier-header {
    display: none;
  }

  .tier-group--collapsed .tier-list {
    display: flex;
  }

  .tier-list {
    display: flex;
    flex-direction: row;
    flex-shrink: 0;
  }

  .tier-item {
    flex-shrink: 0;
    padding: var(--space-sm) var(--space-md);
    padding-left: var(--space-md);
    border-left: none;
    border-bottom: 3px solid transparent;
    white-space: nowrap;
    font-size: 0.75rem;
  }

  .tier-item--active {
    border-left-color: transparent;
    border-bottom-color: var(--color-accent-primary);
  }

  .tier-item--locked::before {
    position: static;
    transform: none;
    margin-left: var(--space-xs);
  }

  /* Tier separator lines */
  .tier-group + .tier-group::before {
    content: "";
    display: block;
    width: 1px;
    height: 24px;
    background-color: var(--color-border);
    flex-shrink: 0;
    align-self: center;
  }

  /* Workspace takes full width */
  .workshop-workspace {
    padding: var(--space-md);
    gap: var(--space-md);
  }

  .workshop-viewport {
    min-height: 280px;
    border-radius: 8px;
  }

  .workshop-viewport canvas {
    max-height: 50vh;
  }

  /* Technique panel stacks compactly */
  .technique-panel__header {
    padding: var(--space-md);
    flex-wrap: wrap;
  }

  .technique-panel__icon {
    width: 2rem;
    height: 2rem;
    font-size: 1rem;
  }

  .technique-panel__name {
    font-size: 1rem;
  }

  .technique-panel__controls {
    padding: var(--space-md);
  }

  .control-row {
    flex-wrap: wrap;
    gap: var(--space-sm);
  }

  .control-row__label {
    min-width: 80px;
    flex-basis: 100%;
  }

  .control-row__input {
    flex: 1;
  }

  .technique-panel__actions {
    padding: var(--space-sm) var(--space-md);
    flex-wrap: wrap;
  }

  .technique-educational summary {
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
  }

  .technique-educational__content {
    padding: var(--space-sm) var(--space-md) var(--space-md);
  }

  /* Nav compact */
  .workshop-nav {
    padding: var(--space-xs) var(--space-md);
    min-height: 44px;
    gap: var(--space-sm);
  }

  .workshop-nav__title {
    font-size: 1rem;
  }

  .workshop-nav__back span {
    display: none;
  }

  /* Help modal full-width */
  .help-overlay {
    padding: var(--space-md);
  }

  .help-modal {
    max-width: 100%;
    padding: var(--space-lg);
    max-height: 90vh;
  }

  /* Zoom controls */
  .zoom-controls {
    bottom: var(--space-sm);
    right: var(--space-sm);
  }
}

/* ============================================================
   RESPONSIVE: SMALL MOBILE (<480px)
   ============================================================ */

@media (max-width: 480px) {
  .workshop-nav__tools {
    gap: var(--space-xs);
  }

  .workshop-nav__btn {
    padding: var(--space-xs);
    font-size: 0;
  }

  /* Show only icon on tiny screens */
  .workshop-nav__btn .btn-icon {
    font-size: 1rem;
  }

  .technique-panel__actions {
    gap: var(--space-xs);
  }

  .btn-primary,
  .btn-secondary {
    padding: var(--space-xs) var(--space-md);
    font-size: 0.75rem;
  }
}

/* ============================================================
   PRINT
   ============================================================ */

@media print {
  .workshop-nav,
  .workshop-sidebar,
  .technique-panel__actions,
  .zoom-controls,
  .help-overlay,
  .workshop-toast {
    display: none !important;
  }

  .workshop-body {
    display: block;
  }

  .workshop-viewport {
    border: 1px solid #ccc;
    box-shadow: none;
    min-height: auto;
    break-inside: avoid;
  }
}