/* styles/app.css — layout for the M1 single-lesson prototype shell.
   Landscape: side panel + canvas + bottom toolbar (DESIGN.md §4).
   Narrower than 700px viewport width: single-column stack (DESIGN.md §4). */

* {
  box-sizing: border-box;
}

/* The `hidden` attribute must always win over any `display` rule below —
   otherwise a class like `.resume-banner { display: flex }` silently
   re-shows an element whose `hidden` property JS set to true. */
[hidden] {
  display: none !important;
}

html,
body {
  margin: 0;
  height: 100%;
  background: var(--color-bg-workspace);
  color: var(--color-text);
  font-family: var(--font-stack);
  font-size: var(--font-body);
  line-height: var(--line-body);
}

#app {
  display: flex;
  flex-direction: column;
  height: 100dvh;
  min-height: 100%;
}

.app-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-height: 54px;
  padding: var(--space-2) var(--space-5);
  background: var(--color-bg-panel);
  border-bottom: 1px solid var(--color-border);
}

.app-header h1 {
  font-size: 1rem;
  margin: 0;
  flex: 1;
}

.badge {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 2px 10px;
}

.save-status {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  min-width: 8em;
  text-align: right;
}
.save-status[data-state="failed"] {
  color: var(--color-danger);
  font-weight: 600;
}
.save-status[data-state="saved"] {
  color: var(--color-success);
}

.resume-banner {
  background: #eef3ff;
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-2) var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.9rem;
}

.workspace {
  flex: 1;
  display: grid;
  grid-template-columns: minmax(280px, 340px) minmax(0, 1fr);
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  min-height: 0;
}

@media (max-width: 700px) {
  .workspace {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
  }
}

.side-panel {
  background: transparent;
  border: 0;
  border-radius: 0;
  padding: var(--space-2) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  overflow-y: auto;
}

.side-panel h2 {
  font-size: 0.95rem;
  margin: 0;
}

.instructions {
  color: var(--color-text);
}

.step-tabs {
  display: grid;
  gap: var(--space-1);
}

.step-tab {
  min-height: var(--touch-target);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-radius: 10px;
  border: 1px solid transparent;
  background: transparent;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  text-align: left;
}
.step-tab::before {
  content: attr(data-step-number);
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  flex: 0 0 32px;
  border-radius: 50%;
  background: #e7edf5;
  color: var(--color-text);
  font-size: 0.85rem;
}
.step-tab[aria-current="true"] {
  border-color: #2f67d8;
  background: var(--color-accent);
  color: #fff;
}
.step-tab[aria-current="true"]::before {
  background: #fff;
  color: var(--color-accent);
}

.demo-controls {
  display: flex;
  gap: var(--space-2);
}

.reference-preview {
  border: 1px dashed var(--color-border);
  border-radius: 8px;
  background: #fafbfc;
}

.canvas-area {
  position: relative;
  background: var(--color-bg-canvas);
  border: 1px solid var(--color-border);
  border-radius: 14px;
  overflow: hidden;
  min-height: 320px;
}

.canvas-area canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
}

.feedback-banner {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  background: #ffffffee;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: var(--space-2) var(--space-3);
  font-size: 0.9rem;
  display: none;
}
.feedback-banner.visible {
  display: block;
}

.toolbar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  align-self: center;
  width: min(820px, calc(100% - 32px));
  margin: 0 0 var(--space-4);
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-panel);
  border: 1px solid var(--color-border);
  border-radius: 14px;
}

.tool-group {
  display: flex;
  gap: var(--space-2);
}

button {
  font-family: inherit;
  font-size: 0.9rem;
  min-height: var(--touch-target);
  min-width: var(--touch-target);
  border-radius: 8px;
  border: 1px solid var(--color-border);
  background: #fff;
  cursor: pointer;
  padding: 0 var(--space-3);
}
button[aria-pressed="true"] {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}
button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.spacer {
  flex: 1;
}

@media (max-width: 700px) {
  .app-header {
    padding-inline: var(--space-3);
  }

  .badge {
    display: none;
  }

  .workspace {
    padding: var(--space-3);
  }

  .side-panel {
    padding: 0;
  }

  .step-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .step-tab {
    font-size: 0.82rem;
  }

  .toolbar {
    width: calc(100% - 24px);
    margin-bottom: var(--space-3);
  }

  .spacer {
    display: none;
  }
}

.confirm-overlay {
  position: fixed;
  inset: 0;
  background: rgba(20, 24, 32, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
}
.confirm-overlay[hidden] {
  display: none;
}
.confirm-dialog {
  background: #fff;
  border-radius: 12px;
  padding: var(--space-5);
  max-width: 22em;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.confirm-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
}

.backup-section {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.backup-status {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin: 0;
}
.backup-status[data-state="error"] {
  color: var(--color-danger);
  font-weight: 600;
}
.backup-status[data-state="ok"] {
  color: var(--color-success);
}

.confirm-message {
  white-space: pre-line;
}

label.range-label {
  display: flex;
  flex-direction: column;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  gap: 2px;
}