/* Screen layout */
:root {
  --bg: #f5f5f0;
  --panel-bg: #fff;
  --border: #ddd;
  --text: #222;
  --muted: #666;
  --focus-ring: #2a7;
  --paper: #fff;
  --paper-shadow: rgba(0,0,0,0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

.controls-panel {
  background: var(--panel-bg);
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border);
  max-width: 100%;
}

.panel-header h1 {
  margin: 0 0 1rem;
  font-size: 1.25rem;
  font-weight: 600;
}

.worksheet-form {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  align-items: flex-start;
}

.form-row-numbers {
  display: flex;
  flex-wrap: nowrap;
  gap: 1rem 1.5rem;
  align-items: flex-end;
  flex-basis: 100%;
}

.form-group-operators {
  flex-basis: 100%;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  min-width: 0;
}

.form-group .label {
  font-weight: 500;
  font-size: 0.9rem;
}

.form-group label:not(.checkbox-label) {
  font-weight: 500;
  font-size: 0.9rem;
}

.form-group input[type="text"],
.form-group input[type="number"],
.form-group select {
  padding: 0.4rem 0.6rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  width: 100%;
  max-width: 14rem;
}

.form-group select {
  cursor: pointer;
}

.form-group input:focus {
  outline: none;
  border-color: var(--focus-ring);
  box-shadow: 0 0 0 2px rgba(42, 136, 34, 0.2);
}

.checkbox-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
}

.checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: normal;
  cursor: pointer;
}

.checkbox-label input {
  margin: 0;
}

.radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
}

.radio-label {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: normal;
  cursor: pointer;
}

.radio-label input {
  margin: 0;
}

.label-hint {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  font-weight: normal;
  margin-top: 0.2rem;
}

.form-group.conditional .checkbox-label {
  color: var(--text);
}

.info-icon {
  position: relative;
  font-size: 0.85em;
  font-weight: normal;
  color: var(--muted);
  cursor: help;
  margin-left: 0.2em;
}

.info-icon:hover {
  color: var(--text);
}

.info-icon::after {
  display: none;
}

.tooltip-popup {
  position: fixed;
  padding: 0.35rem 0.6rem;
  font-size: 0.75rem;
  font-weight: normal;
  line-height: 1.3;
  color: #fff;
  background: #333;
  border-radius: 4px;
  white-space: normal;
  width: max-content;
  max-width: min(90vw, 800px);
  box-sizing: border-box;
  text-align: center;
  pointer-events: none;
  z-index: 1000;
  visibility: hidden;
  opacity: 0;
  transition: none;
}

.tooltip-popup.visible {
  visibility: visible;
  opacity: 1;
}

.count-group .info-icon.count-help {
  margin-left: 0.25rem;
}

.form-actions {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  flex-basis: 100%;
}

.form-actions button {
  padding: 0.5rem 1rem;
  font-size: 0.95rem;
  font-weight: 500;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--panel-bg);
  color: var(--text);
  cursor: pointer;
}

.form-actions button:hover {
  background: var(--bg);
}

.form-actions button:focus {
  outline: none;
  border-color: var(--focus-ring);
  box-shadow: 0 0 0 2px rgba(42, 136, 34, 0.2);
}

#newWorksheetBtn {
  background: var(--text);
  color: var(--panel-bg);
  border-color: var(--text);
}

#newWorksheetBtn:hover {
  background: #333;
  border-color: #333;
  color: var(--panel-bg);
}

.validation-message {
  margin-top: 0.75rem;
  font-size: 0.9rem;
  min-height: 1.4em;
}

.validation-message.error {
  color: #c00;
}

.validation-message:empty {
  display: none;
}

.more-settings {
  flex-basis: 100%;
  margin-top: 0.25rem;
}

.more-settings summary {
  cursor: pointer;
  font-weight: 500;
  font-size: 0.9rem;
  list-style: none;
  padding: 0.25rem 0;
}

.more-settings summary::-webkit-details-marker {
  display: none;
}

.more-settings summary::before {
  content: '▶ ';
  font-size: 0.7em;
  opacity: 0.7;
}

.more-settings[open] summary::before {
  content: '▼ ';
}

.more-settings-content {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: 0.75rem;
  padding-left: 0.5rem;
}

.settings-section {
  margin-bottom: 1rem;
}

.settings-section:last-child {
  margin-bottom: 0;
}

.settings-section-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--muted);
  margin: 0 0 0.5rem;
  padding: 0;
}

.settings-section .form-group {
  margin-bottom: 0.5rem;
}

.settings-section .form-group:last-child {
  margin-bottom: 0;
}

.count-group-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 1rem;
}

.count-group-row .count-label {
  font-weight: 500;
  font-size: 0.9rem;
  margin: 0;
}

.count-group-row #count {
  width: 4.5rem;
  max-width: none;
}

.form-group-operands .operands-note {
  display: none;
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 0.25rem;
}

.form-group-operands.operands-restricted .operands-note {
  display: block;
}

.form-group-operands.operands-restricted #operands {
  opacity: 0.8;
}

/* Preview area – looks like the printed page */
.preview-wrapper {
  padding: 1.5rem;
  max-width: 100%;
}

.worksheet-print-area {
  max-width: 21cm;
  margin: 0 auto;
}

.worksheet-paper {
  background: var(--paper);
  box-shadow: 0 2px 12px var(--paper-shadow);
  border-radius: 2px;
  padding: 1.2cm 1.5cm;
  min-height: 25cm;
}

.worksheet-title {
  margin: 0 0 1rem;
  font-size: 1.25rem;
  font-weight: 600;
  text-align: center;
}

.equations-container {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem 2rem;
  margin-bottom: 1.5rem;
}

.layout-vertical .equations-container {
  grid-template-columns: repeat(4, 1fr);
}

.equation-row {
  display: flex;
  align-items: baseline;
  gap: 0.25rem;
  font-size: 1rem;
}

/* Font size variants for worksheet (fill US letter by default) */
/* Small = compact */
.worksheet-paper.font-size-small .worksheet-title { font-size: 1.25rem; }
.worksheet-paper.font-size-small .equation-row { font-size: 1rem; }
.worksheet-paper.font-size-small .equations-container { gap: 0.5rem 1.5rem; }
.worksheet-paper.font-size-small .worksheet-footer { font-size: 0.65rem; }
.worksheet-paper.font-size-small .equation-row .blank { min-width: 2em; }

/* Medium = standard */
.worksheet-paper.font-size-medium .worksheet-title { font-size: 1.5rem; }
.worksheet-paper.font-size-medium .equation-row { font-size: 1.2rem; }
.worksheet-paper.font-size-medium .equations-container { gap: 0.75rem 2rem; }
.worksheet-paper.font-size-medium .worksheet-footer { font-size: 0.7rem; }
.worksheet-paper.font-size-medium .equation-row .blank { min-width: 2.5em; }

/* Large = for 4–6 year olds: big numbers and plenty of space to write the answer */
.worksheet-paper.font-size-large .worksheet-title { font-size: 1.75rem; }
.worksheet-paper.font-size-large .equation-row { font-size: 1.6rem; }
.worksheet-paper.font-size-large .equations-container { gap: 1.25rem 2.5rem; }
.worksheet-paper.font-size-large .worksheet-footer { font-size: 0.8rem; }
.worksheet-paper.font-size-large .equation-row .blank {
  min-width: 4em;
  border-bottom-width: 2px;
}

.equation-row .num,
.equation-row .op,
.equation-row .eq {
  font-variant-numeric: tabular-nums;
}

.equation-row .blank {
  display: inline-block;
  min-width: 2em;
  border-bottom: 1px solid var(--text);
  margin: 0 0.1em;
}

/* Vertical layout: stacked, right-aligned for carrying/borrowing */
.layout-vertical .equation-block {
  display: inline-block;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.layout-vertical .equation-line {
  display: flex;
  align-items: baseline;
  justify-content: flex-end;
  gap: 0.35em;
  min-height: 1.35em;
}

.layout-vertical .equation-line-num .num {
  min-width: 1ch;
}

.layout-vertical .equation-line-op .op-left {
  flex-shrink: 0;
}

.layout-vertical .equation-line-op .num {
  min-width: 1ch;
  text-align: right;
}

.layout-vertical .equation-answer .blank {
  display: inline-block;
  min-width: 2em;
  border-bottom: 1px solid var(--text);
}

.layout-vertical .equation-block .num {
  font-variant-numeric: tabular-nums;
}

/* Vertical font sizes (match horizontal equation-row) */
.worksheet-paper.font-size-small.layout-vertical .equation-block { font-size: 1rem; }
.worksheet-paper.font-size-medium.layout-vertical .equation-block { font-size: 1.2rem; }
.worksheet-paper.font-size-large.layout-vertical .equation-block { font-size: 1.6rem; }
.worksheet-paper.font-size-large.layout-vertical .equation-answer .blank { min-width: 4em; border-bottom-width: 2px; }

.worksheet-footer {
  margin-top: auto;
  padding-top: 1rem;
  font-size: 0.7rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
  line-height: 1.4;
}

/* Print: hide controls, show only worksheet; reserve space so content doesn't overlap footer */
@media print {
  @page {
    margin-bottom: 2.2cm;
  }

  body {
    background: #fff;
  }

  .controls-panel {
    display: none !important;
  }

  .preview-wrapper {
    padding: 0;
    box-shadow: none;
  }

  .worksheet-print-area {
    max-width: none;
    box-shadow: none;
  }

  .worksheet-paper {
    box-shadow: none;
    min-height: auto;
    padding: 0.8cm 1.2cm;
  }

  .worksheet-title {
    page-break-after: avoid;
  }

  .equations-container {
    page-break-inside: auto;
  }

  .equation-row,
  .equation-block {
    page-break-inside: avoid;
  }

  .worksheet-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 0.3cm 1.2cm;
    font-size: 0.65rem;
  }
}