/* Shared styles for the times table and division worksheet pages, including
   the stacked problem both pages print, and the fonts and colors the privacy
   page uses too. A page keeps only styles no other page uses inline: the
   one-line problem on the times table page, long division on the division
   page, and the privacy page's reading column.

   Layout: settings column on the left, letter-size paper preview on the right. Stacks on phones. */

/* Fonts are served from this site (fonts/), not a font service, so the pages
   contact no other site (see privacy/). These are the "latin" subsets Google
   Fonts serves: English letters, digits, ×, ÷, and the en dash in titles.
   Other characters fall back to the system fonts in --font-sheet and
   --font-ui. Licenses: fonts/OFL-*.txt. */
@font-face { font-family: "Andika"; font-weight: 400; font-display: swap; src: url("fonts/andika-400.woff2") format("woff2"); }
@font-face { font-family: "Andika"; font-weight: 700; font-display: swap; src: url("fonts/andika-700.woff2") format("woff2"); }
@font-face { font-family: "Atkinson Hyperlegible"; font-weight: 400; font-display: swap; src: url("fonts/atkinson-hyperlegible-400.woff2") format("woff2"); }
@font-face { font-family: "Atkinson Hyperlegible"; font-weight: 700; font-display: swap; src: url("fonts/atkinson-hyperlegible-700.woff2") format("woff2"); }

:root {
  --desk: #e7ecf2;
  --surface: #f6f8fb;
  --text: #17202b;
  --muted: #586473;
  --line: #c9d2dd;
  --field: #ffffff;
  --pencil: #f5c13e;
  --pencil-ink: #2a2206;
  --blue: #2c5ba6;
  --error: #b42318;
  /* Paper stays paper in both themes. */
  --paper: #ffffff;
  --ink: #111111;
  --rule: #9aa3ad;
  --font-sheet: "Andika", "Avenir Next", "Segoe UI", system-ui, sans-serif;
  --font-ui: "Atkinson Hyperlegible", system-ui, -apple-system, "Segoe UI", sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --desk: #0f141b;
    --surface: #161d26;
    --text: #e4e9ef;
    --muted: #98a4b2;
    --line: #2b3542;
    --field: #0f141b;
    --pencil: #f5c13e;
    --pencil-ink: #2a2206;
    --blue: #8eb2ef;
    --error: #ff8f86;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--desk);
  color: var(--text);
  font: 15px/1.45 var(--font-ui);
}

.app {
  display: grid;
  grid-template-columns: minmax(270px, 330px) minmax(0, 1fr);
  min-height: 100vh;
}

/* ---------- Settings panel ---------- */
.panel {
  background: var(--surface);
  border-right: 1px solid var(--line);
  padding: 28px 24px 32px;
  display: flex;
  flex-direction: column;
  gap: 24px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
}
.brand h1 {
  font-family: var(--font-sheet);
  font-weight: 700;
  font-size: 1.6rem;
  line-height: 1.15;
  margin: 0 0 4px;
  text-wrap: balance;
}
.brand p { margin: 0; color: var(--muted); font-size: 0.92rem; }

form { display: flex; flex-direction: column; gap: 20px; }
fieldset { border: 0; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; min-width: 0; }
legend {
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 0;
  margin-bottom: 8px;
}
label { display: flex; flex-direction: column; gap: 4px; font-size: 0.9rem; }
.pair { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

input[type="text"], input[type="number"] {
  font: inherit;
  font-size: 1rem;
  color: var(--text);
  background: var(--field);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 8px 10px;
  width: 100%;
  min-width: 0;
  font-variant-numeric: tabular-nums;
}
input:focus-visible, button:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}
input[aria-invalid="true"] { border-color: var(--error); }
.hint { font-size: 0.82rem; color: var(--muted); }
.err { font-size: 0.82rem; color: var(--error); }

/* Answer key switch: a checkbox drawn as an on/off switch. Colors follow the
   times table page's segmented control: field color when off, text color when on. */
label.switch { flex-direction: row; align-items: center; gap: 10px; cursor: pointer; }
.switch input {
  appearance: none;
  -webkit-appearance: none;
  flex: none;
  position: relative;
  width: 40px;
  height: 24px;
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--field);
  cursor: pointer;
  transition: background-color 0.15s;
}
.switch input::before {
  content: "";
  position: absolute;
  top: 3px;
  left: 3px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--muted);
  transition: transform 0.15s;
}
.switch input:checked { background: var(--text); border-color: var(--text); }
.switch input:checked::before { background: var(--surface); transform: translateX(16px); }

/* Segmented control (radio buttons drawn as one bar), like the Layout choice
   on both pages (two options) and the times table page's "Times-table number
   goes" (three). Every option gets an equal share of the width. */
.seg-caption { font-size: 0.9rem; }
.seg {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}
.seg label { position: relative; display: block; }
.seg input { position: absolute; opacity: 0; inset: 0; margin: 0; cursor: pointer; }
.seg span {
  display: block;
  text-align: center;
  padding: 8px 6px;
  font-size: 0.9rem;
  background: var(--field);
  cursor: pointer;
}
.seg label + label span { border-left: 1px solid var(--line); }
.seg input:checked + span { background: var(--text); color: var(--surface); font-weight: 700; }
.seg input:focus-visible + span { outline: 2px solid var(--blue); outline-offset: 2px; }

.summary {
  font-size: 0.88rem;
  color: var(--muted);
  border-top: 1px solid var(--line);
  padding-top: 16px;
  margin: 0;
}
.summary strong { color: var(--text); font-variant-numeric: tabular-nums; }

.actions { display: flex; flex-direction: column; gap: 10px; }
button {
  font: inherit;
  font-weight: 700;
  font-size: 1rem;
  border-radius: 6px;
  padding: 11px 14px;
  cursor: pointer;
  border: 1px solid transparent;
}
.btn-print { background: var(--pencil); color: var(--pencil-ink); }
.btn-print:hover { filter: brightness(1.05); }
.btn-print:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-shuffle { background: transparent; color: var(--text); border-color: var(--line); }
.btn-shuffle:hover { border-color: var(--muted); }
.print-note { font-size: 0.8rem; color: var(--muted); margin: 0; }
.brand .cross-link { font-size: 0.88rem; margin: 8px 0 0; }
.cross-link a, .panel-footer a { color: var(--blue); }
/* The privacy link, at the very bottom of the panel. margin-top: auto pushes
   it down when the panel is taller than its contents. */
.panel-footer { font-size: 0.82rem; margin: auto 0 0; }

/* ---------- Preview ---------- */
.preview {
  padding: 32px 32px 48px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;
  min-width: 0;
}
.sheet-wrap { width: min(100%, 760px); container-type: inline-size; }
/* While a setting needs fixing, the last good sheet stays up but dimmed, and it
   won't print (see the print rules below), matching the disabled Print button. */
.preview.stale .sheet-wrap { opacity: 0.4; }
.page-label {
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 8px;
}

/* All sheet sizes are in inches so screen and print match. */
.paper {
  --in: calc(100cqw / 8.5);
  width: 100%;
  aspect-ratio: 8.5 / 11;
  background: var(--paper);
  color: var(--ink);
  padding: calc(var(--in) * 0.5);
  display: flex;
  flex-direction: column;
  gap: calc(var(--in) * 0.15);
  font-family: var(--font-sheet);
  box-shadow: 0 1px 2px rgba(15, 25, 40, 0.12), 0 8px 24px rgba(15, 25, 40, 0.10);
  overflow: hidden;
}
.ws-head {
  height: calc(var(--in) * 1.05);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border-bottom: calc(var(--in) * 0.014) solid var(--ink);
  padding-bottom: calc(var(--in) * 0.1);
  flex: none;
}
.ws-fields {
  display: flex;
  gap: calc(var(--in) * 0.35);
  font-size: calc(var(--in) * 12 / 72);
}
.ws-field { display: flex; align-items: flex-end; gap: calc(var(--in) * 0.08); }
.ws-field.name { flex: 1 1 auto; }
.ws-field.date { flex: 0 0 calc(var(--in) * 2.4); }
.ws-field .blank { flex: 1; border-bottom: calc(var(--in) * 0.01) solid var(--ink); height: 1.1em; }
/* Answer key pages put this label where Name and Date go. */
.ws-key-label { align-self: flex-end; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; }
/* The sheet code matches a key to its worksheet: small, at the right end of the line. */
.ws-code {
  align-self: flex-end;
  margin-left: auto;
  font-size: calc(var(--in) * 10 / 72);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
.ws-title {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: calc(var(--in) * 0.2);
}
.ws-title h2 {
  margin: 0;
  font-size: calc(var(--in) * 20 / 72);
  font-weight: 700;
  line-height: 1.1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}
.ws-meta {
  font-size: calc(var(--in) * 10 / 72);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

.ws-grid { display: grid; flex: none; }

/* One stacked problem, on both pages: the top number, then the sign and the
   bottom number over a rule. Built by WorksheetUI.stackedProblem. */
.stacked {
  justify-self: center;
  align-self: start;
  width: 2.8em;
  padding-top: 0.35em;
  line-height: 1.2;
  text-align: right;
  font-variant-numeric: tabular-nums lining-nums;
}
.stacked .n2 {
  display: flex;
  justify-content: space-between;
  border-bottom: 0.08em solid var(--ink);
  padding-bottom: 0.05em;
}
/* The answer spot under the rule: empty on the worksheet, filled on the answer
   key. Rows already leave room for it, so nothing moves. Flex end keeps the
   answer under the ones digits; if a wide fallback font makes 9801 wider than
   the problem, it spills left into the cell's spare room, not into a neighbor. */
.stacked .ans {
  display: flex;
  justify-content: flex-end;
  padding-top: 0.12em;
  font-weight: 700;
}
@media (max-width: 820px) {
  .app { grid-template-columns: minmax(0, 1fr); }
  .panel { position: static; height: auto; border-right: 0; border-bottom: 1px solid var(--line); padding: 24px 16px; }
  .preview { padding: 24px 16px 40px; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }

/* ---------- Print: only the sheets, one per page ----------
   The page margins hold the 0.5 in border that the paper's padding draws on
   screen, and the paper takes only the height it needs: the header, the gap,
   and the grid come to 9.25 in (GRID_H in worksheet-core.js), well inside the
   10 in between the margins. Phones and some browsers ignore @page margins
   and use their own, and iPhone Safari adds a footer, so the spare room keeps
   each sheet on one page there too. A fixed-height paper on a zero-margin
   page did not fit: it overflowed onto a second page. */
@media print {
  @page { size: letter; margin: 0.5in; }
  html, body { background: #fff; }
  .panel, .page-label { display: none !important; }
  .app { display: block; min-height: 0; }
  .preview { display: block; padding: 0; }
  .preview.stale { display: none; }
  .sheet-wrap { width: 7.5in; margin: 0 auto; container-type: normal; }
  .paper {
    --in: 1in;
    width: 7.5in;
    height: auto;
    aspect-ratio: auto;
    padding: 0;
    box-shadow: none;
    break-inside: avoid;
    break-after: page;
  }
  .sheet-wrap:last-child .paper { break-after: auto; }
}