/* Universal Scope - version one.
   A math workbook page: cool recycled-paper sheet, graphite print, a faint red margin rule,
   pale blue quad-ruled work slots, and the student's answers in ballpoint blue.
   Looks: soft (default), dark, high contrast. Every look meets WCAG 2.1 AA contrast. */

:root {
  --size: 18px;
  --desk: #d9dfda;
  --paper: #f3f5f1;
  --ink: #2f3437;
  --soft-ink: #555d61;
  --rule: rgba(52, 104, 160, 0.16);
  --rule-strong: rgba(52, 104, 160, 0.34);
  --margin: #d49b9b;
  --pen: #1f4fa3;
  --control: #ffffff;
  --focus: #1f4fa3;
  --problem: #0f5e5a;   /* the problem itself: its own calm color (Chris 2026-10-03) */
  font-size: var(--size);
}
html[data-look="dark"] {
  --desk: #14181b;
  --paper: #22282c;
  --ink: #e4e8ea;
  --soft-ink: #b4bcc0;
  --rule: rgba(150, 180, 220, 0.14);
  --rule-strong: rgba(150, 180, 220, 0.34);
  --margin: #7c4f4f;
  --pen: #a6c1ff;
  --control: #2c3337;
  --focus: #a6c1ff;
  --problem: #8fe0d2;
}
html[data-look="contrast"] {
  --desk: #000000;
  --paper: #000000;
  --ink: #ffffff;
  --soft-ink: #ffffff;
  --rule: rgba(255, 255, 255, 0.28);
  --rule-strong: #ffffff;
  --margin: #ffffff;
  --pen: #ffe14d;
  --control: #000000;
  --focus: #ffe14d;
  --problem: #7ff0e0;
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--desk);
  color: var(--ink);
  font-family: "Atkinson Hyperlegible", "Segoe UI", system-ui, -apple-system, sans-serif;
  line-height: 1.5;
}

.skip {
  position: absolute; left: -999px; top: 0.5rem;
  background: var(--paper); color: var(--ink); padding: 0.4rem 0.8rem; z-index: 5;
}
.skip:focus { left: 0.5rem; }

:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }

/* ------------------------------------------------ top bar */
.bar {
  position: sticky; top: 0; z-index: 3;
  display: flex; flex-wrap: wrap; align-items: end; gap: 0.6rem 1rem;
  padding: 0.6rem 1rem;
  background: var(--desk);
  border-bottom: 1px solid var(--rule-strong);
}
.mark { font-weight: 700; font-size: 1.05rem; align-self: center; margin-right: 0.5rem; }
.field { display: flex; flex-direction: column; font-size: 0.72rem; color: var(--soft-ink); gap: 0.15rem; }
.field.grow { flex: 1 1 16rem; }
select, button {
  font: inherit; font-size: 0.9rem; color: var(--ink);
  background: var(--control);
  border: 1px solid var(--rule-strong); border-radius: 6px;
  padding: 0.35rem 0.6rem; min-height: 2.25rem;
}
button { cursor: pointer; }
.tools { display: flex; align-items: end; gap: 0.4rem; }
.license { align-self: center; font-size: 0.78rem; color: var(--soft-ink); }

/* ------------------------------------------------ the sheet */
.sheet {
  width: min(46rem, calc(100% - 1.5rem));
  margin: 1.25rem auto 3rem;
  background: var(--paper);
  border-radius: 3px;
  box-shadow: 0 1px 0 var(--rule-strong), 0 12px 30px -18px rgba(0, 0, 0, 0.45);
  padding: 2.25rem 2rem 1.5rem 3.8rem;
  position: relative;
}
.sheet::before {           /* the margin rule */
  content: ""; position: absolute; top: 0; bottom: 0; left: 3.15rem;
  width: 2px; background: var(--margin);
}
.sheet:focus { outline: none; }

.sheet-head { margin-bottom: 1.5rem; }
.book-name { margin: 0; font-size: 0.85rem; color: var(--soft-ink); }
h1 { margin: 0.1rem 0 0.35rem; font-size: 1.75rem; line-height: 1.2; letter-spacing: -0.01em; }
.directions { margin: 0; font-style: italic; }

/* ------------------------------------------------ problems */
.problems { list-style: none; margin: 0; padding: 0; counter-reset: q; }
.problem { counter-increment: q; padding: 0 0 1.6rem; }
.problem + .problem { border-top: 1px dashed var(--rule-strong); padding-top: 1.1rem; }
.prompt { position: relative; margin: 1rem 0 1.2rem; font-size: 1.9rem; line-height: 1.35; color: var(--problem); font-weight: 600; margin-left: 0.8rem; padding: 0.35rem 1.1rem; display: inline-block; border-radius: 14px; background: color-mix(in srgb, var(--problem) 12%, transparent); }   /* bigger, own color, room around it (Chris 2026-10-03) */
.prompt::before {
  content: counter(q) ".";
  position: absolute; left: -2.55rem; width: 1.8rem; text-align: right;
  font-weight: 700; font-size: 1.15rem; color: var(--ink); top: 0.55rem;   /* number stays its old size */
}

.slot-label { display: block; font-size: 0.75rem; color: var(--soft-ink); margin: 0 0 0.2rem; }

.work {
  display: block; width: 100%; min-height: 7.5rem; resize: none; overflow: hidden;
  font: inherit; font-size: 1.05rem; line-height: 1.5rem; color: var(--ink);
  padding: 0 0.4rem;
  border: 1px solid var(--rule-strong); border-radius: 2px;
  background-color: transparent;
  background-image:
    linear-gradient(var(--rule) 1px, transparent 1px),
    linear-gradient(90deg, var(--rule) 1px, transparent 1px);
  background-size: 1.5rem 1.5rem;
  background-position: -1px -1px;
}

.answer-row { display: flex; align-items: baseline; gap: 0.6rem; margin-top: 0.7rem; }
.answer-row .slot-label { margin: 0; font-size: 0.9rem; color: var(--ink); font-weight: 700; }
.answer {
  flex: 1; font: inherit; font-size: 1.2rem; color: var(--pen);
  background: transparent; border: 0; border-bottom: 2px solid var(--ink);
  padding: 0.1rem 0.3rem; min-height: 2.2rem; max-width: 32rem;
}
.work { color: var(--pen); }

/* ------------------------------------------------ page turn */
.turn {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 0.5rem; padding-top: 1rem; border-top: 1px solid var(--rule-strong);
  font-size: 0.9rem; color: var(--soft-ink);
}
.turn button[disabled] { opacity: 0.45; cursor: default; }

.saved { position: fixed; bottom: 0.6rem; right: 0.9rem; margin: 0; font-size: 0.78rem; color: var(--soft-ink); }

.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;
}

@media (max-width: 560px) {
  .sheet { padding: 1.5rem 1rem 1rem 2.9rem; }
  .sheet::before { left: 2.35rem; }
  .prompt::before { left: -2.3rem; width: 1.6rem; }
  .mark { width: 100%; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }
@media print {
  .bar, .turn, .saved, .skip { display: none; }
  body { background: #fff; }
  .sheet { box-shadow: none; margin: 0; width: 100%; }
}

/* entries: more space between characters so each symbol and digit is easy to read */
.work, .answer { letter-spacing: 0.42em; word-spacing: 0.3em; }   /* Chris 2026-09-29: wider gaps between digits and symbols - like  A  B, not AB */
.read-line { letter-spacing: 0.18em; }

/* answer clue: faint, friendly, readable in every look */
.answer::placeholder { color: var(--soft-ink); opacity: 0.6; font-style: italic; }
html[data-look="contrast"] .answer::placeholder { opacity: 0.85; }

/* what to do, above every problem (Chris 2026-10-05) */
.prob-dir { margin: 0 0 .3rem; font-style: italic; opacity: .85; }

/* what the student tried, kept in view after a wrong answer (Chris 2026-10-05) */
.tried { margin: .3rem 0 0; opacity: .8; }

/* factoring clues (Chris 2026-10-05) */
.factor-clues { margin: .4rem 0 .6rem; }
.factor-clues .clue { margin: .2rem 0; }
.factor-clues .sign-tip { opacity: .85; }
.factor-pairs-btn { margin-top: .3rem; }
.factor-pairs { margin-top: .4rem; border-collapse: collapse; }
.factor-pairs th, .factor-pairs td { padding: .25rem .8rem; border-bottom: 1px solid currentColor; text-align: left; }
.factor-pairs td.hit { font-weight: 700; }
.problem > .clue { margin: .3rem 0 .5rem; opacity: .9; }

/* ALL THE STEPS, notebook look (Chris 2026-10-08). Uses the page's own colors, so it matches every Look. */
.nb-card{margin:1.2rem 0;padding:1.4rem 1.2rem;border-radius:14px;background-color:var(--paper);color:var(--ink);border:1px solid var(--rule-strong);
  font-family:"Apple Chancery","Cormorant Garamond",serif;font-size:2rem;line-height:1.5;overflow-x:auto;
  background-image:linear-gradient(var(--rule) 1px,transparent 1px),linear-gradient(90deg,var(--rule) 1px,transparent 1px);background-size:28px 28px}
.nb-title{margin:0 0 .6rem;font-weight:700;font-size:1.5rem}
.nb-grid{display:grid;grid-template-columns:auto auto auto 1fr;column-gap:.8rem;row-gap:.1rem;align-items:center}
.nb-l{text-align:right}.nb-e{text-align:center}.nb-r{text-align:left}
.nb-op{color:var(--pen);font-size:1.5rem}
.nb-why{padding-left:1.4rem;font-size:1.15rem;color:var(--soft-ink)}
.nb-fin{color:var(--problem);font-weight:700}
.nb-check{margin-top:1rem;padding-top:.6rem;border-top:2px dashed var(--rule-strong);font-size:1.4rem}
.nb-chk-head{font-weight:700}
.nb-ok{margin:.3rem 0 0;color:var(--problem);font-weight:700}
@media (max-width:640px){.nb-card{font-size:1.5rem}.nb-grid{grid-template-columns:auto auto auto}.nb-why{grid-column:1/-1;text-align:center;padding:0;font-size:1rem}}

/* PROBLEMS IN THE ITALIC LOOK (Chris 2026-10-08): the problem and the student's answer, like "All the steps". */
.prompt{font-family:"Apple Chancery","Cormorant Garamond",serif;font-weight:400;font-size:2.3rem;letter-spacing:.02em;background:transparent;padding:.2rem .4rem}
.answer{font-family:"Apple Chancery","Cormorant Garamond",serif;font-size:2rem;line-height:1.4;min-height:3.4rem;min-width:12rem;padding:.2rem .6rem;overflow:visible}
.answer::placeholder{color:var(--pen);opacity:.9;font-style:normal}   /* the ? is easy to see (Chris 2026-10-08) */
.nb-new{animation:nbIn .45s ease-out}   /* the line this step just added */
@keyframes nbIn{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
@media (prefers-reduced-motion:reduce){.nb-new{animation:none}}
/* HIGH CONTRAST = plain, easy-read letters, no fancy italic (Chris 2026-10-08) */
html[data-look="contrast"] .nb-card, html[data-look="contrast"] .prompt, html[data-look="contrast"] .answer{font-family:"Atkinson Hyperlegible",system-ui,sans-serif;font-style:normal;font-weight:700}