/* Financial Statement Textbook — "Finance Desk" look.
   Deep navy band, white cards on a cool grey ground, monospace numbers,
   square corners, hairline rules. Chosen by the user from three options. */

:root {
  --navy: #10233f;
  --navy-soft: #25405f;
  --ink: #1b2430;
  --muted: #5c7085;
  --line: #d8dee7;
  --line-soft: #e7ebf1;
  --bg: #f1f3f6;
  --card: #ffffff;
  --tint: #f8fafc;
  --gold: #c9a227;
  --gold-ink: #6b5410;
  --good: #1c6b52;
  --bad: #a3312a;
  --radius: 2px;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 0 0 56px;
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.65;
}

/* ---------- header ---------- */

.appbar {
  background: var(--navy);
  color: #fff;
  padding: 16px 18px 14px;
}

.appbar h1 {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.logo { flex: 0 0 auto; color: #fff; }

.tagline {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.55;
  color: #c3d2e4;
  max-width: 46em;
}

.progress-line {
  margin: 11px 0 0;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: #9fb3cc;
}

.progress-bar {
  height: 4px;
  background: var(--navy-soft);
  margin-top: 7px;
  max-width: 640px;
}

.progress-bar i {
  display: block;
  height: 100%;
  width: 0;
  background: var(--gold);
  transition: width 200ms ease;
}

/* ---------- tabs ---------- */

.tabs {
  display: flex;
  background: var(--navy);
  padding: 0 10px;
  gap: 2px;
  overflow-x: auto;
}

.tab {
  min-height: 46px;
  padding: 0 14px;
  background: transparent;
  border: 0;
  border-bottom: 3px solid transparent;
  color: #9fb3cc;
  font: inherit;
  font-size: 15px;
  white-space: nowrap;
  cursor: pointer;
}

.tab[aria-pressed="true"] {
  color: #fff;
  border-bottom-color: var(--gold);
  font-weight: 600;
}

.tab:hover { color: #fff; }

/* ---------- layout ---------- */

main {
  max-width: 680px;
  margin: 0 auto;
  padding: 20px 18px 0;
}

h2 {
  font-size: 24px;
  line-height: 1.25;
  letter-spacing: -0.01em;
  margin: 0 0 10px;
}

h3 {
  font-size: 18px;
  margin: 26px 0 8px;
}

p { margin: 0 0 14px; }

.eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.11em;
  color: var(--muted);
  margin: 0 0 5px;
}

.lead { color: #3d4a5a; }

.empty {
  background: var(--card);
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  color: var(--muted);
  font-size: 15px;
}

.disclaimer {
  margin-top: 26px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- buttons ---------- */

.btn {
  min-height: 46px;
  padding: 11px 20px;
  font: inherit;
  font-size: 15px;
  border-radius: var(--radius);
  cursor: pointer;
}

.btn.primary {
  background: var(--navy);
  color: #fff;
  border: 1px solid var(--navy);
  font-weight: 600;
  letter-spacing: 0.03em;
}

.btn.primary:hover { background: #1a3358; }

.btn.primary:disabled {
  background: #b9c3d0;
  border-color: #b9c3d0;
  cursor: not-allowed;
}

.btn.ghost {
  background: var(--card);
  border: 1px solid #c3ccd8;
  color: var(--ink);
}

.btn.ghost:hover { background: var(--tint); }

.btn.ghost:disabled { color: #a4afbd; cursor: not-allowed; }

.btn.link {
  display: block;
  width: 100%;
  margin: 14px 0 0;
  background: none;
  border: 0;
  color: var(--muted);
  text-decoration: underline;
}

.btn.wide { display: block; width: 100%; margin-top: 16px; }

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

/* ---------- chapter list ---------- */

.chapter-list {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--card);
}

.chapter-list li + li { border-top: 1px solid var(--line-soft); }

.chapter-row {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  min-height: 62px;
  padding: 12px 14px;
  background: none;
  border: 0;
  font: inherit;
  text-align: left;
  color: inherit;
  cursor: pointer;
}

.chapter-row:hover { background: var(--tint); }

.chapter-no {
  flex: 0 0 auto;
  width: 30px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--muted);
}

.chapter-main { flex: 1 1 auto; min-width: 0; }

.chapter-name { display: block; font-size: 16px; font-weight: 600; }

.chapter-sub {
  display: block;
  font-size: 13.5px;
  color: var(--muted);
  line-height: 1.45;
}

.chapter-mark {
  flex: 0 0 auto;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--good);
}

.chapter-mark.todo { color: #a4afbd; }

/* ---------- chapter body ---------- */

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  margin: 0 0 16px;
}

.card-cap {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 12px;
}

.note {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 4px solid var(--gold);
  border-radius: var(--radius);
  padding: 12px 15px;
  margin: 0 0 16px;
  font-size: 15.5px;
}

.bullets { margin: 0 0 16px; padding-left: 20px; }
.bullets li { margin-bottom: 7px; }

/* figure tables */

.figures { width: 100%; border-collapse: collapse; font-size: 15px; }

.figures th,
.figures td {
  padding: 8px 0;
  border-bottom: 1px solid var(--line-soft);
  text-align: left;
  font-weight: 400;
}

.figures td.num {
  text-align: right;
  font-family: var(--mono);
  font-size: 14.5px;
  white-space: nowrap;
}

.figures tr.total th,
.figures tr.total td {
  border-top: 2px solid var(--ink);
  border-bottom: 0;
  font-weight: 700;
}

.figures tr.indent th { padding-left: 14px; color: var(--muted); }

/* balance-sheet blocks */

.dia { display: flex; gap: 12px; align-items: flex-start; }
.dia .side { flex: 1; }
.dia .stack { display: flex; flex-direction: column; gap: 3px; }

.blk {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 8px 10px;
  color: #fff;
}

.blk b { font-size: 12px; letter-spacing: 0.05em; font-weight: 700; }
.blk span { font-family: var(--mono); font-size: 15px; font-weight: 700; }

.blk.assets { background: var(--navy); }
.blk.liab { background: var(--muted); }
.blk.equity { background: var(--gold); color: #2a2000; }

/* proportional bars (income statement) */

.bars { margin: 0; }

.bar-row { margin-bottom: 12px; }

.bar-row:last-child { margin-bottom: 0; }

.bar-head {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-size: 14px;
  margin-bottom: 4px;
}

.bar-head b { font-weight: 600; }
.bar-head span { font-family: var(--mono); white-space: nowrap; }

.bar-track { height: 20px; background: var(--line-soft); }
.bar-track i { display: block; height: 100%; background: var(--navy); }
.bar-row.accent .bar-track i { background: var(--gold); }

/* cash flow: bars either side of a zero line */

.cf-row { margin-bottom: 12px; }

.cf-head {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-size: 14px;
  margin-bottom: 4px;
}

.cf-head span { font-family: var(--mono); white-space: nowrap; }
.cf-head span.plus { color: var(--good); }
.cf-head span.minus { color: var(--bad); }

.cf-track {
  position: relative;
  height: 20px;
  background: var(--line-soft);
}

.cf-track::before {
  content: "";
  position: absolute;
  left: 50%;
  top: -3px;
  bottom: -3px;
  width: 1px;
  background: var(--muted);
}

.cf-track i {
  position: absolute;
  top: 0;
  height: 100%;
}

.cf-track i.plus { left: 50%; background: var(--good); }
.cf-track i.minus { right: 50%; background: #9aa8b8; }

/* three-question cards */

.qcards { display: grid; gap: 10px; }

.qcard {
  border: 1px solid var(--line);
  border-left: 4px solid var(--navy);
  border-radius: var(--radius);
  padding: 11px 13px;
  background: var(--tint);
}

.qcard b {
  display: block;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 3px;
}

.qcard span { font-size: 16px; font-weight: 600; }

/* ratio formulas */

.formula { margin: 0 0 12px; }

.formula:last-child { margin-bottom: 0; }

.formula b { display: block; font-size: 15.5px; }

.formula code {
  display: block;
  font-family: var(--mono);
  font-size: 14px;
  color: var(--muted);
  margin: 3px 0 3px;
  word-break: break-word;
}

.formula .val {
  font-family: var(--mono);
  font-size: 19px;
  font-weight: 700;
  color: var(--navy);
}

.formula em { font-style: normal; font-size: 14.5px; color: #3d4a5a; }

.formula + .formula { border-top: 1px solid var(--line-soft); padding-top: 12px; }

/* ---------- quiz ---------- */

.quiz {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  margin: 22px 0 0;
}

.quiz h3 { margin: 0 0 2px; font-size: 18px; }

.quiz-count {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0 0 10px;
}

.quiz-question { font-size: 16.5px; font-weight: 600; margin: 0 0 12px; }

.opt {
  display: block;
  width: 100%;
  min-height: 46px;
  text-align: left;
  background: var(--tint);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 11px 13px;
  margin: 0 0 8px;
  font: inherit;
  font-size: 16px;
  color: inherit;
  cursor: pointer;
}

.opt:hover:not(:disabled) { background: #eef2f7; }

.opt[aria-pressed="true"] {
  border-color: var(--navy);
  background: #eaeff5;
  box-shadow: inset 3px 0 0 var(--navy);
}

.opt.correct {
  border-color: var(--good);
  background: #e8f3ef;
  box-shadow: inset 3px 0 0 var(--good);
}

.opt.wrong {
  border-color: var(--bad);
  background: #f8ecea;
  box-shadow: inset 3px 0 0 var(--bad);
}

.opt:disabled { cursor: default; opacity: 1; }

.quiz-feedback {
  border-left: 4px solid var(--line);
  padding: 2px 0 2px 12px;
  margin: 4px 0 14px;
  font-size: 15px;
}

.quiz-feedback.ok { border-left-color: var(--good); }
.quiz-feedback.no { border-left-color: var(--bad); }

.quiz-feedback b { display: block; }

.quiz-result {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--mono);
  font-size: 14px;
  color: var(--muted);
}

/* ---------- chapter nav ---------- */

.chapter-nav { display: flex; gap: 8px; margin-top: 18px; }
.chapter-nav .btn { flex: 1; }

/* ---------- glossary ---------- */

.field-label {
  display: block;
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 5px;
}

#glossarySearch {
  width: 100%;
  min-height: 46px;
  padding: 10px 12px;
  font: inherit;
  font-size: 16px;
  color: var(--ink);
  background: var(--card);
  border: 1px solid #c3ccd8;
  border-radius: var(--radius);
  margin-bottom: 16px;
}

.glossary {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--card);
}

.glossary div { padding: 13px 15px; }
.glossary div + div { border-top: 1px solid var(--line-soft); }
.glossary dt { font-weight: 700; font-size: 16px; }
.glossary dd { margin: 3px 0 0; font-size: 15px; color: #3d4a5a; }

/* ---------- help ---------- */

.help-list { margin: 0 0 8px; padding-left: 20px; }
.help-list li { margin-bottom: 8px; }

/* ---------- toast ---------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: 18px;
  transform: translateX(-50%);
  max-width: 92vw;
  margin: 0;
  padding: 11px 16px;
  background: var(--navy);
  color: #fff;
  border-radius: var(--radius);
  font-size: 15px;
  box-shadow: 0 6px 18px rgba(16, 35, 63, 0.28);
  z-index: 10;
}

/* ---------- wider screens ---------- */

@media (min-width: 700px) {
  .appbar { padding: 20px 24px 16px; }
  .appbar h1 { font-size: 19px; }
  main { padding-top: 26px; }
  h2 { font-size: 27px; }
  .qcards { grid-template-columns: repeat(3, 1fr); }
}