/* Interpreter Bench — shared styles (landing + app).
   Light theme by default, dark via prefers-color-scheme. Class names used by app.js
   (card, btn, choice, nav-cell, flashcard, ord-*) are kept stable. */
:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --surface-2: #eef2f7;
  --text: #0f1b2d;
  --muted: #4b5768;
  --border: #e2e8f0;
  --border-strong: #d5dce6;
  --accent: #1d4ed8;
  --accent-hover: #1e40af;
  --accent-ink: #ffffff;
  --accent-soft: #eaf0fb;
  --accent-text: #1e3a8a;
  --good: #047857;
  --good-soft: #ecfdf5;
  --good-border: #a7f3d0;
  --bad: #b91c1c;
  --bad-soft: #fef2f2;
  --bad-border: #fecaca;
  --warn: #b45309;
  --warn-soft: #fff7ed;
  --flag: #b45309;
  --flag-soft: #fff7ed;
  --ink-strong: #0f1b2d;
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 1px 2px rgba(15, 27, 45, .04), 0 4px 14px rgba(15, 27, 45, .05);
  --shadow-lg: 0 20px 50px rgba(15, 27, 45, .08);
  --font-head: "Plus Jakarta Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Source Sans 3", system-ui, -apple-system, "Segoe UI", sans-serif;
}
/* Light is the default. Dark is opt-in via the header toggle (theme.js sets html[data-theme]). */
html[data-theme="dark"] {
    --bg: #0f141b;
    --surface: #171d26;
    --surface-2: #212a36;
    --text: #e8edf4;
    --muted: #9ba8b8;
    --border: #2a3441;
    --border-strong: #394554;
    --accent: #6ea0ff;
    --accent-hover: #88b1ff;
    --accent-ink: #0b1630;
    --accent-soft: #1b2a45;
    --accent-text: #bcd2ff;
    --good: #5ad19a;
    --good-soft: #15302a;
    --good-border: #1f5a45;
    --bad: #f28b8b;
    --bad-soft: #3a1f21;
    --bad-border: #6b2d31;
    --warn: #f0b35c;
    --warn-soft: #3a2a14;
    --flag: #f0b35c;
    --flag-soft: #3a2a14;
    --ink-strong: #0b1220;
    --shadow: none;
    --shadow-lg: none;
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 17px/1.55 var(--font-body);
}
h1, h2, h3 { font-family: var(--font-head); letter-spacing: -0.01em; }
h1 { font-size: 30px; line-height: 1.15; margin: 8px 0 6px; font-weight: 800; }
h2 { font-size: 21px; margin: 28px 0 10px; font-weight: 700; }
h3 { font-size: 17px; margin: 0 0 6px; font-weight: 700; }
a { color: var(--accent); }
a:hover { color: var(--accent-hover); }
.muted { color: var(--muted); }
.small { font-size: 14px; }
.container { max-width: 1120px; margin: 0 auto; padding: 24px 24px 80px; }
.narrow { max-width: 760px; }

/* ---------- app shell ---------- */
.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 24px; flex-wrap: wrap;
  padding: 0 24px; min-height: 64px; background: var(--surface); border-bottom: 1px solid var(--border);
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-family: var(--font-head); font-weight: 800; font-size: 17px; text-decoration: none; color: var(--text); white-space: nowrap; }
.brand:hover { color: var(--text); }
.brand .mark { display: inline-flex; width: 32px; height: 32px; border-radius: 8px; background: var(--accent); align-items: center; justify-content: center; flex: none; }
.tabnav { display: flex; gap: 4px; flex-wrap: wrap; }
.tabnav a { padding: 20px 10px 18px; font-weight: 600; font-size: 15px; text-decoration: none; color: var(--muted); border-bottom: 2px solid transparent; }
.tabnav a:hover { color: var(--text); }
.tabnav a.on { color: var(--text); border-bottom-color: var(--accent); }
.topbar-right { display: flex; align-items: center; gap: 10px; flex-shrink: 0; margin-left: auto; }
.timer { font-family: var(--font-head); font-variant-numeric: tabular-nums; font-weight: 700; padding: 5px 12px; border-radius: 8px; background: var(--surface-2); border: 1px solid var(--border); }
.timer.warn { background: var(--warn-soft); color: var(--warn); }
.timer.danger { background: var(--bad-soft); color: var(--bad); }
.chip { display: inline-flex; align-items: center; gap: 6px; padding: 5px 12px; border-radius: 999px; background: var(--accent-soft); color: var(--accent-text); font-weight: 600; font-size: 14px; text-decoration: none; }
.chip:hover { color: var(--accent-text); filter: brightness(.97); }
.chip.good { background: var(--good-soft); color: var(--good); }
.upsell { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; margin-bottom: 16px; background: var(--accent-soft); border-color: var(--accent-soft); font-size: 15px; }
.upsell .btn { flex: none; }

/* ---------- primitives ---------- */
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px; box-shadow: var(--shadow);
}
.card.flat { box-shadow: none; }
.grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.cols { display: grid; gap: 16px; grid-template-columns: 1.4fr 1fr; align-items: start; }
.stat { font-family: var(--font-head); font-size: 32px; font-weight: 800; line-height: 1.1; }
.stat.big { font-size: 60px; line-height: 1; }
.pill { display: inline-block; padding: 2px 10px; border-radius: 999px; font-size: 13px; font-weight: 700; background: var(--surface-2); color: var(--muted); }
.pill.good { background: var(--good-soft); color: var(--good); }
.pill.bad { background: var(--bad-soft); color: var(--bad); }
.pill.warn { background: var(--warn-soft); color: var(--warn); }
.eyebrow { font-weight: 600; color: var(--accent); font-size: 13px; letter-spacing: .06em; text-transform: uppercase; }
.label { font-size: 13px; font-weight: 600; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; }

table.blueprint { width: 100%; border-collapse: collapse; font-size: 15px; }
table.blueprint th, table.blueprint td { text-align: left; padding: 9px 8px; border-bottom: 1px solid var(--border); }
table.blueprint th { font-size: 13px; color: var(--muted); font-weight: 600; text-transform: uppercase; letter-spacing: .04em; }
table.blueprint td.num, table.blueprint th.num { text-align: right; font-variant-numeric: tabular-nums; }
table.blueprint tr.part td { font-weight: 700; background: var(--surface-2); }

.btn {
  appearance: none; display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  border: 1px solid var(--border-strong); background: var(--surface); color: var(--text);
  font: inherit; font-size: 15px; font-weight: 600; min-height: 44px; padding: 0 18px; border-radius: var(--radius-sm); cursor: pointer; text-decoration: none;
}
.btn:hover { background: var(--surface-2); color: var(--text); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--accent-ink); }
.btn.big { min-height: 50px; font-size: 16px; padding: 0 24px; }
.btn.small { min-height: 36px; font-size: 14px; padding: 0 12px; }
.btn.danger { color: var(--bad); }
.btn.icon { width: 38px; min-height: 38px; padding: 0; color: var(--muted); }
.btn.icon:hover { color: var(--text); }
.btn.flagged { background: var(--flag-soft); color: var(--flag); border-color: var(--flag); }
.btn:disabled { opacity: .45; cursor: default; }
.btn-row { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; align-items: center; }

/* ---------- dashboard ---------- */
.dash-head { display: flex; justify-content: space-between; align-items: flex-end; gap: 12px; flex-wrap: wrap; margin-bottom: 20px; }
.top3 { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 16px; margin-bottom: 16px; }
.ready-bar { position: relative; height: 10px; border-radius: 999px; background: var(--surface-2); overflow: visible; margin-top: 8px; }
.ready-bar > .fill { position: absolute; left: 0; top: 0; height: 100%; border-radius: 999px; background: var(--warn); }
.ready-bar > .fill.good { background: var(--good); }
.ready-bar > .mark { position: absolute; top: -3px; width: 2px; height: 16px; background: var(--text); }
.sec-row { display: grid; grid-template-columns: minmax(140px, 180px) 1fr 52px 54px; gap: 12px; align-items: center; padding: 9px 0; border-top: 1px solid var(--border); font-size: 15px; }
.sec-row .num { text-align: right; font-weight: 600; font-variant-numeric: tabular-nums; }
.plan-item { display: flex; align-items: center; gap: 10px; padding: 9px 0; border-top: 1px solid var(--border); font-size: 15px; }
.plan-item input { width: 18px; height: 18px; margin: 0; accent-color: var(--accent); }
.plan-item.done span { text-decoration: line-through; color: var(--muted); }

/* ---------- forms ---------- */
.opt { display: flex; align-items: center; gap: 12px; padding: 14px 16px; border: 1px solid var(--border-strong); border-radius: 12px; background: var(--surface); cursor: pointer; width: 100%; }
.opt:has(input:checked) { border: 2px solid var(--accent); background: var(--accent-soft); padding: 13px 15px; }
.opt input { width: 18px; height: 18px; margin: 0; accent-color: var(--accent); flex: none; }
.field { display: flex; flex-direction: column; gap: 6px; font-weight: 600; font-size: 15px; }
select, input[type=number], input[type=date], input[type=search], input[type=text], input[type=email] {
  font: inherit; font-size: 16px; padding: 9px 12px; border-radius: var(--radius-sm); border: 1px solid var(--border-strong);
  background: var(--surface); color: var(--text); min-height: 44px;
}
.checks { display: grid; gap: 8px; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.checks label { display: flex; gap: 10px; align-items: center; font-size: 15px; }
.checks input { width: 18px; height: 18px; margin: 0; accent-color: var(--accent); }
.steps { display: flex; align-items: center; gap: 10px; margin-bottom: 18px; }
.steps span { height: 6px; flex: 1; border-radius: 999px; background: var(--surface-2); }
.steps span.on { background: var(--accent); }

/* ---------- question screen ---------- */
.qlayout { display: grid; grid-template-columns: 1fr 300px; gap: 20px; align-items: start; }
.qside { display: flex; flex-direction: column; gap: 16px; }
.qtop { display: flex; align-items: center; gap: 14px; margin-bottom: 16px; }
.qtop .progress { flex: 1; }
.section-banner { display: inline-block; font-size: 14px; color: var(--accent-text); background: var(--accent-soft); padding: 6px 12px; border-radius: 999px; font-weight: 600; }
.section-banner strong { font-weight: 700; }
.qmeta { display: flex; justify-content: space-between; align-items: center; gap: 10px; margin-bottom: 14px; font-size: 14px; color: var(--muted); flex-wrap: wrap; }
.instr { font-size: 14px; color: var(--muted); margin: 0 0 10px; }
.stem { font-family: var(--font-head); font-size: 21px; font-weight: 600; line-height: 1.4; margin: 4px 0 18px; }
.stem.word { font-size: 28px; font-weight: 700; }
.stem u { text-decoration-thickness: 2px; text-underline-offset: 4px; }
.choices { display: grid; gap: 10px; }
.choice {
  display: flex; gap: 14px; align-items: flex-start; text-align: left; width: 100%;
  font: inherit; font-size: 17px; color: var(--text); background: var(--surface); border: 1px solid var(--border-strong);
  border-radius: 12px; padding: 13px 16px; cursor: pointer;
}
.choice:hover:not(:disabled) { border-color: var(--accent); }
.choice .letter {
  flex: 0 0 30px; height: 30px; border-radius: 50%; display: grid; place-items: center;
  font-weight: 700; font-size: 14px; border: 1px solid var(--border-strong); color: var(--muted);
}
.choice.selected { border: 2px solid var(--accent); background: var(--accent-soft); padding: 12px 15px; }
.choice.selected .letter { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.choice.correct { border: 2px solid var(--good); background: var(--good-soft); padding: 12px 15px; }
.choice.correct .letter { background: var(--good); border-color: var(--good); color: #fff; }
.choice.wrong { border: 2px solid var(--bad); background: var(--bad-soft); padding: 12px 15px; }
.choice.wrong .letter { background: var(--bad); border-color: var(--bad); color: #fff; }
.choice:disabled { cursor: default; }
.explain { margin-top: 16px; padding: 14px 16px; border-radius: 12px; background: var(--surface-2); font-size: 15px; line-height: 1.5; }
.explain.ok { background: var(--good-soft); border: 1px solid var(--good-border); }
.explain.no { background: var(--bad-soft); border: 1px solid var(--bad-border); }
.explain .verdict { display: block; font-weight: 700; margin-bottom: 4px; }
.explain.ok .verdict { color: var(--good); }
.explain.no .verdict { color: var(--bad); }

.nav-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 6px; }
.nav-cell {
  font: inherit; font-size: 13px; font-weight: 600; font-variant-numeric: tabular-nums; height: 34px; border-radius: 8px; cursor: pointer;
  border: 1px solid var(--border-strong); background: var(--surface); color: var(--text);
}
.nav-cell.answered { background: var(--accent-soft); border-color: var(--accent); color: var(--accent-text); }
.nav-cell.flag { box-shadow: inset 0 -3px 0 var(--flag); }
.nav-cell.current { outline: 2px solid var(--accent); outline-offset: 1px; }
.nav-cell.correct { background: var(--good-soft); border-color: var(--good-border); color: var(--good); }
.nav-cell.wrong { background: var(--bad-soft); border-color: var(--bad-border); color: var(--bad); }
.nav-part { font-size: 13px; font-weight: 600; color: var(--muted); margin: 12px 0 6px; text-transform: uppercase; letter-spacing: .04em; }
.legend { display: flex; flex-wrap: wrap; gap: 12px; font-size: 13px; color: var(--muted); margin-top: 10px; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; vertical-align: middle; margin-right: 5px; }

.progress { height: 8px; background: var(--surface-2); border-radius: 999px; overflow: hidden; }
.progress > div { height: 100%; background: var(--accent); border-radius: 999px; }
.progress > div.good { background: var(--good); }
.progress > div.bad { background: var(--warn); }
.bar-row { display: grid; grid-template-columns: minmax(120px, 1.4fr) 2fr 64px; gap: 10px; align-items: center; padding: 6px 0; font-size: 15px; }
.bar-row .num { text-align: right; font-variant-numeric: tabular-nums; }

.review-item { padding: 14px 0; border-top: 1px solid var(--border); }
.review-item .stem { font-size: 17px; margin: 4px 0 8px; }
.review-item .ans { font-size: 15px; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; margin: 10px 0; }
.tab { font: inherit; font-size: 14px; font-weight: 600; padding: 6px 14px; border-radius: 999px; border: 1px solid var(--border-strong); background: var(--surface); color: var(--text); cursor: pointer; }
.tab.active { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }

.modal { position: fixed; inset: 0; background: rgba(15, 27, 45, .5); display: grid; place-items: center; padding: 16px; z-index: 50; }
.modal.hidden { display: none; }
.modal .card { max-width: 460px; width: 100%; }
.kbd { font: 12px ui-monospace, monospace; padding: 1px 6px; border: 1px solid var(--border-strong); border-radius: 4px; background: var(--surface-2); }
.hidden { display: none !important; }
.footer { margin-top: 28px; padding-top: 16px; padding-bottom: 32px; border-top: 1px solid var(--border); line-height: 1.5; }

/* ---------- flashcards ---------- */
.flashcard {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 8px;
  width: 100%; min-height: 300px; padding: 32px 24px; text-align: center; cursor: pointer;
  font: inherit; color: var(--text); background: var(--surface);
  border: 1px solid var(--border-strong); border-radius: 16px; box-shadow: var(--shadow);
}
.flashcard:hover { border-color: var(--accent); }
.flashcard.flipped { border: 2px solid var(--accent); }
.fc-label { font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); }
.fc-front, .fc-back { font-size: 19px; max-width: 640px; }
.fc-term { font-family: var(--font-head); font-size: 28px; font-weight: 700; line-height: 1.25; }
.fc-expl { max-width: 640px; line-height: 1.45; }
.fc-divider { width: 60px; height: 2px; background: var(--border); margin: 10px 0; }
.fc-hint { margin-top: 14px; }
.btn.fc-again { color: var(--bad); border-color: var(--bad); }

/* ---------- ordering quiz ---------- */
.ord-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.ord-pool { display: grid; gap: 8px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.ord-item {
  display: flex; gap: 12px; align-items: flex-start; width: 100%; text-align: left;
  padding: 11px 14px; border: 1px solid var(--border-strong); border-radius: 10px;
  background: var(--surface); color: var(--text); font: inherit; cursor: pointer;
}
.ord-item:hover { border-color: var(--accent); }
.ord-item.placed { background: var(--accent-soft); border-color: var(--accent); }
.ord-n {
  flex: none; min-width: 28px; height: 28px; display: inline-flex; align-items: center; justify-content: center;
  border-radius: 999px; background: var(--surface-2); color: var(--muted); font-weight: 700; font-size: 14px;
}
.ord-item.placed .ord-n { background: var(--accent); color: var(--accent-ink); }
.ord-row, .ord-list.plain li { display: flex; gap: 12px; align-items: flex-start; padding: 11px 14px; border: 1px solid var(--border-strong); border-radius: 10px; background: var(--surface); }
.ord-list.plain li { border: 0; border-top: 1px solid var(--border); border-radius: 0; padding: 10px 0; }
.ord-row.ok { border-color: var(--good-border); background: var(--good-soft); }
.ord-row.no { border-color: var(--bad-border); background: var(--bad-soft); }
.ord-row.ok .ord-n { background: var(--good); color: #fff; }
.ord-row.no .ord-n { background: var(--bad); color: #fff; }
.ord-mark { margin-left: auto; font-weight: 700; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .top3, .cols { grid-template-columns: 1fr; }
  .qlayout { grid-template-columns: 1fr; }
  .qside.collapsed { display: none; }
  .tabnav a { padding: 14px 8px 12px; }
}
@media (min-width: 901px) {
  .btn.navtoggle { display: none; }
}
@media (max-width: 560px) {
  body { font-size: 16px; }
  .container { padding: 16px 16px 64px; }
  .stem { font-size: 19px; }
  .stem.word { font-size: 24px; }
  .bar-row { grid-template-columns: 1fr 64px; }
  .bar-row .progress { grid-column: 1 / -1; grid-row: 2; }
  .sec-row { grid-template-columns: 1fr 48px 54px; }
  .sec-row .progress { grid-column: 1 / -1; grid-row: 2; }
  .brand span.txt { display: none; }
  .flashcard { min-height: 240px; }
  .fc-term { font-size: 22px; }
  .stat.big { font-size: 48px; }
}