/* SAT Maths · Topic page shared styles */
@import url("/assets/chrome.css");
:root {
  --brand: #0000ff;
  --brand-dark: #0000cc;
  --brand-deep: #000080;
  --brand-soft: #e0e7ff;
  --brand-soft-2: #f5f7ff;
  --text: #1a1d23;
  --good: #2a8c39;
  --good-bg: #e9f8ec;
  --bad: #c33054;
  --bad-bg: #fde9ee;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(180deg, var(--brand-soft-2) 0%, #ffffff 600px);
  color: var(--text);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  line-height: 1.55;
}
.wrap { max-width: 820px; margin: 0 auto; padding: 22px 22px 80px; }


.hdr { display: flex; align-items: center; gap: 14px; margin-bottom: 6px; flex-wrap: wrap; }
.badge {
  background: var(--brand); color: #fff;
  font-weight: 800; letter-spacing: 1.5px;
  font-size: 11px; padding: 5px 10px; border-radius: 5px;
}
.topic-num {
  color: var(--brand-dark);
  font-size: 11px; font-weight: 800;
  letter-spacing: 1.8px; text-transform: uppercase;
}
h1 {
  font-size: 24px; font-weight: 800; margin: 0;
  color: var(--brand-deep); letter-spacing: -0.3px;
}
.sub { font-size: 14px; color: var(--muted); margin: 4px 0 22px; }

.card {
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: 14px;
  padding: 22px 24px;
  margin-bottom: 18px;
  box-shadow: 0 6px 18px rgba(0, 0, 204, 0.06);
}
.card h2 {
  font-size: 12px; font-weight: 800;
  letter-spacing: 2px; text-transform: uppercase;
  color: var(--brand-dark);
  margin: 0 0 14px;
}
.card h3 { font-size: 16px; font-weight: 700; color: var(--text); margin: 0 0 8px; }
.card p { margin: 0 0 12px; font-size: 14.5px; }
.card p:last-child { margin-bottom: 0; }
.card ul { margin: 0 0 12px; padding-left: 22px; font-size: 14.5px; }
.card li { margin-bottom: 5px; }
.math {
  font-family: 'Cambria Math', 'Times New Roman', serif;
  font-style: italic;
  font-size: 1.05em;
}
code.eq {
  background: var(--brand-soft);
  color: var(--brand-deep);
  font-family: 'Cambria Math', serif;
  font-style: italic;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.96em;
}

/* Worked example */
.ex {
  background: var(--brand-soft-2);
  border-left: 4px solid var(--brand);
  border-radius: 6px;
  padding: 14px 18px;
  margin: 12px 0;
}
.ex-h {
  font-size: 11.5px; font-weight: 800;
  letter-spacing: 1.5px; text-transform: uppercase;
  color: var(--brand-dark);
  margin-bottom: 6px;
}
.ex .step { margin: 4px 0; font-size: 14px; }
.ex .step .lbl {
  display: inline-block;
  min-width: 56px;
  color: var(--brand-dark);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 0.5px;
}
.ex .ans {
  margin-top: 10px;
  padding: 8px 12px;
  background: #fff;
  border-radius: 6px;
  border: 1px solid var(--border);
  font-size: 14px;
}
.ex .ans strong { color: var(--good); }

/* Tool callout */
.tool-cta {
  display: inline-flex; align-items: center; gap: 8px;
  background: linear-gradient(135deg, var(--brand) 0%, var(--brand-dark) 100%);
  color: #fff;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 8px;
  font-size: 13px; font-weight: 700;
  margin-top: 6px;
  margin-right: 8px;
  transition: transform 0.15s, box-shadow 0.15s;
}
.tool-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 18px rgba(0, 0, 255, 0.35);
}

/* Test gate */
.gate { text-align: center; padding: 28px 22px; }
.gate h2 {
  font-size: 14px; font-weight: 800;
  letter-spacing: 2px; text-transform: uppercase;
  color: var(--brand-dark);
  margin: 0 0 6px;
}
.gate p { font-size: 14px; color: var(--muted); margin: 0 0 18px; }
.gate .gate-btn {
  background: var(--brand);
  color: #fff;
  border: none;
  font-size: 15px; font-weight: 800;
  letter-spacing: 0.5px;
  padding: 12px 28px;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.18s;
  box-shadow: 0 6px 16px rgba(0, 0, 255, 0.3);
}
.gate .gate-btn:hover {
  background: var(--brand-dark);
  transform: translateY(-2px);
  box-shadow: 0 10px 22px rgba(0, 0, 204, 0.4);
}

/* Quiz */
.quiz { display: none; }
.quiz.shown { display: block; }
.quiz-head {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 14px;
  flex-wrap: wrap; gap: 10px;
}
.qmeta {
  font-size: 12px; font-weight: 700;
  color: var(--brand-dark);
  letter-spacing: 1.2px; text-transform: uppercase;
}
.qprog { font-size: 12px; color: var(--muted); }
.qprog .pscore { color: var(--brand-deep); font-weight: 800; }
.qprog-bar {
  width: 100%; height: 5px;
  background: var(--brand-soft);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 18px;
}
.qprog-bar > div {
  height: 100%; background: var(--brand);
  transition: width 0.3s;
}
.qstem { font-size: 16px; margin: 0 0 16px; line-height: 1.5; }
.qopts { display: flex; flex-direction: column; gap: 8px; }
.qopt {
  display: flex; align-items: flex-start;
  gap: 12px;
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
  cursor: pointer;
  transition: all 0.15s;
  font-size: 14.5px;
  text-align: left;
  color: var(--text);
  width: 100%;
  font-family: inherit;
}
.qopt:hover { border-color: var(--brand); background: var(--brand-soft-2); }
.qopt.selected { border-color: var(--brand); background: var(--brand-soft); }
.qopt.selected .qmark { background: var(--brand); color: #fff; }
.qopt .qmark {
  background: var(--brand-soft);
  color: var(--brand-dark);
  font-weight: 800;
  font-size: 12.5px;
  width: 26px; height: 26px;
  border-radius: 6px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.qopt.correct { border-color: var(--good); background: var(--good-bg); }
.qopt.correct .qmark { background: var(--good); color: #fff; }
.qopt.wrong { border-color: var(--bad); background: var(--bad-bg); }
.qopt.wrong .qmark { background: var(--bad); color: #fff; }
.qopt:disabled { cursor: default; }
.qopt:disabled:hover { border-color: var(--border); background: #fff; }
.qopt:disabled.correct:hover { border-color: var(--good); background: var(--good-bg); }
.qopt:disabled.wrong:hover { border-color: var(--bad); background: var(--bad-bg); }

.feedback {
  display: none;
  margin-top: 16px;
  padding: 12px 16px;
  border-radius: 10px;
  font-size: 13.5px;
  line-height: 1.55;
}
.feedback.shown { display: block; }
.feedback.ok { background: var(--good-bg); border-left: 4px solid var(--good); color: #1d5e26; }
.feedback.no { background: var(--bad-bg); border-left: 4px solid var(--bad); color: #7a1f3a; }
.feedback strong { display: block; margin-bottom: 4px; }

.action-hint {
  font-size: 13px; color: var(--muted);
  margin-top: 14px; margin-bottom: 4px;
}
.qnav {
  display: flex; gap: 10px; justify-content: flex-end;
  margin-top: 8px;
  flex-wrap: wrap;
}
.nav-btn {
  background: var(--brand);
  color: #fff;
  border: none;
  font-weight: 700; font-size: 13.5px;
  padding: 9px 18px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s;
}
.nav-btn:hover { background: var(--brand-dark); }
.nav-btn:disabled { background: var(--border); color: var(--muted); cursor: not-allowed; }
.nav-btn.ghost { background: #fff; color: var(--brand-dark); border: 1.5px solid var(--border); }
.nav-btn.ghost:hover { background: var(--brand-soft); border-color: var(--brand); }

/* Result */
.result { text-align: center; padding: 22px 18px; }
.result .score-big {
  font-size: 44px; font-weight: 800;
  color: var(--brand-deep);
  margin: 8px 0;
  font-family: 'Inter', sans-serif;
}
.result .score-out { color: var(--muted); font-size: 16px; }
.result .verdict { font-size: 14px; margin: 12px 0 22px; color: var(--text); }
.result .actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }

/* Inline math helpers */
.frac {
  display: inline-flex; flex-direction: column;
  vertical-align: middle; line-height: 1.05;
  text-align: center; padding: 0 3px;
  font-style: italic;
}
.frac > span:first-child { border-bottom: 1.4px solid currentColor; padding: 0 5px 1px; }
.frac > span:last-child { padding: 1px 5px 0; }