/**
 * Quantrex Academy — Best-in-class Typography
 *
 * UI:        Inter (system-clear, modern)
 * Questions: Source Serif 4 + Literata (long-form exam reading)
 * Math:      STIX Two Math + KaTeX
 * Mono:      system mono for codes
 */

:root {
  --qx-font-display: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --qx-font-ui: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --qx-font-question: "Source Serif 4", "Literata", "STIX Two Text", Georgia, "Times New Roman", serif;
  --qx-font-body: "Inter", system-ui, sans-serif;
  --qx-font-math: "STIX Two Math", "STIX Two Text", "Cambria Math", "Latin Modern Math", "Source Serif 4", serif;
  --qx-font-mono: ui-monospace, "SF Mono", "Cascadia Code", Consolas, monospace;

  --qx-fw-regular: 400;
  --qx-fw-medium: 500;
  --qx-fw-semibold: 600;
  --qx-fw-bold: 700;

  --qx-ls-tight: -0.022em;
  --qx-ls-snug: -0.012em;
  --qx-ls-normal: -0.006em;
  --qx-ls-wide: 0.02em;

  --qx-lh-tight: 1.28;
  --qx-lh-snug: 1.45;
  --qx-lh-body: 1.6;
  --qx-lh-question: 1.78;

  /* NTA CBT: 18px stem; math uses KaTeX fonts via qx-math-system.css */
  --nta-q: 18px;
  --nta-math: 1.22em;
  --qx-fs-q: var(--nta-q, 16px);
  --qx-fs-opt: var(--nta-q, 16px);
  --qx-fs-sol: var(--nta-q, 16px);
  --qx-fs-ui: 0.9375rem;  /* 15px UI */
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1, "ss01" 0;
  font-size: 16px;
}

body,
.main,
.content,
#app-main {
  font-family: var(--qx-font-ui) !important;
  font-weight: var(--qx-fw-regular);
  letter-spacing: var(--qx-ls-normal);
  line-height: var(--qx-lh-body);
  color: var(--text, #0f172a);
  font-size: var(--qx-fs-ui);
}

/* ── UI headings / nav ── */
h1, h2, h3, h4, h5, h6,
.page-head h1,
.logo-text,
.dash-greet-left h1,
.ds strong,
.sec-title,
.cpyqb-exam-bank-head h1,
.cpyqb-marks-head h1,
.qx-all-topics-label,
.qx-subject-hero h1,
.btn-primary,
.btn-soft,
.qx-top-exam,
.nav-item,
.chip,
.tag,
.subj-card strong,
.ch-card strong {
  font-family: var(--qx-font-display) !important;
  font-weight: var(--qx-fw-bold);
  letter-spacing: var(--qx-ls-tight);
  line-height: var(--qx-lh-tight);
}

button,
.btn-primary,
.btn-soft,
.mtk-btn,
.qx-bm-btn,
.qx-diff-chip,
input,
select,
label {
  font-family: var(--qx-font-ui) !important;
  letter-spacing: var(--qx-ls-snug);
}

/* ═══════════════════════════════════════════════════
   QUESTIONS · OPTIONS · SOLUTIONS — best reading fonts
   ═══════════════════════════════════════════════════ */

.mtk-q-text,
.qx-prac-q,
.qx-content.qx-q-text-only,
.qx-question-body,
.qx-q-seg-text,
.q-text,
.q-card .q-text,
.qa-q,
.mtk-main .mtk-q-text,
.allen-practice .mtk-q-text,
.qx-practice-page .qx-prac-q,
.qx-marks-native,
.qx-marks-native-q {
  font-family: var(--qx-font-question) !important;
  font-size: var(--qx-fs-q) !important;
  font-weight: 500 !important;
  line-height: var(--qx-lh-question) !important;
  letter-spacing: 0.01em !important;
  word-spacing: 0.06em !important;
  font-optical-sizing: auto;
  font-variation-settings: "opsz" 18;
  color: inherit !important;
}

.mtk-opt-text,
.qx-prac-opt-text,
.qa-opt,
#qaOpts .qx-content,
#qxOpts .mtk-opt-text,
.mtk-opt .qx-content,
.qx-prac-opt .qx-content,
.qx-letter-opt,
.qx-practice-page .qx-prac-opt-text {
  font-family: var(--qx-font-question) !important;
  font-size: var(--qx-fs-opt) !important;
  font-weight: 500 !important;
  line-height: var(--qx-lh-question) !important;
  letter-spacing: 0.01em !important;
  word-spacing: 0.05em !important;
  font-optical-sizing: auto;
  color: inherit !important;
}

.sol-body,
.qx-sol-body,
.qx-sol-step-body,
.qx-sol-para,
.qx-sol-shortcut-text,
.qx-content.sol-body,
.mtk-sol .qx-content,
.result-box .qx-content {
  font-family: var(--qx-font-question) !important;
  font-size: var(--qx-fs-sol) !important;
  font-weight: 450 !important;
  line-height: 1.82 !important;
  letter-spacing: 0.01em !important;
  word-spacing: 0.05em !important;
  font-optical-sizing: auto;
}

/* Subject-tinted solution badges stay UI font */
.qx-sol-badge,
.qx-sol-shortcut-title,
.qx-sol-step-label {
  font-family: var(--qx-font-ui) !important;
  font-weight: 700 !important;
  letter-spacing: 0.04em !important;
}

/* Paper meta chips — compact UI */
.qx-paper-meta,
.qx-paper-chip,
.tag {
  font-family: var(--qx-font-ui) !important;
  font-size: 0.75rem !important;
  font-weight: 600 !important;
}

/* ── KaTeX + MathJax: size only. Never override .katex * font-family
   (KaTeX_Main / KaTeX_Math / KaTeX_Size1–4 must remain). ── */
.katex {
  font-size: var(--nta-math, 1.22em) !important;
  line-height: 1.35 !important;
  color: inherit !important;
  text-rendering: geometricPrecision;
  -webkit-font-smoothing: antialiased;
}

.MathJax,
.MathJax_Display,
mjx-container {
  font-family: var(--qx-font-math) !important;
}

/* Tables inside questions */
.mtk-q-text table,
.qx-content table,
.sol-body table {
  font-family: var(--qx-font-question) !important;
  font-size: 0.95em !important;
  line-height: 1.55 !important;
}

/* Mobile: slightly larger stems for thumb reading */
@media (max-width: 640px) {
  :root {
    --qx-lh-question: 1.7;
  }
}

/* Desktop large screens: same uniform size, slightly more line height */
@media (min-width: 1100px) {
  :root {
    --qx-fs-q: 1.125rem;
    --qx-fs-opt: 1.125rem;
    --qx-fs-sol: 1.125rem;
  }
}