/* ===== MA Economics Sem I — Study Site Styles ===== */
:root {
  --bg: #fafaf7;
  --bg-elev: #ffffff;
  --bg-soft: #f3f1ea;
  --fg: #1f2328;
  --fg-soft: #4b5563;
  --fg-muted: #6b7280;
  --accent: #b45309;        /* warm earth-ochre */
  --accent-soft: #fde8c8;
  --accent-2: #1d4ed8;      /* indigo */
  --border: #e5e1d6;
  --border-strong: #c9c2b1;
  --good: #166534;
  --warn: #b45309;
  --bad: #b91c1c;
  --code-bg: #f4efe2;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.05);
  --radius: 10px;
  --font-en: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-ne: "Noto Sans Devanagari", "Mangal", "Kalimati", "Preeti", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

body[data-theme="dark"] {
  --bg: #14171c;
  --bg-elev: #1c2129;
  --bg-soft: #232932;
  --fg: #e6e9ee;
  --fg-soft: #c7cdd6;
  --fg-muted: #9aa3af;
  --accent: #f59e0b;
  --accent-soft: #3a2a10;
  --accent-2: #60a5fa;
  --border: #2a313b;
  --border-strong: #3a414c;
  --code-bg: #232932;
  --shadow: 0 1px 2px rgba(0,0,0,0.4), 0 4px 12px rgba(0,0,0,0.3);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-en);
  font-size: 16.5px;
  line-height: 1.65;
  scroll-behavior: smooth;
}

body[data-lang="ne"] {
  font-family: var(--font-ne);
  font-size: 17px;
  line-height: 1.85;
}

body[data-lang="en"] .lang-ne { display: none; }
body[data-lang="ne"] .lang-en { display: none; }

/* When Nepali block is hidden, ensure its math doesn't reserve space */
.lang { display: block; }
span.lang { display: inline; }

/* ===== Topbar ===== */
.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
  padding: 10px 18px;
  display: flex;
  align-items: center;
  gap: 14px;
  box-shadow: var(--shadow);
}
.topbar .brand {
  font-weight: 700;
  font-size: 17px;
  color: var(--fg);
  text-decoration: none;
}
.topbar .brand .dot { color: var(--accent); }
.topbar nav {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  flex: 1;
}
.topbar nav a {
  color: var(--fg-soft);
  text-decoration: none;
  font-size: 14.5px;
  padding: 4px 8px;
  border-radius: 6px;
}
.topbar nav a:hover,
.topbar nav a.active {
  background: var(--bg-soft);
  color: var(--accent);
}
.topbar .controls { display: flex; gap: 8px; }
.btn {
  background: var(--bg-soft);
  color: var(--fg);
  border: 1px solid var(--border);
  padding: 5px 11px;
  border-radius: 7px;
  font: inherit;
  font-size: 13.5px;
  cursor: pointer;
}
.btn:hover { border-color: var(--accent); }
.btn.primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

/* ===== Layout ===== */
.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 28px 22px 80px;
}
.page-title {
  font-size: 28px;
  margin: 6px 0 4px;
  line-height: 1.25;
}
.page-subtitle {
  color: var(--fg-muted);
  margin: 0 0 24px;
  font-size: 15px;
}

.toc {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 28px;
}
.toc h3 {
  margin: 0 0 8px;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
}
.toc ol { margin: 0; padding-left: 22px; }
.toc a { color: var(--accent-2); text-decoration: none; }
.toc a:hover { text-decoration: underline; }

/* ===== Unit blocks ===== */
.unit {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 18px 0;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.unit > summary {
  cursor: pointer;
  list-style: none;
  padding: 16px 20px;
  background: var(--bg-soft);
  font-weight: 600;
  font-size: 17px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  border-bottom: 1px solid var(--border);
}
.unit > summary::-webkit-details-marker { display: none; }
.unit > summary::after {
  content: "▾";
  color: var(--fg-muted);
  font-size: 13px;
}
.unit[open] > summary::after { content: "▴"; }
.unit > .body { padding: 18px 22px 22px; }

.hours {
  font-size: 12px;
  color: var(--fg-muted);
  font-weight: 500;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 2px 8px;
  border-radius: 99px;
}

/* ===== Topic blocks ===== */
.topic {
  border-left: 3px solid var(--accent-soft);
  padding: 4px 0 4px 14px;
  margin: 20px 0;
}
.topic > h4 {
  margin: 0 0 6px;
  font-size: 17px;
  color: var(--accent);
}
.topic > h4 .badge {
  font-size: 11px;
  background: var(--accent-soft);
  color: var(--accent);
  padding: 1px 7px;
  border-radius: 99px;
  margin-left: 8px;
  vertical-align: middle;
}

.note {
  background: var(--bg-soft);
  border-left: 4px solid var(--accent);
  padding: 10px 14px;
  margin: 12px 0;
  border-radius: 4px;
  font-size: 15px;
}
.note.tip { border-left-color: var(--good); }
.note.warn { border-left-color: var(--warn); }
.note.exam { border-left-color: var(--accent-2); }
.note .label {
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-muted);
  font-weight: 700;
  display: block;
  margin-bottom: 2px;
}

/* ===== Math ===== */
.math-block {
  background: var(--code-bg);
  padding: 10px 14px;
  border-radius: 6px;
  margin: 10px 0;
  overflow-x: auto;
  font-size: 15.5px;
}

/* ===== Example & derivation ===== */
.example, .derivation, .definition {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  margin: 14px 0;
}
.example .label, .derivation .label, .definition .label {
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--fg-muted);
  display: block;
  margin-bottom: 4px;
}
.example .label { color: var(--good); }
.derivation .label { color: var(--accent-2); }
.definition .label { color: var(--accent); }

/* ===== References ===== */
.refs {
  font-size: 13.5px;
  color: var(--fg-soft);
  background: var(--bg-soft);
  border-radius: 8px;
  padding: 12px 16px;
  margin: 22px 0 6px;
}
.refs h4 { margin: 0 0 8px; font-size: 13px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--fg-muted); }
.refs ul { margin: 0; padding-left: 20px; }
.refs a { color: var(--accent-2); }

/* ===== Cards (subject hub) ===== */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin: 22px 0;
}
.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  text-decoration: none;
  color: var(--fg);
  transition: transform 0.1s ease, border-color 0.1s ease;
  box-shadow: var(--shadow);
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}
.card .code {
  font-size: 11px;
  color: var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-weight: 700;
}
.card h3 { margin: 6px 0 6px; font-size: 18px; }
.card p { margin: 0; color: var(--fg-muted); font-size: 14px; }

/* ===== Tables ===== */
table.eco {
  border-collapse: collapse;
  margin: 12px 0;
  width: 100%;
  font-size: 14.5px;
}
table.eco th, table.eco td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}
table.eco th { background: var(--bg-soft); font-weight: 600; }
table.eco tr:nth-child(even) td { background: var(--bg-soft); }

/* ===== Interactive widget ===== */
.widget {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin: 16px 0;
}
.widget .controls-row {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 10px;
  font-size: 13.5px;
}
.widget label { display: flex; align-items: center; gap: 6px; }
.widget input[type=range] { width: 140px; }

/* ===== SVG chart helpers ===== */
.chart-svg {
  width: 100%;
  max-width: 520px;
  height: auto;
  display: block;
  margin: 8px auto;
}
.chart-svg .axis { stroke: var(--fg-muted); stroke-width: 1; }
.chart-svg .axis-label { fill: var(--fg-soft); font-size: 11px; font-family: var(--font-en); }
.chart-svg .curve { fill: none; stroke-width: 2.2; }
.chart-svg .c-blue { stroke: #2563eb; }
.chart-svg .c-red { stroke: #dc2626; }
.chart-svg .c-green { stroke: #059669; }
.chart-svg .c-purple { stroke: #7c3aed; }
.chart-svg .c-orange { stroke: #ea580c; }
.chart-svg .grid { stroke: var(--border); stroke-width: 0.5; stroke-dasharray: 2,2; }
.chart-svg text.label { fill: var(--fg-soft); font-size: 11px; font-family: var(--font-en); }

/* ===== Glossary ===== */
.gloss {
  border-bottom: 1px dotted var(--accent);
  cursor: help;
}
.gloss:hover { background: var(--accent-soft); }

/* ===== Quiz ===== */
.quiz {
  background: var(--bg-soft);
  border-radius: 8px;
  padding: 12px 16px;
  margin: 14px 0;
}
.quiz .q { font-weight: 600; margin-bottom: 8px; }
.quiz .opts { display: flex; flex-direction: column; gap: 4px; }
.quiz button.opt {
  text-align: left;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
  font: inherit;
  font-size: 14px;
}
.quiz button.opt:hover { border-color: var(--accent); }
.quiz button.opt.correct { background: #d1fae5; border-color: var(--good); color: #064e3b; }
.quiz button.opt.wrong { background: #fee2e2; border-color: var(--bad); color: #7f1d1d; }
body[data-theme="dark"] .quiz button.opt.correct { background: #064e3b; color: #d1fae5; }
body[data-theme="dark"] .quiz button.opt.wrong { background: #7f1d1d; color: #fee2e2; }
.quiz .explain {
  display: none;
  margin-top: 8px;
  font-size: 13.5px;
  color: var(--fg-soft);
}
.quiz.answered .explain { display: block; }

/* ===== Past-paper question tags ===== */
.pq-tag {
  display: inline-block;
  font-size: 11px;
  padding: 1px 7px;
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 99px;
  margin-right: 5px;
  font-weight: 600;
}

/* ===== Code (for formulas in text) ===== */
code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 0.92em;
}

/* ===== Responsive ===== */
@media (max-width: 700px) {
  .topbar { flex-wrap: wrap; gap: 8px; }
  .topbar nav { order: 3; width: 100%; }
  .page-title { font-size: 22px; }
}

/* ===== Print ===== */
@media print {
  .topbar, .controls, .quiz button { display: none; }
  details.unit { page-break-inside: avoid; }
  details.unit[open] > summary::after { content: ""; }
  details.unit > summary { background: none; }
}

/* Utility */
.row { display: flex; gap: 16px; flex-wrap: wrap; align-items: flex-start; }
.col { flex: 1 1 280px; min-width: 0; }
.tight p { margin: 6px 0; }
.muted { color: var(--fg-muted); font-size: 13.5px; }
.kbd {
  font-family: var(--font-mono);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  padding: 0 5px;
  border-radius: 4px;
  font-size: 12px;
}
hr { border: none; border-top: 1px solid var(--border); margin: 22px 0; }