:root {
  --bg: #eeeae0;
  --card: #f7f4ec;
  --ink: #1b1a14;
  --muted: #8a8575;
  --muted-2: #a6a191;
  --accent: #3f5d3a;
  --accent-dark: #2c4327;
  --accent-soft: #e3e6d8;
  --amber: #a9822e;
  --border: #ddd7c6;
  --border-strong: #cfc8b3;
  --dark: #1a1912;
  --dark-2: #242217;
  --bad: #a13c2f;
  --bad-soft: #f3ded9;
  --radius: 10px;
  --serif: "Playfair Display", Georgia, serif;
  --mono: "JetBrains Mono", "SFMono-Regular", Menlo, monospace;
  --sans: "Inter", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  background: var(--bg);
  color: var(--ink);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

header {
  padding: 26px 40px;
  border-bottom: none;
}

.header-inner {
  max-width: 1040px;
  margin: 0 auto;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}

.brand { display: flex; align-items: center; gap: 12px; }

.brand-mark { width: 26px; height: 26px; color: var(--ink); flex-shrink: 0; }

header h1 {
  margin: 0 0 2px;
  font-family: var(--serif);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

header .tag {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.header-progress { text-align: right; min-width: 200px; }

.header-progress-row {
  display: flex;
  align-items: baseline;
  justify-content: flex-end;
  gap: 10px;
  margin-bottom: 8px;
}

.header-progress-label {
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.header-progress-value {
  font-family: var(--serif);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--accent);
}

.header-progress-value .pct-sign { font-size: 15px; margin-left: 1px; }

.header-bar-track { width: 200px; height: 3px; margin-left: auto; }

.site-nav {
  display: flex;
  gap: 18px;
  margin-top: 10px;
  justify-content: flex-end;
}
.site-nav a {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.site-nav a:hover { color: var(--accent-dark); border-color: var(--accent); }
.site-nav a.active { color: var(--accent-dark); border-color: var(--accent); }

.value-strip {
  background: var(--accent-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 20px;
}
.value-strip p { margin: 0; font-size: 13.5px; line-height: 1.6; color: #3a3a2e; max-width: 720px; }
.value-strip a { color: var(--accent-dark); font-weight: 600; }

main {
  max-width: 1040px;
  margin: 0 auto;
  padding: 8px 40px 100px;
}

.hidden { display: none !important; }

.rule { border: none; border-top: 1px solid var(--border); margin: 34px 0; }

.eyebrow {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--amber);
  margin-bottom: 10px;
}

.section-title {
  font-family: var(--serif);
  font-size: 26px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 10px;
}

.section-desc {
  color: #5c5848;
  font-size: 14.5px;
  line-height: 1.6;
  margin: 0 0 22px;
  max-width: 640px;
}

.section-heading-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 20px;
  flex-wrap: wrap;
}

.threshold-caption {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--muted);
  white-space: nowrap;
  margin-bottom: 22px;
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.section-block { animation: fadeInUp 0.4s ease both; }

.setup-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 28px;
}

.field-group { margin-bottom: 18px; }
.field-group:last-of-type { margin-bottom: 0; }

label {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink);
  display: block;
  margin-bottom: 8px;
}

.hint { display: block; margin-top: 7px; font-size: 12px; color: var(--muted); font-family: var(--sans); }
.hint a { color: var(--accent-dark); }

select, input[type="text"], input[type="password"], textarea {
  width: 100%;
  padding: 11px 13px;
  border: 1.5px solid var(--border-strong);
  border-radius: 8px;
  font-size: 14px;
  font-family: var(--sans);
  background: #fff;
  color: var(--ink);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

select:focus, input:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(63, 93, 58, 0.14);
}

select { cursor: pointer; appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20' fill='%238a8575'%3E%3Cpath fill-rule='evenodd' d='M5.23 7.21a.75.75 0 011.06.02L10 11.168l3.71-3.938a.75.75 0 111.08 1.04l-4.25 4.5a.75.75 0 01-1.08 0l-4.25-4.5a.75.75 0 01.02-1.06z' clip-rule='evenodd'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 12px center; background-size: 16px; padding-right: 36px; }

textarea { min-height: 170px; resize: vertical; line-height: 1.55; }

.key-row { display: flex; gap: 10px; }
.key-row input { flex: 1; }

.action-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 6px; }

button {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  font-size: 13.5px;
  padding: 11px 18px;
  font-family: var(--sans);
  transition: transform 0.1s ease, box-shadow 0.15s ease, background 0.15s ease, opacity 0.15s ease, border-color 0.15s ease;
}

button:active:not(:disabled) { transform: translateY(1px); }

.primary-btn { background: var(--accent); color: #fdfcf7; }
.primary-btn:hover:not(:disabled) { background: var(--accent-dark); }
.primary-btn:disabled { opacity: 0.5; cursor: not-allowed; }

.secondary-btn { background: transparent; color: var(--accent-dark); border: 1.5px solid var(--border-strong); }
.secondary-btn:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-soft); }

.ghost-btn { background: transparent; color: var(--muted); border: 1.5px solid var(--border-strong); }
.ghost-btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent-dark); }

.chip-btn {
  background: #fff;
  border: 1.5px solid var(--border-strong);
  color: var(--ink);
  border-radius: 999px;
  padding: 8px 16px;
  font-size: 13px;
}
.chip-btn:hover { border-color: var(--accent); background: var(--accent-soft); }

#statusMsg { min-height: 20px; font-size: 13px; margin-top: 14px; font-weight: 500; }

/* Concept graph */
.concept-graph {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 14px;
}

.concept-card {
  position: relative;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 16px 22px;
  overflow: hidden;
  transition: border-color 0.3s ease;
}

.concept-card-top {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 14px;
}

.concept-name {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 15.5px;
  line-height: 1.3;
}

.concept-code {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted-2);
  flex-shrink: 0;
}

.concept-card-bottom { display: flex; justify-content: space-between; align-items: flex-end; }

.concept-status { display: flex; flex-direction: column; gap: 3px; }

.status-label {
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.status-sub { font-family: var(--mono); font-size: 10.5px; color: var(--muted-2); }

.concept-pct {
  font-family: var(--serif);
  font-size: 26px;
  font-weight: 700;
}

.concept-card-bar {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 3px;
  background: var(--border);
}

.concept-card-bar-fill { height: 100%; transition: width 0.6s cubic-bezier(0.22, 1, 0.36, 1); }

.concept-card.locked { opacity: 0.55; }
.concept-card.locked .status-label { color: var(--muted); }
.concept-card.locked .concept-pct { color: var(--muted); }
.concept-card.locked .concept-card-bar-fill { background: var(--muted-2); }

.concept-card.in-progress .status-label { color: var(--amber); }
.concept-card.in-progress .concept-pct { color: var(--amber); }
.concept-card.in-progress .concept-card-bar-fill { background: var(--amber); }
.concept-card.in-progress.current { border-color: var(--amber); }

.concept-card.mastered { border-color: var(--accent); }
.concept-card.mastered .status-label { color: var(--accent); }
.concept-card.mastered .concept-pct { color: var(--accent); }
.concept-card.mastered .concept-card-bar-fill { background: var(--accent); }

/* Mastery bars */
.bar-row { display: flex; align-items: center; gap: 14px; margin-bottom: 14px; }
.bar-label { width: 220px; font-size: 13.5px; font-weight: 600; flex-shrink: 0; }
.bar-track { position: relative; flex: 1; height: 7px; background: #e6e1d2; border-radius: 5px; overflow: visible; }
.bar-track::after {
  content: "";
  position: absolute;
  left: 90%;
  top: -3px;
  bottom: -3px;
  width: 1px;
  border-left: 1.5px dashed var(--muted-2);
}
.bar-fill { height: 100%; border-radius: 5px; background: var(--accent); transition: width 0.6s cubic-bezier(0.22, 1, 0.36, 1), background 0.3s ease; overflow: hidden; }
.bar-pct { width: 42px; text-align: right; font-family: var(--mono); font-size: 12.5px; font-weight: 600; color: var(--muted); }

#quizPanel h3 {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 10px;
}

.question { font-family: var(--serif); font-size: 19px; font-weight: 700; margin: 4px 0 18px; line-height: 1.4; }

.confidence-toggle { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin: 0 0 16px; }
.confidence-label { font-family: var(--mono); font-size: 11.5px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.05em; }
.confidence-btn {
  background: #fff;
  border: 1.5px solid var(--border-strong);
  color: var(--muted);
  border-radius: 999px;
  padding: 5px 14px;
  font-size: 12.5px;
  font-weight: 600;
  font-family: var(--sans);
}
.confidence-btn:hover:not(:disabled) { border-color: var(--accent); }
.confidence-btn.active { background: var(--accent-soft); border-color: var(--accent); color: var(--accent-dark); }
.confidence-btn:disabled { cursor: default; opacity: 0.6; }
.confidence-echo { font-weight: 400; opacity: 0.75; font-size: 0.92em; }

.choices { display: flex; flex-direction: column; gap: 9px; }
.choice-btn {
  text-align: left;
  background: var(--card);
  border: 1.5px solid var(--border-strong);
  padding: 13px 16px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  color: var(--ink);
  font-family: var(--sans);
}
.choice-btn:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-soft); }
.choice-btn.correct { background: var(--accent-soft); border-color: var(--accent); font-weight: 700; }
.choice-btn.incorrect { background: var(--bad-soft); border-color: var(--bad); font-weight: 700; }
.choice-btn:disabled { cursor: default; }

.feedback { margin-top: 16px; font-size: 14px; font-weight: 600; padding: 12px 14px; border-radius: 8px; background: var(--card); border: 1px solid var(--border); }
.feedback-correct { color: var(--accent-dark); border-color: var(--accent); background: var(--accent-soft); }
.feedback-incorrect { color: var(--bad); border-color: var(--bad); background: var(--bad-soft); }

#recommendation {
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--accent-dark);
  margin-bottom: 16px;
  text-transform: uppercase;
}

/* Course-complete banner */
.completion-banner {
  background: var(--dark);
  border-radius: 14px;
  padding: 30px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  color: #f2efe4;
}

.completion-pill {
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border: 1px solid #4a4838;
  color: #cfcabb;
  padding: 6px 12px;
  border-radius: 999px;
  flex-shrink: 0;
}

.completion-text { flex: 1; min-width: 240px; }
.completion-text h3 { font-family: var(--serif); font-size: 22px; font-weight: 700; margin: 0 0 6px; }
.completion-text p { margin: 0; font-size: 13.5px; color: #b7b2a0; line-height: 1.5; }

.completion-btn {
  background: var(--accent);
  color: #fdfcf7;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  padding: 13px 20px;
  border-radius: 8px;
  white-space: nowrap;
}
.completion-btn:hover { background: #4c6f46; }

.divider { margin: 22px 0; border: none; border-top: 1px solid var(--border); }
.analogy-title { display: block; margin-bottom: 12px; font-size: 14px; font-family: var(--sans); }
.analogy-choices { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; }

#analogyResult {
  font-size: 14px;
  line-height: 1.65;
  background: var(--card);
  border: 1.5px solid var(--border);
  padding: 18px;
  border-radius: 10px;
  white-space: pre-wrap;
}

/* Loading overlay */
.loading-overlay {
  position: fixed;
  inset: 0;
  background: rgba(26, 25, 18, 0.4);
  backdrop-filter: blur(3px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
}

.loading-card {
  background: #fdfcf7;
  border-radius: 12px;
  padding: 24px 30px;
  display: flex;
  align-items: center;
  gap: 14px;
  box-shadow: 0 20px 45px rgba(20, 20, 10, 0.25);
  font-weight: 600;
  font-size: 14px;
  color: var(--ink);
  font-family: var(--sans);
}

.spinner {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 3px solid var(--accent-soft);
  border-top-color: var(--accent);
  animation: spin 0.7s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

footer {
  text-align: center;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  padding: 30px;
}

.footer-highlight { color: var(--amber); font-weight: 600; }

@media (max-width: 640px) {
  header { padding: 20px 20px; }
}

/* Learned-vs-default BKT parameter readout (wired in with bktFit.js) */
.param-readout { margin-top: 14px; padding: 12px 14px; border: 1px solid rgba(0,0,0,0.12); border-radius: 8px; display: flex; flex-direction: column; gap: 4px; font-family: "JetBrains Mono", monospace; font-size: 0.8rem; }
.param-tag { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.65rem; color: #a9822e; font-weight: 600; }
.param-tag-learned { color: #3f5d3a; }
.param-line { font-weight: 600; }
.param-note { opacity: 0.7; font-size: 0.72rem; }

/* Calibration check panel (predicted vs actual, wired in with the calibration log) */
.calibration-panel { margin-top: 12px; padding: 12px 14px; border: 1px solid rgba(0,0,0,0.12); border-radius: 8px; font-family: "JetBrains Mono", monospace; font-size: 0.8rem; }
.calib-tag { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.65rem; color: #3f5d3a; font-weight: 600; margin-bottom: 6px; }
.calib-brier { font-weight: 600; margin-bottom: 6px; }
.calib-row { display: flex; justify-content: space-between; gap: 12px; padding: 2px 0; }
.calib-band { opacity: 0.85; }
.calib-nums { opacity: 0.85; }
.calib-note { opacity: 0.6; font-size: 0.72rem; margin-top: 6px; }
.calib-chart { margin: 8px 0 6px; max-width: 280px; }
.calib-chart svg text { font-family: "JetBrains Mono", monospace; }

/* Misconception diagnosis line (shown under a wrong answer) */
.misconception { margin-top: 12px; padding: 10px 14px; border-left: 3px solid #a9822e; background: rgba(169,130,46,0.08); border-radius: 4px; display: flex; flex-direction: column; gap: 4px; }
.misconception-tag { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.65rem; color: #a9822e; font-weight: 700; font-family: "JetBrains Mono", monospace; }
.misconception-text { font-size: 0.92rem; line-height: 1.45; }

/* Spaced-repetition review panel (wired in with spaced.js) */
.review-panel { margin-top: 12px; padding: 12px 14px; border: 1px solid rgba(0,0,0,0.12); border-radius: 8px; font-family: "JetBrains Mono", monospace; font-size: 0.8rem; }
.review-tag { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.65rem; color: #a9822e; font-weight: 600; margin-bottom: 6px; }
.review-row { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 3px 0; flex-wrap: wrap; }
.review-name { font-weight: 600; }
.review-ret { opacity: 0.8; }
.review-status { opacity: 0.85; }
.review-due { color: #a13c2f; font-weight: 700; }
.review-controls { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }