:root {
  --navy: #1a2744;
  --navy-light: #243460;
  --gold: #c9a84c;
  --gold-light: #e8c97a;
  --cream: #f5f0e8;
  --white: #ffffff;
  --gray: #6b7280;
  --light: #ede8de;
  --green: #16a34a;
  --green-bg: #f0fdf4;
  --green-text: #14532d;
  --red: #dc2626;
  --red-bg: #fef2f2;
  --red-text: #7f1d1d;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: Georgia, 'Times New Roman', serif;
  background: var(--cream);
  color: var(--navy);
  min-height: 100vh;
}

/* ── HEADER ── */
header {
  background: var(--navy);
  color: var(--gold);
  text-align: center;
  padding: 1.25rem 1rem 1rem;
  border-bottom: 2px solid var(--gold);
}
header h1 {
  font-size: 1.5rem;
  letter-spacing: 3px;
  font-weight: normal;
}
header p { font-size: 0.78rem; color: rgba(201,168,76,0.6); margin-top: 0.2rem; letter-spacing: 1px; }

/* ── NAV ── */
nav {
  display: flex;
  background: var(--navy);
}
nav button {
  flex: 1;
  padding: 0.65rem 0.25rem;
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  color: rgba(201,168,76,0.5);
  cursor: pointer;
  font-size: 0.78rem;
  font-family: Georgia, serif;
  letter-spacing: 0.5px;
  transition: color 0.2s, border-color 0.2s;
}
nav button:hover { color: var(--gold-light); }
nav button.active { color: var(--gold); border-bottom-color: var(--gold); }

/* ── MAIN ── */
main {
  max-width: 680px;
  margin: 0 auto;
  padding: 1.75rem 1rem 3rem;
}

.screen { display: none; }
.screen.active { display: block; }

/* ── SHARED COMPONENTS ── */
.btn {
  padding: 0.65rem 1.25rem;
  border: 2px solid var(--navy);
  background: none;
  border-radius: 6px;
  cursor: pointer;
  font-family: Georgia, serif;
  font-size: 0.875rem;
  color: var(--navy);
  transition: background 0.15s, color 0.15s;
}
.btn:hover { background: var(--navy); color: var(--white); }
.btn-primary { background: var(--navy); color: var(--white); }
.btn-primary:hover { background: var(--navy-light); }
.btn-gold { background: var(--gold); color: var(--navy); border-color: var(--gold); }
.btn-gold:hover { background: var(--gold-light); border-color: var(--gold-light); }
.btn-full { width: 100%; }
.btn-sm { padding: 0.4rem 0.8rem; font-size: 0.78rem; }
.btn-green { border-color: var(--green); color: var(--green); }
.btn-green:hover { background: var(--green); color: white; border-color: var(--green); }
.btn-red { border-color: var(--red); color: var(--red); }
.btn-red:hover { background: var(--red); color: white; border-color: var(--red); }

/* ── HOME ── */
.stats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  margin-bottom: 1.75rem;
}
.stat-card {
  background: var(--white);
  border: 1px solid rgba(26,39,68,0.15);
  border-radius: 8px;
  padding: 1rem 0.75rem;
  text-align: center;
}
.stat-value { font-size: 1.9rem; color: var(--navy); line-height: 1; }
.stat-label { font-size: 0.72rem; color: var(--gray); margin-top: 0.3rem; letter-spacing: 0.5px; }

.mode-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.875rem;
}
.mode-card {
  background: var(--white);
  border: 2px solid rgba(26,39,68,0.18);
  border-radius: 10px;
  padding: 1.5rem 1.25rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, transform 0.15s, box-shadow 0.15s;
}
.mode-card:hover {
  border-color: var(--gold);
  background: var(--navy);
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(26,39,68,0.15);
}
.mode-card .mc-icon {
  font-size: 1.75rem;
  display: block;
  margin-bottom: 0.5rem;
  color: var(--gold);
}
.mode-card:hover .mc-icon { color: var(--gold-light); }
.mode-card h3 { font-size: 1rem; font-weight: normal; margin-bottom: 0.35rem; }
.mode-card p { font-size: 0.78rem; color: var(--gray); line-height: 1.4; }
.mode-card:hover p { color: rgba(255,255,255,0.65); }

/* ── FLASHCARDS ── */
.fc-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}
.progress-bar {
  height: 3px;
  background: rgba(26,39,68,0.1);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 0.35rem;
}
.progress-fill {
  height: 100%;
  background: var(--gold);
  transition: width 0.35s ease;
}
.progress-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--gray);
}

.fc-wrap {
  perspective: 1200px;
  height: 310px;
  margin: 1.25rem 0;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.fc {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.45s cubic-bezier(0.4,0,0.2,1);
}
.fc.flipped { transform: rotateY(180deg); }

.fc-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.75rem 2rem;
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
}
.fc-front {
  background: var(--white);
  border: 2px solid rgba(26,39,68,0.12);
}
.fc-back {
  background: var(--navy);
  color: var(--white);
  transform: rotateY(180deg);
  border: 2px solid var(--navy);
}

.fc-num {
  font-size: 3.5rem;
  color: var(--gold);
  line-height: 1;
  margin-bottom: 0.25rem;
}
.fc-cat {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--gray);
  margin-bottom: 0.75rem;
}
.fc-hint {
  font-size: 0.95rem;
  color: var(--navy);
  text-align: center;
  font-style: italic;
  opacity: 0.55;
  line-height: 1.5;
}
.fc-tap {
  position: absolute;
  bottom: 1rem;
  font-size: 0.7rem;
  color: var(--gray);
  letter-spacing: 0.5px;
}
.fc-back-num {
  position: absolute;
  top: 0.9rem;
  left: 1.25rem;
  font-size: 0.7rem;
  color: var(--gold);
  opacity: 0.7;
}
.fc-text {
  font-size: 0.95rem;
  line-height: 1.75;
  text-align: center;
}
.fc-status-badge {
  position: absolute;
  top: 0.9rem;
  right: 1.25rem;
  font-size: 0.65rem;
  padding: 0.2rem 0.5rem;
  border-radius: 10px;
  letter-spacing: 0.5px;
}
.badge-learned { background: rgba(22,163,74,0.2); color: #4ade80; }
.badge-practice { background: rgba(220,38,38,0.2); color: #fca5a5; }

.fc-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.75rem;
}
.fc-actions .btn { flex: 1; }

.fc-nav {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.75rem;
}
.fc-nav .btn { flex: 1; }

.fc-tools {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 1rem;
  justify-content: center;
}

/* ── CATEGORY PICKER ── */
.cat-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 1rem;
}
.cat-card {
  background: var(--white);
  border: 2px solid rgba(26,39,68,0.15);
  border-radius: 8px;
  padding: 1rem;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}
.cat-card:hover { border-color: var(--gold); background: var(--light); }
.cat-name { font-size: 0.875rem; margin-bottom: 0.25rem; }
.cat-count { font-size: 0.72rem; color: var(--gray); }
.cat-progress-bar {
  height: 3px;
  background: rgba(26,39,68,0.1);
  border-radius: 2px;
  margin-top: 0.5rem;
  overflow: hidden;
}
.cat-progress-fill {
  height: 100%;
  background: var(--gold);
}

/* ── QUIZ ── */
.quiz-meta {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
  align-items: center;
}
.quiz-badge {
  background: var(--navy);
  color: var(--gold);
  padding: 0.35rem 0.875rem;
  border-radius: 20px;
  font-size: 0.8rem;
}
.quiz-q-card {
  background: var(--white);
  border: 2px solid rgba(26,39,68,0.12);
  border-radius: 10px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.25rem;
}
.quiz-q-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--gold);
  margin-bottom: 0.6rem;
}
.quiz-q-text { font-size: 0.975rem; line-height: 1.65; }

.quiz-options { display: flex; flex-direction: column; gap: 0.625rem; }
.quiz-opt {
  background: var(--white);
  border: 2px solid rgba(26,39,68,0.18);
  border-radius: 8px;
  padding: 0.875rem 1.1rem;
  cursor: pointer;
  font-family: Georgia, serif;
  font-size: 0.875rem;
  text-align: left;
  line-height: 1.55;
  transition: border-color 0.12s, background 0.12s;
}
.quiz-opt:hover:not(:disabled) { border-color: var(--navy); background: var(--light); }
.quiz-opt.correct { border-color: var(--green); background: var(--green-bg); color: var(--green-text); }
.quiz-opt.wrong   { border-color: var(--red);   background: var(--red-bg);   color: var(--red-text); }
.quiz-opt:disabled { cursor: default; }

.quiz-feedback {
  border-radius: 8px;
  padding: 0.875rem 1.1rem;
  margin-top: 1rem;
  font-size: 0.9rem;
  display: none;
}
.quiz-feedback.ok   { background: var(--green-bg); color: var(--green-text); }
.quiz-feedback.fail { background: var(--red-bg);   color: var(--red-text); }

.quiz-result {
  text-align: center;
  padding: 2rem 0;
  display: none;
}
.result-score {
  font-size: 3.5rem;
  color: var(--gold);
  line-height: 1;
  margin-bottom: 0.5rem;
}
.result-msg { font-size: 0.975rem; color: var(--gray); margin-bottom: 2rem; line-height: 1.5; }
.result-btns { display: flex; gap: 0.875rem; justify-content: center; }

/* ── OVERVIEW ── */
.search-wrap { position: relative; margin-bottom: 1rem; }
.search-input {
  width: 100%;
  padding: 0.7rem 1rem;
  border: 2px solid rgba(26,39,68,0.18);
  border-radius: 8px;
  font-size: 0.875rem;
  font-family: Georgia, serif;
  background: var(--white);
  color: var(--navy);
  transition: border-color 0.15s;
}
.search-input:focus { outline: none; border-color: var(--navy); }
.search-input::placeholder { color: var(--gray); }

.cat-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}
.filter-btn {
  padding: 0.3rem 0.7rem;
  border: 1px solid rgba(26,39,68,0.25);
  background: none;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.75rem;
  font-family: Georgia, serif;
  color: var(--navy);
  transition: background 0.12s, color 0.12s;
  white-space: nowrap;
}
.filter-btn:hover, .filter-btn.active {
  background: var(--navy);
  color: var(--white);
  border-color: var(--navy);
}

.cat-section-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--gray);
  padding-bottom: 0.4rem;
  border-bottom: 1px solid rgba(26,39,68,0.1);
  margin: 1.5rem 0 0.75rem;
}
.cat-section-title:first-child { margin-top: 0; }

.rule-row {
  display: flex;
  gap: 0.875rem;
  align-items: flex-start;
  background: var(--white);
  border-left: 3px solid var(--gold);
  border-radius: 0 8px 8px 0;
  padding: 0.875rem 1rem;
  margin-bottom: 0.5rem;
  transition: border-left-color 0.2s;
}
.rule-row.is-learned  { border-left-color: var(--green); }
.rule-row.is-practice { border-left-color: var(--red); }
.rule-id {
  font-size: 1rem;
  font-weight: bold;
  color: var(--gold);
  min-width: 2rem;
  padding-top: 0.1rem;
}
.rule-row.is-learned  .rule-id { color: var(--green); }
.rule-row.is-practice .rule-id { color: var(--red); }
.rule-text { flex: 1; font-size: 0.875rem; line-height: 1.65; }

.no-results {
  text-align: center;
  padding: 3rem 0;
  color: var(--gray);
  font-style: italic;
}

/* ── LOADING ── */
.loading {
  text-align: center;
  padding: 4rem 1rem;
  color: var(--gray);
  font-style: italic;
}

/* ── RESPONSIVE ── */
@media (max-width: 480px) {
  .mode-grid { grid-template-columns: 1fr; }
  .stats-row { grid-template-columns: 1fr 1fr 1fr; }
  .fc-wrap   { height: 270px; }
  .fc-num    { font-size: 2.75rem; }
  .cat-grid  { grid-template-columns: 1fr; }
}