:root {
  --bg: #0f1020;
  --fg: #e8e8f0;

  /* Brand accent: violet family (replaces the old pink-red). */
  --accent: #a78bfa;            /* primary violet (text/links/active) */
  --accent-strong: #8b5cf6;     /* filled buttons / pills */
  --accent-hover: #c4b5fd;      /* lighter tint for hover/focus */
  --accent-ink: #160a2e;        /* dark text drawn on top of accent fills */
  --accent-soft: rgba(167, 139, 250, 0.12);   /* subtle fills/highlights */
  --accent-line: rgba(167, 139, 250, 0.45);   /* subtle borders */

  --panel: #1b1c33;
  --panel-2: #15162e;           /* nested/recessed card surface */
  --panel-3: #26274a;           /* raised chips, table headers */
  --border: #33345a;

  /* Semantic colors (kept distinct from the brand accent). */
  --success: #6bff9e;
  --gold: #e0b53a;
  --danger: #ff6b6b;            /* errors / incorrect — stays warm red */
  --danger-ink: #ff9e9e;

  /* Spacing scale (4px base). Use these for padding/margins/gaps. */
  --sp-1: 0.25rem;   /* 4px  */
  --sp-2: 0.5rem;    /* 8px  */
  --sp-3: 0.75rem;   /* 12px */
  --sp-4: 1rem;      /* 16px */
  --sp-5: 1.5rem;    /* 24px */
  --sp-6: 2rem;      /* 32px */
  --radius: 8px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.5;
}

header {
  padding: var(--sp-5) var(--sp-6);
  border-bottom: 1px solid var(--border);
}

header h1 {
  margin: 0;
  color: var(--accent);
}

.tagline {
  margin: var(--sp-1) 0 0;
  opacity: 0.7;
}

main {
  padding: var(--sp-6);
}

section {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--sp-5);
  max-width: 720px;
}

.status {
  font-style: italic;
  opacity: 0.85;
  margin: 0 var(--sp-6) var(--sp-4);
}

.status.error {
  color: var(--danger);
  font-style: normal;
  font-weight: 600;
  white-space: pre-wrap;
}

.status.ready {
  color: var(--success);
}

table {
  border-collapse: collapse;
  width: 100%;
}

th, td {
  border: 1px solid var(--border);
  padding: 0.4rem 0.75rem;
  text-align: left;
}

th {
  background: var(--panel-3);
}

/* --- Phase 3: workbench layout ------------------------------------------- */

main.workbench {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--sp-5);
  align-items: start;
  max-width: none;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--sp-4);
}

.schema-panel {
  max-height: 80vh;
  overflow-y: auto;
  position: sticky;
  top: 1rem;
}

.workspace {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--sp-5);
  max-width: none;
  min-width: 0;
}

.editor-wrap {
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: var(--sp-3);
}

.editor {
  min-height: 140px;
}

.editor .cm-editor {
  min-height: 140px;
}

.editor .cm-editor.cm-focused {
  outline: 2px solid var(--accent);
}

.toolbar {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  flex-wrap: wrap;
  margin-bottom: var(--sp-4);
}

.btn {
  background: var(--panel-3);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.45rem 0.9rem;
  font-size: 0.95rem;
  cursor: pointer;
  transition: border-color 0.12s ease, background 0.12s ease;
}

.btn:hover {
  border-color: var(--accent);
}

/* Visible keyboard focus everywhere (a11y). */
a:focus-visible,
button:focus-visible,
input:focus-visible,
.btn:focus-visible,
.nav-link:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid #ffd45c;
  outline-offset: 2px;
  border-radius: 4px;
}
.editor .cm-editor.cm-focused {
  outline: 3px solid #ffd45c;
}

.btn-primary {
  background: var(--accent-strong);
  color: #fff;
  border-color: var(--accent-strong);
  font-weight: 600;
}

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: var(--accent-ink);
}

.persist {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.9rem;
  opacity: 0.9;
}

.toolbar .hint {
  margin-left: auto;
  font-size: 0.8rem;
  opacity: 0.6;
}

.result {
  overflow-x: auto;
}

/* --- Schema panel -------------------------------------------------------- */

.schema-table {
  margin-bottom: 0.75rem;
  border-radius: 6px;
  padding: 0.25rem;
}

.schema-table.highlighted {
  outline: 2px solid var(--accent);
  background: var(--accent-soft);
}

.schema-table-name {
  display: block;
  width: 100%;
  text-align: left;
  background: var(--panel-3);
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.35rem 0.5rem;
  font-weight: 600;
  cursor: pointer;
}

.schema-table-name:hover {
  border-color: var(--accent);
}

.schema-cols {
  list-style: none;
  margin: 0.25rem 0 0;
  padding: 0 0 0 0.5rem;
}

.schema-col {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  width: 100%;
  text-align: left;
  background: transparent;
  color: var(--fg);
  border: none;
  border-radius: 4px;
  padding: 0.15rem 0.4rem;
  font-size: 0.85rem;
  cursor: pointer;
}

.schema-col:hover {
  background: rgba(255, 255, 255, 0.06);
}

.col-marker {
  font-size: 0.7rem;
  opacity: 0.7;
  color: #5cc8ff;
  white-space: nowrap;
}

/* --- Results: NULL badges, legend, unmatched rows ------------------------ */

.null {
  font-style: italic;
  color: #ffb55c;
  opacity: 0.9;
}

tr.unmatched {
  background: var(--accent-soft);
}

tr.unmatched td {
  border-color: var(--accent-line);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.5rem;
  font-size: 0.8rem;
  opacity: 0.85;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.swatch {
  display: inline-block;
  width: 0.8rem;
  height: 0.8rem;
  border-radius: 2px;
}

.cap-notice {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  opacity: 0.85;
}

.show-all-btn {
  background: var(--panel-3);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.2rem 0.6rem;
  cursor: pointer;
}

.result-error {
  color: var(--danger);
  font-weight: 600;
  white-space: pre-wrap;
  padding: var(--sp-3);
  border: 1px solid var(--danger);
  border-radius: 6px;
  background: rgba(255, 107, 107, 0.08);
}

.result-info {
  color: var(--success);
  font-weight: 600;
  padding: var(--sp-2) 0;
}

.result-empty {
  opacity: 0.6;
}

@media (max-width: 720px) {
  main.workbench {
    grid-template-columns: 1fr;
  }
}

/* --- Phase 4: header nav, views, lesson map, runner, hints --------------- */

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.topnav {
  display: flex;
  gap: 0.5rem;
}
.nav-link {
  color: var(--fg);
  text-decoration: none;
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  opacity: 0.75;
}
.nav-link:hover { opacity: 1; border-color: var(--accent); }
.nav-link.active {
  background: var(--accent-strong);
  color: #fff;
  border-color: var(--accent-strong);
  opacity: 1;
  font-weight: 600;
}

.view.hidden { display: none; }

/* Lesson map / home */
.map-header {
  display: flex;
  justify-content: space-between;
  gap: var(--sp-4);
  flex-wrap: wrap;
  margin-bottom: var(--sp-5);
}
.map-header h2 { margin: 0; }
.map-stats { text-align: right; }
.stat-big { font-size: 1.4rem; font-weight: 700; color: var(--accent); }
.stat-sub { opacity: 0.85; font-size: 0.9rem; }
.lesson-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--sp-4);
}
.lesson-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--sp-4);
  background: var(--panel-2);
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
  transition: border-color 0.12s ease, transform 0.12s ease;
}
.lesson-card:hover { border-color: var(--accent); }
.lesson-card.complete {
  border-color: var(--success);
  box-shadow: 0 0 0 1px var(--success), 0 0 14px rgba(107, 255, 158, 0.22);
}
/* The capstone is the finale — keep its special look (no lock). */
.lesson-card.capstone {
  border-color: var(--gold);
  background: linear-gradient(160deg, var(--panel-2), rgba(224, 181, 58, 0.08));
}
.lesson-card.capstone.complete {
  box-shadow: 0 0 0 1px var(--gold), 0 0 16px rgba(224, 181, 58, 0.3);
}
.lesson-card h3 { margin: 0; }
.lesson-num { font-size: 0.8rem; opacity: 0.7; }
.lesson-card.capstone .lesson-num { color: var(--gold); opacity: 1; font-weight: 700; }
.lesson-card-head { display: flex; justify-content: space-between; align-items: center; }
.lesson-card-status { font-size: 0.85rem; opacity: 0.8; }

/* Per-lesson completion indicators (map cards). */
.lesson-card-progress { display: flex; flex-direction: column; gap: var(--sp-2); margin-top: auto; }
.lesson-medals { display: flex; gap: var(--sp-2); font-size: 1.4rem; line-height: 1; }
.medal {
  filter: grayscale(1) opacity(0.4);
  transition: filter 0.15s ease, transform 0.15s ease;
}
.medal.medal-solved { filter: none; transform: translateY(-1px); }
/* Lit medals get a tier-tinted glow so "solved" reads at a glance (the title/
   aria text carries the non-color signal). */
.medal.medal-bronze.medal-solved { text-shadow: 0 0 8px rgba(176, 122, 58, 0.85); }
.medal.medal-silver.medal-solved { text-shadow: 0 0 8px rgba(154, 163, 178, 0.85); }
.medal.medal-gold.medal-solved   { text-shadow: 0 0 9px rgba(224, 181, 58, 0.95); }
.medal.medal-absent { filter: grayscale(1) opacity(0.14); }
.lesson-card-meta {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--sp-2);
  font-size: 0.85rem;
}
.lesson-counter { opacity: 0.8; font-variant-numeric: tabular-nums; }
.lesson-complete-flag { color: var(--success); font-weight: 700; }
.btn-capstone {
  background: var(--gold);
  color: #11122a;
  border-color: var(--gold);
  font-weight: 700;
}
.btn-capstone:hover { background: #f0c956; }

/* Badges */
.badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  background: #33345a;
  color: #e8e8f0;
}
.badge.tier-bronze { background: #b07a3a; color: #fff; }
.badge.tier-silver { background: #9aa3b2; color: #11122a; }
.badge.tier-gold { background: var(--gold); color: #11122a; }
.badge.kind-dml { background: #5cc8ff; color: #11122a; }
.badge.joincore { background: var(--accent-strong); color: #fff; }
.badge.solved { background: var(--success); color: #11122a; }

/* Lesson runner */
.lesson-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 0.5rem; }
.lesson-stats .stat {
  margin-left: 0.75rem;
  font-size: 0.9rem;
  opacity: 0.9;
}
.lesson-title { margin: 0.25rem 0 0.75rem; display: flex; gap: 0.5rem; align-items: center; }
.progress-bars { display: flex; gap: 1.5rem; margin-bottom: 1rem; flex-wrap: wrap; }
.progress-bars label { font-size: 0.85rem; opacity: 0.85; display: flex; flex-direction: column; gap: 0.25rem; }
.progress-bars progress { width: 200px; height: 0.6rem; }
.lesson-concept {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--sp-4);
  margin-bottom: var(--sp-4);
}
.lesson-concept code { background: var(--panel-3); padding: 0 0.25rem; border-radius: 3px; }

.exercise-tabs { display: flex; gap: var(--sp-2); margin-bottom: var(--sp-3); flex-wrap: wrap; }
.exercise-tab {
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--fg);
  border-radius: 6px;
  padding: 0.3rem 0.7rem;
  cursor: pointer;
}
.exercise-tab.active { border-color: var(--accent); background: var(--accent-soft); }
.exercise-tab.done { border-color: var(--success); }
.exercise-tab.locked { opacity: 0.4; cursor: not-allowed; }

.exercise-head { display: flex; gap: var(--sp-2); margin-bottom: var(--sp-2); }
.exercise-prompt { margin-bottom: var(--sp-3); }
.exercise-prompt code { background: var(--panel-3); padding: 0 0.25rem; border-radius: 3px; }

.btn-hint { border-color: var(--gold); }

.lesson-hints { margin: var(--sp-2) 0; }
.hint-revealed {
  background: rgba(224, 181, 58, 0.12);
  border-left: 3px solid var(--gold);
  padding: var(--sp-2) var(--sp-3);
  margin-bottom: var(--sp-1);
  border-radius: 4px;
}
.hint-next { font-size: 0.85rem; opacity: 0.8; }

.lesson-verdict { margin: var(--sp-3) 0; padding: var(--sp-3) var(--sp-4); border-radius: 6px; }
.lesson-verdict:empty { display: none; }
.lesson-verdict.correct { background: rgba(107, 255, 158, 0.1); border: 1px solid var(--success); }
.lesson-verdict.incorrect { background: rgba(255, 107, 107, 0.1); border: 1px solid var(--danger); }
.lesson-verdict .diagnosis { font-family: ui-monospace, monospace; opacity: 0.85; }
.lesson-verdict .xp-gain { color: var(--success); font-weight: 700; }
.lesson-verdict .badges-earned { color: var(--gold); margin-top: var(--sp-1); }
.lesson-verdict .nudge { margin-top: var(--sp-1); opacity: 0.9; font-style: italic; }
.common-mistake { margin-top: var(--sp-1); opacity: 0.9; }

.btn.disabled { opacity: 0.5; cursor: not-allowed; }
.btn-small { font-size: 0.8rem; padding: 0.25rem 0.6rem; }
.btn-danger { border-color: var(--danger); color: var(--danger-ink); }
.btn-danger:hover { background: rgba(255, 107, 107, 0.15); border-color: var(--danger); }

/* Result tables scroll horizontally on narrow viewports without breaking layout. */
.result-set { overflow-x: auto; }
.result table { min-width: max-content; }

/* --- Phase 8: schema-panel collapse toggle ------------------------------- */
.schema-toggle {
  display: none; /* shown only on narrow viewports via the media query */
  width: 100%;
  text-align: left;
  background: var(--panel-3);
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: var(--sp-2) var(--sp-3);
  font-weight: 600;
  cursor: pointer;
  margin-bottom: var(--sp-2);
}
.schema-panel.collapsed #schema-panel { display: none; }

/* --- Phase 8: home hero -------------------------------------------------- */
.hero {
  background: linear-gradient(135deg, #1b1c33 0%, #2a1a52 100%);
  border: 1px solid var(--accent-line);
  border-radius: 12px;
  padding: var(--sp-6);
  margin-bottom: var(--sp-5);
}
.hero-title { margin: 0 0 var(--sp-2); font-size: 1.8rem; color: var(--accent); }
.hero-line { margin: 0 0 var(--sp-4); max-width: 60ch; opacity: 0.9; }
.hero-cta { display: flex; gap: var(--sp-3); flex-wrap: wrap; margin-bottom: var(--sp-4); }
.hero-cta .btn { text-decoration: none; }
.hero-note { font-size: 0.85rem; opacity: 0.7; max-width: 70ch; margin: 0; }
.hero-note .source-link { color: #5cc8ff; }

/* --- Phase 8: profile / achievements ------------------------------------ */
.profile { max-width: 920px; }
.profile h2 { margin-top: 0; color: var(--accent); }
.profile h3 { margin: var(--sp-5) 0 var(--sp-1); }
.profile-sub { margin: 0 0 var(--sp-3); opacity: 0.75; font-size: 0.9rem; }

.profile-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--sp-3);
  margin: var(--sp-4) 0 var(--sp-5);
}
.profile-stat {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: var(--sp-4);
  text-align: center;
}
.profile-stat-value { font-size: 1.5rem; font-weight: 700; color: var(--accent); }
.profile-stat-label { font-size: 0.8rem; opacity: 0.75; margin-top: var(--sp-1); }

.level-progress { margin-bottom: var(--sp-2); }
.level-progress label { display: block; font-size: 0.9rem; margin-bottom: 0.3rem; }
.level-progress progress { width: 100%; height: 0.9rem; }

.badge-grid {
  list-style: none;
  margin: var(--sp-2) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--sp-3);
}
.badge-card {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-rows: auto auto auto;
  gap: var(--sp-1) var(--sp-3);
  align-items: center;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: var(--sp-3) var(--sp-4);
}
.badge-card .badge-emblem { grid-row: 1 / 3; font-size: 1.8rem; }
.badge-card .badge-name { font-weight: 700; }
.badge-card .badge-state { font-size: 0.78rem; font-weight: 700; }
.badge-card .badge-criteria { grid-column: 1 / 3; font-size: 0.8rem; opacity: 0.8; margin-top: var(--sp-1); }
.badge-card.earned { border-color: var(--gold); box-shadow: 0 0 0 1px rgba(224,181,58,0.35) inset; }
.badge-card.earned .badge-state { color: var(--success); }
.badge-card.locked { opacity: 0.55; filter: grayscale(0.85); }
.badge-card.locked .badge-state { color: var(--danger-ink); }

.profile-table-wrap { overflow-x: auto; }
.profile-lessons { width: 100%; border-collapse: collapse; margin-top: var(--sp-2); }
.profile-lessons th[scope="row"] { text-align: left; font-weight: 600; }
.lesson-row.complete th { color: var(--success); }
.lesson-row.locked { opacity: 0.55; }
.lesson-status-text { font-size: 0.85rem; }

.profile-actions { margin-top: var(--sp-5); }

/* --- Phase 8: capstone score screen ------------------------------------- */
.capstone-score { text-align: center; padding: var(--sp-2) 0; }
.capstone-score h3 { margin: 0 0 var(--sp-2); color: var(--accent); font-size: 1.4rem; }
.capstone-culprit { font-size: 1.1rem; }
.capstone-xp { font-size: 1.6rem; font-weight: 800; color: var(--success); margin: var(--sp-2) 0; }
.capstone-badges { color: var(--gold); font-weight: 600; margin: var(--sp-1) 0; }
.capstone-rank { opacity: 0.9; }
.capstone-actions { display: flex; gap: var(--sp-3); justify-content: center; flex-wrap: wrap; margin-top: var(--sp-3); }
.capstone-actions .btn { text-decoration: none; }

/* --- Phase 8: responsive / mobile --------------------------------------- */
@media (max-width: 720px) {
  header { padding: var(--sp-4); }
  main.workbench { padding: var(--sp-4); gap: var(--sp-4); }
  .status { margin: 0 var(--sp-4) var(--sp-4); }
  .hero { padding: var(--sp-4); }
  .schema-toggle { display: block; }
  /* Schema panel is full-width on narrow screens; the toggle collapses it to
     reclaim space (it starts expanded; .collapsed hides the table list). */
  .schema-panel { position: static; max-height: none; }
  .schema-panel #schema-panel { max-height: 45vh; overflow-y: auto; }
  .hero-title { font-size: 1.4rem; }
  .map-header { flex-direction: column; }
  .map-stats { text-align: left; }
  .progress-bars { gap: var(--sp-3); }
  .progress-bars progress { width: 100%; }
  .lesson-grid { grid-template-columns: 1fr; }
  .toolbar { gap: 0.5rem; }
  .toolbar .hint { margin-left: 0; flex-basis: 100%; }
}