/* ── 1. Design tokens ─────────────────────────────────────────── */
:root {
  --gan-bg:         #0d0f1a;
  --gan-surface:    #161929;
  --gan-border:     #2a2f4a;
  --gan-text:       #e8eaf6;
  --gan-muted:      #8890b5;
  --gan-accent:     #7c83ff;
  --gan-accent2:    #4fc3f7;
  --gan-danger:     #ff8a65;
  --gan-radius:     10px;
  --gan-shadow:     0 2px 16px rgba(0, 0, 0, .45);
  --gan-transition: 0.18s ease;
}

/* ── 2. App layout ────────────────────────────────────────────── */
#grokking-app {
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
  color: var(--gan-text);
  font-family: system-ui, sans-serif;
}

/* ── 3. Header ────────────────────────────────────────────────── */
.gan-header {
  text-align: center;
  margin-bottom: 2rem;
}

.gan-header h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 .5rem;
  background: linear-gradient(135deg, var(--gan-accent) 0%, var(--gan-accent2) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.gan-subtitle {
  color: var(--gan-muted);
  font-size: 1rem;
  margin: 0;
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.6;
}

/* ── 4. Controls ──────────────────────────────────────────────── */
.gan-controls {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem 1.25rem;
  align-items: flex-end;
  background: var(--gan-surface);
  border: 1px solid var(--gan-border);
  border-radius: var(--gan-radius);
  padding: 1.1rem 1.25rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--gan-shadow);
}

.gan-param {
  display: flex;
  flex-direction: column;
  gap: .3rem;
  min-width: 110px;
}

.gan-param label {
  font-size: .75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--gan-muted);
}

.gan-param select {
  background: var(--gan-bg);
  border: 1px solid var(--gan-border);
  color: var(--gan-text);
  border-radius: 6px;
  padding: .4rem .6rem;
  font-size: .9rem;
  cursor: pointer;
  transition: border-color var(--gan-transition);
}

.gan-param select:focus-visible {
  outline: 2px solid var(--gan-accent);
  outline-offset: 2px;
}

.gan-param select:hover { border-color: var(--gan-accent); }

.gan-actions {
  display: flex;
  gap: .6rem;
  align-items: flex-end;
  margin-left: auto;
}

/* ── 5. Buttons ───────────────────────────────────────────────── */
.btn-primary,
.btn-secondary {
  padding: .45rem 1.1rem;
  border-radius: 6px;
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: opacity var(--gan-transition), transform var(--gan-transition);
}

.btn-primary {
  background: var(--gan-accent);
  color: #fff;
}

.btn-secondary {
  background: transparent;
  color: var(--gan-muted);
  border: 1px solid var(--gan-border);
}

.btn-primary:hover  { opacity: .85; }
.btn-secondary:hover { color: var(--gan-text); border-color: var(--gan-accent); }
.btn-primary:active, .btn-secondary:active { transform: scale(.97); }

.btn-primary:disabled {
  opacity: .4;
  cursor: not-allowed;
}

.btn-primary:focus-visible,
.btn-secondary:focus-visible { outline: 2px solid var(--gan-accent); outline-offset: 2px; }

/* ── 6. Stats bar ─────────────────────────────────────────────── */
.gan-stats {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-bottom: .6rem;
}

.stat-item {
  flex: 1 1 80px;
  background: var(--gan-surface);
  border: 1px solid var(--gan-border);
  border-radius: 8px;
  padding: .55rem .75rem;
  display: flex;
  flex-direction: column;
  gap: .15rem;
}

.stat-label {
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--gan-muted);
}

.stat-value {
  font-size: 1rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--c, var(--gan-text));
}

.stat-epoch { color: var(--gan-accent); }

/* ── 7. Info line ─────────────────────────────────────────────── */
.gan-info {
  font-size: .8rem;
  color: var(--gan-muted);
  margin: .4rem 0 .8rem;
  min-height: 1.2em;
}

/* ── 8. Charts ────────────────────────────────────────────────── */
.gan-charts {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.chart-wrap {
  background: var(--gan-surface);
  border: 1px solid var(--gan-border);
  border-radius: var(--gan-radius);
  overflow: hidden;
  box-shadow: var(--gan-shadow);
}

.chart-wrap canvas {
  display: block;
  width: 100%;
  height: 220px;
  --gan-chart-bg: #161929;
}

/* ── 9. Explainer ─────────────────────────────────────────────── */
.gan-explainer details {
  background: var(--gan-surface);
  border: 1px solid var(--gan-border);
  border-radius: var(--gan-radius);
  padding: .75rem 1rem;
}

.gan-explainer summary {
  cursor: pointer;
  font-weight: 600;
  font-size: .9rem;
  color: var(--gan-accent);
  list-style: none;
  display: flex;
  align-items: center;
  gap: .5rem;
}

.gan-explainer summary::before {
  content: "▸";
  transition: transform var(--gan-transition);
}

.gan-explainer details[open] summary::before { transform: rotate(90deg); }

.explainer-body {
  margin-top: .75rem;
  font-size: .88rem;
  color: var(--gan-muted);
  line-height: 1.7;
}

.explainer-body p { margin: 0 0 .6rem; }
.explainer-body ul { margin: 0 0 .6rem; padding-left: 1.4rem; }
.explainer-body li { margin-bottom: .3rem; }
.explainer-body code {
  background: rgba(124, 131, 255, .15);
  color: var(--gan-accent2);
  padding: .1em .35em;
  border-radius: 4px;
  font-size: .85em;
}

/* ── 10. Modal d'authentification ────────────────────────────── */
.gan-modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, .65);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.gan-modal.visible { display: flex; }

.gan-modal-inner {
  background: var(--gan-surface);
  border: 1px solid var(--gan-border);
  border-radius: var(--gan-radius);
  padding: 2rem 1.75rem 1.5rem;
  width: min(90vw, 340px);
  box-shadow: 0 8px 40px rgba(0, 0, 0, .7);
}

.modal-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 .4rem;
  color: var(--gan-text);
}

.modal-hint {
  font-size: .85rem;
  color: var(--gan-muted);
  margin: 0 0 1rem;
}

.modal-input {
  width: 100%;
  box-sizing: border-box;
  background: var(--gan-bg);
  border: 1px solid var(--gan-border);
  color: var(--gan-text);
  border-radius: 6px;
  padding: .5rem .75rem;
  font-size: 1.1rem;
  letter-spacing: .2em;
  transition: border-color var(--gan-transition);
}

.modal-input:focus-visible {
  outline: 2px solid var(--gan-accent);
  outline-offset: 2px;
}

.modal-input.error { border-color: var(--gan-danger); }

.auth-error {
  font-size: .82rem;
  color: var(--gan-danger);
  min-height: 1.2em;
  margin: .4rem 0 .75rem;
}

.modal-actions {
  display: flex;
  gap: .6rem;
  justify-content: flex-end;
  margin-top: .5rem;
}

/* ── 11. Responsive ───────────────────────────────────────────── */
@media (max-width: 600px) {
  .gan-controls { flex-direction: column; }
  .gan-actions  { margin-left: 0; width: 100%; }
  .btn-primary, .btn-secondary { flex: 1; text-align: center; }
  .gan-charts   { grid-template-columns: 1fr; }
  .gan-stats    { gap: .35rem; }
  .stat-item    { flex: 1 1 calc(50% - .35rem); }
}