:root {
  --bt-paper: #f7f2e8;
  --bt-paper-deep: #eee6d8;
  --bt-surface: #fffdf8;
  --bt-wine: #7b3345;
  --bt-wine-deep: #592131;
  --bt-navy: #17324d;
  --bt-sage: #54715d;
  --bt-ink: #28322c;
  --bt-ink-soft: #5e665f;
  --bt-line: #c9c1b5;
  --bt-focus: #005fcc;
  --bt-success: #176b4d;
  --bt-warning: #8a5200;
  --bt-error: #b42318;
  --bt-info: #1d4e89;
  --bt-space-1: 4px;
  --bt-space-2: 8px;
  --bt-space-3: 12px;
  --bt-space-4: 16px;
  --bt-space-6: 24px;
  --bt-space-8: 32px;
  --bt-space-12: 48px;
  --bt-space-16: 64px;
  --bt-radius-sm: 8px;
  --bt-radius-md: 12px;
  --bt-radius-lg: 18px;
  --bt-font-sans: "Avenir Next", "Helvetica Neue", "Yu Gothic", "Hiragino Sans", "Noto Sans JP", sans-serif;
  --bt-font-serif: "Yu Mincho", "Hiragino Mincho ProN", "Noto Serif JP", serif;
}

:focus-visible {
  outline: 3px solid var(--bt-focus) !important;
  outline-offset: 2px !important;
}

.bt-learning-card {
  display: grid;
  gap: var(--bt-space-6);
  padding: clamp(24px, 4vw, 40px);
  border: 1px solid var(--bt-line);
  border-radius: var(--bt-radius-lg);
  color: var(--bt-ink);
  background: var(--bt-surface);
  box-shadow: 0 16px 36px rgba(40, 50, 44, 0.09);
}

.bt-learning-card__heading,
.bt-learning-card__metric,
.bt-learning-card__status {
  margin: 0;
}

.bt-learning-card__heading {
  color: var(--bt-wine);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.bt-learning-card__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--bt-space-4);
}

.bt-learning-card__metric {
  min-width: 0;
  padding: var(--bt-space-6);
  border-left: 4px solid var(--bt-wine);
  border-radius: var(--bt-radius-md);
  background: var(--bt-paper);
}

.bt-learning-card__metric dt {
  color: var(--bt-ink-soft);
  font-size: 0.8rem;
  font-weight: 700;
}

.bt-learning-card__metric dd {
  margin: var(--bt-space-2) 0 0;
  color: var(--bt-wine-deep);
  font-family: var(--bt-font-serif);
  font-size: clamp(1.65rem, 4vw, 2.5rem);
  font-weight: 700;
  line-height: 1.2;
}

.bt-learning-card__metric small {
  display: block;
  margin-top: var(--bt-space-2);
  color: var(--bt-ink-soft);
  font-family: var(--bt-font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  line-height: 1.6;
}

.bt-learning-card__status {
  min-height: 1.6em;
  color: var(--bt-ink-soft);
  font-size: 0.8rem;
  line-height: 1.6;
}

.bt-learning-card__status[data-state="error"],
.bt-learning-card__status[data-state="storage-unavailable"] {
  color: var(--bt-error);
  font-weight: 700;
}

.bt-learning-card__reset {
  justify-self: start;
  min-height: 44px;
  padding: 8px 14px;
  border: 1px solid var(--bt-line);
  border-radius: var(--bt-radius-sm);
  color: var(--bt-wine-deep);
  background: transparent;
  font: inherit;
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
}

.bt-state-banner {
  display: none;
  margin: var(--bt-space-4) 0;
  padding: var(--bt-space-3) var(--bt-space-4);
  border: 1px solid currentColor;
  border-radius: var(--bt-radius-sm);
  color: var(--bt-warning);
  background: var(--bt-surface);
  font-size: 0.85rem;
  line-height: 1.6;
}

.bt-state-banner[data-visible="true"] { display: block; }

@media (max-width: 620px) {
  .bt-learning-card__grid { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}