/* Concept Library — layered on top of the hub's literacy.css, which owns the
   palette (--cyan/--mint/--gold/--panel/--line) and base typography. */

.library-hero {
  padding: 1rem 0 0.5rem;
  max-width: 46rem;
}

.library-intro {
  font-size: 1.05rem;
}

.library-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.4rem 0 0;
}

.library-stats > div {
  flex: 1 1 8rem;
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--panel);
}

.library-stats dt {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.library-stats dd {
  margin: 0.3rem 0 0;
  font-size: 1.75rem;
  font-weight: 900;
  line-height: 1;
  color: var(--cyan);
}

.today-panel {
  margin: 1.5rem 0 0;
  padding: 1.1rem 1.2rem;
  border: 1px solid rgba(var(--rgb1), 0.4);
  border-left: 4px solid var(--mint);
  border-radius: 0.5rem;
  background: var(--panel-strong);
}

.today-panel h2 {
  margin-bottom: 0.4rem;
  font-size: clamp(1.35rem, 2.4vw, 1.9rem);
}

.today-panel .button {
  margin-top: 0.5rem;
}

.library-controls {
  display: grid;
  gap: 1rem;
  margin: 1.75rem 0 1rem;
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--panel);
  grid-template-columns: minmax(0, 1fr);
}

.search-field label,
.filter-group legend {
  display: block;
  margin-bottom: 0.45rem;
  padding: 0;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.search-field input {
  width: 100%;
  min-height: 2.75rem;
  padding: 0.6rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: rgba(5, 8, 21, 0.7);
  color: var(--text);
  font: inherit;
  font-size: 1rem; /* keeps iOS from zooming the viewport on focus */
}

.search-field input::placeholder { color: rgba(197, 204, 236, 0.6); }

.search-field input:focus-visible,
.chip:focus-visible,
.concept-permalink:focus-visible,
.concept-card:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.filter-group {
  margin: 0;
  padding: 0;
  border: 0;
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.chip {
  min-height: 2.25rem;
  padding: 0.4rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
}

.chip:hover { border-color: rgba(104, 231, 255, 0.5); }

.chip[aria-pressed="true"] {
  border-color: transparent;
  background: var(--mint);
  color: #06101c;
}

.result-count {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 700;
}

.concept-grid {
  display: grid;
  /* 21rem suited full cards; summaries are far shorter, so a narrower track
     fits three or four columns on a desktop instead of two and roughly
     halves the scroll again. */
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 17.5rem), 1fr));
  gap: 1rem;
  align-items: start;
}

.concept-card {
  padding: 1rem 1.05rem 1.05rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--panel);
  backdrop-filter: blur(14px);
  scroll-margin-top: 1.5rem;
}

.concept-card:target {
  border-color: var(--cyan);
  box-shadow: 0 0 0 1px var(--cyan), 0 18px 50px rgba(0, 0, 0, 0.5);
}

.concept-card h2 {
  margin: 0.55rem 0 0.35rem;
  font-size: 1.3rem;
  line-height: 1.2;
}

.concept-card h3 {
  margin: 0.9rem 0 0.25rem;
  color: var(--cyan);
  font-size: 0.72rem;
  font-weight: 900;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.concept-card p { margin-bottom: 0; font-size: 0.94rem; }
.concept-definition { color: var(--text); }

.concept-tags { display: flex; flex-wrap: wrap; gap: 0.35rem; }

.tag {
  padding: 0.2rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.05);
  color: var(--muted);
  font-size: 0.68rem;
  font-weight: 900;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* Three explicit steps rather than the old --mint/--cyan/--gold: diego.css
   bridges both --mint and --cyan onto --neon2, which rendered Beginner and
   Intermediate in the identical colour. Fallbacks keep the ramp sane if the
   Hub theme file is ever unlinked. */
.tag-beginner     { border-color: color-mix(in srgb, var(--level-beginner, #a78bfa) 55%, transparent);
                    color: var(--level-beginner, #a78bfa); }
.tag-intermediate { border-color: color-mix(in srgb, var(--level-intermediate, #c084fc) 55%, transparent);
                    color: var(--level-intermediate, #c084fc); }
.tag-advanced     { border-color: color-mix(in srgb, var(--level-advanced, #f0abfc) 55%, transparent);
                    color: var(--level-advanced, #f0abfc); }

.concept-featured {
  margin: 0 0 0.7rem;
  color: var(--gold);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.04em;
}

.concept-featured-pending { color: rgba(197, 204, 236, 0.7); font-weight: 700; }

.concept-permalink {
  display: inline-block;
  margin-top: 0.95rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  text-decoration: none;
  border-bottom: 1px solid var(--line);
}

.concept-permalink:hover { color: var(--cyan); border-bottom-color: var(--cyan); }

.library-loading,
.library-empty {
  grid-column: 1 / -1;
  margin: 0;
  padding: 2rem 0;
  text-align: center;
}

footer {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.5rem 0 2.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.85rem;
}

@media (min-width: 60rem) {
  .library-controls {
    grid-template-columns: minmax(14rem, 0.9fr) auto auto auto;
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; }
}

/* ── progressive disclosure ────────────────────────────────────────
   The card is a summary until asked otherwise. The control is a real
   button with aria-expanded rather than a <details>, so the label can
   say what it reveals instead of a generic disclosure triangle. */
.concept-more {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.85rem;
  padding: 0.5rem 0;
  min-height: 44px;
  background: none;
  border: 0;
  color: var(--cyan);
  font: inherit;
  font-size: 0.74rem;
  font-weight: 900;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  cursor: pointer;
}
.concept-more:hover { color: #fff; }
.concept-more:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; }
.concept-more-mark {
  width: 0.5rem;
  height: 0.5rem;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg) translate(-1px, -1px);
  transition: transform 0.18s cubic-bezier(0.25, 1, 0.5, 1);
}
.concept-card.is-open .concept-more-mark {
  transform: rotate(225deg) translate(-2px, -2px);
}
.concept-detail { animation: concept-open 0.22s cubic-bezier(0.25, 1, 0.5, 1) both; }
@keyframes concept-open {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: none; }
}
.concept-card.is-open { border-color: rgba(167, 139, 250, 0.55); }

@media (prefers-reduced-motion: reduce) {
  .concept-more-mark { transition: none; }
  .concept-detail { animation: none; }
}