/* ==========================================================================
   Topic Pages, Topic Tiles & Guided Learning Paths
   ========================================================================== */

/* Topics Overview Grid — /topics/ listing */
.topic-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-top: 2rem;
}

.topic-tile {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-height: 0;
  padding: 18px 20px 16px;
  text-decoration: none;
  position: relative;
  overflow: hidden;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-m, 14px);
  box-shadow: var(--card-shadow);
  transition: transform 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.topic-tile,
.topic-tile *,
.topic-tile *:hover {
  text-decoration: none !important;
}

/* Left accent bar */
.topic-tile::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--tc-line, var(--accent));
  border-radius: 3px 0 0 3px;
  opacity: 0.85;
}

/* Subtle top-left colour wash */
.topic-tile::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--tc-bg, transparent) 0%, transparent 55%);
  pointer-events: none;
  z-index: 0;
}

.topic-tile > * { position: relative; z-index: 1; }

.topic-tile:hover {
  transform: translateY(-2px);
  border-color: var(--tc-line, var(--card-hover-border));
  box-shadow: var(--card-hover-shadow);
}

.topic-tile-head {
  display: flex;
  align-items: center;
  gap: 8px;
}

.topic-tile-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--tc-line, var(--accent));
  flex-shrink: 0;
}

.topic-tile h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--ink);
  margin: 0;
  letter-spacing: -0.02em;
  line-height: 1.3;
  transition: color 0.15s ease;
}

.topic-tile:hover h3 {
  color: var(--tc, var(--accent-text));
}

.topic-tile p {
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.5;
  margin: 0;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.topic-tile .count {
  margin-top: auto;
  padding-top: 8px;
  display: inline-flex;
  align-self: flex-start;
  font: 500 0.74rem var(--font-text);
  color: var(--tc, var(--muted));
  border-top: 1px solid var(--line);
  width: 100%;
}

/* Topic Hub Landing (_layouts/topic.html) */
.page-topic {
  padding-top: 0;
}

.topic-hero {
  position: relative;
  overflow: hidden;
  isolation: isolate;
  padding: clamp(24px, 4vw, 44px);
  margin-top: clamp(2rem, 4vw, 3rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  background: var(--tc-bg, var(--surface-2));
  margin-bottom: 2.5rem;
}

/* Halftone accent in the topic's own colour */
.topic-hero::after {
  content: "";
  position: absolute;
  z-index: -1;
  top: -60px;
  right: -60px;
  width: min(420px, 70%);
  aspect-ratio: 1;
  background: radial-gradient(circle, var(--tc-line, var(--accent)) 0 2px, transparent 2.6px) 0 0 / 15px 15px;
  -webkit-mask-image: radial-gradient(circle at 62% 38%, #000 0%, transparent 66%);
  mask-image: radial-gradient(circle at 62% 38%, #000 0%, transparent 66%);
  opacity: 0.55;
  pointer-events: none;
}

.topic-hero .chip {
  margin-bottom: 1rem;
}

.topic-hero h1 {
  font-size: clamp(2.3rem, 5vw, 3.4rem);
  letter-spacing: -0.03em;
  color: var(--ink);
  margin: 0 0 10px;
}

.topic-hero .lead {
  font-size: 1.15rem;
  color: var(--ink);
  max-width: 65ch;
  line-height: 1.6;
}

.topic-purpose {
  margin-top: 10px;
  color: var(--muted);
  max-width: 68ch;
  line-height: 1.65;
}

/* Guided Route / Learning Path */
.learning-path {
  margin-top: clamp(2.5rem, 6vw, 3.75rem);
  margin-bottom: 3rem;
  padding: clamp(1.25rem, 3vw, 2.25rem);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-m, 14px);
  box-shadow: var(--card-shadow);
}

.section-heading {
  max-width: 44rem;
  margin-bottom: 1.5rem;
}

.section-heading .eyebrow {
  display: block;
  color: var(--accent-text);
  font: 700 0.78rem var(--font-text);
  letter-spacing: 0.09em;
  text-transform: uppercase;
  margin-bottom: 0.4rem;
}

.section-heading h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  letter-spacing: -0.02em;
  color: var(--ink);
  margin: 0;
}

.section-heading p {
  margin-top: 0.5rem;
  color: var(--muted);
  line-height: 1.6;
}

.learning-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.learning-step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 16px;
  padding: 1.25rem 0;
  border-top: 1px solid var(--line);
  align-items: start;
}

.learning-step:first-child {
  border-top: none;
}

.step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 9px;
  background: var(--surface-2);
  border: 1px solid var(--line);
  color: var(--accent-text);
  font: 800 0.88rem var(--font-mono);
}

.step-label {
  display: inline-block;
  font: 700 0.72rem var(--font-text);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 3px;
}

.learning-step h3 {
  font: 700 1.15rem/1.35 var(--font-text);
  margin: 0;
}

.learning-step h3 a {
  color: var(--ink);
  text-decoration: none;
}

.learning-step h3 a:hover {
  color: var(--accent-text);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.learning-step p {
  color: var(--muted);
  margin-top: 0.4rem;
  font-size: 0.94rem;
  line-height: 1.6;
}

.page-actions {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
}

/* Principles Band */
.principles {
  background: var(--surface-2);
  border-block: 1px solid var(--line);
  padding: clamp(40px, 6vw, 68px) 0;
}

.principles-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) repeat(3, minmax(0, 1fr));
  gap: clamp(24px, 4vw, 48px);
  align-items: start;
}

.principles h2 {
  font-size: clamp(1.9rem, 3.6vw, 2.6rem);
  letter-spacing: -0.02em;
  color: var(--ink);
  margin: 0;
}

.principle h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
  color: var(--ink);
}

.principle p {
  color: var(--muted);
  font-size: 0.98rem;
  line-height: 1.65;
  margin: 0;
}

.principles .text-link {
  display: inline-block;
  margin-top: 1.25rem;
}

/* Responsive */
@media (max-width: 960px) {
  .topic-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }
  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }
  .principles-grid {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
  }
  .principles-grid > :first-child {
    grid-column: 1 / -1;
  }
}

@media (max-width: 700px) {
  .topic-hero {
    padding: 16px 18px !important;
    margin-top: 1rem !important;
    margin-bottom: 1.5rem !important;
    border-radius: 14px !important;
  }
  .topic-hero .chip {
    margin-bottom: 0.5rem !important;
  }
  .topic-hero h1 {
    font-size: clamp(1.8rem, 7vw, 2.4rem) !important;
  }
  .topic-hero .lead {
    font-size: 0.98rem !important;
  }
  .topic-purpose {
    font-size: 0.88rem !important;
    margin-top: 6px !important;
  }
  .topic-list,
  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    gap: 8px !important;
    margin-top: 1.25rem !important;
  }
  .topic-tile {
    min-height: 0 !important;
    padding: 14px 16px !important;
    border-radius: 12px !important;
    gap: 6px !important;
  }
  .topic-tile h3 {
    font-size: 0.92rem !important;
  }
  .topic-tile p {
    font-size: 0.8rem !important;
    line-height: 1.45 !important;
  }
  .learning-path {
    margin-top: 1.5rem !important;
    margin-bottom: 1.5rem !important;
    padding: 14px 16px !important;
    border-radius: 12px !important;
  }
  .learning-steps {
    gap: 12px !important;
  }
  .principles {
    padding: 28px 0 !important;
  }
  .principles-grid {
    grid-template-columns: minmax(0, 1fr) !important;
    gap: 14px !important;
  }
}