/* ── Think Tank article list ───────────────────────────────────────────────── */
.tt-filters {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-8);
  flex-wrap: wrap;
  align-items: center;
}
.tt-filters__btn {
  padding: 7px 18px;
  border-radius: 20px;
  font-size: var(--text-sm);
  font-weight: 500;
  border: 1px solid var(--color-border, #e2e8f0);
  background: transparent;
  cursor: pointer;
  color: var(--color-charcoal);
  text-decoration: none;
  transition: background .15s, color .15s;
}
.tt-filters__btn:hover,
.tt-filters__btn--active {
  background: var(--color-charcoal);
  color: var(--color-white);
  border-color: var(--color-charcoal);
  text-decoration: none;
}

/* Article grid */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}
.article-card {
  display: flex;
  flex-direction: column;
  background: var(--color-white);
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: var(--radius-md);
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  transition: box-shadow .2s, transform .2s;
}
.article-card:hover {
  box-shadow: 0 8px 32px rgba(27,42,73,.1);
  transform: translateY(-2px);
  text-decoration: none;
}
.article-card__cover {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
  background: var(--color-foggy-day, #f5f7fc);
}
.article-card__cover-placeholder {
  width: 100%;
  aspect-ratio: 16/9;
  background: linear-gradient(135deg, var(--color-electric-blue, #0037ff) 0%, var(--color-charcoal, #1b2a49) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: rgba(255,255,255,.15);
}
.article-card__body  { padding: var(--space-6); flex: 1; display: flex; flex-direction: column; }
.article-card__meta  { display: flex; align-items: center; gap: var(--space-2); margin-bottom: var(--space-3); flex-wrap: wrap; }
.article-card__badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .3px;
}
.article-card__badge--free { background: #e0f2fe; color: #0369a1; }
.article-card__badge--paid { background: #fef3c7; color: #92400e; }
.article-card__category { font-size: 11px; text-transform: uppercase; letter-spacing: 1px; color: var(--color-muted, #64748b); }
.article-card__title { font-size: var(--text-lg); font-weight: 600; margin-bottom: var(--space-2); color: var(--color-charcoal); line-height: 1.35; }
.article-card__subtitle { font-size: var(--text-sm); color: var(--color-muted, #64748b); margin-bottom: var(--space-4); line-height: 1.55; flex: 1; }
.article-card__footer { margin-top: auto; padding-top: var(--space-4); border-top: 1px solid var(--color-border, #e2e8f0); display: flex; align-items: center; justify-content: space-between; gap: var(--space-2); }
.article-card__author { font-size: 12px; color: var(--color-muted, #64748b); }
.article-card__price  { font-size: 13px; font-weight: 600; color: var(--color-charcoal); }
.tt-empty { text-align: center; padding: var(--space-16) 0; color: var(--color-muted, #64748b); }
.tt-empty h3 { font-size: var(--text-xl); margin-bottom: var(--space-3); }

/* ── Individual article page ───────────────────────────────────────────────── */
.article-hero { padding: var(--space-16) 0 var(--space-12); }
.article-hero__meta { display: flex; gap: var(--space-3); align-items: center; margin-bottom: var(--space-6); flex-wrap: wrap; }
.article-hero__title { font-size: var(--text-4xl); font-weight: 700; line-height: 1.15; margin-bottom: var(--space-4); }
.article-hero__subtitle { font-size: var(--text-xl); color: var(--color-muted, #64748b); font-weight: 300; line-height: 1.6; margin-bottom: var(--space-6); }
.article-hero__author { font-size: var(--text-sm); color: var(--color-muted, #64748b); }
.article-hero__author strong { color: var(--color-charcoal); }
.article-cover { width: 100%; max-height: 440px; object-fit: cover; border-radius: var(--radius-md); margin-bottom: var(--space-10); }

/* Content layout */
.article-body { max-width: 740px; margin: 0 auto; }
.article-content { font-size: var(--text-base); line-height: 1.8; color: var(--color-charcoal); }
.article-content h2 { font-size: var(--text-2xl); margin: var(--space-10) 0 var(--space-4); }
.article-content h3 { font-size: var(--text-xl); margin: var(--space-8) 0 var(--space-3); }
.article-content p  { margin-bottom: var(--space-5); }
.article-content ul, .article-content ol { padding-left: var(--space-6); margin-bottom: var(--space-5); }
.article-content li { margin-bottom: var(--space-2); }
.article-content blockquote { border-left: 3px solid var(--color-electric-blue, #0037ff); padding-left: var(--space-5); margin: var(--space-8) 0; font-style: italic; color: var(--color-muted, #64748b); }
.article-content strong { font-weight: 600; }
.article-content a { color: var(--color-electric-blue, #0037ff); }

/* Paywall */
.article-paywall {
  margin: var(--space-12) 0;
  background: linear-gradient(180deg, rgba(255,255,255,0) 0%, var(--color-white) 60%);
  padding-top: var(--space-12);
  margin-top: calc(-1 * var(--space-12));
  position: relative;
}
.article-paywall__box {
  background: var(--color-foggy-day, #f5f7fc);
  border: 1px solid var(--color-border, #e2e8f0);
  border-radius: var(--radius-md);
  padding: var(--space-10);
  text-align: center;
  max-width: 520px;
  margin: 0 auto;
}
.article-paywall__icon { font-size: 2.5rem; margin-bottom: var(--space-4); }
.article-paywall__title { font-size: var(--text-xl); font-weight: 700; margin-bottom: var(--space-3); }
.article-paywall__desc { color: var(--color-muted, #64748b); margin-bottom: var(--space-6); line-height: 1.6; }
.article-paywall__price { font-size: var(--text-2xl); font-weight: 700; color: var(--color-electric-blue, #0037ff); margin-bottom: var(--space-6); }
.article-paywall__actions { display: flex; gap: var(--space-3); justify-content: center; flex-wrap: wrap; }

/* Purchase success */
.purchase-success {
  background: #dcfce7; border: 1px solid #bbf7d0; border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-6); margin-bottom: var(--space-8);
  display: flex; align-items: center; gap: var(--space-3); font-size: var(--text-sm); color: #15803d;
}

@media (max-width: 768px) {
  .article-hero__title { font-size: var(--text-3xl); }
  .article-grid { grid-template-columns: 1fr; }
}