/* =====================================================================
   LEARNING MEDIA HUB — BLOG STYLESHEET (brand-unified)
   ---------------------------------------------------------------------
   Loads AFTER styles.css and reuses its design tokens & chrome
   (header, footer, buttons, theme system). This file contains ONLY
   blog-specific components, restyled to match the main marketing site:
   Sky Blue #4DB6E8 · Red #D14545 · Orange #F58239 · Yellow-Green #E0DC45
   Headings: Poppins · Body: Inter · Light/Dark via [data-theme]
   ===================================================================== */

/* ---------- 1. Blog layout primitives ---------- */
.container--read {
  max-width: 760px;
}

/* ---------- 2. Blog index hero (uses main-site .hero gradient) ---------- */
.blog-hero .container{position:relative;z-index:1}
.blog-hero h1{max-width:24ch}
.blog-hero .hero-sub{max-width:62ch;margin-bottom:0}
.blog-hero .hero-badge{margin-bottom:24px}

/* ---------- 3. Controls (search + filter pills) ---------- */
.controls {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2);
  align-items: center;
  padding-block: var(--space-2);
  border-bottom: 1px solid var(--border-color);
  margin-bottom: var(--space-3);
}
.search-box { position: relative; }
.search-box input {
  width: 100%;
  padding: 13px 18px 13px 46px;
  background: var(--bg-surface);
  border: 1.5px solid var(--card-border);
  border-radius: 50px;
  font: inherit;
  font-size: 0.95rem;
  color: var(--text-body);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast);
}
.search-box input::placeholder { color: var(--gray-400); }
.search-box input:focus {
  outline: none;
  border-color: var(--royal-blue);
  box-shadow: 0 0 0 3px rgba(77,182,232,0.2);
}
.search-box__icon {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  width: 18px; height: 18px;
  color: var(--gray-400);
  pointer-events: none;
}

.filter-pills {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.filter-pill {
  padding: 8px 16px;
  background: var(--bg-surface);
  border: 1.5px solid var(--card-border);
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-nav);
  cursor: pointer;
  transition: border-color var(--transition-fast), color var(--transition-fast), background var(--transition-fast), box-shadow var(--transition-fast);
}
.filter-pill:hover {
  border-color: var(--royal-blue);
  color: var(--royal-blue);
}
.filter-pill.is-active {
  background: var(--royal-blue);
  border-color: var(--royal-blue);
  color: #fff;
  box-shadow: 0 4px 14px rgba(77,182,232,0.35);
}
.filter-pill:focus-visible,
.search-box input:focus-visible,
.tag-strip input:focus-visible {
  outline: 2px solid var(--royal-blue);
  outline-offset: 2px;
}

/* ---------- 4. Section title row ---------- */
.section-title {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: var(--space-3);
}
.section-title h2 { margin: 0; font-size: clamp(1.4rem, 2.5vw, 1.8rem); }
.section-title__count {
  font-size: 0.85rem;
  color: var(--text-muted);
  background: var(--gray-100);
  padding: 4px 12px;
  border-radius: 50px;
  font-weight: 600;
  white-space: nowrap;
}
.section-title__rule {
  flex-grow: 1;
  height: 1px;
  background: var(--border-color);
}

/* ---------- 5. Card grid (index) ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 24px;
  margin-bottom: var(--space-5);
}
.card {
  background: var(--bg-surface);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}
/* Top brand bar on hover — mirrors main-site .value-card */
.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--royal-blue), var(--royal-blue-light));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: transparent;
}
.card:hover::before { transform: scaleX(1); }

.card__top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
  gap: 8px;
}
.card__badge {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 50px;
  background: rgba(77,182,232,0.12);
  color: var(--royal-blue-dark);
}
/* Per-category badge colors cycle through the logo palette */
.card[data-category="for-parents"] .card__badge,
.card[data-category="sequences"] .card__badge,
.card[data-category="statistics"] .card__badge {
  background: rgba(245,130,57,0.14);
  color: #C2621A;
}
.card[data-category="functions"] .card__badge,
.card[data-category="finance"] .card__badge,
.card[data-category="trigonometry"] .card__badge {
  background: rgba(209,69,69,0.12);
  color: var(--brand-red-dark);
}
.card[data-category="exponents"] .card__badge,
.card[data-category="probability"] .card__badge {
  background: rgba(224,220,69,0.22);
  color: #6E6B0E;
}
[data-theme="dark"] .card__badge { color: var(--royal-blue-light); }
[data-theme="dark"] .card[data-category="for-parents"] .card__badge,
[data-theme="dark"] .card[data-category="sequences"] .card__badge,
[data-theme="dark"] .card[data-category="statistics"] .card__badge { color: var(--brand-orange-light); }
[data-theme="dark"] .card[data-category="functions"] .card__badge,
[data-theme="dark"] .card[data-category="finance"] .card__badge,
[data-theme="dark"] .card[data-category="trigonometry"] .card__badge { color: var(--brand-red); }
[data-theme="dark"] .card[data-category="exponents"] .card__badge,
[data-theme="dark"] .card[data-category="probability"] .card__badge { color: var(--brand-yellow); }

.card__audience {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  white-space: nowrap;
}
.card__title {
  font-family: var(--font-heading);
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
  margin-bottom: 10px;
}
.card__title a { color: inherit; }
.card__title a:hover { color: var(--royal-blue); }
.card__excerpt {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: var(--space-2);
  flex-grow: 1;
}
.card__meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 12px;
  border-top: 1px solid var(--border-color);
  font-size: 0.8rem;
  color: var(--text-muted);
}
.card__readtime {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}
.card__readtime::before { content: "⏱"; font-size: 0.9em; }
.card__link {
  font-weight: 600;
  color: var(--royal-blue);
  font-size: 0.85rem;
}
.card__link:hover { color: var(--royal-blue-dark); }

.is-hidden { display: none !important; }
.no-results {
  padding: var(--space-5);
  text-align: center;
  color: var(--text-muted);
  font-size: 1.05rem;
  background: var(--gray-100);
  border-radius: var(--radius-lg);
  grid-column: 1 / -1;
}

/* ---------- 6. Category page hero ---------- */
.cat-hero {
  padding: 100px 0 48px;
  background:
    radial-gradient(ellipse at top right, rgba(77,182,232,0.12), transparent 55%),
    linear-gradient(180deg, rgba(245,130,57,0.05), transparent 70%),
    var(--bg-body);
  border-bottom: 1px solid var(--border-color);
}
.cat-hero__crumb {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}
.cat-hero__crumb a { color: var(--text-nav); font-weight: 500; }
.cat-hero__crumb a:hover { color: var(--royal-blue); }
.cat-hero h1 {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  margin-bottom: var(--space-2);
}
.cat-hero__lede {
  font-size: 1.08rem;
  color: var(--text-body);
  max-width: 70ch;
  margin-bottom: 0;
}

/* ---------- 7. Search within category ---------- */
.tag-strip {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  padding-top: var(--space-3);
}
.tag-strip input {
  flex-grow: 1;
  padding: 12px 18px;
  border-radius: 50px;
  border: 1.5px solid var(--card-border);
  background: var(--bg-surface);
  font: inherit;
  font-size: 0.95rem;
  color: var(--text-body);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.tag-strip input::placeholder { color: var(--gray-400); }
.tag-strip input:focus {
  outline: none;
  border-color: var(--royal-blue);
  box-shadow: 0 0 0 3px rgba(77,182,232,0.2);
}

/* ---------- 8. Article / post ---------- */
.article-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  padding-block: var(--space-3) var(--space-5);
}
.post {
  background: var(--bg-surface);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: clamp(var(--space-3), 5vw, var(--space-4));
  scroll-margin-top: 90px;
  box-shadow: var(--shadow-sm);
}
.post__header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: var(--space-3);
  margin-bottom: var(--space-3);
}
.post__meta-top {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 12px;
}
.post__category {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 4px 12px;
  border-radius: 50px;
  background: rgba(77,182,232,0.12);
  color: var(--royal-blue-dark);
}
[data-theme="dark"] .post__category { color: var(--royal-blue-light); }
.post__audience {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
  background: var(--gray-100);
  padding: 4px 10px;
  border-radius: 50px;
}
.post__title {
  font-size: clamp(1.5rem, 3vw, 1.95rem);
  margin-bottom: 10px;
}
.post__subhead {
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--text-muted);
  font-style: italic;
}
.post__meta {
  display: flex;
  gap: 16px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 10px;
}
.post__readtime { display: inline-flex; align-items: center; gap: 5px; }
.post__readtime::before { content: "⏱"; }
.post__body { font-size: 1.05rem; line-height: 1.75; color: var(--text-body); }
.post__body h3 {
  margin-top: var(--space-3);
  margin-bottom: 12px;
  color: var(--text-primary);
  font-size: 1.28rem;
}
.post__body p { margin-bottom: var(--space-2); }
.post__body strong { color: var(--text-primary); }
.post__body ul, .post__body ol { margin-bottom: var(--space-2); }

/* ---------- 9. Callout blocks (brand palette) ---------- */
.callout {
  margin-block: var(--space-3);
  padding: var(--space-3);
  border-radius: var(--radius-md);
  border-left: 4px solid;
}
.callout > h4 {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 10px;
}
.callout > p:last-child { margin-bottom: 0; }

/* Common mistake — brand red */
.callout--mistake {
  background: rgba(209,69,69,0.08);
  border-color: var(--brand-red);
}
.callout--mistake > h4 { color: var(--brand-red-dark); }
.callout--mistake > h4::before { content: "✕"; font-size: 1.1em; }
[data-theme="dark"] .callout--mistake { background: rgba(209,69,69,0.14); }
[data-theme="dark"] .callout--mistake > h4 { color: var(--brand-red); }

/* Worked example — brand sky blue */
.callout--example {
  background: rgba(77,182,232,0.08);
  border-color: var(--royal-blue);
}
.callout--example > h4 { color: var(--royal-blue-dark); }
.callout--example > h4::before { content: "✓"; font-size: 1.1em; }
[data-theme="dark"] .callout--example { background: rgba(77,182,232,0.14); }
[data-theme="dark"] .callout--example > h4 { color: var(--royal-blue-light); }

/* Tip — brand orange */
.callout--tip {
  background: rgba(245,130,57,0.1);
  border-color: var(--brand-orange);
}
.callout--tip > h4 { color: #C2621A; }
.callout--tip > h4::before { content: "★"; font-size: 1em; }
[data-theme="dark"] .callout--tip { background: rgba(245,130,57,0.16); }
[data-theme="dark"] .callout--tip > h4 { color: var(--brand-orange-light); }

/* Worked-example maths block */
.maths {
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;
  background: var(--gray-100);
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--royal-blue);
  margin-block: 10px;
  overflow-x: auto;
  font-size: 0.95rem;
  line-height: 1.7;
}
.maths__step {
  display: block;
  padding: 4px 0;
  white-space: pre;
  color: var(--text-body);
}
.maths__arrow { color: var(--brand-orange); font-weight: 700; padding: 0 8px; }

/* ---------- 10. CTA block (mirrors main-site hero panels) ---------- */
.cta {
  margin-top: var(--space-4);
  padding: var(--space-4);
  background: linear-gradient(165deg, #231F20 0%, #1F4A5C 100%);
  color: #fff;
  border-radius: var(--radius-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
[data-theme="dark"] .cta { background: linear-gradient(165deg, #0A0809 0%, #1F2A30 100%); }
.cta::before {
  content: '';
  position: absolute;
  top: -60%; right: -15%;
  width: 320px; height: 320px;
  background: radial-gradient(circle, rgba(77,182,232,0.25) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}
.cta h3 {
  color: #fff;
  margin-bottom: 10px;
  font-size: 1.4rem;
  position: relative;
}
.cta p {
  color: rgba(255, 255, 255, 0.8);
  max-width: 52ch;
  margin: 0 auto var(--space-3);
  font-size: 1rem;
  position: relative;
}
.cta__btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  position: relative;
}
.cta__btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background: var(--royal-blue);
  color: #fff;
  font-weight: 600;
  border-radius: 50px;
  font-size: 0.95rem;
  box-shadow: 0 4px 14px rgba(77,182,232,0.4), 0 3px 0 0 var(--brand-yellow);
  transition: background var(--transition-base), box-shadow var(--transition-base), transform var(--transition-base), color var(--transition-base);
}
.cta__btn:hover {
  background: var(--royal-blue-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(77,182,232,0.5), 0 3px 0 0 var(--brand-orange);
}
.cta__btn--ghost {
  background: transparent;
  color: #fff;
  border: 1.5px solid rgba(255, 255, 255, 0.35);
  box-shadow: none;
}
.cta__btn--ghost:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.6);
  box-shadow: none;
}

/* ---------- 11. Prev/Next navigation ---------- */
.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2);
  margin-top: var(--space-4);
  padding-top: var(--space-3);
  border-top: 1px solid var(--border-color);
}
.post-nav__item {
  display: block;
  padding: var(--space-2) 18px;
  background: var(--gray-100);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  transition: border-color var(--transition-base), transform var(--transition-base), box-shadow var(--transition-base);
}
.post-nav__item:hover {
  border-color: var(--royal-blue);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}
.post-nav__item--next { text-align: right; }
.post-nav__label {
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 4px;
  display: block;
}
.post-nav__title {
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.95rem;
  line-height: 1.35;
}
@media (max-width: 600px) {
  .post-nav { grid-template-columns: 1fr; }
}

/* ---------- 12. Back-to-top (stacked above WhatsApp float) ---------- */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 96px;
  width: 44px;
  height: 44px;
  background: var(--royal-blue);
  color: #fff;
  border: none;
  border-radius: 50%;
  font-size: 1.2rem;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 14px rgba(77,182,232,0.4);
  z-index: 899;
  cursor: pointer;
  transition: background var(--transition-base), transform var(--transition-base), box-shadow var(--transition-base);
}
.back-to-top:hover {
  background: var(--royal-blue-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(77,182,232,0.5);
}
.back-to-top.is-visible { display: flex; }

/* ---------- 13. Utilities ---------- */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--royal-blue);
  color: #fff;
  padding: 10px 18px;
  border-radius: 0 0 8px 0;
  z-index: 1001;
}
.skip-link:focus { left: 0; }

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 14. Print friendliness ---------- */
@media print {
  .header, .footer, .mobile-menu, .controls, .tag-strip,
  .back-to-top, .whatsapp-float, .post-nav, .cta { display: none !important; }
  .post { page-break-inside: avoid; border: none; box-shadow: none; }
  .cat-hero, .hero { background: none; }
  .hero h1, .page-hero h1 { color: var(--text-primary); }
}