/* ── Learning Page Styles ────────────────────────────────────── */

/* Search Bar */
.learning-search {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: 14px 20px;
  margin-bottom: var(--space-lg);
}

.search-icon {
  width: 20px;
  height: 20px;
  stroke: var(--color-text-muted);
  fill: none;
  stroke-width: 2;
  flex-shrink: 0;
}

.search-input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--color-text);
  font-size: 0.95rem;
}

.search-input::placeholder {
  color: var(--color-text-muted);
}

/* Category Tabs */
.topic-categories {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.topic-tab {
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  background: var(--color-surface);
  border: var(--glass-border);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.topic-tab:hover {
  color: var(--color-primary);
  background: rgba(79, 70, 229, 0.08);
}

.topic-tab.active {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

/* Learning Cards Grid */
.learning-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.learning-card {
  padding: var(--space-xl);
  cursor: pointer;
  display: flex;
  flex-direction: column;
}

.learning-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
}

.learning-icon {
  width: 46px;
  height: 46px;
  border-radius: var(--border-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

.learning-icon svg {
  width: 22px;
  height: 22px;
  stroke: white;
  fill: none;
  stroke-width: 2;
}

.learning-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.learning-card p {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  line-height: 1.65;
  flex: 1;
}

.learning-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: var(--glass-border);
}

.read-time {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

@media (max-width: 1024px) {
  .learning-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 580px) {
  .learning-grid { grid-template-columns: 1fr; }
}


/* ============================================================
   DETAIL OVERLAY — Full-screen reading view
   ============================================================
   Opens when a learning card is clicked. Covers the entire
   viewport with a scrollable article + YouTube embed.
   Uses CSS variables for automatic dark/light mode support.
   ============================================================ */

.learning-detail-overlay {
  position: fixed;
  inset: 0;
  z-index: 1500;
  background: var(--color-bg);
  overflow-y: auto;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
}

.learning-detail-overlay.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}


/* ── Sticky Back Header ─────────────────────────────────────── */

.detail-back-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--color-surface);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-bottom: var(--glass-border);
  padding: var(--space-md) var(--space-xl);
}

.detail-back-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 8px 16px;
  border-radius: var(--border-radius-xs);
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--color-primary);
  background: transparent;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.detail-back-btn:hover {
  background: rgba(79, 70, 229, 0.08);
}

.detail-back-btn svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}


/* ── Article Container ──────────────────────────────────────── */

.detail-article {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-xl) var(--space-3xl);
}

/* Meta row: badge, difficulty, read time */
.detail-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
  margin-bottom: var(--space-lg);
}

.detail-meta .read-time {
  margin-left: auto;
}

/* Article Title */
.detail-article h1 {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.25;
  color: var(--color-text);
  margin-bottom: var(--space-xl);
  letter-spacing: -0.02em;
}

/* Section Headings */
.detail-article h2 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-border);
}

/* Body Paragraphs — optimized for long-form reading */
.detail-article p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

/* Lists */
.detail-article ul {
  margin: var(--space-md) 0;
  padding-left: var(--space-lg);
}

.detail-article ul li {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  position: relative;
  list-style: none;
  padding-left: var(--space-md);
}

.detail-article ul li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-weight: 700;
}

/* Highlighted callout box */
.detail-callout {
  background: rgba(79, 70, 229, 0.06);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--border-radius-xs) var(--border-radius-xs) 0;
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--color-text);
}

[data-theme="dark"] .detail-callout {
  background: rgba(79, 70, 229, 0.12);
}


/* ── YouTube Video Embed ────────────────────────────────────── */

.video-section-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.video-container {
  position: relative;
  width: 100%;
  padding-top: 56.25%;       /* 16:9 Aspect Ratio */
  border-radius: var(--border-radius);
  overflow: hidden;
  background: #000;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
  margin-bottom: var(--space-xl);
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}


/* ── Responsive ─────────────────────────────────────────────── */

@media (max-width: 768px) {
  .detail-article {
    padding: var(--space-xl) var(--space-md) var(--space-2xl);
  }

  .detail-article h1 {
    font-size: 1.6rem;
  }

  .detail-back-header {
    padding: var(--space-sm) var(--space-md);
  }
}

@media (max-width: 480px) {
  .detail-article h1 {
    font-size: 1.35rem;
  }

  .detail-article h2 {
    font-size: 1.1rem;
  }

  .detail-meta {
    flex-direction: column;
    align-items: flex-start;
  }

  .detail-meta .read-time {
    margin-left: 0;
  }
}