/* ============================================================
   BatchBrain Feed System v2
   Tokens + primitives for the learning feed. Extends
   layout-system.css. Reference discipline: one accent,
   content-type legibility at a glance, progress as a
   first-class citizen, horizontal card layout.
   ============================================================ */

:root {
  /* ── Content-type palette ─────────────────────────────────── */
  --ct-course:        #6E71EF;
  --ct-course-soft:   rgba(110,113,239,0.14);
  --ct-course-bg:     linear-gradient(135deg, #6E71EF, #3F3FA8);
  --ct-article:       #2FB088;
  --ct-article-soft:  rgba(47,176,136,0.14);
  --ct-article-bg:    linear-gradient(135deg, #2FB088, #1B7A5E);
  --ct-book:          #D97757;
  --ct-book-soft:     rgba(217,119,87,0.14);
  --ct-book-bg:       linear-gradient(135deg, #D97757, #A9532E);
  --ct-quiz:          #3B82F6;
  --ct-quiz-soft:     rgba(59,130,246,0.14);
  --ct-roadmap:       #F59E0B;
  --ct-roadmap-soft:  rgba(245,158,11,0.14);

  /* ── Card tokens ──────────────────────────────────────────── */
  --feed-card-radius: 12px;
  --feed-card-gap:    16px;
  --feed-thumb-size:  88px;

  /* ── Progress ring ────────────────────────────────────────── */
  --progress-ring-size:   28px;
  --progress-ring-stroke: 3;
}

/* ============================================================
   FILTER TABS — underline style (reference pattern)
   ============================================================ */
.feed-tabs {
  display: flex; gap: var(--space-1);
  padding: 0 var(--space-6); margin-bottom: var(--space-5);
  border-bottom: 1px solid var(--bb-border, #e2e8f0);
}

.feed-tab {
  padding: var(--space-3) var(--space-1);
  font-size: 13.5px; font-weight: 600;
  color: var(--text-light, #9ca3af);
  border-bottom: 2px solid transparent;
  margin-right: var(--space-4);
  text-decoration: none;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  cursor: pointer;
  white-space: nowrap;
}
.feed-tab:hover { color: var(--text-secondary, #4b5563); }
.feed-tab.active {
  color: var(--text-primary, #111827);
  border-bottom-color: var(--accent, #009fff);
}

/* Mobile: fixed filter bar above bottom nav, horizontally scrollable */
@media (max-width: 991.98px) {
  .feed-tabs {
    position: fixed !important;
    bottom: calc(var(--bottom-nav-height) + env(safe-area-inset-bottom, 0px));
    left: 0; right: 0;
    z-index: 1029;
    flex-wrap: nowrap; overflow-x: auto; overflow-y: hidden;
    margin-bottom: 0; padding: 8px 12px;
    background: var(--bb-surface, #fff);
    border-bottom: none;
    border-top: 1px solid var(--bb-border, #e2e8f0);
    scrollbar-width: none; -ms-overflow-style: none;
  }
  .feed-tabs::-webkit-scrollbar { display: none; }
  .feed-tab { margin-right: var(--space-3); }
}

/* ============================================================
   FEED CARD — horizontal layout (thumbnail left, body right)
   Reference pattern: 88×88px gradient thumbnail, type badge,
   title, description, footer with progress ring + save/cta.
   ============================================================ */
.feed-card {
  display: flex; gap: var(--space-4);
  background: var(--bb-surface, #fff);
  border: 1px solid var(--bb-border-soft, var(--bb-border, #e2e8f0));
  border-radius: var(--feed-card-radius);
  padding: var(--space-4);
  margin-bottom: var(--feed-card-gap);
  text-decoration: none; color: inherit;
  transition: border-color var(--transition-fast);
}
.feed-card:hover {
  border-color: var(--bb-border, #cbd5e1);
}

/* ── Thumbnail — gradient background per content type ────────── */
.feed-card-thumb {
  width: var(--feed-thumb-size); height: var(--feed-thumb-size);
  border-radius: var(--radius-sm); flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display, serif);
  font-weight: 800; font-size: 20px; color: #fff;
  overflow: hidden;
}
.feed-card-thumb img {
  width: 100%; height: 100%; object-fit: cover;
}
.feed-card-thumb--course  { background: var(--ct-course-bg); }
.feed-card-thumb--article { background: var(--ct-article-bg); }
.feed-card-thumb--book    { background: var(--ct-book-bg); }
.feed-card-thumb--quiz    {
  background: var(--ct-quiz-soft); color: var(--ct-quiz);
  font-size: 28px;
}
.feed-card-thumb--roadmap {
  background: var(--ct-roadmap-soft); color: var(--ct-roadmap);
  font-size: 28px;
}

/* ── Body — flex: 1, min-width: 0 prevents overflow ─────────── */
.feed-card-body { flex: 1; min-width: 0; }

/* ── Meta row: type badge + source ──────────────────────────── */
.feed-card-meta {
  display: flex; align-items: center; gap: var(--space-2);
  margin-bottom: var(--space-1);
}

/* Type badge — content-type legibility at a glance */
.feed-card-type-badge {
  font-family: var(--font-mono, monospace);
  font-size: 10.5px; font-weight: 500;
  letter-spacing: 0.05em; text-transform: uppercase;
  padding: 2px 7px; border-radius: 4px;
}
.feed-card-type-badge--course  { color: var(--ct-course);  background: var(--ct-course-soft); }
.feed-card-type-badge--article { color: var(--ct-article); background: var(--ct-article-soft); }
.feed-card-type-badge--book    { color: var(--ct-book);    background: var(--ct-book-soft); }
.feed-card-type-badge--quiz    { color: var(--ct-quiz);    background: var(--ct-quiz-soft); }
.feed-card-type-badge--roadmap { color: var(--ct-roadmap); background: var(--ct-roadmap-soft); }

.feed-card-source {
  font-size: 12px; color: var(--text-light, #9ca3af);
}

/* ── Title ──────────────────────────────────────────────────── */
.feed-card-title {
  font-family: var(--font-display, serif);
  font-weight: 700; font-size: 15.5px;
  letter-spacing: -0.01em; line-height: 1.35;
  margin: 2px 0 var(--space-1);
  color: var(--text-primary, #111827);
  display: -webkit-box; -webkit-line-clamp: 2;
  -webkit-box-orient: vertical; overflow: hidden;
}

/* ── Description ────────────────────────────────────────────── */
.feed-card-desc {
  font-size: 13px; color: var(--text-secondary, #4b5563);
  line-height: 1.5;
  display: -webkit-box; -webkit-line-clamp: 2;
  -webkit-box-orient: vertical; overflow: hidden;
  margin-bottom: var(--space-3);
}

/* ── Badge row ──────────────────────────────────────────────── */
.feed-card-badges {
  display: flex; flex-wrap: wrap; gap: 4px;
  margin-bottom: var(--space-2);
}
.feed-card-badge {
  font-size: 0.62rem; font-weight: 600;
  padding: 2px 8px; border-radius: 5px;
}
.feed-card-badge--blue   { color: var(--ct-quiz);    background: var(--ct-quiz-soft); }
.feed-card-badge--green  { color: var(--ct-article); background: var(--ct-article-soft); }
.feed-card-badge--amber  { color: var(--ct-roadmap); background: var(--ct-roadmap-soft); }
.feed-card-badge--purple { color: var(--ct-course);  background: var(--ct-course-soft); }

/* ── Footer: stats on left, progress ring + CTA on right ───── */
.feed-card-footer {
  display: flex; align-items: center; gap: var(--space-4);
}

.feed-card-stat {
  display: flex; align-items: center; gap: 5px;
  font-size: 12px; color: var(--text-light, #9ca3af);
}

/* ── Progress wrap (ring + percentage) ──────────────────────── */
.feed-progress-wrap {
  margin-left: auto;
  display: flex; align-items: center; gap: var(--space-2);
}
.feed-progress-pct {
  font-family: var(--font-mono, monospace);
  font-size: 11px; color: var(--text-secondary, #4b5563);
}

/* SVG Progress Ring — signature detail from reference */
.feed-progress-ring {
  position: relative; width: 28px; height: 28px;
}
.feed-progress-ring svg { transform: rotate(-90deg); overflow: visible; }
.feed-progress-ring__bg {
  fill: none; stroke: var(--bb-border, #e2e8f0); stroke-width: 3;
}
.feed-progress-ring__fill {
  fill: none; stroke: var(--accent, #009fff);
  stroke-width: 3; stroke-linecap: round;
  transition: stroke-dashoffset 300ms ease;
}

/* ── Save/bookmark button ───────────────────────────────────── */
.feed-save-btn {
  width: 28px; height: 28px;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-sm);
  background: transparent; border: none;
  color: var(--text-light, #9ca3af);
  cursor: pointer;
  transition: color var(--transition-fast), background var(--transition-fast);
}
.feed-save-btn:hover {
  color: var(--accent-text, #0077cc);
  background: var(--accent-soft, #eef7ff);
}

/* ── CTA button ─────────────────────────────────────────────── */
.feed-card-cta {
  display: inline-flex; align-items: center; gap: 5px;
  padding: 6px 14px; border-radius: 7px;
  font-size: 0.72rem; font-weight: 600;
  background: var(--accent, #009fff); color: #fff;
  text-decoration: none; white-space: nowrap;
  transition: background 150ms ease;
}
.feed-card-cta:hover { background: var(--accent-hover, #0088dd); }

/* ── Progress bar (alternate, used for simple progress) ─────── */
.feed-card-progress-bar {
  height: 4px; background: var(--bb-border, #e2e8f0);
  border-radius: 2px; overflow: hidden; margin-bottom: 8px;
}
.feed-card-progress-fill {
  height: 100%; border-radius: 2px;
  background: var(--accent, #009fff);
  transition: width 300ms ease;
}

/* ── Mobile: smaller thumbnail ──────────────────────────────── */
@media (max-width: 640px) {
  .feed-card-thumb {
    width: 64px; height: 64px;
  }
  .feed-card { padding: var(--space-3); gap: var(--space-3); }
  .feed-card-title { font-size: 14px; }
}

/* ============================================================
   SOCIAL POST CARD
   Different structure: publisher header, text body, media,
   attachments, interaction row. Not link-wrapped.
   ============================================================ */
.feed-post-card {
  border: 1px solid var(--bb-border, #e2e8f0);
  border-radius: var(--feed-card-radius);
  background: var(--bb-surface, #fff); overflow: hidden;
  margin-bottom: var(--space-2);
}

.feed-post-header {
  display: flex; align-items: flex-start; justify-content: space-between;
  padding: 12px 16px 8px;
}
.feed-post-avatar {
  width: 44px; height: 44px; border-radius: 8px;
  object-fit: cover; flex-shrink: 0;
}

.feed-post-publisher {
  display: flex; align-items: flex-start; gap: 8px;
  text-decoration: none; flex: 1; min-width: 0;
}

.feed-post-body { padding: 0 16px 8px; }
.feed-post-text {
  font-size: 0.88rem; line-height: 1.6; white-space: break-spaces;
  color: var(--text-primary, #212529); margin-bottom: 12px;
}

.feed-post-media {
  display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 8px;
}
.feed-post-media img {
  max-width: 200px; max-height: 200px; object-fit: cover;
  border-radius: 8px; cursor: pointer;
}
.feed-post-attachment {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 12px; border-radius: 8px;
  border: 1px solid var(--bb-border, #e2e8f0);
  background: var(--bb-border-light, #f1f5f9);
  font-size: 0.78rem; text-decoration: none; margin-bottom: 6px;
}

.feed-post-actions {
  display: flex; gap: 4px;
  border-top: 1px solid var(--bb-border, #e2e8f0);
  padding: 8px 16px;
}
.feed-post-action-btn {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 5px 10px; border-radius: 7px; border: none;
  background: transparent; color: var(--text-secondary, #6c757d);
  font-size: 0.74rem; font-weight: 500; cursor: pointer;
  transition: background 150ms, color 150ms;
}
.feed-post-action-btn:hover { background: var(--bb-border-light, #f1f5f9); }
.feed-post-action-btn--liked { color: #dc3545; }

/* ============================================================
   CREATE-POST CARD
   ============================================================ */
.feed-create-post {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; border-radius: var(--feed-card-radius);
  border: 1px solid var(--bb-border, #e2e8f0);
  background: var(--bb-surface, #fff);
  cursor: pointer; margin-bottom: 14px;
  transition: border-color var(--transition-fast);
}
.feed-create-post:hover { border-color: var(--accent-border, #b3dfff); }

.feed-create-post-avatar {
  width: 44px; height: 44px; border-radius: 8px;
  object-fit: cover; flex-shrink: 0;
}

.feed-create-post-input {
  flex: 1; height: 44px; border-radius: 50px;
  background: var(--bb-border-light, #f1f5f9); border: none;
  padding: 0 18px; font-size: 0.88rem;
  color: var(--text-secondary, #6c757d); cursor: pointer;
}

/* ============================================================
   PAGE HEADER — eyebrow + title + subtitle (reference pattern)
   ============================================================ */
.feed-page-header {
  padding: var(--space-6) var(--space-6) var(--space-4);
}
.feed-page-eyebrow {
  font-family: var(--font-mono, monospace);
  font-size: 11px; color: var(--accent-text, #0077cc);
  letter-spacing: 0.04em; margin-bottom: var(--space-2);
}
.feed-page-title {
  font-family: var(--font-display, serif);
  font-weight: 800; font-size: 24px;
  letter-spacing: -0.02em; margin: 0 0 var(--space-1);
}
.feed-page-subtitle {
  color: var(--text-secondary, #4b5563);
  font-size: 14px; margin: 0;
}

/* ============================================================
   SKELETON LOADERS
   ============================================================ */
.feed-skeleton {
  display: flex; gap: var(--space-4);
  border: 1px solid var(--bb-border, #e2e8f0);
  border-radius: var(--feed-card-radius);
  padding: var(--space-4); margin-bottom: 12px;
  background: var(--bb-surface, #fff);
}
.feed-skeleton-thumb {
  width: var(--feed-thumb-size); height: var(--feed-thumb-size);
  border-radius: var(--radius-sm); flex-shrink: 0;
  background: var(--bb-border-light, #f1f5f9);
}
.feed-skeleton-body { flex: 1; min-width: 0; }
.feed-skeleton-line {
  height: 12px; border-radius: 6px; margin-bottom: 8px;
  background: var(--bb-border-light, #f1f5f9);
}
.feed-skeleton-line--sm { width: 60%; }
.feed-skeleton-line--md { width: 80%; }
.feed-skeleton-line--lg { width: 100%; }
.feed-skeleton-badge {
  height: 22px; width: 70px; border-radius: 4px;
  background: var(--bb-border-light, #f1f5f9);
  margin-bottom: 8px;
}

.feed-skeleton-shimmer {
  background: linear-gradient(90deg, transparent 25%, rgba(255,255,255,0.5) 37%, transparent 63%);
  background-size: 400% 100%;
  animation: feed-shimmer 1.6s ease infinite;
}
@keyframes feed-shimmer {
  0% { background-position: 100% 0; }
  100% { background-position: -100% 0; }
}

[data-bs-theme="dark"] .feed-skeleton .feed-skeleton-thumb,
[data-bs-theme="dark"] .feed-skeleton .feed-skeleton-line,
[data-bs-theme="dark"] .feed-skeleton .feed-skeleton-badge {
  background: rgba(255,255,255,0.04);
}
[data-bs-theme="dark"] .feed-skeleton .feed-skeleton-shimmer {
  background-image: linear-gradient(90deg, transparent 25%, rgba(255,255,255,0.04) 37%, transparent 63%);
}

/* ============================================================
   FEED STATES
   ============================================================ */
.feed-empty-state {
  text-align: center; padding: 48px 16px;
}
.feed-empty-state-icon {
  font-size: 2.5rem; opacity: 0.1;
  color: var(--text-secondary, #6c757d); margin-bottom: 12px;
}
.feed-end-marker {
  text-align: center; padding: 32px 16px;
  color: var(--text-secondary, #6c757d); font-size: 0.78rem;
}
.feed-end-marker i {
  display: block; font-size: 1.4rem; opacity: 0.12; margin-bottom: 8px;
}

.feed-loading-more {
  text-align: center; padding: 16px;
  display: flex; align-items: center; justify-content: center; gap: 8px;
}
.feed-spinner {
  width: 20px; height: 20px;
  border: 2px solid var(--bb-border, #e9ecef);
  border-top-color: var(--accent, #009fff);
  border-radius: 50%;
  animation: feed-spin 0.7s linear infinite;
  display: inline-block;
}
@keyframes feed-spin { to { transform: rotate(360deg); } }

/* ── Card entrance animation ────────────────────────────────── */
@keyframes feed-card-enter {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}
.feed-card-animate { animation: feed-card-enter 0.4s ease both; }
.feed-card-animate:nth-child(1) { animation-delay: 0s; }
.feed-card-animate:nth-child(2) { animation-delay: 0.04s; }
.feed-card-animate:nth-child(3) { animation-delay: 0.08s; }
.feed-card-animate:nth-child(4) { animation-delay: 0.12s; }
.feed-card-animate:nth-child(5) { animation-delay: 0.15s; }

/* ============================================================
   FEED SIDEBAR
   ============================================================ */
.feed-sidebar-stat {
  padding: 12px 14px;
  border: 1px solid var(--bb-border, #e2e8f0);
  border-radius: 10px; background: var(--bb-surface, #fff);
  margin-bottom: 8px;
}
.feed-sidebar-stat-num {
  font-size: 1.4rem; font-weight: 700;
  color: var(--accent, #009fff); line-height: 1;
}
.feed-sidebar-stat-label {
  font-size: 0.68rem; color: var(--text-secondary, #6c757d);
  margin-top: 2px;
}

.feed-sidebar-suggestion {
  display: flex; align-items: center; gap: 8px;
  padding: 8px; border-radius: 8px; cursor: pointer;
  transition: background 150ms; margin-bottom: 2px;
}
.feed-sidebar-suggestion:hover { background: var(--bb-border-light, #f1f5f9); }

.feed-sidebar-suggestion-icon {
  width: 32px; height: 32px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  background: var(--ct-quiz-soft); color: var(--ct-quiz);
  font-size: 0.8rem;
}

/* ── FAB (mobile) ───────────────────────────────────────────── */
.feed-fab {
  position: fixed;
  bottom: calc(var(--bottom-nav-height) + 60px);
  right: 16px; z-index: 1040;
  width: 52px; height: 52px; border-radius: 50%;
  border: none; background: var(--accent, #009fff); color: #fff;
  font-size: 26px;
  box-shadow: 0 4px 16px rgba(0,159,255,0.25);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: transform 0.2s, box-shadow 0.2s;
}
.feed-fab:hover {
  transform: scale(1.08);
  box-shadow: 0 6px 20px rgba(0,159,255,0.4);
}

/* ── Feed column widths ─────────────────────────────────────── */
.feed-col {
  max-width: var(--content-narrow); width: 100%;
}