/* hub.css — Educational Hub styles: editorial, brass-and-slate palette */

:root {
  --slate-900: #0f172a;
  --slate-700: #334155;
  --slate-500: #64748b;
  --slate-200: #e2e8f0;
  --slate-100: #f1f5f9;
  --brass: #b8860b;
  --brass-light: #d4a017;
  --brass-dark: #8b6508;
  --cream: #faf9f7;
  --white: #ffffff;
  --amber-50: #fffbeb;
}

body {
  background: var(--cream);
  color: var(--slate-900);
  font-family: 'Georgia', 'Times New Roman', serif;
  line-height: 1.7;
}

.hub-nav {
  background: var(--slate-900);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  gap: 0;
  height: 60px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.hub-nav-logo {
  color: var(--brass-light);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  text-decoration: none;
  font-family: system-ui, sans-serif;
  margin-right: auto;
}

.hub-nav-links {
  display: flex;
  gap: 0;
  list-style: none;
  margin: 0;
  padding: 0;
}

.hub-nav-links li a {
  color: var(--slate-200);
  text-decoration: none;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-family: system-ui, sans-serif;
  padding: 0 1rem;
  height: 60px;
  display: flex;
  align-items: center;
  border-bottom: 3px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.hub-nav-links li a:hover,
.hub-nav-links li a.active {
  color: var(--brass-light);
  border-bottom-color: var(--brass-light);
}

/* Hero */
.hub-hero {
  background: var(--slate-900);
  color: var(--white);
  padding: 5rem 2rem 4rem;
  text-align: center;
}

.hub-hero h1 {
  font-size: 2.8rem;
  font-weight: 400;
  margin: 0 0 1rem;
  letter-spacing: -0.01em;
}

.hub-hero p {
  font-size: 1.15rem;
  color: var(--slate-200);
  max-width: 600px;
  margin: 0 auto 2rem;
  font-family: system-ui, sans-serif;
  line-height: 1.6;
}

/* Search */
.hub-search {
  max-width: 500px;
  margin: 0 auto;
  position: relative;
}

.hub-search input {
  width: 100%;
  padding: 0.75rem 1rem 0.75rem 2.5rem;
  border-radius: 4px;
  border: 1px solid rgba(255,255,255,0.2);
  background: rgba(255,255,255,0.1);
  color: var(--white);
  font-size: 1rem;
  font-family: system-ui, sans-serif;
  outline: none;
  box-sizing: border-box;
}

.hub-search input::placeholder {
  color: rgba(255,255,255,0.5);
}

.hub-search-icon {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: rgba(255,255,255,0.5);
  pointer-events: none;
}

/* Category Filters */
.hub-filters {
  background: var(--white);
  border-bottom: 1px solid var(--slate-200);
  padding: 0.75rem 2rem;
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  flex-wrap: nowrap;
}

.filter-btn {
  padding: 0.4rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--slate-200);
  background: transparent;
  color: var(--slate-700);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  font-family: system-ui, sans-serif;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--slate-900);
  color: var(--brass-light);
  border-color: var(--slate-900);
}

/* Content Area */
.hub-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem;
}

/* Category Section */
.hub-category {
  margin-bottom: 3rem;
}

.hub-category h2 {
  font-size: 1.4rem;
  font-weight: 400;
  color: var(--slate-700);
  margin: 0 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--slate-200);
}

.hub-category-label {
  color: var(--brass);
}

/* Article Grid */
.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.article-card {
  background: var(--white);
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--slate-200);
  transition: box-shadow 0.2s, transform 0.2s;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: block;
}

.article-card:hover {
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  transform: translateY(-2px);
}

.article-card-image {
  height: 160px;
  background: var(--slate-100);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
}

.article-card-body {
  padding: 1.25rem;
}

.article-card-category {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brass);
  font-family: system-ui, sans-serif;
  margin-bottom: 0.4rem;
}

.article-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 0 0 0.5rem;
  line-height: 1.3;
}

.article-card p {
  font-size: 0.88rem;
  color: var(--slate-500);
  margin: 0 0 1rem;
  line-height: 1.5;
}

.article-card-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.75rem;
  color: var(--slate-500);
  font-family: system-ui, sans-serif;
}

.article-card-meta svg {
  flex-shrink: 0;
}

.bookmark-btn {
  margin-left: auto;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--slate-500);
  padding: 0.2rem;
  transition: color 0.15s;
  flex-shrink: 0;
}

.bookmark-btn:hover,
.bookmark-btn.bookmarked {
  color: var(--brass);
}

/* Bookmarks Section */
.bookmarks-section {
  background: var(--amber-50);
  border: 1px solid var(--brass-light);
  border-radius: 4px;
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.bookmarks-section h3 {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--brass-dark);
  font-family: system-ui, sans-serif;
  margin: 0 0 1rem;
}

.bookmark-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.bookmark-chip {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--white);
  border: 1px solid var(--brass-light);
  border-radius: 999px;
  padding: 0.3rem 0.75rem 0.3rem 0.5rem;
  text-decoration: none;
  color: var(--slate-700);
  font-size: 0.8rem;
  font-family: system-ui, sans-serif;
  transition: background 0.15s;
}

.bookmark-chip:hover {
  background: var(--slate-100);
}

.bookmark-chip svg {
  color: var(--brass);
  flex-shrink: 0;
}

/* Article Page */
.article-page {
  max-width: 720px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.article-back {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--slate-500);
  text-decoration: none;
  font-size: 0.85rem;
  font-family: system-ui, sans-serif;
  margin-bottom: 2rem;
  transition: color 0.15s;
}

.article-back:hover { color: var(--brass); }

.article-header {
  margin-bottom: 2rem;
}

.article-category-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--brass);
  background: var(--amber-50);
  border: 1px solid var(--brass-light);
  padding: 0.2rem 0.6rem;
  border-radius: 2px;
  font-family: system-ui, sans-serif;
  margin-bottom: 0.75rem;
}

.article-page h1 {
  font-size: 2.2rem;
  font-weight: 700;
  line-height: 1.2;
  margin: 0 0 0.75rem;
}

.article-subtitle {
  font-size: 1.15rem;
  color: var(--slate-500);
  font-style: italic;
  margin: 0 0 1.25rem;
}

.article-meta-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.82rem;
  color: var(--slate-500);
  font-family: system-ui, sans-serif;
  padding: 1rem 0;
  border-top: 1px solid var(--slate-200);
  border-bottom: 1px solid var(--slate-200);
}

.article-actions {
  margin-left: auto;
  display: flex;
  gap: 0.5rem;
}

.action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--slate-200);
  background: transparent;
  color: var(--slate-700);
  font-size: 0.75rem;
  font-family: system-ui, sans-serif;
  cursor: pointer;
  transition: all 0.15s;
}

.action-btn:hover {
  border-color: var(--brass);
  color: var(--brass-dark);
}

.action-btn.completed {
  background: var(--brass);
  color: var(--white);
  border-color: var(--brass);
}

.action-btn.bookmarked {
  color: var(--brass);
  border-color: var(--brass);
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.8;
}

.article-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 2.5rem 0 1rem;
  color: var(--slate-900);
}

.article-content h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 2rem 0 0.75rem;
}

.article-content p {
  margin: 0 0 1.25rem;
}

.article-content ul, .article-content ol {
  margin: 0 0 1.25rem 1.5rem;
}

.article-content li {
  margin-bottom: 0.4rem;
}

.article-content strong {
  color: var(--slate-900);
  font-weight: 700;
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
}

.article-content table th {
  background: var(--slate-900);
  color: var(--white);
  font-family: system-ui, sans-serif;
  font-weight: 600;
  text-align: left;
  padding: 0.6rem 0.9rem;
}

.article-content table td {
  padding: 0.6rem 0.9rem;
  border: 1px solid var(--slate-200);
  font-family: system-ui, sans-serif;
}

.article-content table tr:nth-child(even) td {
  background: var(--slate-100);
}

/* Category Icons */
.cat-icon { font-size: 1.8rem; display: block; text-align: center; }

/* Loading */
.hub-loading {
  text-align: center;
  padding: 3rem;
  color: var(--slate-500);
  font-family: system-ui, sans-serif;
}

/* Responsive */
@media (max-width: 600px) {
  .hub-hero h1 { font-size: 1.8rem; }
  .hub-content { padding: 1rem; }
  .article-page { padding: 2rem 1rem; }
  .article-page h1 { font-size: 1.6rem; }
  .hub-grid { grid-template-columns: 1fr; }
  .hub-nav { padding: 0 1rem; }
}