:root {
  --bg-color: #0f172a;
  --card-bg: #1e293b;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent-color: #38bdf8;
  --border-color: #334155;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: var(--font-main);
  line-height: 1.6;
  padding: 2rem 1rem;
}

.container {
  max-width: 800px;
  margin: 0 auto;
}

header {
  margin-bottom: 3rem;
  text-align: center;
}

header h1 {
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(to right, #38bdf8, #818cf8);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
}

header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

#digest-container {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

#filter-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  margin: -0.5rem -1rem 1rem;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  overflow-x: auto;
  scrollbar-width: none;
}

#filter-bar::-webkit-scrollbar {
  display: none;
}

.filter-btn {
  flex-shrink: 0;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.4rem 1rem;
  border-radius: 9999px;
  font-family: var(--font-main);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.filter-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border-color: var(--accent-color);
}

.filter-btn.active {
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent-color);
  border-color: var(--accent-color);
}

.category-section.hidden {
  display: none;
}

.category-section {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.category-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.category-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(to right, #38bdf8, #818cf8);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.category-count {
  background: rgba(129, 140, 248, 0.15);
  color: #818cf8;
  padding: 0.2rem 0.6rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.post-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  display: flex;
  gap: 1.5rem;
  overflow: hidden;
  transition: transform 0.2s ease, border-color 0.2s ease;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.post-thumbnail {
  flex: 0 0 140px;
  height: auto;
  min-height: 100%;
  background: #1e293b;
  border-right: 1px solid var(--border-color);
}

.post-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.post-content {
  flex: 1;
  padding: 1.5rem;
}

.post-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-color);
}

.post-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.source-badge {
  background: rgba(56, 189, 248, 0.1);
  color: var(--accent-color);
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.post-date {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.post-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.post-title a {
  color: var(--text-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.post-title a:hover {
  color: var(--accent-color);
}

.post-description {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 1rem;
}

.toggle-content {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
}

.toggle-content:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
}

.content-preview {
  font-size: 0.9rem;
  color: #cbd5e1;
  line-height: 1.6;
  margin-bottom: 0.75rem;
}

.collapsible-content {
  display: none;
  margin-top: 0.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.9rem;
  color: #cbd5e1;
  white-space: pre-wrap;
  word-wrap: break-word;
  background: rgba(0, 0, 0, 0.2);
  padding: 1rem;
  border-radius: 8px;
}

.collapsible-content.expanded {
  display: block;
  animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 600px) {
  .post-card {
    flex-direction: column;
    gap: 0;
  }
  
  .post-thumbnail {
    flex: 0 0 160px;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .post-content {
    padding: 1.25rem;
  }
}

footer {
  margin-top: 4rem;
  padding-bottom: 2rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
}