/* ========== CSS Custom Properties ========== */
:root {
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", Menlo, monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);

  --transition: 0.15s ease;
  --max-width: 1080px;
}

/* Light theme */
[data-theme="light"] {
  --bg-primary: #f5f6f8;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f0f1f5;
  --bg-hover: #ecedf2;
  --bg-active: #e2e4ea;

  --text-primary: #111318;
  --text-secondary: #4b5063;
  --text-tertiary: #8790a5;
  --text-inverse: #ffffff;

  --border: #e0e2e9;
  --border-light: #ecedf2;

  --accent: #4f6df5;
  --accent-hover: #3b57d9;
  --accent-light: #edf0ff;
  --accent-text: #4361d9;

  --success: #16a34a;
  --success-light: #ecfdf5;
  --warning: #d97706;
  --warning-light: #fffbeb;
  --danger: #dc2626;
  --danger-light: #fef2f2;
  --info: #2563eb;
  --info-light: #eff6ff;

  --score-high: #16a34a;
  --score-mid: #d97706;
  --score-low: #94a3b8;

  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.04), 0 0 0 1px rgba(0, 0, 0, 0.03);
  --card-shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.06), 0 0 0 1px rgba(0, 0, 0, 0.04);

  --navbar-bg: rgba(255, 255, 255, 0.85);
  --navbar-blur: blur(12px);
}

/* Dark theme */
[data-theme="dark"] {
  --bg-primary: #0c0d12;
  --bg-secondary: #16181f;
  --bg-tertiary: #1e2029;
  --bg-hover: #252732;
  --bg-active: #2e313e;

  --text-primary: #e8eaf0;
  --text-secondary: #9299ad;
  --text-tertiary: #5f6680;
  --text-inverse: #0c0d12;

  --border: #252732;
  --border-light: #1e2029;

  --accent: #6b8aff;
  --accent-hover: #8aa2ff;
  --accent-light: #161d35;
  --accent-text: #8aa2ff;

  --success: #34d399;
  --success-light: #0c2419;
  --warning: #fbbf24;
  --warning-light: #231c07;
  --danger: #f87171;
  --danger-light: #231010;
  --info: #60a5fa;
  --info-light: #0f1a2e;

  --score-high: #34d399;
  --score-mid: #fbbf24;
  --score-low: #5f6680;

  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.15), 0 0 0 1px rgba(255, 255, 255, 0.03);
  --card-shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.25), 0 0 0 1px rgba(255, 255, 255, 0.05);

  --navbar-bg: rgba(12, 13, 18, 0.85);
  --navbar-blur: blur(12px);
}

/* ========== Reset & Base ========== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: var(--accent-text);
  text-decoration: none;
  transition: color var(--transition);
}

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

/* ========== Navbar ========== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--navbar-bg);
  backdrop-filter: var(--navbar-blur);
  -webkit-backdrop-filter: var(--navbar-blur);
  border-bottom: 1px solid var(--border);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 56px;
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
}

.nav-brand:hover {
  color: var(--text-primary);
}

.brand-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  background: var(--accent);
  color: var(--text-inverse);
  border-radius: var(--radius-sm);
}

.nav-links {
  display: flex;
  gap: 2px;
}

.nav-link {
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  font-size: 0.87rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.nav-link.active {
  color: var(--accent-text);
  background: var(--accent-light);
  font-weight: 600;
}

/* ========== Container ========== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font-sans);
  white-space: nowrap;
}

.btn:hover {
  background: var(--bg-hover);
  border-color: var(--text-tertiary);
}

.btn:active {
  background: var(--bg-active);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: var(--text-inverse);
  border-color: var(--accent);
  font-weight: 600;
}

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

.btn-sm {
  padding: 0.3rem 0.7rem;
  font-size: 0.8rem;
}

.btn-icon {
  padding: 0.45rem;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
}

.btn-icon:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.icon {
  width: 18px;
  height: 18px;
}

[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

/* ========== Page Header ========== */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.page-actions {
  display: flex;
  gap: 0.5rem;
}

.page-title {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
}

.page-subtitle {
  color: var(--text-tertiary);
  font-size: 0.87rem;
  margin-top: 0.2rem;
}

/* ========== Cards ========== */
.card {
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow);
  overflow: hidden;
  transition: box-shadow var(--transition);
}

.card-body {
  padding: 1.1rem 1.25rem;
}

/* ========== Feed / Items ========== */
.filter-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.search-input {
  flex: 1;
  min-width: 200px;
  padding: 0.55rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.87rem;
  font-family: var(--font-sans);
  transition: border-color var(--transition), box-shadow var(--transition);
  outline: none;
}

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

.search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.filter-select {
  padding: 0.55rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.83rem;
  font-family: var(--font-sans);
  cursor: pointer;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%236b7185' viewBox='0 0 16 16'%3E%3Cpath d='M4 6l4 4 4-4'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.6rem center;
  padding-right: 2rem;
}

.filter-select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.item-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* ========== Item Card ========== */
.item-card {
  display: flex;
  gap: 0.9rem;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-light);
  transition: background var(--transition);
  align-items: flex-start;
}

.item-card:hover {
  background: var(--bg-hover);
}

.item-card:last-child {
  border-bottom: none;
}

.item-score {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  font-weight: 700;
  font-family: var(--font-mono);
  margin-top: 0.15rem;
}

.item-score.high {
  background: var(--success-light);
  color: var(--score-high);
}

.item-score.mid {
  background: var(--warning-light);
  color: var(--score-mid);
}

.item-score.low {
  background: var(--bg-tertiary);
  color: var(--score-low);
}

.item-content {
  flex: 1;
  min-width: 0;
}

.item-title {
  font-size: 0.93rem;
  font-weight: 600;
  line-height: 1.45;
  color: var(--text-primary);
  display: block;
  transition: color var(--transition);
}

.item-title:hover {
  color: var(--accent-text);
}

.item-meta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.35rem;
  font-size: 0.78rem;
  color: var(--text-tertiary);
  flex-wrap: wrap;
}

.item-author {
  color: var(--accent-text);
  font-weight: 600;
}

.item-meta-divider {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--text-tertiary);
  opacity: 0.4;
  flex-shrink: 0;
}

.item-summary {
  margin-top: 0.4rem;
  font-size: 0.83rem;
  color: var(--text-secondary);
  line-height: 1.55;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.item-tags {
  display: flex;
  gap: 0.35rem;
  margin-top: 0.45rem;
  flex-wrap: wrap;
}

.tag {
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.tag-source {
  background: var(--accent-light);
  color: var(--accent-text);
}

.tag-type {
  background: var(--bg-tertiary);
  color: var(--text-tertiary);
}

.tag-type-paper {
  background: var(--info-light);
  color: var(--info);
}

.tag-type-repo {
  background: var(--success-light);
  color: var(--success);
}

.tag-type-post {
  background: var(--warning-light);
  color: var(--warning);
}

.tag-type-discussion {
  background: var(--danger-light);
  color: var(--danger);
}

/* ========== Pagination ========== */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 0;
  padding: 0.85rem;
  border-top: 1px solid var(--border-light);
}

.pagination-info {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  margin: 0 0.75rem;
  font-variant-numeric: tabular-nums;
}

/* ========== Sources ========== */
.source-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 0.75rem;
}

.source-card {
  padding: 1.1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  transition: box-shadow var(--transition);
}

.source-card:hover {
  box-shadow: var(--card-shadow-hover);
}

.source-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.source-name {
  font-weight: 600;
  font-size: 0.93rem;
}

.source-badge {
  padding: 0.15rem 0.55rem;
  border-radius: 20px;
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.source-badge.enabled {
  background: var(--success-light);
  color: var(--success);
}

.source-badge.disabled {
  background: var(--danger-light);
  color: var(--danger);
}

.source-url {
  font-size: 0.78rem;
  color: var(--text-tertiary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.source-type {
  font-size: 0.78rem;
  color: var(--text-secondary);
}

.source-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.15rem;
}

/* ========== Digest ========== */
.digest-content {
  padding: 1.75rem;
  line-height: 1.75;
}

.digest-content h1 {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-light);
  letter-spacing: -0.03em;
}

.digest-content h2 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.digest-content h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-top: 1rem;
  margin-bottom: 0.35rem;
  color: var(--text-secondary);
}

.digest-content p {
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.digest-content ul, .digest-content ol {
  margin-bottom: 0.75rem;
  padding-left: 1.5rem;
}

.digest-content li {
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
}

.digest-content a {
  color: var(--accent-text);
}

.digest-content strong {
  color: var(--text-primary);
  font-weight: 600;
}

.digest-content code {
  background: var(--bg-tertiary);
  padding: 0.15rem 0.35rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.85em;
}

.digest-meta {
  padding: 0.85rem 1.25rem;
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.82rem;
  color: var(--text-secondary);
  flex-wrap: wrap;
}

.digest-meta strong {
  color: var(--text-primary);
}

/* ========== Stats Row ========== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.stat-card {
  text-align: center;
  padding: 1.25rem 1rem;
}

.stat-value {
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  font-family: var(--font-mono);
}

.stat-label {
  font-size: 0.72rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
  margin-top: 0.25rem;
}

/* ========== Empty / Loading States ========== */
.empty-state {
  text-align: center;
  padding: 3rem 1.5rem;
  color: var(--text-tertiary);
}

.empty-state-icon {
  font-size: 2.5rem;
  margin-bottom: 0.75rem;
  opacity: 0.35;
}

.empty-state-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.35rem;
}

.empty-state-text {
  font-size: 0.85rem;
  max-width: 360px;
  margin: 0 auto;
  line-height: 1.5;
}

.skeleton {
  background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--bg-hover) 50%, var(--bg-tertiary) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.skeleton-line {
  height: 14px;
  margin-bottom: 0.5rem;
}

.skeleton-line:last-child {
  width: 60%;
}

.skeleton-card {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  gap: 0.9rem;
}

.skeleton-score {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
}

.skeleton-content {
  flex: 1;
}

/* ========== Loading Spinner ========== */
.spinner {
  width: 18px;
  height: 18px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  display: inline-block;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-overlay {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 2.5rem;
  color: var(--text-tertiary);
  font-size: 0.85rem;
}

/* ========== Toast ========== */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  z-index: 200;
}

.toast {
  padding: 0.7rem 1.1rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  animation: toast-in 0.3s ease;
  max-width: 380px;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.toast.success {
  background: var(--success);
  color: #fff;
}

.toast.error {
  background: var(--danger);
  color: #fff;
}

.toast.info {
  background: var(--info);
  color: #fff;
}

@keyframes toast-in {
  from { opacity: 0; transform: translateY(10px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

.toast-exit {
  animation: toast-out 0.2s ease forwards;
}

@keyframes toast-out {
  to { opacity: 0; transform: translateY(10px) scale(0.95); }
}

/* ========== Sync Status ========== */
.sync-results {
  margin-top: 1rem;
}

.sync-result-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--border-light);
  font-size: 0.85rem;
}

.sync-result-item:last-child {
  border-bottom: none;
}

.sync-stat {
  display: flex;
  gap: 0.75rem;
}

.sync-stat span {
  color: var(--text-tertiary);
}

.sync-stat strong {
  color: var(--text-primary);
}

/* ========== Responsive ========== */
@media (max-width: 640px) {
  .navbar-inner {
    padding: 0 1rem;
  }

  .nav-left {
    gap: 1rem;
  }

  .brand-text {
    display: none;
  }

  .nav-link {
    padding: 0.4rem 0.6rem;
    font-size: 0.83rem;
  }

  .container {
    padding: 1.25rem 1rem;
  }

  .filter-bar {
    flex-direction: column;
  }

  .search-input {
    min-width: auto;
    width: 100%;
  }

  .filter-bar .filter-select,
  .filter-bar .btn {
    width: 100%;
    justify-content: center;
  }

  .source-grid {
    grid-template-columns: 1fr;
  }

  .stats-row {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .page-title {
    font-size: 1.3rem;
  }

  .item-score {
    width: 38px;
    height: 38px;
    font-size: 0.72rem;
  }
}

/* ========== Paper Action Buttons ========== */
.paper-actions {
  display: flex;
  gap: 0.4rem;
  margin-left: auto;
  flex-shrink: 0;
}

.btn-summary {
  color: var(--accent-text);
  border-color: var(--accent-light);
  background: var(--accent-light);
}

.btn-summary:hover {
  background: var(--accent);
  color: var(--text-inverse);
  border-color: var(--accent);
}

.btn-notebook {
  color: var(--success);
  border-color: var(--success-light);
  background: var(--success-light);
}

.btn-notebook:hover {
  background: var(--success);
  color: var(--text-inverse);
  border-color: var(--success);
}