:root {
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: #1e293b;
  --bg-card-hover: #26354a;
  --bg-input: #0f172a;
  --border-color: #334155;
  --border-focus: #38bdf8;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #38bdf8;
  --accent-hover: #0284c7;
  --accent-glow: rgba(56, 189, 248, 0.18);
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover {
  color: #7dd3fc;
  text-decoration: underline;
}

/* Header & Nav */
.site-header {
  background: rgba(17, 24, 39, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.brand-logo:hover {
  text-decoration: none;
}

.brand-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, #38bdf8 0%, #6366f1 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 16px var(--accent-glow);
}

.brand-icon svg {
  width: 20px;
  height: 20px;
  fill: #ffffff;
}

.brand-tagline {
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-weight: 500;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  margin-left: 0.25rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.nav-item a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 0.92rem;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.2s ease;
}

.nav-item a:hover {
  color: var(--text-primary);
  background: var(--bg-card);
  text-decoration: none;
}

.nav-item.active a {
  color: var(--accent);
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

/* Hero Section */
.hero-section {
  padding: 3rem 1.5rem 2rem;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  color: var(--accent);
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
}

.hero-title {
  font-size: clamp(2rem, 4.5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #ffffff 30%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-title span {
  background: linear-gradient(135deg, #38bdf8 0%, #818cf8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 2rem;
}

/* Action Control Bar */
.control-bar {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 0.5rem;
  display: flex;
  gap: 0.5rem;
  box-shadow: var(--shadow-lg);
  max-width: 800px;
  margin: 0 auto 1.5rem;
}

.input-wrapper {
  flex: 1;
  display: flex;
  align-items: center;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 0.4rem 1rem;
  gap: 0.75rem;
}

.input-wrapper:focus-within {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.input-wrapper svg {
  color: var(--text-muted);
  width: 18px;
  height: 18px;
}

.tool-input {
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: 1rem;
}

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

.btn-primary {
  background: linear-gradient(135deg, #0284c7 0%, #2563eb 100%);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-lg);
  padding: 0.75rem 1.6rem;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.btn-primary:hover {
  background: linear-gradient(135deg, #0369a1 0%, #1d4ed8 100%);
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Sample Quick Pills */
.sample-feeds {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 2.5rem;
}

.sample-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}

.sample-pill {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.82rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.sample-pill:hover {
  background: var(--bg-card-hover);
  color: var(--accent);
  border-color: rgba(56, 189, 248, 0.4);
}

/* Main Content Container */
.main-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
  width: 100%;
  flex: 1;
}

/* Feed Header Metadata Banner */
.feed-header-banner {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.75rem;
}

.feed-meta-info {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.feed-meta-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.feed-meta-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.feed-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.view-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.45rem 0.8rem;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.15s ease;
}

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

.view-btn.active {
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent);
  border-color: rgba(56, 189, 248, 0.4);
}

/* Executive Briefing Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.5rem;
}

.cards-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* Executive Briefing Card */
.briefing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  position: relative;
}

.briefing-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: rgba(56, 189, 248, 0.35);
}

.card-media {
  width: 100%;
  height: 190px;
  background: var(--bg-secondary);
  position: relative;
  overflow: hidden;
}

.card-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.3s ease;
}

.briefing-card:hover .card-media img {
  transform: scale(1.03);
}

.card-media-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
  color: var(--text-muted);
}

.card-content {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.card-meta-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 0.6rem;
}

.card-source {
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 0.72rem;
}

.card-title {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--text-primary);
  margin-bottom: 0.6rem;
}

.card-title a {
  color: inherit;
  text-decoration: none;
}

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

.card-snippet {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1.2rem;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 0.75rem;
  margin-top: auto;
}

.read-modal-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

.read-modal-btn:hover {
  background: var(--accent);
  color: #0b0f19;
  border-color: var(--accent);
}

.btn-refresh-meta {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.35rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color 0.15s ease;
}

.btn-refresh-meta:hover {
  color: var(--accent);
}

.spin-anim {
  animation: spin 0.6s linear infinite;
}

@keyframes spin {
  100% { transform: rotate(360deg); }
}

/* List View Variant */
.cards-list .briefing-card {
  flex-direction: row;
  height: auto;
}

.cards-list .card-media {
  width: 220px;
  height: auto;
  min-height: 140px;
  flex-shrink: 0;
}

/* Modal Reader */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(6px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 1rem;
}

.modal-overlay.active {
  display: flex;
}

.modal-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  max-width: 780px;
  width: 100%;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  animation: modalIn 0.2s ease-out;
}

@keyframes modalIn {
  from { opacity: 0; transform: scale(0.96); }
  to { opacity: 1; transform: scale(1); }
}

.modal-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.modal-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;
}

.modal-close {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.2rem 0.5rem;
  line-height: 1;
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 1.5rem;
  overflow-y: auto;
  font-size: 1rem;
  color: #cbd5e1;
  line-height: 1.7;
}

.modal-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  margin: 1rem 0;
}

.modal-footer {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Feature Grid & Educational Content */
.features-section {
  border-top: 1px solid var(--border-color);
  padding: 4rem 0 2rem;
  margin-top: 4rem;
}

.section-heading {
  text-align: center;
  margin-bottom: 3rem;
}

.section-heading h2 {
  font-size: 1.85rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.section-heading p {
  color: var(--text-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.feature-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
}

.feature-box .f-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
  display: inline-block;
}

.feature-box h3 {
  font-size: 1.15rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.feature-box p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* Validator & Builder Specific Styles */
.score-gauge-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 2rem;
  text-align: center;
  margin-bottom: 2rem;
}

.score-dial {
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1;
  margin: 0.5rem 0;
  font-family: var(--font-mono);
}

.score-excellent { color: var(--success); }
.score-warning { color: var(--warning); }
.score-danger { color: var(--danger); }

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 600;
}

.badge-pass {
  background: rgba(16, 185, 129, 0.12);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-warn {
  background: rgba(245, 158, 11, 0.12);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.badge-fail {
  background: rgba(239, 68, 68, 0.12);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.diagnostics-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.diagnostics-table th,
.diagnostics-table td {
  padding: 0.9rem 1.25rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.9rem;
}

.diagnostics-table th {
  background: var(--bg-card);
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}

.code-preview-box {
  background: #030712;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #a5f3fc;
  overflow-x: auto;
  max-height: 400px;
}

/* Footer */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 2.5rem 1.5rem;
  margin-top: auto;
}

.footer-container {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 1.25rem;
}

.footer-links a {
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: var(--text-primary);
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    align-items: flex-start;
  }
  .control-bar {
    flex-direction: column;
    border-radius: var(--radius-lg);
  }
  .btn-primary {
    width: 100%;
    justify-content: center;
  }
  .cards-list .briefing-card {
    flex-direction: column;
  }
  .cards-list .card-media {
    width: 100%;
    height: 180px;
  }
}