@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

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

:root {
  --indigo-100: #e0e7ff;
  --indigo-300: #a5b4fc;
  --indigo-600: #4f46e5;
  --indigo-700: #4338ca;
  --indigo-950: #1e1b4b;
  --purple-100: #f3e8ff;
  --purple-300: #d8b4fe;
  --purple-600: #9333ea;
  --purple-700: #7e22ce;
  --teal-100: #ccfbf1;
  --teal-300: #5eead4;
  --teal-600: #0d9488;
  --teal-700: #0f766e;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-600: #4b5563;
  --gray-900: #111827;
  --slate-900: #0f172a;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--gray-50);
  color: var(--gray-900);
  min-height: 100vh;
  line-height: 1.6;
}

/* NAV */
.nav {
  background: white;
  border-bottom: 1px solid var(--gray-200);
  position: sticky;
  top: 0;
  z-index: 50;
}
.nav-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--indigo-600);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-brand img { width: 32px; height: 32px; border-radius: 8px; }
.nav-links { display: flex; gap: 1.5rem; align-items: center; }
.nav-links a {
  color: var(--gray-600);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.15s;
}
.nav-links a:hover { color: var(--indigo-600); }
.nav-external { opacity: 0.7; }

/* PAGE HEADER - white card like AI Hub */
.page-header {
  max-width: 1280px;
  margin: 1.5rem auto 0;
  padding: 0 1rem;
}
.page-header-card {
  background: white;
  border-radius: 0.75rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  border: 1px solid var(--gray-200);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.page-header-card img { width: 3rem; height: 3rem; border-radius: 0.5rem; }
.page-header-card h1 { font-size: 1.5rem; font-weight: 700; color: var(--gray-900); }
.page-header-card p { color: var(--gray-600); font-size: 0.875rem; }

/* HERO - Dark gradient matching AI Hub "Built on Real Science" */
.hero {
  max-width: 1280px;
  margin: 1.5rem auto 0;
  padding: 0 1rem;
}
.hero-card {
  background: linear-gradient(to bottom right, #0f172a, var(--indigo-950), #0f172a);
  border-radius: 1rem;
  padding: 1.5rem 2rem;
  color: white;
  position: relative;
  overflow: hidden;
}
@media (min-width: 768px) { .hero-card { padding: 2rem; } }

/* Background blur circles */
.hero-card::before {
  content: '';
  position: absolute;
  top: 0; right: 0;
  width: 16rem; height: 16rem;
  background: #818cf8;
  border-radius: 50%;
  filter: blur(48px);
  opacity: 0.1;
}
.hero-card::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0;
  width: 12rem; height: 12rem;
  background: #a78bfa;
  border-radius: 50%;
  filter: blur(48px);
  opacity: 0.1;
}
.hero-content { position: relative; z-index: 10; }
.hero-top {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}
.hero-top img {
  width: 3.5rem; height: 3.5rem;
  border-radius: 0.75rem;
  filter: brightness(0) invert(1);
}
.hero-top h2 { font-size: 1.125rem; font-weight: 700; }
@media (min-width: 768px) { .hero-top h2 { font-size: 1.25rem; } }
.hero-top .subtitle { color: var(--indigo-300); font-size: 0.875rem; }
.hero-text {
  color: #d1d5db;
  font-size: 0.875rem;
  line-height: 1.7;
  margin-bottom: 1.25rem;
}
@media (min-width: 768px) { .hero-text { font-size: 1rem; } }
.hero-text strong { color: white; font-weight: 600; }
.hero-note { color: #9ca3af; font-size: 0.75rem; margin-top: 1rem; }

/* STAT BOXES - cross-browser compatible */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
@media (min-width: 768px) { .stats-grid { grid-template-columns: repeat(4, 1fr); } }
.stat-card {
  background: rgba(255, 255, 255, 0.1);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-radius: 0.75rem;
  padding: 0.75rem;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, 0.08);
}
/* Fallback for browsers without backdrop-filter */
@supports not (backdrop-filter: blur(8px)) {
  .stat-card { background: rgba(255, 255, 255, 0.15); }
}
.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: white;
}
@media (min-width: 768px) { .stat-value { font-size: 1.875rem; } }
.stat-label {
  font-size: 0.75rem;
  color: var(--indigo-300);
  margin-top: 0.25rem;
}

/* FEATURE CARDS - matching AI Hub exactly */
.features-section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 1.5rem 1rem 10rem;
}
@media (min-width: 768px) { .features-section { padding-top: 2rem; } }
.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}
@media (min-width: 768px) { .features-grid { grid-template-columns: repeat(3, 1fr); } }
.feature-card {
  background: white;
  border-radius: 1rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  border: 1px solid var(--gray-200);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.2s, border-color 0.2s;
}
.feature-card:hover { box-shadow: 0 4px 12px rgba(0,0,0,0.08); }
.feature-card.indigo:hover { border-color: var(--indigo-300); }
.feature-card.purple:hover { border-color: var(--purple-300); }
.feature-card.teal:hover { border-color: var(--teal-300); }

.feature-top { display: flex; align-items: flex-start; gap: 1rem; margin-bottom: 1rem; }
.feature-icon {
  padding: 0.75rem;
  border-radius: 0.75rem;
  flex-shrink: 0;
  font-size: 1.75rem;
  line-height: 1;
}
.feature-icon.indigo { background: var(--indigo-100); color: var(--indigo-600); }
.feature-icon.purple { background: var(--purple-100); color: var(--purple-600); }
.feature-icon.teal { background: var(--teal-100); color: var(--teal-600); }

.feature-title { font-size: 1.125rem; font-weight: 700; color: var(--gray-900); margin-bottom: 0.25rem; }
.feature-tags { display: flex; flex-wrap: wrap; gap: 0.375rem; }
.feature-tag {
  font-size: 0.6875rem;
  padding: 0.125rem 0.5rem;
  background: var(--gray-100);
  color: var(--gray-600);
  border-radius: 9999px;
  font-weight: 500;
}
.feature-desc {
  font-size: 0.875rem;
  color: var(--gray-600);
  line-height: 1.6;
  margin-bottom: 1.25rem;
  flex: 1;
}
.feature-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border-radius: 0.5rem;
  color: white;
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background 0.15s;
  width: fit-content;
}
.feature-btn.indigo { background: var(--indigo-600); }
.feature-btn.indigo:hover { background: var(--indigo-700); }
.feature-btn.purple { background: var(--purple-600); }
.feature-btn.purple:hover { background: var(--purple-700); }
.feature-btn.teal { background: var(--teal-600); }
.feature-btn.teal:hover { background: var(--teal-700); }
.feature-btn svg { width: 1rem; height: 1rem; }

/* FINDER FORM */
.finder-section {
  max-width: 1280px;
  margin: 1.5rem auto 0;
  padding: 0 1rem;
}
.finder-form {
  background: white;
  border-radius: 1rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  border: 1px solid var(--gray-200);
  padding: 1.5rem;
}
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; font-size: 0.875rem; font-weight: 600; color: var(--gray-900); margin-bottom: 0.375rem; }
.form-group textarea,
.form-group input,
.form-group select {
  width: 100%;
  padding: 0.625rem 0.875rem;
  border: 1px solid var(--gray-200);
  border-radius: 0.5rem;
  font-size: 0.875rem;
  font-family: inherit;
  transition: border-color 0.15s;
  background: white;
}
.form-group textarea:focus,
.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--indigo-600);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}
.form-group textarea { resize: vertical; }
.char-count { font-size: 0.75rem; color: var(--gray-600); text-align: right; margin-top: 0.25rem; }
.form-row { display: grid; grid-template-columns: 1fr; gap: 1rem; }
@media (min-width: 768px) { .form-row { grid-template-columns: 1fr 1fr; } }
.filters-toggle { margin-bottom: 1rem; }
.filters-toggle summary { font-size: 0.875rem; font-weight: 500; color: var(--indigo-600); cursor: pointer; padding: 0.5rem 0; }
.filters-grid { display: grid; grid-template-columns: 1fr; gap: 1rem; padding-top: 0.75rem; }
@media (min-width: 768px) { .filters-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .filters-grid { grid-template-columns: repeat(4, 1fr); } }

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 2rem;
  background: var(--indigo-600);
  color: white;
  border: none;
  border-radius: 0.5rem;
  font-size: 0.9375rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
  width: 100%;
}
.btn-primary:hover { background: var(--indigo-700); }

/* RESULTS */
.results { margin-top: 1.5rem; }
.results h2 { font-size: 1.25rem; font-weight: 700; margin-bottom: 1rem; }
.result-card {
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: 0.75rem;
  padding: 1rem 1.25rem;
  margin-bottom: 0.75rem;
  transition: border-color 0.15s;
}
.result-card:hover { border-color: var(--indigo-300); }
.result-card h3 { font-size: 1rem; font-weight: 600; color: var(--gray-900); margin-bottom: 0.25rem; }
.result-meta { font-size: 0.8125rem; color: var(--gray-600); display: flex; flex-wrap: wrap; gap: 0.75rem; }
.result-score {
  display: inline-block;
  background: var(--indigo-100);
  color: var(--indigo-600);
  font-weight: 600;
  font-size: 0.8125rem;
  padding: 0.125rem 0.5rem;
  border-radius: 9999px;
}

/* ERROR */
.error-msg {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  background: #fef2f2;
  border: 1px solid #fecaca;
  border-radius: 0.5rem;
  color: #dc2626;
  font-size: 0.875rem;
}

/* FOOTER */
.footer {
  background: white;
  border-top: 1px solid var(--gray-200);
  padding: 2rem 1rem;
  margin-top: 3rem;
}
.footer-inner { max-width: 1280px; margin: 0 auto; }
.footer-brand { font-size: 0.875rem; color: var(--gray-600); margin-bottom: 0.5rem; }
.footer-brand a { color: var(--indigo-600); text-decoration: none; }
.footer-info { font-size: 0.8125rem; color: var(--gray-600); margin-bottom: 0.75rem; }
.footer-info p { margin-bottom: 0.25rem; }
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a { font-size: 0.8125rem; color: var(--gray-600); text-decoration: none; }
.footer-links a:hover { color: var(--indigo-600); }

/* EXPLORE & SIMILAR pages */
.page-section {
  max-width: 1280px;
  margin: 1.5rem auto 0;
  padding: 0 1rem 5rem;
}
.page-section h1 { font-size: 1.5rem; font-weight: 700; margin-bottom: 1rem; }
.page-section h2 { font-size: 1.25rem; font-weight: 600; margin-bottom: 0.75rem; }

.journal-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}
.journal-table th {
  text-align: left;
  padding: 0.625rem 0.75rem;
  background: var(--gray-50);
  border-bottom: 2px solid var(--gray-200);
  font-weight: 600;
  color: var(--gray-600);
}
.journal-table td {
  padding: 0.625rem 0.75rem;
  border-bottom: 1px solid var(--gray-100);
}
.journal-table tr:hover { background: var(--gray-50); }

.cluster-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1rem; }
.cluster-card {
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: 0.75rem;
  padding: 1rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.cluster-card:hover { border-color: var(--indigo-300); box-shadow: 0 4px 12px rgba(0,0,0,0.05); }
.cluster-card h3 { font-size: 0.9375rem; font-weight: 600; margin-bottom: 0.25rem; }
.cluster-card p { font-size: 0.8125rem; color: var(--gray-600); }

.search-box {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}
.search-box input {
  flex: 1;
  padding: 0.625rem 0.875rem;
  border: 1px solid var(--gray-200);
  border-radius: 0.5rem;
  font-size: 0.875rem;
  font-family: inherit;
}
.search-box input:focus { outline: none; border-color: var(--indigo-600); }
.search-box button {
  padding: 0.625rem 1.25rem;
  background: var(--indigo-600);
  color: white;
  border: none;
  border-radius: 0.5rem;
  font-weight: 500;
  cursor: pointer;
}