:root {
  /* Color tokens */
  --bg: #f8fafc;
  --bg-soft: #eef2ff;
  --panel: #ffffff;
  --panel-tint: rgba(255, 255, 255, 0.96);
  --panel-strong: #ffffff;
  --text: #0f172a;
  --text-soft: #334155;
  --muted: #475569;
  --line: #e2e8f0;
  --line-strong: #cbd5e1;
  --accent: #2563eb;
  --primary: #19c28f;
  --primary-text: #052e16;
  --warn-bg: #fef3c7;
  --warn-text: #92400e;
  --danger-bg: #fee2e2;
  --danger-text: #991b1b;

  /* Typography tokens */
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: clamp(1.5rem, 3vw, 2.25rem);
  --text-display: clamp(2rem, 5vw, 3.625rem);

  /* Spacing + radius + size tokens */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --radius-sm: 0.75rem;
  --radius-md: 0.875rem;
  --radius-lg: 1.125rem;
  --radius-xl: 1.5rem;
  --radius-pill: 999px;
  --container-max: 1200px;
  --tap-min: 44px;

  /* Effects + breakpoints */
  --shadow: 0 18px 48px rgba(15, 23, 42, 0.08);
  --shadow-hero: 0 28px 72px rgba(15, 23, 42, 0.2);
  --shadow-lg: 0 24px 60px rgba(15, 23, 42, 0.12);
  --bp-tablet: 900px;
  --bp-mobile: 680px;
}

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

html,
body {
  max-width: 100%;
  overflow-x: hidden;
}

body {
  margin: 0;
  background:
    radial-gradient(1200px 520px at 15% -10%, #dbeafe 0%, transparent 60%),
    radial-gradient(1200px 520px at 85% -20%, #e0e7ff 0%, transparent 62%),
    linear-gradient(180deg, var(--bg), var(--bg-soft));
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--text);
  line-height: 1.6;
}

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

img {
  max-width: 100%;
  height: auto;
}

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: clamp(1rem, 2.2vw, 1.5rem);
}

.site-shell {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

.site-main {
  flex: 1;
  width: min(100%, 1120px);
  margin: 0 auto;
  padding-block: var(--space-8);
}

.site-header {
  position: sticky;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  box-shadow: 0 8px 28px rgba(15, 23, 42, 0.08);
  z-index: 20;
}

.nav-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-4);
}

.brand {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.02em;
}

.nav-toggle {
  display: none;
  min-width: var(--tap-min);
  min-height: var(--tap-min);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--panel);
  color: var(--text);
  font-weight: 700;
  cursor: pointer;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--tap-min);
  padding: 0 var(--space-4);
  border-radius: var(--radius-pill);
  color: var(--text-soft);
  font-weight: 600;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.nav a:hover,
.nav a:focus-visible {
  background: #e0e7ff;
}

.hero {
  padding: clamp(1.75rem, 4vw, 2.75rem) 0 var(--space-10);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.35fr 0.65fr;
  gap: var(--space-6);
}

.hero-panel {
  padding: var(--space-8);
  border-radius: 30px;
  background: linear-gradient(130deg, #0f172a, #1d4ed8 52%, #2563eb);
  color: #ffffff;
  box-shadow: var(--shadow-hero);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.hero-panel h1 {
  margin: 0 0 var(--space-3);
  font-size: var(--text-display);
  line-height: 1.05;
}

.hero-panel p {
  margin: 0;
  font-size: var(--text-lg);
  opacity: 0.92;
}

.hero-card,
.card,
.content-card {
  background: linear-gradient(180deg, var(--panel-strong), var(--panel-tint));
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-lg);
}

.cta-row {
  margin-top: var(--space-6);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--tap-min);
  padding: 0 var(--space-5);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  font-weight: 800;
  cursor: pointer;
  transition: transform 0.15s ease, opacity 0.15s ease, background-color 0.2s ease;
}

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

.btn.ghost {
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.22);
}

.btn.secondary {
  background: #e0e7ff;
  color: #1e3a8a;
}

.btn:active {
  transform: scale(0.98);
}

.btn[disabled],
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.6;
  pointer-events: none;
}

.section-head {
  margin: var(--space-6) 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: end;
  gap: var(--space-3);
}

.section-head h1,
.section-head h2 {
  margin: 0;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--space-6);
}

.card {
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 28px 64px rgba(15, 23, 42, 0.14);
}

.cover {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius-lg);
}

.content-body {
  line-height: 1.85;
  word-wrap: break-word;
}

.prose {
  font-size: var(--text-base);
}

.prose h1,
.prose h2,
.prose h3,
.prose h4 {
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.prose p,
.prose ul,
.prose ol,
.prose pre,
.prose blockquote,
.prose table {
  margin: 0 0 var(--space-4);
}

.prose ul,
.prose ol {
  padding-left: var(--space-6);
}

.prose code {
  padding: 0 var(--space-2);
  border-radius: 6px;
  background: #e2e8f0;
  font-size: var(--text-sm);
}

.prose pre {
  overflow-x: auto;
  border-radius: var(--radius-md);
  background: #0f172a;
  color: #e2e8f0;
  padding: var(--space-4);
}

.prose blockquote {
  padding: var(--space-3) var(--space-4);
  border-left: 4px solid var(--accent);
  background: #eff6ff;
  color: #1e3a8a;
}

.prose img {
  display: block;
  max-width: 100%;
  border-radius: var(--radius-lg);
}

.prose .table-scroll {
  width: 100%;
  overflow-x: auto;
}

.prose table {
  width: 100%;
  min-width: 640px;
  border-collapse: collapse;
}

.prose th,
.prose td {
  padding: var(--space-3);
  border: 1px solid var(--line);
  text-align: left;
}

.breadcrumbs {
  margin-bottom: var(--space-3);
  color: var(--muted);
  font-size: var(--text-sm);
}

.muted {
  color: var(--muted);
}

.search-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.search-row input {
  flex: 1;
  min-width: 240px;
  min-height: var(--tap-min);
  padding: 0 var(--space-4);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
}

.search-row input:focus-visible,
.auth-card input:focus-visible {
  border-color: #93c5fd;
  outline: none;
  box-shadow: 0 0 0 4px rgba(147, 197, 253, 0.28);
}

.badge {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 700;
}

.badge.warn {
  background: var(--warn-bg);
  color: var(--warn-text);
}

.empty-state {
  margin: var(--space-6) 0;
  padding: var(--space-8);
  border: 1px dashed var(--line);
  border-radius: var(--radius-xl);
  background: var(--panel);
  text-align: center;
}

.site-footer {
  padding: var(--space-8) 0;
  color: #64748b;
  border-top: 1px solid rgba(148, 163, 184, 0.2);
  margin-top: var(--space-10);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-3);
  align-items: center;
}

.footer-nav {
  justify-content: flex-end;
}

.auth-wrap {
  min-height: calc(100vh - 180px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding-block: var(--space-8);
}

.auth-card {
  max-width: 540px;
  width: 100%;
  border-radius: 24px;
}

.auth-card h1 {
  margin: 0 0 var(--space-4);
  letter-spacing: -0.02em;
}

.auth-card .grid {
  gap: var(--space-4);
}

.auth-card label {
  display: block;
  margin-bottom: var(--space-2);
  font-weight: 700;
  color: var(--text-soft);
}

.auth-card input {
  width: 100%;
  min-height: 48px;
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  padding: 0 var(--space-3);
  font-size: var(--text-base);
  background: #ffffff;
}

.auth-btn {
  width: 100%;
}

.alert {
  margin-bottom: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
}

.alert.error {
  background: var(--danger-bg);
  color: var(--danger-text);
}

.alert.info {
  background: #dbeafe;
  color: #1e3a8a;
}

.pagination {
  margin-top: var(--space-6);
  display: flex;
  gap: var(--space-2);
  justify-content: center;
  flex-wrap: wrap;
}

.pagination-gap {
  display: inline-flex;
  align-items: center;
  color: var(--muted);
  padding: 0 var(--space-2);
}

:focus-visible {
  outline: 3px solid #93c5fd;
  outline-offset: 2px;
}

@media (max-width: 900px) {
  .container {
    padding: var(--space-5);
  }

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

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

  .footer-nav {
    justify-content: flex-start;
  }
}

@media (max-width: 680px) {
  .container {
    padding: var(--space-4);
  }

  .nav-row {
    flex-wrap: wrap;
    align-items: center;
  }

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .nav {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: var(--space-2);
    padding-top: var(--space-3);
  }

  .nav.is-open {
    display: flex;
  }

  .nav a {
    width: 100%;
    justify-content: flex-start;
    border: 1px solid var(--line);
    border-radius: var(--radius-md);
    background: #ffffff;
  }

  .hero-panel,
  .hero-card,
  .card,
  .content-card,
  .empty-state {
    padding: var(--space-5);
    border-radius: var(--radius-lg);
  }

  .btn {
    width: 100%;
  }

  .cta-row .btn {
    width: auto;
    flex: 1 1 180px;
  }

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

  .search-row input {
    min-width: 0;
    width: 100%;
  }

  .prose .table-scroll {
    margin-inline: -16px;
    width: calc(100% + 32px);
    padding-inline: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}