:root {
  /* Backgrounds */
  --bg-primary: #0a0a0c;
  --bg-secondary: #141416;
  --bg-tertiary: #1a1a1e;
  --bg-input: #1a1a1e;
  --bg-hover: rgba(255, 255, 255, 0.04);

  /* Text */
  --text-primary: #ffffff;
  --text-secondary: #a1a1aa;
  --text-muted: #9ca3af;

  /* Accent */
  --accent: #f97316;
  --accent-dim: rgba(249, 115, 22, 0.15);
  --accent-hover: #fb923c;
  --accent-text: #fdba74;
  --accent-border: rgba(249, 115, 22, 0.25);

  /* Borders */
  --border: rgba(255, 255, 255, 0.10);
  --border-strong: rgba(255, 255, 255, 0.16);

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-8: 3rem;
  --space-10: 4rem;
  --space-12: 5rem;

  /* Typography */
  --font-body: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3.5rem;

  /* Layout */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-full: 9999px;

  --nav-height: 64px;
  --container-width: 1200px;
  --reading-width: 720px;

  /* Transitions */
  --transition-fast: 150ms ease;

  /* State colors */
  --success: #22c55e;
  --error: #ef4444;
  --warning: #f97316;
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  font-weight: 400;
  line-height: 1.65;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  flex: 1 1 auto;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-4);
}

h1 { font-size: var(--font-size-5xl); font-weight: 700; letter-spacing: -0.02em; }
h2 { font-size: var(--font-size-4xl); }
h3 { font-size: var(--font-size-3xl); }
h4 { font-size: var(--font-size-2xl); }

p {
  margin-bottom: var(--space-4);
}

a {
  color: var(--text-secondary);
  text-decoration: underline;
  transition: color var(--transition-fast);
}

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

::selection {
  background: var(--accent-dim);
  color: var(--text-primary);
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.reading-container {
  max-width: var(--reading-width);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  background: var(--accent);
  color: var(--bg-primary);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-md);
  font-weight: 600;
  z-index: 200;
}

.skip-link:focus {
  top: var(--space-4);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: var(--font-size-base);
  border: 1px solid transparent;
  background: transparent;
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
  min-height: 44px;
  text-decoration: none;
}

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

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

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

.btn-secondary:hover {
  border-color: var(--border-strong);
  color: var(--text-primary);
}

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

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

/* Shared header / nav / logo / mobile menu styles (base layer)
   These were previously only in public-shell.css. Auth pages (login, signup),
   and any app-shell pages that still render the common <header> from header.php
   were missing horizontal nav, sticky bar, .nav-cta button treatment, and mobile toggle.
   Placing here (ai-design-system is always loaded) ensures consistent chrome
   without changing shell loading logic or duplicating maintenance. */
body > header {
  height: var(--nav-height);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  position: sticky;
  top: 0;
  background: var(--bg-primary);
  z-index: 100;
}

.site-shell main {
  padding-top: var(--space-4);
}

body > header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: 600;
  font-size: var(--font-size-lg);
  white-space: nowrap;
  color: var(--text-primary);
}

.logo:hover {
  color: var(--accent);
}

.logo img {
  height: 32px;
  width: 32px;
}

body > header nav ul {
  display: flex;
  gap: var(--space-2);
  list-style: none;
  align-items: center;
  margin: 0;
  padding: 0;
}

body > header nav a {
  font-weight: 500;
  font-size: var(--font-size-sm);
  display: block;
  line-height: 1.5;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  text-decoration: none;
}

body > header nav a:hover,
body > header nav a.active {
  color: var(--accent);
  background: var(--bg-hover);
}

body > header nav a.nav-cta {
  background: var(--accent);
  color: var(--bg-primary);
  font-weight: 600;
}

body > header nav a.nav-cta:hover {
  background: var(--accent-hover);
  color: var(--bg-primary);
}

body > header nav a.nav-android,
.chat-route-actions a.nav-android {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-width: 38px;
  min-height: 38px;
  padding: var(--space-2) var(--space-3);
  color: #3ddc84;
  border-radius: var(--radius-md);
}

body > header nav a.nav-android:hover,
body > header nav a.nav-android:focus-visible,
body > header nav a.nav-android.active,
.chat-route-actions a.nav-android:hover,
.chat-route-actions a.nav-android:focus-visible,
.chat-route-actions a.nav-android.active {
  color: #6fe9a8;
  background: rgba(61, 220, 132, 0.12);
}

body > header nav a.nav-android .nav-android-icon,
.chat-route-actions a.nav-android .nav-android-icon {
  flex-shrink: 0;
  display: block;
}

body > header nav a.nav-android .nav-android-label,
.chat-route-actions a.nav-android .nav-android-label {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.chat-route-actions a.nav-android.chat-route-link {
  color: #3ddc84;
  min-width: 38px;
  padding-inline: var(--space-2);
}

.chat-route-actions a.nav-android.chat-route-link:hover,
.chat-route-actions a.nav-android.chat-route-link:focus-visible {
  color: #6fe9a8;
  border-color: rgba(61, 220, 132, 0.45);
  background: rgba(61, 220, 132, 0.1);
}

@media (max-width: 768px) {
  body > header nav a.nav-android {
    width: 100%;
    justify-content: flex-start;
  }

  body > header nav a.nav-android .nav-android-label {
    position: static;
    width: auto;
    height: auto;
    margin: 0;
    overflow: visible;
    clip: auto;
    white-space: normal;
    font-weight: 500;
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
  }

  body > header nav a.nav-android:hover .nav-android-label,
  body > header nav a.nav-android:focus-visible .nav-android-label,
  body > header nav a.nav-android.active .nav-android-label {
    color: #6fe9a8;
  }
}

.chat-route-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.chat-route-link {
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: var(--font-size-sm);
  font-weight: 700;
  text-decoration: none;
}

.chat-route-link:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.chat-route-link--quiet {
  color: var(--text-secondary);
}

.chat-sidebar-trigger {
  font: inherit;
  cursor: pointer;
  background: transparent;
}

@media (min-width: 768px) {
  .chat-sidebar-trigger {
    display: none;
  }
}

.menu-toggle {
  display: none;
  cursor: pointer;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  gap: 5px;
  border-radius: var(--radius-md);
  background: transparent;
  border: 1px solid var(--border);
}

.menu-toggle span {
  display: block;
  height: 2px;
  width: 20px;
  background-color: var(--text-primary);
  border-radius: 2px;
}

@media (max-width: 768px) {
  .menu-toggle {
    display: flex;
  }

  body > header nav ul {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: var(--space-4);
    gap: var(--space-2);
  }

  body > header nav ul.active {
    display: flex;
  }

  body > header nav ul li {
    width: 100%;
  }

  body > header nav ul li a {
    width: 100%;
  }
}

input,
textarea,
select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  margin-bottom: var(--space-4);
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: var(--font-size-base);
  transition: border-color var(--transition-fast);
  -webkit-appearance: none;
  appearance: none;
}

input:focus,
textarea:focus,
select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-color: var(--accent);
}

input[type="checkbox"],
input[type="radio"] {
  width: auto;
  appearance: auto;
  -webkit-appearance: auto;
  background: transparent;
  border: none;
  padding: 0;
  margin: 0 0.5rem 0 0;
  vertical-align: middle;
}

input::placeholder,
textarea::placeholder {
  color: var(--text-muted);
}

select {
  /* Arrow color matches --text-muted; update the SVG stroke if the token changes. */
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%239ca3af' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

label {
  display: block;
  margin-bottom: var(--space-2);
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  font-weight: 500;
}

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
}

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

.alert-error {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  font-weight: 500;
}

.alert-success {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border);
  color: var(--text-secondary);
}

.alert-warning {
  background: var(--accent-dim);
  border: 1px solid var(--accent-border);
  color: var(--accent-text);
}

.text-center { text-align: center; }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }
.mt-4 { margin-top: var(--space-6); }
.mb-4 { margin-bottom: var(--space-6); }
.mb-5 { margin-bottom: var(--space-8); }

@media (max-width: 768px) {
  h1 { font-size: var(--font-size-4xl); }
  h2 { font-size: var(--font-size-3xl); }
  .container,
  .reading-container {
    padding: 0 var(--space-4);
  }
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Site footer — shared on every page */
.site-footer {
  flex-shrink: 0;
  padding: var(--space-8) 0 var(--space-6);
  border-top: 1px solid var(--border);
  margin-top: auto;
  font-size: var(--font-size-sm);
  color: var(--text-muted);
  background: var(--bg-primary);
}

.site-footer .footer-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.site-footer-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

@media (min-width: 768px) {
  .site-footer-grid {
    flex-direction: row;
    justify-content: space-between;
    align-items: flex-start;
  }
}

.site-footer-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: 600;
  font-size: var(--font-size-base);
  color: var(--text-primary);
  text-decoration: none;
  margin-bottom: var(--space-3);
}

.site-footer-brand:hover {
  color: var(--accent);
}

.site-footer-brand img {
  flex-shrink: 0;
}

.site-footer-copy {
  margin: 0;
  color: var(--text-muted);
  font-size: var(--font-size-sm);
  line-height: 1.6;
  max-width: 36ch;
}

.site-footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3) var(--space-4);
  align-items: center;
}

.site-footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
}

.site-footer-links a:hover {
  color: var(--accent);
}

.site-footer-bottom {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border);
}

@media (min-width: 768px) {
  .site-footer-bottom {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

.footer-copyright,
.footer-credit {
  margin: 0;
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.footer-credit a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
}

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