/* ============================================================
   The AI Disciple — Design System
   Art direction: warm cream paper + deep ink navy + cobalt blue accent.
   Display: Zodiak (serif) · Body: Satoshi (sans)
   ============================================================ */

:root {
  /* Type scale (fluid) */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.8125rem);
  --text-sm: clamp(0.875rem, 0.83rem + 0.2vw, 0.9375rem);
  --text-base: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  --text-lg: clamp(1.125rem, 1.05rem + 0.45vw, 1.375rem);
  --text-xl: clamp(1.5rem, 1.25rem + 1.1vw, 2.125rem);
  --text-2xl: clamp(2rem, 1.35rem + 2.4vw, 3.25rem);
  --text-3xl: clamp(2.5rem, 1.5rem + 3.6vw, 4.25rem);

  /* Spacing (4px base) */
  --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;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Fonts */
  --font-display: 'Zodiak', 'Iowan Old Style', Georgia, serif;
  --font-body: 'Satoshi', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

  /* Radii & shadows */
  --radius-sm: 4px;
  --radius: 8px;
  --radius-lg: 14px;
  --shadow-sm: 0 1px 2px rgb(23 26 33 / 0.05), 0 1px 3px rgb(23 26 33 / 0.04);
  --shadow-md: 0 4px 12px rgb(23 26 33 / 0.07), 0 2px 4px rgb(23 26 33 / 0.04);
  --shadow-lg: 0 18px 40px rgb(23 26 33 / 0.11), 0 4px 10px rgb(23 26 33 / 0.05);

  /* Motion */
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --dur: 0.35s;

  /* Layout */
  --container: 1180px;
  --container-narrow: 760px;
}

/* ---------- Light theme (default) ---------- */
:root,
[data-theme='light'] {
  --color-bg: #faf7f1;
  --logo-knock: #faf7f1;
  --color-surface: #ffffff;
  --color-surface-2: #f3eee3;
  --color-surface-3: #ece5d7;
  --color-border: #e0d8c8;
  --color-divider: #ebe4d7;

  --color-text: #171a21;
  --color-text-muted: #5b6070;
  --color-text-faint: #8b909d;

  --color-accent: #0b4f9e;
  --color-accent-hover: #08407f;
  --color-accent-soft: #e4edf9;

  --color-ink: #10141c;
  --color-ink-2: #1a202b;
  --color-on-ink: #f2ece0;
  --color-on-ink-muted: #a5abb8;
  --color-on-ink-accent: #5f9ae0;
  --color-ink-border: #2b323e;

  --shadow-color: 23 26 33;
  color-scheme: light;
}

/* ---------- Dark theme ---------- */
[data-theme='dark'] {
  --color-bg: #0e1218;
  --logo-knock: #0e1218;
  --color-surface: #151a23;
  --color-surface-2: #1b212c;
  --color-surface-3: #232a36;
  --color-border: #2b323e;
  --color-divider: #232a36;

  --color-text: #ece7dc;
  --color-text-muted: #9aa1ae;
  --color-text-faint: #6d7482;

  --color-accent: #5f9ae0;
  --color-accent-hover: #85b6ea;
  --color-accent-soft: #16202e;

  --color-ink: #080b10;
  --color-ink-2: #10141c;
  --color-on-ink: #ece7dc;
  --color-on-ink-muted: #9aa1ae;
  --color-on-ink-accent: #5f9ae0;
  --color-ink-border: #232a36;

  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.4);
  --shadow-md: 0 4px 12px rgb(0 0 0 / 0.45);
  --shadow-lg: 0 18px 40px rgb(0 0 0 / 0.55);
  color-scheme: dark;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    --color-bg: #0e1218;
    --logo-knock: #0e1218;
    --color-surface: #151a23;
    --color-surface-2: #1b212c;
    --color-surface-3: #232a36;
    --color-border: #2b323e;
    --color-divider: #232a36;
    --color-text: #ece7dc;
    --color-text-muted: #9aa1ae;
    --color-text-faint: #6d7482;
    --color-accent: #5f9ae0;
    --color-accent-hover: #85b6ea;
    --color-accent-soft: #16202e;
    --color-ink: #080b10;
    --color-ink-2: #10141c;
    --color-on-ink: #ece7dc;
    --color-on-ink-muted: #9aa1ae;
    --color-ink-border: #232a36;
    --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.4);
    --shadow-md: 0 4px 12px rgb(0 0 0 / 0.45);
    --shadow-lg: 0 18px 40px rgb(0 0 0 / 0.55);
    color-scheme: dark;
  }
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}
* {
  margin: 0;
}
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
}
body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}
img,
picture,
svg,
video,
iframe {
  display: block;
  max-width: 100%;
}
img {
  height: auto;
}
input,
button,
textarea,
select {
  font: inherit;
  color: inherit;
}
button {
  cursor: pointer;
  background: none;
  border: none;
}
a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover {
  color: var(--color-accent-hover);
}
h1,
h2,
h3,
h4 {
  font-weight: 600;
  line-height: 1.15;
  text-wrap: balance;
  letter-spacing: -0.015em;
}
p {
  text-wrap: pretty;
}
ul,
ol {
  padding-left: 1.15em;
}
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 2px;
}

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

/* ---------- Layout primitives ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(var(--space-5), 5vw, var(--space-10));
}
.container--narrow {
  max-width: var(--container-narrow);
}
.section {
  padding-block: clamp(var(--space-16), 9vw, var(--space-32));
}
.section--tight {
  padding-block: clamp(var(--space-12), 6vw, var(--space-20));
}
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-accent);
  color: #fff;
  padding: var(--space-3) var(--space-5);
  z-index: 200;
  border-radius: 0 0 var(--radius) 0;
}
.skip-link:focus {
  left: 0;
  color: #fff;
}

/* ---------- Typography helpers ---------- */
.eyebrow {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}
.eyebrow::before {
  content: '';
  width: 1.75rem;
  height: 1px;
  background: currentColor;
  flex: none;
}
.eyebrow--center {
  justify-content: center;
}
.display {
  font-family: var(--font-display);
  font-weight: 500;
  letter-spacing: -0.025em;
}
h1.display {
  font-size: var(--text-3xl);
  line-height: 1.05;
}
h2.display {
  font-size: var(--text-2xl);
  line-height: 1.1;
}
h3.display {
  font-size: var(--text-xl);
  line-height: 1.15;
}
.lede {
  font-size: var(--text-lg);
  line-height: 1.55;
  color: var(--color-text-muted);
  max-width: 60ch;
}
.muted {
  color: var(--color-text-muted);
}
.prose > * + * {
  margin-top: var(--space-5);
}
.prose h2,
.prose h3 {
  margin-top: var(--space-12);
}
.prose p,
.prose li {
  max-width: 68ch;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: -0.005em;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius);
  border: 1px solid transparent;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 0.2s var(--ease), border-color 0.2s var(--ease),
    color 0.2s var(--ease), transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.btn:hover {
  transform: translateY(-1px);
}
.btn:active {
  transform: translateY(0);
}
.btn--primary {
  background: var(--color-accent);
  color: #fff;
  box-shadow: var(--shadow-sm);
}
[data-theme='dark'] .btn--primary {
  color: #0b1620;
}

/* On ink-backed sections the deep accent sinks into the background
   (2.3:1), so use the lighter on-ink accent instead (6.3:1). */
.hero .btn--primary,
.trust .btn--primary,
.section--ink .btn--primary,
.cta-band .btn--primary {
  background: var(--color-on-ink-accent);
  color: #0b1620;
}
.hero .btn--primary:hover,
.trust .btn--primary:hover,
.section--ink .btn--primary:hover,
.cta-band .btn--primary:hover {
  background: #85b6ea;
  color: #0b1620;
}
.btn--primary:hover {
  background: var(--color-accent-hover);
  color: #fff;
  box-shadow: var(--shadow-md);
}
[data-theme='dark'] .btn--primary:hover {
  color: #0b1620;
}
.btn--outline {
  border-color: var(--color-border);
  color: var(--color-text);
  background: transparent;
}
.btn--outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-surface);
}
.btn--on-ink {
  border-color: rgb(255 255 255 / 0.22);
  color: var(--color-on-ink);
  background: rgb(255 255 255 / 0.04);
  backdrop-filter: blur(6px);
}
.btn--on-ink:hover {
  border-color: var(--color-on-ink-accent);
  color: var(--color-on-ink-accent);
  background: rgb(255 255 255 / 0.08);
}
.btn--lg {
  padding: 1rem 1.9rem;
  font-size: var(--text-base);
}
.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

/* Arrow link */
.arrow-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  color: var(--color-accent);
}
.arrow-link svg {
  transition: transform 0.25s var(--ease);
}
.arrow-link:hover svg {
  transform: translateX(4px);
}

/* ---------- Scroll reveal (no layout shift) ---------- */
.reveal {
  opacity: 1;
}
@media (prefers-reduced-motion: no-preference) {
  @supports (animation-timeline: view()) {
    .reveal {
      opacity: 0;
      animation: reveal-fade linear both;
      animation-timeline: view();
      animation-range: entry 5% cover 22%;
    }
  }
}
@keyframes reveal-fade {
  to {
    opacity: 1;
  }
}