/* Base Styles - Adaptive Human
 *
 * Typography, layout foundation, and theme infrastructure.
 * Designed for landing page content (not app interface).
 */

/* ============================================
   FONT IMPORTS
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:ital,wght@0,200..800;1,200..800&family=Source+Code+Pro:ital,wght@0,200..900;1,200..900&family=Syne:wght@400..800&display=swap');


/* ============================================
   UNIVERSAL RESET
   ============================================ */

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


/* ============================================
   ROOT & BODY SETUP
   ============================================ */

html {
  /* Smooth scrolling for anchor links */
  scroll-behavior: smooth;

  /* Prevent horizontal overflow */
  overflow-x: hidden;
}

/* Disable smooth scroll for users who prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  /* Background and text colors from tokens */
  background: var(--bg-primary);
  color: var(--text-primary);

  /* Typography */
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: var(--line-relaxed);
  letter-spacing: var(--tracking-normal);

  /* Smooth theme transitions */
  transition: background-color var(--transition-medium),
              color var(--transition-medium);

  /* Prevent horizontal overflow */
  overflow-x: hidden;

  /* Better font rendering */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}


/* ============================================
   TYPOGRAPHY BASELINE
   ============================================ */

/* Headings */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--font-bold);
  line-height: var(--line-tight);
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}

h1 {
  font-size: var(--text-5xl);
  letter-spacing: var(--tracking-tight);
  margin-bottom: var(--space-6);
}

h2 {
  font-size: var(--text-4xl);
  letter-spacing: var(--tracking-tight);
  margin-bottom: var(--space-5);
}

h3 {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

h4 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-4);
}

h5 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-3);
}

h6 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-3);
  font-weight: var(--font-semibold);
}

/* Body text */

p {
  margin-bottom: var(--space-5);
  color: var(--text-secondary);
}

p:last-child {
  margin-bottom: 0;
}

/* Text emphasis */

strong, b {
  font-weight: var(--font-semibold);
  color: var(--text-primary);
}

em, i {
  font-style: italic;
}

small {
  font-size: var(--text-sm);
}

/* Links */

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: var(--transition-all-fast);
  cursor: pointer;
}

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

a:focus-visible {
  outline: var(--border-width-thick) solid var(--border-focus);
  outline-offset: var(--space-1);
  border-radius: var(--radius-sm);
}

/* Lists */

ul, ol {
  margin-bottom: var(--space-5);
  padding-left: var(--space-6);
  color: var(--text-secondary);
}

li {
  margin-bottom: var(--space-2);
}

li:last-child {
  margin-bottom: 0;
}

/* Inline code */

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--bg-tertiary);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  color: var(--color-accent);
  border: var(--border-width) solid var(--border-light);
}

/* Code blocks */

pre {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  background: var(--bg-tertiary);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin-bottom: var(--space-5);
  border: var(--border-width) solid var(--border-color);
}

pre code {
  background: none;
  padding: 0;
  border: none;
  color: var(--text-primary);
}

/* Blockquotes */

blockquote {
  border-left: var(--border-width-thicker) solid var(--color-accent);
  padding-left: var(--space-6);
  margin-bottom: var(--space-5);
  font-style: italic;
  color: var(--text-secondary);
}

blockquote p {
  margin-bottom: var(--space-3);
}

/* Horizontal rule */

hr {
  border: none;
  border-top: var(--border-width) solid var(--border-color);
  margin: var(--space-12) 0;
}


/* ============================================
   SELECTION STYLING
   ============================================ */

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

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


/* ============================================
   SCROLLBAR STYLING (WEBKIT)
   ============================================ */

::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: var(--radius-full);
  border: 2px solid var(--bg-secondary);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--border-dark);
}


/* ============================================
   THEME TRANSITION SMOOTHING
   ============================================ */

/* Apply smooth transitions to all elements that change with theme */
*,
*::before,
*::after {
  transition-property: background-color, border-color, color, fill, stroke;
  transition-duration: var(--transition-medium);
  transition-timing-function: var(--ease-in-out);
}

/* Preserve other transitions */
a,
button,
input,
textarea,
select {
  transition-property: background-color, border-color, color, fill, stroke, opacity, transform, box-shadow;
}


/* ============================================
   FOCUS VISIBLE SUPPORT
   ============================================ */

/* Remove default focus outline, rely on focus-visible */
*:focus {
  outline: none;
}

/* Apply visible focus styles for keyboard navigation */
*:focus-visible {
  outline: var(--border-width-thick) solid var(--border-focus);
  outline-offset: var(--space-1);
}


/* ============================================
   IMAGE & MEDIA DEFAULTS
   ============================================ */

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

img {
  /* Prevent alt text from causing layout shift */
  font-style: italic;
}


/* ============================================
   UTILITIES
   ============================================ */

/* Visually hidden but accessible to screen readers */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Skip to content link for accessibility */
.skip-to-content {
  position: absolute;
  top: var(--space-4);
  left: var(--space-4);
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  font-weight: var(--font-medium);
  z-index: var(--z-modal);
  transform: translateY(-200%);
  transition: transform var(--transition-normal);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-lg);
}

.skip-to-content:focus {
  transform: translateY(0);
}


/* ============================================
   RESPONSIVE TYPOGRAPHY
   ============================================ */

/* Slightly larger base font on larger screens */
@media (min-width: 768px) {
  body {
    font-size: var(--text-md);
  }

  h1 {
    font-size: var(--text-6xl);
  }

  h2 {
    font-size: var(--text-5xl);
  }

  h3 {
    font-size: var(--text-4xl);
  }
}

@media (min-width: 1024px) {
  h1 {
    font-size: var(--text-7xl);
  }

  h2 {
    font-size: var(--text-6xl);
  }
}


/* ============================================
   DESIGN NOTES
   ============================================

   TYPOGRAPHY APPROACH:
   Landing page focused - generous spacing, clear hierarchy.
   Headings use Syne (geometric, modern), body uses Plus Jakarta Sans
   (humanist, readable), code uses Source Code Pro.

   THEME TRANSITIONS:
   Smooth transitions on theme change for professional feel.
   All color properties transition together.

   ACCESSIBILITY:
   - Reduced motion support
   - Focus-visible for keyboard navigation
   - Skip to content link
   - Semantic HTML support

   RESPONSIVE:
   Base font scales up on larger screens for better readability.
   Heading sizes grow for more dramatic hierarchy on desktop.

   ============================================ */