/* ============================================
   CORE CSS - Design System Foundation
   Digital Scholar Design System
   ============================================ */

/* ============================================
   CSS RESET & BASE STYLES
   ============================================ */

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

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  line-height: 1.6;
  font-family: var(--font-primary);
  font-size: var(--text-base);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

input, button, textarea, select {
  font: inherit;
}

p, h1, h2, h3, h4, h5, h6 {
  overflow-wrap: break-word;
}

/* ============================================
   CSS VARIABLES - DESIGN TOKENS
   ============================================ */

:root {
  /* ===== COLOR PALETTE: DIGITAL SCHOLAR ===== */

  /* Core Brand Colors (from Quarto blog) */
  --color-blue: #3f597c;        /* Nav bar blue - matches Quarto blog */
  --color-teal: #00bc8c;        /* Bright teal - modern, energetic */
  --color-green: #00966f;       /* Forest green - distinctive accent */
  --color-slate: #2a2e33;       /* Dark slate for contrast */
  --color-dark: var(--color-slate); /* Unified dark background */

  /* Neutral Colors - Light Mode */
  --neutral-50: #f8f9fa;
  --neutral-100: #e9ecef;
  --neutral-200: #dee2e6;
  --neutral-300: #ced4da;
  --neutral-400: #adb5bd;
  --neutral-500: #6c757d;
  --neutral-600: #495057;
  --neutral-700: #343a40;
  --neutral-800: #2a2e33;
  --neutral-900: #222222;

  /* ===== LIGHT MODE (DEFAULT) ===== */
  --bg-primary: #ffffff;
  --bg-secondary: var(--neutral-50);
  --bg-tertiary: var(--neutral-100);
  --bg-accent: var(--color-blue);

  --text-primary: var(--neutral-900);
  --text-secondary: var(--neutral-600);
  --text-tertiary: var(--neutral-500);
  --text-on-accent: #ffffff;

  --border-color: var(--neutral-200);
  --border-color-hover: var(--neutral-300);

  --link-color: var(--color-blue);
  --link-hover: var(--color-teal);

  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

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

  /* Font Families */
  --font-primary: 'Source Sans 3', system-ui, -apple-system, sans-serif;
  --font-headings: 'Audiowide', sans-serif;
  --font-mono: 'Fira Code', 'Consolas', monospace;

  /* Font Sizes - Responsive */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.825rem + 0.25vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1.05rem + 0.375vw, 1.25rem);
  --text-xl: clamp(1.25rem, 1.125rem + 0.5vw, 1.5rem);
  --text-2xl: clamp(1.5rem, 1.25rem + 1vw, 2rem);
  --text-3xl: clamp(2rem, 1.5rem + 2vw, 3rem);
  --text-4xl: clamp(2.5rem, 1.75rem + 3vw, 4rem);

  /* Font Weights */
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  /* Line Heights */
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.6;
  --leading-relaxed: 1.75;
  --leading-loose: 2;

  /* ===== SPACING SYSTEM ===== */
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-5xl: 8rem;

  /* ===== LAYOUT ===== */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1280px;
  --container-2xl: 1536px;

  --border-radius-sm: 0.25rem;
  --border-radius-md: 0.5rem;
  --border-radius-lg: 0.75rem;
  --border-radius-xl: 1rem;
  --border-radius-2xl: 1.5rem;
  --border-radius-full: 9999px;

  /* ===== TRANSITIONS ===== */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;

  /* ===== Z-INDEX SCALE ===== */
  --z-base: 0;
  --z-dropdown: 1000;
  --z-sticky: 1100;
  --z-fixed: 1200;
  --z-modal-backdrop: 1300;
  --z-modal: 1400;
  --z-popover: 1500;
  --z-tooltip: 1600;
}

/* ============================================
   TYPOGRAPHY STYLES
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-headings);
  font-weight: var(--font-semibold);
  line-height: var(--leading-tight);
  color: var(--text-primary);
  margin-bottom: var(--space-md);
}

h1 {
  font-size: var(--text-4xl);
  font-weight: var(--font-bold);
}

h2 {
  font-size: var(--text-3xl);
  border-bottom: 2px solid var(--color-teal);
  padding-bottom: var(--space-sm);
  margin-bottom: var(--space-lg);
}

h3 {
  font-size: var(--text-2xl);
}

h4 {
  font-size: var(--text-xl);
}

h5 {
  font-size: var(--text-lg);
}

h6 {
  font-size: var(--text-base);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

p {
  margin-bottom: var(--space-md);
  line-height: var(--leading-relaxed);
}

a {
  color: var(--link-color);
  text-decoration: none;
  transition: color var(--transition-fast);
  border-bottom: 1px solid transparent;
}

a:hover {
  color: var(--link-hover);
  border-bottom-color: var(--link-hover);
}

a:focus-visible {
  outline: 2px solid var(--color-teal);
  outline-offset: 2px;
  border-radius: 2px;
}

strong, b {
  font-weight: var(--font-bold);
}

em, i {
  font-style: italic;
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: var(--color-green);
  background-color: var(--bg-tertiary);
  padding: 0.125rem 0.375rem;
  border-radius: var(--border-radius-sm);
}

pre {
  font-family: var(--font-mono);
  background-color: var(--neutral-900);
  color: var(--neutral-200);
  padding: var(--space-lg);
  border-radius: var(--border-radius-lg);
  overflow-x: auto;
  margin-bottom: var(--space-md);
  border-left: 3px solid var(--color-teal);
}

pre code {
  background-color: transparent;
  padding: 0;
  color: inherit;
}

blockquote {
  border-left: 4px solid var(--color-blue);
  padding-left: var(--space-lg);
  margin: var(--space-xl) 0;
  font-style: italic;
  color: var(--text-secondary);
}

/* ============================================
   LISTS
   ============================================ */

ul, ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-xl);
}

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

/* ============================================
   UTILITY CLASSES
   ============================================ */

/* Container */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-lg);
  padding-right: var(--space-lg);
}

.container-sm { max-width: var(--container-sm); }
.container-md { max-width: var(--container-md); }
.container-lg { max-width: var(--container-lg); }
.container-2xl { max-width: var(--container-2xl); }

/* Text Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-accent { color: var(--color-blue); }

.font-normal { font-weight: var(--font-normal); }
.font-medium { font-weight: var(--font-medium); }
.font-semibold { font-weight: var(--font-semibold); }
.font-bold { font-weight: var(--font-bold); }

/* Spacing Utilities */
.mt-auto { margin-top: auto; }
.mb-auto { margin-bottom: auto; }
.my-auto { margin-top: auto; margin-bottom: auto; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* Display Utilities */
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }
.flex { display: flex; }
.inline-flex { display: inline-flex; }
.grid { display: grid; }

/* Flexbox Utilities */
.flex-row { flex-direction: row; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-around { justify-content: space-around; }
.gap-xs { gap: var(--space-xs); }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }

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

/* ============================================
   RESPONSIVE BREAKPOINTS
   ============================================ */

@media (min-width: 640px) {
  .container {
    padding-left: var(--space-xl);
    padding-right: var(--space-xl);
  }
}

@media (min-width: 1024px) {
  .container {
    padding-left: var(--space-2xl);
    padding-right: var(--space-2xl);
  }
}