/* ==========================================================================
   Design Tokens (Variables)
   ========================================================================== */

:root {
  /* HINT: Let the browser know this site supports both color schemes for its own UI */
  color-scheme: light dark;

  /* Colors */
  --color-primary: #4a5568;
  --color-primary-hover: #2d3748;
  --color-secondary: #718096;
  --color-text: #2d3748;
  --color-text-muted: #718096;
  --color-background: #ffffff;
  --color-surface: #f7fafc; /* For cards, headers, etc. */
  --color-border: #e2e8f0;
  --color-border-focus: var(--color-primary);
  --color-code-bg: #f7fafc;
  --color-code-text: #4a5568;
  --color-success: #68d391;
  --color-warning: #f6e05e;
  --color-error: #fc8181;

  /* Typography */
  --font-family-base: 'Open Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-family-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, 'Courier New', monospace;
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-lg: 1.125rem;   /* 18px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */
  --font-size-3xl: 1.875rem;  /* 30px */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --font-weight-normal: 400;
  --font-weight-medium: 600;
  --font-weight-bold: 700;

  /* Spacing */
  --spacing-xs: 0.25rem;   /* 4px */
  --spacing-sm: 0.5rem;    /* 8px */
  --spacing-md: 0.75rem;   /* 12px */
  --spacing-lg: 1rem;      /* 16px */
  --spacing-xl: 1.5rem;    /* 24px */
  --spacing-2xl: 2rem;     /* 32px */
  --spacing-3xl: 3rem;     /* 48px */

  /* Layout */
  --max-width-content: 65ch;
  --max-width-full: 1200px;
  --border-radius-sm: 0.25rem;
  --border-radius-md: 0.375rem;
  --border-radius-lg: 0.5rem;

  /* Effects */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.2s ease;
  --transition-slow: 0.3s ease;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --focus-ring: 0 0 0 3px rgba(74, 85, 104, 0.2);
}

/* Dark mode variables */
@media (prefers-color-scheme: dark) {
  :root {
    --color-text: #e2e8f0;
    --color-text-muted: #a0aec0;
    --color-background: #1a202c;
    --color-surface: #2d3748;
    --color-border: #4a5568;
    --color-code-bg: #2d3748;
    --color-code-text: #a0aec0;
    --color-primary: #718096;
    --color-primary-hover: #a0aec0;
    --color-secondary: #a0aec0;
    --focus-ring: 0 0 0 3px rgba(113, 128, 150, 0.25);
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --color-border: #000000;
    --color-text: #000000;
    --color-background: #ffffff;
    --color-surface: #ffffff;
  }
}

@media (prefers-color-scheme: dark) and (prefers-contrast: high) {
  :root {
    --color-border: #ffffff;
    --color-text: #ffffff;
    --color-background: #000000;
    --color-surface: #000000;
  }
}

/* ==========================================================================
   Base & Global Styles
   ========================================================================== */

/* Basic Reset & Typography */
body {
  font-family: var(--font-family-base);
  line-height: var(--line-height-relaxed);
  background-color: var(--color-background);
  color: var(--color-text);
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

a {
  color: var(--color-primary);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-hover);
  text-decoration-thickness: 2px;
}

a:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
  border-radius: var(--border-radius-sm);
  text-decoration: none;
}

/* ==========================================================================
   Layout
   ========================================================================== */

/* Header & Navigation */
header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-lg) var(--spacing-2xl);
  box-shadow: var(--shadow-sm);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

header nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: var(--max-width-full);
  margin: 0 auto;
}

header h1 {
  margin: 0;
  font-size: var(--font-size-2xl);
}

header ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  gap: var(--spacing-xl);
}

/* Main Content */
main {
  flex: 1;
  max-width: var(--max-width-full);
  width: 100%;
  margin: var(--spacing-2xl) auto;
  padding: 0 var(--spacing-2xl);
  box-sizing: border-box;
}

main h2 {
  font-size: var(--font-size-xl);
  color: var(--color-text-muted);
  font-weight: var(--font-weight-normal);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: var(--spacing-lg);
  margin-top: 0;
  margin-bottom: var(--spacing-xl);
}

/* ==========================================================================
   Components
   ========================================================================== */

/* Search Bar */
.search-bar {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: var(--font-size-base);
  color: var(--color-text);
  background-color: var(--color-surface);
  border-radius: var(--border-radius-md);
  border: 1px solid var(--color-border);
  margin-bottom: var(--spacing-2xl);
  box-sizing: border-box;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-normal), color var(--transition-normal);
}

.search-bar:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: var(--focus-ring);
}

/* Notes Styling */
.note {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  margin-bottom: var(--spacing-lg);
  overflow: hidden;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.note summary {
  padding: var(--spacing-lg) var(--spacing-xl);
  cursor: pointer;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-medium);
  outline: none;
  user-select: none;
  transition: background-color var(--transition-fast);
}

.note summary:hover {
  /* Use code-bg as a subtle hover color that works in both themes */
  background-color: var(--color-code-bg);
}

.note details[open] > summary {
  border-bottom: 1px solid var(--color-border);
}

.note .gist-content {
  padding: 0 var(--spacing-xl) var(--spacing-xl) var(--spacing-xl);
  margin-top: var(--spacing-lg);
}

.note .gist-content p {
  margin-top: 0;
  line-height: var(--line-height-relaxed);
}

.note .file-header {
  font-size: var(--font-size-sm);
  font-family: var(--font-family-mono);
  color: var(--color-text-muted);
  background-color: var(--color-code-bg);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  margin: var(--spacing-lg) 0 var(--spacing-sm);
}

/* Code blocks */
pre {
  background-color: var(--color-code-bg);
  color: var(--color-code-text);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius-md);
  overflow-x: auto;
  font-size: 0.9em;
  line-height: var(--line-height-normal);
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

code {
  font-family: var(--font-family-mono);
}

/* Loading/Error Indicators */
.indicator {
  color: var(--color-text-muted);
  font-style: italic;
  text-align: center;
  padding: var(--spacing-2xl);
}