/* Layout System */

:root {
  /* Colors - Light Mode (Default) */
  --color-bg-primary: #fafafa;
  --color-bg-secondary: #f5f5f5;
  --color-bg-tertiary: #ffffff;
  
  --color-text-primary: #1a1a1a;
  --color-text-secondary: #4a4a4a;
  --color-text-muted: #6b6b6b;
  
  --color-accent: #0066cc;
  --color-accent-hover: #004d99;
  
  --color-border: #e5e5e5;
  --color-border-strong: #d0d0d0;
  
  --color-code-bg: #f5f5f5;
  --color-code-text: #1a1a1a;

  /* Spacing scale (8px base) */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.5rem;    /* 24px */
  --space-6: 2rem;      /* 32px */
  --space-8: 3rem;      /* 48px */
  --space-10: 4rem;     /* 64px */
  --space-12: 6rem;     /* 96px */

  /* Layout widths */
  --width-content: 65ch;
  --width-wide: 900px;
  --width-max: 1200px;

  /* Header height */
  --header-height: 64px;
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg-primary: #121212;
    --color-bg-secondary: #1e1e1e;
    --color-bg-tertiary: #2a2a2a;
    
    --color-text-primary: #f0f0f0;
    --color-text-secondary: #c0c0c0;
    --color-text-muted: #888888;
    
    --color-accent: #66b3ff;
    --color-accent-hover: #99ccff;
    
    --color-border: #333333;
    --color-border-strong: #444444;
    
    --color-code-bg: #1e1e1e;
    --color-code-text: #f0f0f0;
  }
}

/* Manual dark mode override */
[data-theme="dark"] {
  --color-bg-primary: #121212;
  --color-bg-secondary: #1e1e1e;
  --color-bg-tertiary: #2a2a2a;
  
  --color-text-primary: #f0f0f0;
  --color-text-secondary: #c0c0c0;
  --color-text-muted: #888888;
  
  --color-accent: #66b3ff;
  --color-accent-hover: #99ccff;
  
  --color-border: #333333;
  --color-border-strong: #444444;
  
  --color-code-bg: #1e1e1e;
  --color-code-text: #f0f0f0;
}

/* Base body styles */
body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
}

/* Container */
.container {
  width: 100%;
  max-width: var(--width-max);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--space-6);
  }
}

/* Site Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-bg-primary);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.nav__logo {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  text-decoration: none;
}

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

.nav__menu {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}

.nav__link {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-2) 0;
  transition: color 0.2s ease;
}

.nav__link:hover,
.nav__link--active {
  color: var(--color-accent);
}

.nav__toggle {
  display: none;
  padding: var(--space-2);
  color: var(--color-text-primary);
}

/* Mobile Navigation */
@media (max-width: 768px) {
  .nav__toggle {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .nav__menu {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: var(--space-4);
    background-color: var(--color-bg-primary);
    border-top: 1px solid var(--color-border);
    overflow-y: auto;
  }

  .nav__menu.is-open {
    display: flex;
  }

  .nav__link {
    width: 100%;
    padding: var(--space-4) 0;
    font-size: var(--text-base);
    border-bottom: 1px solid var(--color-border);
  }
}

/* Main Content */
.main {
  flex: 1;
  padding: var(--space-8) 0;
}

.main > .container {
  max-width: var(--width-content);
}

.main--wide > .container {
  max-width: var(--width-wide);
}

/* Sections */
.section {
  margin-bottom: var(--space-10);
}

.section:last-child {
  margin-bottom: 0;
}

.section__title {
  margin-bottom: var(--space-5);
}

/* Site Footer */
.site-footer {
  padding: var(--space-6) 0;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.site-footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  text-align: center;
}

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

.footer__links {
  display: flex;
  gap: var(--space-4);
}

.footer__link {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

/* Page Header */
.page-header {
  margin-bottom: var(--space-8);
}

.page-header__title {
  margin-bottom: var(--space-4);
}

.page-header__description {
  color: var(--color-text-secondary);
  font-size: var(--text-lg);
  max-width: 65ch;
}

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

.mb-0 { margin-bottom: 0; }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }