/* CSS Variables for consistent theming */
:root {
  /* Dark theme colors */
  --color-bg: #0a0a0a;
  --color-bg-secondary: #1a1a1a;
  --color-text: #e0e0e0;
  --color-text-secondary: #a0a0a0;
  --color-accent: #6366f1;
  --color-accent-hover: #4f46e5;
  --color-border: #333333;
  --color-shadow: rgba(0, 0, 0, 0.5);
  
  /* Typography */
  --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  --font-size-base: 1rem;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --line-height-base: 1.6;
  --line-height-tight: 1.4;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  
  /* Layout */
  --container-max-width: 1200px;
  --header-height: 60px;
  --border-radius: 8px;
  --transition: all 0.3s ease;
}

/* Reset and base styles */
*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-accent);
  color: white;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius);
  text-decoration: none;
  font-weight: 600;
  z-index: 1000;
  transition: var(--transition);
}

.skip-link:focus {
  top: 6px;
}

/* Header styles - mobile first */
.site-header {
  position: sticky;
  top: 0;
  background-color: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  backdrop-filter: blur(10px);
}

.header-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.site-title a {
  color: var(--color-text);
  text-decoration: none;
  font-size: var(--font-size-xl);
  font-weight: 700;
  line-height: var(--line-height-tight);
}

.site-title a:hover {
  color: var(--color-accent);
  transition: var(--transition);
}

/* Mobile navigation toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  width: 24px;
  height: 24px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 101;
}

.hamburger {
  width: 100%;
  height: 2px;
  background-color: var(--color-text);
  transition: var(--transition);
}

.nav-toggle[aria-expanded="true"] .hamburger:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle[aria-expanded="true"] .hamburger:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .hamburger:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -6px);
}

/* Mobile navigation */
.site-nav {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background-color: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: var(--transition);
}

.site-nav.nav-open {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: var(--space-md);
}

.nav-item {
  margin-bottom: var(--space-sm);
}

.nav-link {
  display: block;
  color: var(--color-text);
  text-decoration: none;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.nav-link:hover,
.nav-link:focus {
  background-color: var(--color-bg);
  color: var(--color-accent);
}

.nav-link.current {
  color: var(--color-accent);
  background-color: rgba(99, 102, 241, 0.1);
}

/* Main content */
.main-content {
  min-height: calc(100vh - var(--header-height) - 60px);
  padding: var(--space-xl) 0;
}

.content-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-text);
  line-height: var(--line-height-tight);
  margin-top: 0;
  margin-bottom: var(--space-lg);
}

h1 {
  font-size: var(--font-size-3xl);
  font-weight: 800;
}

h2 {
  font-size: var(--font-size-2xl);
  font-weight: 700;
}

h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
}

p {
  margin-top: 0;
  margin-bottom: var(--space-lg);
  color: var(--color-text);
}

a {
  color: var(--color-accent);
  text-decoration: underline;
  transition: var(--transition);
}

a:hover,
a:focus {
  color: var(--color-accent-hover);
  text-decoration: none;
}

/* Lists */
ul, ol {
  margin-top: 0;
  margin-bottom: var(--space-lg);
  padding-left: var(--space-xl);
}

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

/* Code */
code {
  font-family: var(--font-family-mono);
  font-size: 0.9em;
  background-color: var(--color-bg-secondary);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
}

pre {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  overflow-x: auto;
  margin-bottom: var(--space-lg);
}

pre code {
  background: none;
  padding: 0;
  border: none;
}

/* Footer */
.site-footer {
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--space-xl) 0;
}

.footer-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
  text-align: center;
}

.site-footer p {
  color: var(--color-text-secondary);
  margin: 0;
  font-size: var(--font-size-sm);
}

/* Responsive design - Tablet and up */
@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
  
  .site-nav {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    background: none;
    border: none;
  }
  
  .nav-list {
    display: flex;
    padding: 0;
    margin: 0;
  }
  
  .nav-item {
    margin-bottom: 0;
    margin-left: var(--space-md);
  }
  
  .nav-link {
    padding: var(--space-sm);
  }
  
  .content-container {
    padding: 0 var(--space-xl);
  }
  
  h1 {
    font-size: 3rem;
  }
  
  h2 {
    font-size: 2.25rem;
  }
}

/* Large screens */
@media (min-width: 1024px) {
  .content-container {
    padding: 0 var(--space-2xl);
  }
  
  h1 {
    font-size: 3.5rem;
  }
}

/* Focus styles for accessibility */
:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus,
a:focus {
  outline-color: var(--color-accent);
}

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

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

/* dark theme contact form */
form {
  display: grid;
  gap: 1rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

form label {
  font-weight: 600;
}

input[type="text"],
input[type="email"],
textarea {
  background: #1f2937; /* lighter than page bg */
  width: 100%;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem;
  font-size: 1rem;
}

input::placeholder,
textarea::placeholder {
  color: #d1d5db; /* light gray placeholder text */
}

input:focus,
textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  background: #374151; /* slightly lighter on focus */
}

button[type="submit"] {
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.2rem;
  cursor: pointer;
  transition: background 0.2s ease;
}

button[type="submit"]:hover {
  background: #3b82f6; /* slightly lighter */
}