/* Brand tokens */
:root {
  --color-navy: #0f172a;
  --color-navy-light: #1e293b;
  --color-indigo: #6366F1;
  --color-indigo-dim: #4338CA;
  --color-indigo-light: #818CF8;
  --color-indigo-deep: #312e81;
  --color-indigo-rgb: 99, 102, 241;
  --color-indigo-dim-rgb: 67, 56, 202;

  --color-text: #f0f4f8;
  --color-text-muted: #8b9cbb;
  --color-text-secondary: #8b9cbb;
  --color-white: #ffffff;
  --color-border: #2a3a5c;

  /* App design system aliases */
  --color-surface-base: var(--color-navy);
  --color-surface-raised: #162038;
  --color-surface-overlay: #1b2945;
  --color-brand-700: var(--color-indigo-dim);
  --color-brand-500: var(--color-indigo);
  --color-brand-400: var(--color-indigo-light);

  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Fira Code', 'Cascadia Code', 'Consolas', monospace;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;

  --max-width: 1200px;
  --nav-height: 44px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background-color: var(--color-navy);
  color: var(--color-text);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
}

/* Typography scale */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  color: var(--color-white);
  font-weight: 700;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.75rem); }
h4 { font-size: 1.25rem; }

p {
  color: var(--color-text);
  margin-bottom: var(--spacing-md);
}

a {
  color: var(--color-indigo);
  text-decoration: none;
}

a:hover {
  color: var(--color-white);
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

/* Layout utilities */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: calc(var(--nav-height) + var(--spacing-xl)) 0 var(--spacing-xl);
}

.section--alt {
  background-color: var(--color-navy-light);
}

/* Button utilities */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: opacity 0.2s, transform 0.1s;
  text-decoration: none;
}

.btn:hover {
  opacity: 0.9;
  transform: translateY(-1px);
  text-decoration: none;
}

.btn--primary {
  background-color: var(--color-indigo);
  color: var(--color-white);
}

.btn--secondary {
  background-color: transparent;
  color: var(--color-indigo);
  border: 2px solid var(--color-indigo);
}

/* Grid utility */
.grid {
  display: grid;
  gap: var(--spacing-md);
}

/* Text utilities */
.text-indigo { color: var(--color-indigo); }
.text-muted { color: var(--color-text-muted); }
.text-center { text-align: center; }

/* Main content area */
main {
  min-height: 100vh;
}

/* Article content styles */
.prose {
  max-width: 72ch;
  margin: 0 auto;
}

.prose h1, .prose h2, .prose h3 {
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

.prose p {
  margin-bottom: var(--spacing-md);
}

.prose ul, .prose ol {
  padding-left: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

.prose li {
  margin-bottom: var(--spacing-sm);
}

.prose code {
  background: var(--color-navy-light);
  padding: 0.1em 0.4em;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: var(--color-indigo-light);
}

.prose pre {
  background: var(--color-navy-light);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

.prose pre code {
  background: none;
  padding: 0;
}

.prose a {
  color: var(--color-indigo);
}

.prose blockquote {
  border-left: 4px solid var(--color-indigo);
  padding-left: var(--spacing-md);
  color: var(--color-text-muted);
  margin: var(--spacing-md) 0;
}

/* Table styles */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--spacing-md);
}

th, td {
  padding: 0.75rem var(--spacing-md);
  border: 1px solid var(--color-border);
  text-align: left;
}

th {
  background-color: var(--color-navy-light);
  color: var(--color-indigo-light);
  font-weight: 600;
}

tr:nth-child(even) {
  background-color: rgba(255,255,255,0.02);
}