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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 1.5rem);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Typography Base */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(2.25rem, 4.5vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.03em;
}

h2 {
  font-size: clamp(1.6rem, 3vw, 2.15rem);
  margin-bottom: var(--space-sm);
}

h3 {
  font-size: clamp(1.2rem, 2vw, 1.4rem);
  font-weight: 600;
}

p {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.65;
}

p.lead {
  font-size: clamp(1.05rem, 1.5vw, 1.2rem);
  color: var(--text-secondary);
  line-height: 1.6;
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-hover);
}

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

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

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

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

/* Section Wrapper */
.section {
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-3xl);
  border-bottom: 1px solid var(--border-light);
}

.section-header {
  margin-bottom: var(--space-2xl);
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent-primary);
  background-color: var(--accent-subtle);
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-xs);
  border: 1px solid var(--accent-border);
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 640px;
}

/* Focus States for Accessibility */
:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

/* Screen Reader Only Utility */
.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;
}