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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: var(--lh-body);
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography Selection & Hierarchy */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: var(--lh-heading);
  color: var(--color-text);
  margin-bottom: var(--spacing-4);
}

h1 {
  font-size: clamp(var(--text-4xl), 8vw, var(--text-7xl));
  font-weight: 800;
  letter-spacing: -0.03em;
}

h2 {
  font-size: clamp(var(--text-3xl), 5vw, var(--text-5xl));
  letter-spacing: -0.02em;
}

h3 {
  font-size: clamp(var(--text-2xl), 3vw, var(--text-3xl));
  letter-spacing: -0.01em;
}

h4 {
  font-size: var(--text-2xl);
  font-weight: 600;
}

p {
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-6);
  font-size: clamp(var(--text-base), 1.5vw, var(--text-lg));
  max-width: 65ch; /* Comfortable reading width */
}

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

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

/* Layout Containers & Utilities */
.container {
  width: 100%;
  max-width: var(--max-width-site);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-6);
  padding-right: var(--spacing-6);
}

@media (min-width: 768px) {
  .container {
    padding-left: var(--spacing-12);
    padding-right: var(--spacing-12);
  }
}

.section-padding {
  padding-top: var(--spacing-16);
  padding-bottom: var(--spacing-16);
}

@media (min-width: 768px) {
  .section-padding {
    padding-top: var(--spacing-24);
    padding-bottom: var(--spacing-24);
  }
}

/* Accessible Keyboard Navigation & Utility */
:focus-visible {
  outline: var(--focus-ring);
  outline-offset: 4px;
}

.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* Skip link for keyboard navigation */
.skip-link {
  position: absolute;
  top: -100px;
  left: var(--spacing-6);
  background-color: var(--color-brand);
  color: var(--color-white);
  padding: var(--spacing-3) var(--spacing-6);
  border-radius: var(--border-radius-sm);
  font-family: var(--font-heading);
  font-weight: 600;
  z-index: 9999;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--spacing-4);
  outline: none;
}