/* assets/css/style.css */
:root {
  /* -- Colors -- */
  --color-bg: #ffffff;
  --color-text: #1a1a1a;
  --color-primary: #2563eb; /* Blue from Kalkhan */
  --color-primary-light: #3b82f6; /* Lighter blue */
  --color-bg-dark-section: #111111; /* Dark background for footer and certain sections, deeper black */
  --color-text-on-dark: #f8f8f8;    /* Light text color for dark backgrounds */
  --color-border-dark: #374151;     /* Dark border for separation */
  --color-overlay-dark: rgba(0, 0, 0, 0.65); /* Darker overlay for hero images */

  /* -- Typography -- */
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* -- Layout -- */
  --max-width: 1200px;

  /* Standard Tokens (pre-defined by VoxelSite, for reference) */
  --text-xs: 0.75rem; --text-sm: 0.875rem; --text-base: 1rem; --text-lg: 1.125rem; --text-xl: 1.25rem;
  --text-2xl: 1.5rem; --text-3xl: 1.875rem; --text-4xl: 2.25rem; --text-5xl: 3rem; --text-6xl: 3.75rem;

  --space-xs: 0.25rem; --space-sm: 0.5rem; --space-md: 1rem; --space-lg: 1.5rem; --space-xl: 2rem;
  --space-2xl: 3rem; --space-3xl: 4rem; --space-4xl: 6rem;

  --radius-default: 4px; --radius-sm: 4px; --radius-md: 8px; --radius-lg: 12px; --radius-xl: 16px; --radius-full: 9999px;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
}

html { scroll-behavior: smooth; }
body { margin: 0; }

/* Base typography */
body { font-family: var(--font-body); line-height: 1.6; }
h1, h2, h3, h4, h5, h6 { font-family: var(--font-heading, var(--font-body)); line-height: 1.15; font-weight: 700; }
h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); line-height: 1.05; }
h2 { font-size: clamp(2rem, 4vw, 3.5rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2.5rem); }

/* Sticky Header with Scroll Effect */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  transition: background-color 0.4s cubic-bezier(0.33, 1, 0.68, 1),
              box-shadow 0.4s cubic-bezier(0.33, 1, 0.68, 1);
  background-color: transparent; /* Default transparent */
}

.site-header.is-scrolled {
  background-color: var(--color-bg-dark-section); /* Opaque dark background on scroll */
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(8px); /* Subtle blur effect */
}

/* Nav Link Underline Effect */
.nav-link {
  position: relative;
  display: inline-block;
  padding-bottom: 5px; /* Space for the underline */
}

.nav-underline {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width 0.3s cubic-bezier(0.33, 1, 0.68, 1);
}

.nav-link:hover .nav-underline,
.nav-link.active .nav-underline {
  width: 100%;
}

/* Mobile Menu Animations */
#mobile-menu.is-open {
  transform: translateX(0);
}
#mobile-menu {
  transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Scroll Reveal Animation */
[data-reveal] {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}
[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered Reveal Animation */
[data-reveal-stagger] > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}
[data-reveal-stagger].is-visible > *:nth-child(1) { transition-delay: 0ms; }
[data-reveal-stagger].is-visible > *:nth-child(2) { transition-delay: 100ms; }
[data-reveal-stagger].is-visible > *:nth-child(3) { transition-delay: 200ms; }
[data-reveal-stagger].is-visible > *:nth-child(4) { transition-delay: 300ms; }
[data-reveal-stagger].is-visible > *:nth-child(5) { transition-delay: 400ms; }
[data-reveal-stagger].is-visible > *:nth-child(6) { transition-delay: 500ms; }
[data-reveal-stagger].is-visible > * { opacity: 1; transform: translateY(0); }

/* Icon Styling */
.icon {
  display: inline-block;
  width: 1.25em;
  height: 1.25em;
  vertical-align: -0.15em;
  flex-shrink: 0;
}
.icon-sm { width: 1em; height: 1em; }
.icon-lg { width: 1.5em; height: 1.5em; }
.icon-xl { width: 2em; height: 2em; }

/* Reduced motion preference */
@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;
  }
}