:root {
  /* Colors */
  --primary: #2563EB;
  /* Blue */
  --primary-dark: #1D4ED8;
  --primary-light: #60A5FA;
  --accent: #06B6D4;
  /* Cyan/Teal */

  --bg-color: #FFFFFF;
  --bg-light: #F9FAFB;
  /* Light grey */
  --bg-dark: #0F172A;
  /* For dark sections like footer/hero overlay */

  --text-main: #1F2937;
  /* Dark Grey */
  --text-muted: #6B7280;
  --text-light: #F3F4F6;

  --border-color: #E5E7EB;

  /* Typography Scale (Fluid) */
  --fs-h1: clamp(2rem, 6vw, 4rem);       /* 32px - 64px */
  --fs-h2: clamp(1.75rem, 4vw, 2.5rem);   /* 28px - 40px */
  --fs-h3: clamp(1.375rem, 2.5vw, 1.75rem); /* 22px - 28px */
  --fs-body: clamp(1rem, 1.5vw, 1.125rem);  /* 16px - 18px */
  --fs-subline: clamp(1.125rem, 2vw, 1.5rem); /* 18px - 24px */
  --fs-small: clamp(0.8125rem, 1vw, 0.875rem); /* 13px - 14px */

  --lh-tight: 1.1;
  --lh-heading: 1.2;
  --lh-subheading: 1.3;
  --lh-body: 1.6;
  --lh-body-mb: 1.5;

  --font-heading: 'Inter', sans-serif;
  --font-body: 'Roboto', sans-serif;

  /* Layout */
  --container-max: 1280px;
  --section-padding: 80px 20px;

  /* Transitions */
  --transition: all 0.3s ease;
  --radius: 8px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-body);
  color: var(--text-main);
  background-color: var(--bg-color);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  -webkit-font-smoothing: antialiased;
}

@media (max-width: 768px) {
  body {
    line-height: var(--lh-body-mb);
  }
}

body.no-scroll {
  overflow: hidden;
}

/* Typography Base */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-main);
  margin-top: 2.5rem; /* Vertical Rhythm: More space above */
  margin-bottom: 1.125rem; /* Standard bottom margin */
}

h1:first-child, 
h2:first-child, 
h3:first-child {
  margin-top: 0;
}

h1 {
  font-size: var(--fs-h1);
  line-height: var(--lh-tight);
  font-weight: 800;
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--fs-h2);
  line-height: var(--lh-heading);
  font-weight: 700; /* Guide says Semi-Bold 600, but often Inter 700 looks better for sections. I'll use 700 as requested for "Section Heading" in common practice or 600 if specific. User said "Semi-Bold (600)". I'll stick to 600. */
  font-weight: 600;
  letter-spacing: -0.01em;
}

h3 {
  font-size: var(--fs-h3);
  line-height: var(--lh-subheading);
  font-weight: 600;
}

p {
  font-size: var(--fs-body);
  margin-bottom: var(--fs-body); /* Guide: spacing = body font size */
  color: var(--text-muted);
}

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

a:hover {
  color: var(--primary-dark);
}

li {
  list-style-type: none;
}

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