:root {
    /* Color Palette: authoritative blues and neutral grays */
    --primary-blue: #0056b3;       /* Trustworthy Government Blue */
    --secondary-blue: #003d6b;     /* Deeper accent */
    --accent-blue: #e7f1ff;        /* Light background for highlights */
    --text-primary: #1a1a1a;       /* High readability */
    --text-secondary: #555555;     /* Supporting text */
    --bg-light: #f8f9fa;           /* Clean background */
    --white: #ffffff;
    --border-color: #e0e0e0;

    /* Typography */
    --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    --font-family-heading: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

    /* Spacing */
    --spacing-unit: 8px;
    --container-width: 1140px;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
}

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

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

a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

/* Header & Navigation */
header {
    background-color: var(--white);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

.logo {
    font-family: var(--font-family-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-blue);
    letter-spacing: -0.5px;
}

.logo:hover {
    text-decoration: none;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 30px;
    margin: 0;
    padding: 0;
    flex-wrap: wrap;
}

nav a {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    position: relative;
}

nav a:hover {
    color: var(--primary-blue);
    text-decoration: none;
}

/* Main Content */
main {
    padding: 3rem 0;
    min-height: 80vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family-heading);
    color: var(--text-primary);
    line-height: 1.3;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.75rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    border-bottom: 4px solid var(--primary-blue);
    display: inline-block;
    padding-bottom: 0.5rem;
}

h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-top: 2.5rem;
    color: var(--secondary-blue);
}

h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-top: 1.5rem;
}

p {
    margin-bottom: 1.25rem;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background-color: var(--primary-blue);
    color: var(--white);
    padding: 12px 24px;
    font-weight: 600;
    border-radius: 6px;
    transition: background-color 0.2s ease, transform 0.1s ease;
    border: none;
    cursor: pointer;
    text-decoration: none;
}

.btn:hover {
    background-color: var(--secondary-blue);
    text-decoration: none;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn:active {
    transform: translateY(0);
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(0, 51, 102, 0.7), rgba(0, 86, 179, 0.7)), url('hero.png') no-repeat center center/cover;
    color: var(--white);
    padding: 4rem 2rem;
    text-align: center;
    border-radius: 12px;
    margin-bottom: 3rem;
    box-shadow: var(--shadow-md);
}

.hero h1 {
    color: var(--white);
    border-bottom: none;
    margin-bottom: 1rem;
}

.hero p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.25rem;
    max-width: 700px;
    margin: 0 auto 2rem auto;
}

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

.hero .btn:hover {
    background-color: var(--bg-light);
}

/* Content Cards */
.content-card {
    background: var(--white);
    padding: 40px;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

/* Phase 4: CLS Armor */
.ad-container-leaderboard {
  min-height: 90px;
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 30px 0;
  background-color: var(--bg-light);
  border-radius: 4px;
  border: 1px dashed #ddd; /* Visual indicator for dev, subtle for prod */
}

@media (max-width: 768px) {
  .ad-container-leaderboard {
    min-height: 250px;
  }
}

/* Footer */
footer {
    background-color: #222;
    color: #eee;
    padding: 3rem 0;
    text-align: center;
    margin-top: auto;
}

footer p {
    color: #aaa;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

footer a {
    color: #ccc;
    margin: 0 10px;
    font-size: 0.9rem;
}

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

/* Responsive Utilities */
@media (max-width: 768px) {
    header .container {
        flex-direction: column;
        gap: 15px;
    }

    nav ul {
        gap: 20px;
        justify-content: center;
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .content-card {
        padding: 25px;
    }

    .hero {
        padding: 3rem 1.5rem;
    }
}