:root {
    /* Colors - Modern Palette */
    --primary-color: #3b82f6;
    /* Blue 500 */
    --primary-dark: #2563eb;
    /* Blue 600 */
    --secondary-color: #10b981;
    /* Emerald 500 */
    --accent-color: #f59e0b;
    /* Amber 500 */

    --bg-color: #f8fafc;
    /* Slate 50 */
    --bg-card: #ffffff;
    --text-color: #1e293b;
    /* Slate 800 */
    --text-muted: #64748b;
    /* Slate 500 */

    --border-color: #e2e8f0;
    /* Slate 200 */

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-serif: 'Merriweather', serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --container-width: 1200px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #0f172a;
        /* Slate 900 */
        --bg-card: #1e293b;
        /* Slate 800 */
        --text-color: #f1f5f9;
        /* Slate 100 */
        --text-muted: #94a3b8;
        /* Slate 400 */
        --border-color: #334155;
        /* Slate 700 */
    }
}

/* Modern Reset */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

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

ul {
    list-style: none;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.75rem;
}

/* Utilities */
.container {
    width: 90%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-1px);
}

/* Navigation Base */
.navbar {
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-sm) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.nav-logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
}

.nav-toggle {
    display: none;
    /* Hidden on desktop */
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
}

@media (max-width: 768px) {
    .nav-toggle {
        display: block;
        /* Show on mobile */
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--bg-card);
        flex-direction: column;
        padding: var(--spacing-sm);
        border-bottom: 1px solid var(--border-color);
        box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links li {
        width: 100%;
        text-align: center;
    }

    .nav-links a {
        display: block;
        padding: 0.5rem;
    }
}

/* Advertising */
.ad-container {
    width: 100%;
    margin: 2rem auto;
    text-align: center;
    overflow: hidden;
}

.ad-placeholder {
    background-color: var(--bg-card);
    border: 1px dashed var(--border-color);
    color: var(--text-muted);
    padding: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100px;
    /* Adjust based on ad size */
    font-size: 0.875rem;
}