:root {
    --primary-color: #0d6efd;
    --secondary-color: #6c757d;
    --background-color: #f8f9fa;
    --surface-color: #ffffff;
    --font-family-sans-serif: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif;
}

body {
    font-family: var(--font-family-sans-serif);
    background-color: var(--background-color);
    color: #212529;
}

.navbar {
    transition: background-color 0.3s ease-in-out, padding 0.3s ease-in-out;
}

.navbar.scrolled {
    background-color: var(--surface-color) !important;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.hero-section {
    height: 100vh;
    background-image: linear-gradient(45deg, rgba(13, 110, 253, 0.8), rgba(78, 142, 255, 0.8)), url('https://picsum.photos/seed/hero-main/1600/900');
    background-size: cover;
    background-position: center;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.section-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
}

.card {
    border: none;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    transition: transform 0.2s ease-in-out;
}

.card:hover {
    transform: translateY(-5px);
}

.testimonial-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    object-fit: cover;
}

.about-avatar {
    width: 256px;
    height: 256px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.footer {
    background-color: #343a40;
    color: white;
}

.footer a {
    color: white;
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}