:root {
    --header-bg: rgba(17, 24, 39, 0.85); /* Dark Glassmorphism */
    --accent-color: #818cf8; /* Light Indigo for Dark bg */
    --text-primary: #f9fafb; /* White text */
    --text-secondary: #d1d5db; /* Light gray text */
    --hover-bg: rgba(99, 102, 241, 0.2);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --header-height: 80px;
}

.main-header {
    background: var(--header-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: var(--header-height);
    display: flex;
    align-items: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
}

/* Ensure Header remains Dark in Light Mode */
html.light .main-header {
    background: #111827; /* Solid dark background for consistency */
}

html.light .nav-item a {
    color: var(--text-secondary);
}

html.light .app-name {
    color: var(--text-primary);
}

.header-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 2rem;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    transition: var(--transition);
}

.logo-container:hover {
    transform: translateY(-1px);
}

.app-logo {
    height: 48px;
    width: auto;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1));
}

.app-name {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
    font-family: 'Outfit', 'Inter', sans-serif;
}

.nav-menu ul {
    display: flex;
    list-style-type: none !important;
    gap: 8px;
    margin: 0;
    padding: 0;
}

.nav-item {
    list-style: none !important;
}

.nav-item a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 600;
    padding: 10px 18px;
    border-radius: 12px;
    transition: var(--transition);
    font-size: 0.95rem;
    display: inline-block;
}

.nav-item a:hover {
    background: var(--hover-bg);
    color: var(--accent-color);
}

.nav-item.active a {
    color: var(--accent-color);
    background: var(--hover-bg);
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .header-container {
        padding: 0 1.25rem;
    }
    .nav-menu {
        display: none; /* Add a hamburger menu if needed later */
    }
}