/* =========================================
   HEADER & NAVIGATION
   ========================================= */
header {
    position: fixed;
    top: 0;
    width: 100%;
    padding: var(--space-md) var(--section-padding-x);
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
    mix-blend-mode: difference;
    transition: padding 0.3s ease;
}

header.scrolled {
    padding: var(--space-sm) var(--section-padding-x);
}

.logo {
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    letter-spacing: -0.04em;
}

.lang-toggle {
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    display: flex;
    gap: 4px;
    color: var(--color-text-primary);
    transition: background 0.3s;
    background: rgba(255, 255, 255, 0.05);
    padding: 4px;
    border-radius: var(--radius-pill);
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
}

.lang-btn {
    text-transform: uppercase;
    opacity: 0.6;
    transition: 0.3s;
    padding: 6px 16px;
    border-radius: var(--radius-pill);
}

.lang-btn:hover {
    opacity: 1;
    background: rgba(255, 255, 255, 0.1);
}

.lang-btn.active {
    opacity: 1;
    color: var(--color-bg-primary);
    font-weight: bold;
    background: var(--color-accent);
}

.nav-links {
    display: none;
    gap: var(--space-lg);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
}

@media(min-width: 768px) {
    .nav-links {
        display: flex;
    }
}

.nav-links a:hover {
    color: var(--color-accent);
}