/* ========== HEADER ========== */
.header {
    background: var(--bg-header);
    border-bottom: 3px solid var(--border-accent);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 12px var(--shadow-color);
    transition: background-color 0.3s ease;
    backdrop-filter: blur(12px);
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    min-height: 70px;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.header-nav-left { justify-self: end; margin-right: 0.25rem; transition: margin 0.3s ease; }
.header-nav-right { justify-self: start; margin-left: 0.25rem; transition: margin 0.3s ease; }
.header-content.logo-visible .header-nav-left { margin-right: 1.5rem; }
.header-content.logo-visible .header-nav-right { margin-left: 1.5rem; }

.header-nav a, .theme-toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    color: var(--text-primary);
    background: var(--card-header-bg);
    border: 1px solid var(--border-color);
    transition: all 0.2s ease;
    font-size: 0.875rem;
    font-family: inherit;
    cursor: pointer;
}

.header-nav a:hover, .theme-toggle:hover {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.header-logo-link {
    justify-self: center;
    display: flex;
    align-items: center;
    text-decoration: none;
    visibility: hidden;
    opacity: 0;
    width: 0;
    overflow: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease, width 0.3s ease;
}

.header-logo-link.show {
    visibility: visible;
    opacity: 1;
    width: auto;
}

.header-logo-img {
    height: 56px;
    width: auto;
}

/* ========== RESPONSIVE (header only) ========== */
@media (max-width: 768px) {
    .header-nav { gap: 0.25rem; }
    .header-nav a { font-size: 0.8rem; padding: 0.4rem 0.6rem; }
    .header-nav .nav-label { display: none; }
    .theme-toggle { display: none; }
}

@media (max-width: 480px) {
    .header-content { padding: 0 1rem; min-height: 60px; }
    .header-nav a, .theme-toggle { padding: 0.35rem 0.5rem; font-size: 0.75rem; }
    .header-logo-img { height: 36px; }
}