/* =============================================
   header.css — Sticky nav, lang switcher, dark toggle
   ============================================= */

.header {
    position: sticky;
    top: 0;
    background: var(--header-bg);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    z-index: 200;
    padding: var(--s-3) 0;
    transition: background var(--t), border-color var(--t);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--s-4);
}

.logo { cursor: pointer; display: flex; align-items: center; }
.logo-img { height: 36px; width: auto; }

/* Nav links */
.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--s-1);
}

.nav-menu a {
    color: var(--text);
    font-weight: 600;
    font-size: 12px;
    letter-spacing: 0.04em;
    padding: var(--s-2) var(--s-3);
    border-radius: var(--r-sm);
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: var(--s-1);
    cursor: pointer;
}

.nav-menu a:hover,
.nav-menu a.active {
    background: var(--orange-soft);
    color: var(--orange);
}

[data-theme="dark"] .nav-menu a:hover,
[data-theme="dark"] .nav-menu a.active {
    background: rgba(255,107,53,0.14);
}

/* Right cluster */
.header-right {
    display: flex;
    align-items: center;
    gap: var(--s-2);
}

/* Lang switcher */
.lang-switcher {
    display: flex;
    align-items: center;
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--r-sm);
    padding: 4px var(--s-2);
}

.lang-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-family: var(--font-body);
    font-size: 11px;
    font-weight: 700;
    color: var(--text-muted);
    padding: 2px var(--s-1);
    border-radius: 4px;
    transition: color 0.2s;
}

.lang-btn.active,
.lang-btn:hover { color: var(--orange); }

.lang-divider { color: var(--border); font-size: 11px; margin: 0 4px; }

/* Dark toggle */
.dark-toggle {
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--r-sm);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text);
    transition: all 0.2s;
    flex-shrink: 0;
}

.dark-toggle:hover { border-color: var(--orange); color: var(--orange); }

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun  { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* Mobile toggle */
.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--s-1);
}

.mobile-toggle span {
    width: 22px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
}

/* Mobile open */
.nav-menu.mobile-open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 56px;
    left: 0; right: 0;
    background: var(--header-bg);
    padding: var(--s-3) var(--s-5);
    gap: var(--s-1);
    border-bottom: 1px solid var(--border);
    z-index: 100;
    backdrop-filter: blur(12px);
}

@media (max-width: 900px) {
    .nav-menu:not(.mobile-open) { display: none; }
    .mobile-toggle { display: flex; }
    .header-buttons { display: none; }
}