.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    transition: background var(--t-normal), backdrop-filter var(--t-normal), border-color var(--t-normal);
    border-bottom: 1px solid transparent;
}

.site-header.scrolled {
    background: rgba(2, 6, 23, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom-color: var(--border);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
    gap: var(--s-8);
}

.nav__logo {
    display: flex;
    align-items: center;
    gap: var(--s-3);
    text-decoration: none;
    flex-shrink: 0;
}

.nav__logo-mark {
    width: 40px;
    height: 40px;
    background: var(--grad-accent);
    border-radius: var(--r-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: 900;
    color: #fff;
    letter-spacing: -0.02em;
}

.nav__logo-text {
    font-size: var(--fz-lg);
    font-weight: 800;
    color: var(--text-1);
    letter-spacing: -0.02em;
}

.nav__logo-text span {
    color: var(--accent);
}

.nav__menu {
    display: flex;
    align-items: center;
    gap: var(--s-1);
    flex: 1;
    justify-content: center;
}

.nav__link {
    padding: var(--s-2) var(--s-3);
    font-size: var(--fz-sm);
    font-weight: 500;
    color: var(--text-2);
    border-radius: var(--r-md);
    transition: color var(--t-fast), background var(--t-fast);
    white-space: nowrap;
}

.nav__link:hover,
.nav__link--active {
    color: var(--text-1);
    background: rgba(255, 255, 255, 0.06);
}

.nav__actions {
    display: flex;
    align-items: center;
    gap: var(--s-3);
    flex-shrink: 0;
}

.nav__phone {
    font-size: var(--fz-sm);
    font-weight: 600;
    color: var(--text-1);
    transition: color var(--t-fast);
}

.nav__phone:hover {
    color: var(--accent);
}

/* Burger */
.nav__burger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    cursor: pointer;
    padding: 4px;
}

.nav__burger-line {
    display: block;
    height: 2px;
    background: var(--text-1);
    border-radius: var(--r-full);
    transition: transform var(--t-normal), opacity var(--t-normal);
}

.nav__burger.open .nav__burger-line:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__burger.open .nav__burger-line:nth-child(2) { opacity: 0; }
.nav__burger.open .nav__burger-line:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile overlay */
.nav__mobile {
    display: none;
    position: fixed;
    inset: 72px 0 0 0;
    background: rgba(2, 6, 23, 0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    padding: var(--s-6);
    gap: var(--s-2);
    overflow-y: auto;
    z-index: 99;
    border-top: 1px solid var(--border);
}

.nav__mobile.open {
    display: flex;
}

.nav__mobile-link {
    display: block;
    padding: var(--s-4) var(--s-4);
    font-size: var(--fz-md);
    font-weight: 500;
    color: var(--text-2);
    border-radius: var(--r-md);
    transition: color var(--t-fast), background var(--t-fast);
}

.nav__mobile-link:hover {
    color: var(--text-1);
    background: rgba(255, 255, 255, 0.06);
}

.nav__mobile-divider {
    height: 1px;
    background: var(--border);
    margin-block: var(--s-2);
}

@media (max-width: 1024px) {
    .nav__menu { display: none; }
    .nav__phone { display: none; }
    .nav__burger { display: flex; }
}

@media (max-width: 480px) {
    .nav { height: 64px; }
    .nav__mobile { top: 64px; }
}