.site-header {
    position: fixed;
    z-index: 1000;
    top: 0;
    right: 0;
    left: 0;
    height: var(--header-height);
    border-bottom: 1px solid transparent;
    background: transparent;
    transition: height var(--transition-fast), background-color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.site-header.is-scrolled,
.site-header.is-menu-open {
    height: 70px;
    border-bottom-color: var(--color-border);
    background: var(--navbar-background);
    box-shadow: 0 8px 30px rgba(3, 11, 18, 0.06);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
}

.navbar {
    display: flex;
    height: 100%;
    align-items: center;
    justify-content: space-between;
}

.brand {
    display: inline-flex;
    flex-shrink: 0;
    gap: 11px;
    align-items: center;
    color: var(--navbar-text);
}

.brand--official {
    gap: 10px;
}

.brand__logo {
    width: 52px;
    height: 52px;
    flex: 0 0 52px;
    border: 1px solid color-mix(in srgb, var(--color-primary) 34%, var(--color-border));
    border-radius: 50%;
    background: #FFFFFF;
    box-shadow: 0 9px 24px rgba(7, 24, 42, 0.13);
    object-fit: cover;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-smooth);
}

.brand:hover .brand__logo {
    border-color: var(--color-primary);
    box-shadow: 0 12px 28px color-mix(in srgb, var(--color-primary) 20%, transparent);
    transform: rotate(-2deg) scale(1.03);
}

.brand__mark {
    display: grid;
    width: 41px;
    height: 41px;
    place-items: center;
    border-radius: 13px;
    background: var(--brand-navy);
    color: var(--brand-lime);
    box-shadow: 0 8px 18px rgba(7, 24, 42, 0.16);
}

.brand__mark svg {
    width: 28px;
    height: 28px;
}

.brand__wordmark {
    font-size: 1.19rem;
    font-weight: 800;
    letter-spacing: -0.04em;
}

.brand__wordmark span {
    color: var(--color-primary);
}

.nav-menu {
    display: flex;
    gap: clamp(17px, 2vw, 27px);
    align-items: center;
}

.nav-menu > a:not(.button) {
    position: relative;
    color: var(--navbar-text);
    font-size: 0.88rem;
    font-weight: 620;
}

.nav-menu > a:not(.button)::after {
    position: absolute;
    right: 0;
    bottom: -8px;
    left: 0;
    height: 2px;
    border-radius: 2px;
    background: var(--color-primary);
    content: "";
    transform: scaleX(0);
    transform-origin: right;
    transition: transform var(--transition-fast);
}

.nav-menu > a:not(.button):hover::after,
.nav-menu > a:not(.button).is-active::after {
    transform: scaleX(1);
    transform-origin: left;
}

.navbar__cta {
    min-height: 44px;
    padding-inline: 17px;
}

.theme-toggle {
    display: grid;
    width: 42px;
    height: 42px;
    flex: 0 0 42px;
    padding: 0;
    place-items: center;
    border: 1px solid var(--color-border);
    border-radius: 12px;
    background: var(--color-surface);
    color: var(--color-text);
    cursor: pointer;
    transition: background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
}

.theme-toggle:hover {
    border-color: var(--color-border-strong);
    background: var(--color-surface-hover);
    transform: translateY(-2px);
}

.theme-toggle__icon {
    width: 18px;
    height: 18px;
}

.theme-toggle__icon--sun {
    display: none;
}

[data-theme="dark"] .theme-toggle__icon--sun {
    display: block;
}

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

.nav-toggle {
    display: none;
    width: 44px;
    height: 44px;
    padding: 0 10px;
    border: 1px solid var(--color-border);
    border-radius: 12px;
    background: var(--color-surface);
    cursor: pointer;
}

.nav-toggle > span:not(.sr-only) {
    display: block;
    width: 100%;
    height: 2px;
    margin-block: 6px;
    border-radius: 4px;
    background: var(--color-text);
    transition: transform var(--transition-fast);
}

@media (max-width: 940px) {
    .nav-toggle {
        display: block;
    }

    .nav-toggle[aria-expanded="true"] > span:nth-of-type(2) {
        transform: translateY(4px) rotate(45deg);
    }

    .nav-toggle[aria-expanded="true"] > span:nth-of-type(3) {
        transform: translateY(-4px) rotate(-45deg);
    }

    .nav-menu {
        position: fixed;
        top: 69px;
        right: 0;
        left: 0;
        display: grid;
        max-height: 0;
        gap: 0;
        overflow: hidden;
        border-bottom: 1px solid transparent;
        background: var(--navbar-background);
        opacity: 0;
        -webkit-backdrop-filter: blur(18px);
        backdrop-filter: blur(18px);
        transition: max-height var(--transition-smooth), opacity var(--transition-fast), border-color var(--transition-fast);
    }

    .nav-menu.is-open {
        max-height: calc(100dvh - 69px);
        padding: 18px 24px 28px;
        overflow-y: auto;
        border-bottom-color: var(--color-border);
        opacity: 1;
    }

    .nav-menu > a:not(.button) {
        padding-block: 16px;
        border-bottom: 1px solid var(--color-border);
        font-size: 1.05rem;
    }

    .nav-menu > a:not(.button)::after {
        display: none;
    }

    .theme-toggle {
        width: 100%;
        margin-block: 16px;
    }

    .navbar__cta {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .brand__wordmark {
        font-size: 1.08rem;
    }

    .brand__mark {
        width: 38px;
        height: 38px;
    }

    .brand__logo {
        width: 44px;
        height: 44px;
        flex-basis: 44px;
    }
}