header.site-header {
    position: fixed;
    inset: 0 0 auto 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1rem 1.25rem;
    color: var(--text);
    font-size: 0.95rem;
    background-color: var(--surface);
    width: 100%;
    z-index: 1000;
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.18);
}

header.site-header .brand {
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    font-family: var(--font-heading);
}

header.site-header .site-nav a {
    font-size: 0.95rem;
}

header.site-header .brand a {
    color: inherit;
    text-decoration: none;
}


header.site-header .nav-toggle {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

header.site-header .nav-toggle-label {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.4rem;
    height: 2.4rem;
    cursor: pointer;
    border-radius: 999px;
    border: 1px solid var(--border-strong);
    transition: background-color 0.2s ease, transform 0.2s ease;
}

header.site-header .nav-toggle-label:hover {
    background-color: rgba(37, 99, 235, 0.08);
}

header.site-header .nav-toggle-label span,
header.site-header .nav-toggle-label span::before,
header.site-header .nav-toggle-label span::after {
    display: block;
    width: 1.2rem;
    height: 2px;
    background-color: var(--text);
    position: relative;
    transition: transform 0.2s ease, opacity 0.2s ease;
}

header.site-header .nav-toggle-label span::before,
header.site-header .nav-toggle-label span::after {
    content: '';
    position: absolute;
    left: 0;
}

header.site-header .nav-toggle-label span::before {
    top: -6px;
}

header.site-header .nav-toggle-label span::after {
    top: 6px;
}

header.site-header .site-nav {
    position: absolute;
    inset: calc(100% + 0.5rem) 1.25rem auto auto;
    width: calc(100% - 2.5rem);
    max-width: 320px;
    background: rgba(15, 23, 42, 0.96);
    border: 1px solid var(--border);
    border-radius: 1rem;
    box-shadow: var(--surface-shadow-strong);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-0.5rem);
    transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
    z-index: 10;
}

header.site-header .site-nav ul {
    list-style: none;
    margin: 0;
    padding: 0.75rem 0;
}

header.site-header .site-nav li {
    border-top: 1px solid var(--border-soft);
}

header.site-header .site-nav li:first-child {
    border-top: none;
}

header.site-header .site-nav a {
    display: block;
    padding: 0.9rem 1.25rem;
    color: var(--text);
    text-decoration: none;
    font-weight: 600;
}

header.site-header .site-nav a:hover {
    background: rgba(37, 99, 235, 0.08);
}

header.site-header .nav-toggle:checked + .nav-toggle-label span {
    background-color: transparent;
}

header.site-header .nav-toggle:checked + .nav-toggle-label span::before {
    transform: translateY(6px) rotate(45deg);
}

header.site-header .nav-toggle:checked + .nav-toggle-label span::after {
    transform: translateY(-6px) rotate(-45deg);
}

header.site-header .nav-toggle:checked ~ .site-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

@media (min-width: 768px) {
    header.site-header {
        padding: 1.25rem 2rem;
    }

    header.site-header .nav-toggle-label {
        display: none;
    }

    header.site-header .site-nav {
        position: static;
        width: auto;
        max-width: none;
        background: transparent;
        border: none;
        box-shadow: none;
        opacity: 1;
        visibility: visible;
        transform: none;
        inset: auto;
        margin-left: auto;
    }

    header.site-header .site-nav ul {
        display: flex;
        gap: 1.25rem;
        padding: 0;
    }

    header.site-header .site-nav li {
        border: none;
    }

    header.site-header .site-nav a {
        padding: 0;
        color: var(--text);
    }

    header.site-header .site-nav a:hover {
        background: none;
        color: var(--accent-strong);
    }
}

@media (max-width: 640px) {
    header.site-header {
        padding: 0.85rem 1rem;
        gap: 0.75rem;
    }

    header.site-header .brand {
        font-size: 1rem;
    }

    header.site-header .nav-toggle-label {
        width: 2.1rem;
        height: 2.1rem;
    }

    header.site-header .nav-toggle-label span,
    header.site-header .nav-toggle-label span::before,
    header.site-header .nav-toggle-label span::after {
        width: 1rem;
    }

    header.site-header .site-nav {
        inset: calc(100% + 0.4rem) 1rem auto auto;
        width: calc(100% - 2rem);
        max-width: 280px;
    }
}