/* ========================================
   Site chrome: header + footer, shared by EVERY page
   (homepage, /surface/, /research/, /research/ru/).

   Self-contained on purpose: it sets its own font, line-height, smoothing
   and box model instead of inheriting them from the page, so the header and
   footer land on the same pixels whatever the page's own styles are.
   Change header/footer look here only — nowhere else.
   ======================================== */

/* Reserve the scrollbar lane on every page: otherwise short pages (no
   scrollbar) shift the whole header sideways vs. long ones. */
html { scrollbar-gutter: stable; }

.header,
.footer {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    line-height: 1.7;
    color: #9CA3AF;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-align: left;
}

.header *, .header *::before, .header *::after,
.footer *, .footer *::before, .footer *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

.header .container,
.footer .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.logo { display: flex; align-items: center; text-decoration: none; }
.logo-img { height: 32px; width: auto; display: block; }

/* ---- Header ---- */
.header {
    box-sizing: border-box;
    background: rgba(10, 10, 10, 0.9);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    position: fixed;
    width: 100%;
    top: 0;
    left: 0;
    z-index: 1000;
    padding: 16px 0;
    border-bottom: 1px solid #1f2937;
    transition: background 0.3s ease;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav ul li a {
    color: #9CA3AF;
    text-decoration: none;
    font-weight: 300;
    font-size: 14px;
    transition: color 0.2s ease;
}

.nav ul li a:hover,
.nav ul li a.active { color: #FFFFFF; }

.nav-toggle {
    display: none;
    background: none;
    border: none;
    color: #FFFFFF;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle svg { display: block; }

.lang-switch {
    display: flex;
    gap: 2px;
    margin-left: 20px;
}

.lang-switch button {
    background: transparent;
    color: #9CA3AF;
    border: 1px solid #2a2a2a;
    padding: 4px 9px;
    font-size: 0.72rem;
    font-weight: 600;
    line-height: normal;
    letter-spacing: 0.03em;
    cursor: pointer;
    border-radius: 3px;
    transition: color 0.15s, border-color 0.15s;
}

.lang-switch button:hover { color: #FFFFFF; }
.lang-switch button.active { color: #FFFFFF; border-color: #FFFFFF; }

/* ---- Footer ---- */
.footer {
    padding: 16px 0 48px;
    border-top: 1px solid #1f2937;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.footer-company-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    text-align: center;
}

.footer-company {
    font-size: 13px;
    font-weight: 400;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #9CA3AF;
}

.footer-address {
    font-size: 13px;
    font-weight: 300;
    color: #6B7280;
}

.footer-email {
    font-size: 13px;
    margin-top: 4px;
}

.footer-email a {
    color: #efffcc;
    text-decoration: none;
}

.footer-email a:hover { text-decoration: underline; }

.footer-copyright {
    font-size: 13px;
    font-weight: 300;
    color: #6B7280;
}

/* ---- Six nav items: one line on narrow desktops ---- */
@media (min-width: 769px) and (max-width: 1024px) {
    .nav ul { gap: 18px; }
    .nav ul li a { font-size: 13px; white-space: nowrap; }
}

/* ---- Mobile: burger ---- */
@media (max-width: 768px) {
    .nav ul { display: none; }
    .nav-toggle { display: block; }

    .nav.nav-open ul {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(10, 10, 10, 0.97);
        backdrop-filter: blur(8px);
        -webkit-backdrop-filter: blur(8px);
        padding: 16px 24px;
        border-bottom: 1px solid #1f2937;
        gap: 0;
    }

    .nav.nav-open ul li a {
        display: block;
        padding: 12px 0;
        border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    }

    .nav.nav-open ul li:last-child a { border-bottom: none; }
}