/* ========================================
   LAYOUT — Header, Footer, Floating
   Unitree-Inspired Transparent Nav
   ======================================== */

/* ---- Header ---- */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 var(--space-lg);
    transition: background var(--transition-base), backdrop-filter var(--transition-base);
}

/* Dark gradient overlay so logo/text is always visible */
.site-header::before {
    content: '';
    position: absolute;
    inset: 0;
    z-index: -1;
    transition: opacity var(--transition-base);
}

.site-header.transparent::before {
    background: linear-gradient(180deg, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.25) 60%, transparent 100%);
    opacity: 1;
}

.site-header.scrolled::before {
    opacity: 0;
}

.site-header.scrolled {
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: var(--container-wide);
    margin: 0 auto;
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--color-white);
    font-size: 20px;
    font-weight: var(--fw-extrabold);
    letter-spacing: 0.02em;
    flex-shrink: 0;
}

.logo img,
.logo svg {
    height: 32px;
    width: auto;
    filter: brightness(0) invert(1);
    flex-shrink: 0;
}

/* Nav — Mega Menu */
.mega-nav {
    display: flex;
    align-items: center;
    gap: 0;
}

.mega-link {
    color: rgba(255, 255, 255, 0.85);
    font-size: 14px;
    font-weight: var(--fw-medium);
    padding: 8px 16px;
    text-decoration: none;
    transition: color var(--transition-fast);
    white-space: nowrap;
    cursor: pointer;
}

.mega-link:hover {
    color: var(--color-white);
}

.mega-item {
    position: relative;
}

.mega-item>.mega-link {
    display: flex;
    align-items: center;
    gap: 4px;
}

.mega-item>.mega-link .dd-arrow {
    margin-left: 2px;
    transition: transform 0.2s;
}

.mega-item.open>.mega-link .dd-arrow {
    transform: rotate(180deg);
}

/* Mega Panel */
.mega-panel {
    position: absolute;
    top: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) translateY(-8px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease, transform 0.25s ease;
    z-index: 1001;
}

.mega-item.open .mega-panel {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
    pointer-events: auto;
}

.mega-panel-inner {
    display: flex;
    gap: 32px;
    background: rgba(12, 12, 24, 0.96);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 16px;
    padding: 28px 32px;
    min-width: 320px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.mega-col {
    min-width: 140px;
    flex-shrink: 0;
}

.mega-col h4 {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: rgba(255, 255, 255, 0.35);
    margin-bottom: 12px;
    font-weight: var(--fw-semibold);
}

.mega-product {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    border-radius: 8px;
    text-decoration: none;
    transition: background 0.15s;
    margin-bottom: 2px;
}

.mega-product-img {
    width: 40px;
    height: 40px;
    border-radius: 6px;
    object-fit: cover;
    flex-shrink: 0;
}

.mega-product:hover {
    background: rgba(79, 70, 229, 0.12);
}

.mega-product-name {
    display: block;
    color: var(--color-white);
    font-size: 14px;
    font-weight: var(--fw-semibold);
    white-space: nowrap;
}

.mega-product-desc {
    display: block;
    color: rgba(255, 255, 255, 0.4);
    font-size: 12px;
    margin-top: 2px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 160px;
}

/* Featured card in mega menu */
.mega-featured {
    min-width: 200px;
}

.mega-featured-card {
    display: block;
    border-radius: 12px;
    overflow: hidden;
    text-decoration: none;
    background: rgba(255, 255, 255, 0.04);
    transition: transform 0.2s;
}

.mega-featured-card:hover {
    transform: scale(1.02);
}

.mega-featured-card img {
    width: 100%;
    height: 120px;
    object-fit: cover;
}

.mega-featured-card div {
    padding: 12px;
}

.mega-featured-card strong {
    display: block;
    color: var(--color-white);
    font-size: 16px;
}

.mega-featured-card span {
    display: block;
    color: rgba(255, 255, 255, 0.5);
    font-size: 12px;
    margin-top: 2px;
}

/* Header CTA */
.header-cta {
    display: inline-flex;
    align-items: center;
    padding: 6px 18px;
    background: var(--color-accent);
    color: var(--color-white) !important;
    border-radius: 20px;
    font-size: 13px;
    font-weight: var(--fw-semibold);
    text-decoration: none;
    transition: background 0.2s, transform 0.2s;
}

.header-cta:hover {
    background: var(--color-accent-hover);
    transform: translateY(-1px);
}

/* Mobile groups */
.mobile-group {
    border-bottom: 1px solid var(--color-dark-border);
    padding-bottom: 12px;
    margin-bottom: 12px;
}

.mobile-group strong {
    display: block;
    color: rgba(255, 255, 255, 0.4);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.mobile-group a {
    font-size: 16px !important;
    padding: 8px 0 !important;
    border-bottom: none !important;
}

/* Header actions */
.header-actions {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.lang-toggle {
    display: flex;
    align-items: center;
    gap: 6px;
    color: rgba(255, 255, 255, 0.7);
    font-size: var(--fs-caption);
    cursor: pointer;
    padding: 6px 12px;
    border-radius: var(--radius-full);
    border: 1px solid rgba(255, 255, 255, 0.15);
    background: transparent;
    transition: all var(--transition-fast);
    font-family: var(--font-family);
}

.lang-toggle:hover {
    border-color: rgba(255, 255, 255, 0.3);
    color: var(--color-white);
}

/* Language dropdown */
.lang-switcher {
    position: relative;
}

.lang-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: rgba(15, 15, 30, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: 6px;
    min-width: 160px;
    opacity: 0;
    transform: translateY(-8px);
    pointer-events: none;
    transition: opacity 0.2s ease, transform 0.2s ease;
    z-index: 1001;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
}

.lang-dropdown.show {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

.lang-option {
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    padding: 10px 14px;
    border: none;
    background: transparent;
    color: rgba(255, 255, 255, 0.7);
    font-size: 13px;
    cursor: pointer;
    border-radius: 8px;
    transition: background 0.15s, color 0.15s;
    font-family: var(--font-family);
    text-align: left;
}

.lang-option:hover {
    background: rgba(79, 70, 229, 0.15);
    color: var(--color-white);
}

.lang-option.active {
    color: var(--color-accent);
    font-weight: var(--fw-semibold);
}

.lang-flag {
    font-size: 16px;
}

/* Mobile burger */
.mobile-toggle {
    display: none;
    width: 32px;
    height: 32px;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    cursor: pointer;
    background: none;
    border: none;
    padding: 0;
}

.mobile-toggle span {
    display: block;
    width: 22px;
    height: 1.5px;
    background: var(--color-white);
    transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.mobile-toggle.open span:nth-child(1) {
    transform: rotate(45deg) translate(4px, 4px);
}

.mobile-toggle.open span:nth-child(2) {
    opacity: 0;
}

.mobile-toggle.open span:nth-child(3) {
    transform: rotate(-45deg) translate(4px, -4px);
}

/* ---- Mobile Nav ---- */
.mobile-nav {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(10, 10, 15, 0.97);
    backdrop-filter: var(--blur-glass);
    padding: var(--space-lg);
    z-index: 999;
}

.mobile-nav.open {
    display: block;
}

.mobile-nav a {
    display: block;
    color: var(--color-white);
    font-size: 20px;
    font-weight: var(--fw-semibold);
    padding: 16px 0;
    border-bottom: 1px solid var(--color-dark-border);
    text-decoration: none;
}

/* ---- Footer ---- */
.site-footer {
    background: var(--color-dark);
    color: rgba(255, 255, 255, 0.6);
    padding: var(--space-3xl) 0 var(--space-lg);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr) 1.2fr;
    gap: var(--space-lg);
    max-width: var(--container-wide);
    margin: 0 auto;
    padding: 0 var(--space-md);
}

.footer-col h4 {
    color: var(--color-white);
    font-size: var(--fs-body);
    font-weight: var(--fw-semibold);
    margin-bottom: var(--space-md);
}

.footer-col a {
    display: block;
    color: rgba(255, 255, 255, 0.45);
    font-size: var(--fs-caption);
    padding: 5px 0;
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-col a:hover {
    color: var(--color-white);
}

/* Footer form */
.footer-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.footer-form input,
.footer-form textarea {
    width: 100%;
    padding: 10px 14px;
    background: var(--color-dark-card);
    border: 1px solid var(--color-dark-border);
    border-radius: var(--radius-sm);
    color: var(--color-white);
    font-family: var(--font-family);
    font-size: var(--fs-caption);
    outline: none;
    transition: border-color var(--transition-fast);
}

.footer-form input:focus,
.footer-form textarea:focus {
    border-color: var(--color-accent);
}

.footer-form input::placeholder,
.footer-form textarea::placeholder {
    color: rgba(255, 255, 255, 0.3);
}

.footer-form textarea {
    min-height: 80px;
    resize: vertical;
}

.footer-form button {
    align-self: flex-end;
    padding: 8px 24px;
    background: var(--color-accent);
    color: var(--color-white);
    border: none;
    border-radius: var(--radius-sm);
    font-size: var(--fs-caption);
    font-weight: var(--fw-semibold);
    cursor: pointer;
    font-family: var(--font-family);
    transition: background var(--transition-fast);
}

.footer-form button:hover {
    background: var(--color-accent-hover);
}

/* QR codes */
.footer-qr {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
    margin-top: var(--space-xl);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--color-dark-border);
    max-width: var(--container-wide);
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--space-md);
    padding-right: var(--space-md);
    justify-content: center;
}

.qr-item {
    text-align: center;
}

.qr-item img {
    width: 72px;
    height: 72px;
    border-radius: var(--radius-sm);
    background: var(--color-dark-card);
    margin-bottom: 6px;
}

.qr-item span {
    display: block;
    font-size: var(--fs-small);
    color: rgba(255, 255, 255, 0.35);
}

/* Footer bottom */
.footer-bottom {
    margin-top: var(--space-lg);
    padding-top: var(--space-md);
    border-top: 1px solid var(--color-dark-border);
    max-width: var(--container-wide);
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--space-md);
    padding-right: var(--space-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.footer-bottom a,
.footer-bottom span {
    font-size: var(--fs-small);
    color: rgba(255, 255, 255, 0.3);
}

.footer-bottom a:hover {
    color: rgba(255, 255, 255, 0.6);
}

/* ---- Floating Contact ---- */
.floating-contact {
    position: fixed;
    right: 24px;
    bottom: 24px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 9998;
}

.float-btn {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
    cursor: pointer;
    border: none;
    text-decoration: none;
}

.float-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 28px rgba(0, 0, 0, 0.4);
}

.float-btn.wechat {
    background: #1a6cb7;
}

.float-btn.phone {
    background: var(--color-accent);
}

.float-btn.email {
    background: #1a6cb7;
}

/* ---- Responsive ---- */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    .mega-nav {
        display: none;
    }

    .mobile-toggle {
        display: flex;
    }

    .lang-toggle {
        font-size: 11px;
    }

    .header-cta {
        display: none;
    }

    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }

    .site-header {
        padding: 0 var(--space-sm);
    }
}