/* Header, menu điều hướng, hamburger, menu mobile */

/* Header */
header {
    background: transparent;
    color: white;
    padding: 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
}

/* Header khi cuộn: nền trắng, chữ đen */
header.scrolled .nav-links a {
    color: var(--dark-gray);
}

header.scrolled .nav-links a:hover,
header.scrolled .nav-links a.active {
    color: #000;
    background: rgba(0, 0, 0, 0.05);
}

header.scrolled .hamburger span {
    background: var(--primary-color);
}

header.scrolled .hamburger:hover {
    background: rgba(0, 0, 0, 0.05);
}

header.scrolled .logo-text .brand-name {
    background: linear-gradient(135deg, #111827, #4b5563);
    -webkit-background-clip: text;
    background-clip: text;
}

header.scrolled .logo-text .brand-tagline {
    color: #6b7280;
    opacity: 1;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 0;
    transition: padding 0.4s ease;
}

header.scrolled .header-inner {
    padding: 8px 0;
}

/* nav kept for legacy; header-inner is the actual flex container */

.logo {
    display: flex;
    align-items: center;
    gap: 14px;
    text-decoration: none;
    color: white;
    position: relative;
    z-index: 1001;
}

.logo img {
    height: 46px;
    width: auto;
    border-radius: 10px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.25);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: 2px solid rgba(255, 255, 255, 0.15);
}

header.scrolled .logo img {
    height: 38px;
}

.logo:hover img {
    transform: scale(1.08) rotate(-2deg);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
    border-color: rgba(255, 255, 255, 0.3);
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.logo-text .brand-name {
    font-size: 18px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    line-height: 1.2;
    background: linear-gradient(135deg, #ffffff, #d1d5db);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-text .brand-tagline {
    font-size: 11px;
    opacity: 0.7;
    letter-spacing: 0.5px;
    font-weight: 400;
}

/* Desktop nav links */
.nav-links {
    display: flex;
    list-style: none;
    gap: 6px;
    align-items: center;
}

.nav-links li {
    position: relative;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.85);
    text-decoration: none;
    transition: all 0.3s ease;
    font-weight: 500;
    font-size: 14px;
    padding: 8px 14px;
    border-radius: 8px;
    display: inline-block;
    position: relative;
    white-space: nowrap;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 20px;
    height: 2px;
    background: var(--accent-color);
    border-radius: 2px;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-links a:hover {
    color: white;
    background: rgba(255, 255, 255, 0.08);
}

.nav-links a:hover::after {
    transform: translateX(-50%) scaleX(1);
}

.nav-links a.active {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

.nav-links a.active::after {
    transform: translateX(-50%) scaleX(1);
    background: var(--accent-color);
}

/* Nav CTA button */
.nav-cta {
    margin-left: 10px;
}

.nav-cta a {
    background: linear-gradient(135deg, var(--accent-color), #f97316) !important;
    color: white !important;
    padding: 9px 22px !important;
    border-radius: 50px !important;
    font-weight: 700 !important;
    font-size: 13px !important;
    letter-spacing: 0.3px;
    box-shadow: 0 2px 12px rgba(245, 158, 11, 0.35);
    transition: all 0.3s ease !important;
}

.nav-cta a::after {
    display: none !important;
}

.nav-cta a:hover {
    transform: translateY(-2px) !important;
    box-shadow: 0 6px 20px rgba(245, 158, 11, 0.5) !important;
    background: linear-gradient(135deg, #f97316, var(--accent-color)) !important;
}

/* Hamburger menu */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
    border-radius: 8px;
    transition: background 0.3s;
    z-index: 1001;
    background: none;
    border: none;
}

.hamburger:hover {
    background: rgba(255, 255, 255, 0.1);
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2.5px;
    background: white;
    border-radius: 4px;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: center;
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7.5px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.hamburger.active span:nth-child(3) {
    transform: translateY(-7.5px) rotate(-45deg);
}

/* Mobile menu overlay */
.mobile-menu-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: 999;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.mobile-menu-overlay.active {
    opacity: 1;
}