/* ==========================================
   3SIGMA STUDIO - NAVIGATION & HEADER STYLES
   ========================================== */

header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(10, 10, 10, 0.94);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.85);
}

nav {
    max-width: 1280px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* Brand Logo Styling */
.logo,
.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
}

.logo img,
.nav-brand img {
    height: 42px;
    width: auto;
    display: block;
    filter: drop-shadow(0 0 8px rgba(var(--color-primary-rgb), 0.3));
    transition: transform var(--transition-fast), filter var(--transition-fast);
}

.logo:hover img,
.nav-brand:hover img {
    transform: scale(1.03);
    filter: drop-shadow(0 0 14px rgba(var(--color-primary-rgb), 0.6));
}

/* 3Sigma Studio brand lockup: sigma mark + wordmark.
   The source PNG is artwork on solid black with no alpha, so `screen`
   blending knocks the black backdrop out against the dark page background. */
.brand-mark {
    mix-blend-mode: screen;
}

.brand-wordmark {
    display: flex;
    flex-direction: column;
    line-height: 1;
}

/* "3SIGMA" carries the logo's red-to-purple sweep, clipped to the glyphs */
.brand-name {
    font-family: var(--font-heading);
    font-weight: 900;
    font-size: 1.4rem;
    letter-spacing: 0.08em;
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.brand-sub {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 0.7rem;
    letter-spacing: 0.42em;
    color: var(--color-text-muted);
    margin-top: 0.2rem;
    transition: color var(--transition-fast);
}

.logo:hover .brand-sub {
    color: var(--color-secondary);
}

@media (max-width: 480px) {
    .brand-wordmark { display: none; }
}

.brand-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    background: var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #0A0A0A;
    font-family: var(--font-heading);
    font-weight: 900;
    font-size: 1.2rem;
    box-shadow: var(--shadow-neon-primary);
}

.brand-text {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    font-weight: 900;
    letter-spacing: 0.05em;
    color: #FFFFFF;
    text-transform: uppercase;
}

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

/* Nav Links List */
.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
    list-style: none;
}

.nav-link {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--color-text-muted);
    text-decoration: none;
    position: relative;
    padding: 0.5rem 0;
    transition: color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-brand);
    border-radius: var(--radius-full);
    box-shadow: 0 0 10px rgba(var(--color-secondary-rgb), 0.7);
    transition: width var(--transition-normal);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link.active {
    color: var(--color-primary);
}

/* Mobile Menu Toggle Button */
.mobile-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 20px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1001;
}

.mobile-toggle span {
    width: 100%;
    height: 2.5px;
    background-color: var(--color-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-normal);
}

.mobile-toggle.open span:nth-child(1) {
    transform: translateY(8.5px) rotate(45deg);
}

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

.mobile-toggle.open span:nth-child(3) {
    transform: translateY(-8.5px) rotate(-45deg);
}

/* Mobile Drawer Responsive Styles */
@media (max-width: 768px) {
    .mobile-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 68px;
        right: -100%;
        width: 280px;
        height: calc(100vh - 68px);
        background: rgba(18, 18, 18, 0.97);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-left: 1px solid var(--color-border);
        flex-direction: column;
        align-items: flex-start;
        padding: 2.5rem 2rem;
        gap: 1.5rem;
        transition: right var(--transition-normal);
        box-shadow: -10px 0 30px rgba(0, 0, 0, 0.9);
    }

    .nav-menu.active {
        right: 0;
    }

    .nav-link {
        font-size: 1rem;
        width: 100%;
    }
}