.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    z-index: var(--z-header);
    transition: background-color var(--transition-base),
        box-shadow var(--transition-base),
        backdrop-filter var(--transition-base);
    background-color: var(--color-glass-strong);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.header.scrolled {
    background-color: var(--color-glass-strong);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 1px 0 var(--color-border),
        var(--shadow-md);
}

.header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.header__logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-shrink: 0;
    position: relative;
    z-index: 2;
}

.header__logo-img {
    height: 46px;
    width: auto;
    filter: brightness(0) invert(1);
    transition: filter var(--transition-base),
        transform var(--transition-base);
}

.header__logo:hover .header__logo-img {
    transform: scale(1.03);
    filter: brightness(0) invert(1) drop-shadow(0 0 8px var(--color-accent-glow));
}

.header__nav {
    display: flex;
    align-items: center;
}

.header__nav-list {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    margin: 0;
    padding: 0;
}

.header__nav-link {
    position: relative;
    display: inline-flex;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    font-size: var(--fs-sm);
    font-weight: var(--fw-medium);
    color: var(--color-text-secondary);
    letter-spacing: 0.04em;
    text-transform: uppercase;
    transition: color var(--transition-fast);
    white-space: nowrap;
}

.header__nav-link::after {
    content: '';
    position: absolute;
    bottom: 4px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: calc(100% - var(--space-xl));
    height: 2px;
    background: var(--gradient-accent);
    border-radius: var(--radius-full);
    transition: transform var(--transition-base);
    transform-origin: center;
}

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

.header__nav-link:focus-visible {
    color: var(--color-text-primary);
}

.header__nav-link:hover::after,
.header__nav-link.active::after {
    transform: translateX(-50%) scaleX(1);
}

.header__nav-link:focus-visible::after {
    transform: translateX(-50%) scaleX(1);
}

.header__nav-link.active {
    color: var(--color-accent-light);
}

/* ---- Dropdown ---- */
.header__dropdown {
    position: relative;
}

.header__dropdown-trigger {
    display: flex;
    align-items: center;
}

.header__dropdown-arrow {
    display: inline-block;
    width: 6px;
    height: 6px;
    border-right: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
    transform: rotate(45deg);
    margin-left: 5px;
    margin-bottom: 2px;
    transition: transform var(--transition-fast);
}

.header__dropdown:hover .header__dropdown-arrow {
    transform: rotate(-135deg);
}

.header__dropdown:focus-within .header__dropdown-arrow {
    transform: rotate(-135deg);
}

.header__dropdown-toggle {
    display: none;
}

.header__dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    min-width: 240px;
    padding: var(--space-sm) 0;
    margin: 0;
    list-style: none;
    background: rgba(17, 24, 39, 0.95);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 16px 48px rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
    z-index: 100;
}

.header__dropdown:hover .header__dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}

.header__dropdown:focus-within .header__dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}

.header__dropdown-menu li a {
    display: block;
    padding: 10px 20px;
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: color var(--transition-fast), background var(--transition-fast), padding-left var(--transition-fast);
    border-left: 2px solid transparent;
    white-space: nowrap;
}

.header__dropdown-menu li a:hover {
    color: var(--color-text-primary);
    background: rgba(0, 180, 216, 0.06);
    border-left-color: var(--color-accent);
    padding-left: 24px;
}

.header__cta {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: 10px 24px;
    margin-left: var(--space-md);
    font-size: var(--fs-sm);
    font-weight: var(--fw-semibold);
    letter-spacing: 0.03em;
    text-transform: uppercase;
    color: var(--color-bg-primary);
    background: #f59e0b;
    border-radius: var(--radius-full);
    transition: transform var(--transition-fast),
        box-shadow var(--transition-fast);
}

.header__cta:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-glow);
}

.header__cta:active {
    transform: translateY(0);
}

.header__menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    gap: 6px;
    cursor: pointer;
    position: relative;
    z-index: 2;
}

.header__menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text-primary);
    border-radius: var(--radius-full);
    transition: transform var(--transition-base),
        opacity var(--transition-fast);
    transform-origin: center;
}

.header__menu-toggle.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.header__menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.header__menu-toggle.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

.header__mobile-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    z-index: var(--z-overlay);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-base);
}

.header__mobile-overlay.visible {
    opacity: 1;
    pointer-events: auto;
}

@media (max-width: 900px) {
    .header__menu-toggle {
        display: flex;
    }

    .header__nav {
        position: fixed;
        top: 0;
        right: 0;
        width: 300px;
        max-width: 85vw;
        height: 100vh;
        flex-direction: column;
        align-items: stretch;
        padding: calc(var(--header-height) + var(--space-xl)) var(--space-xl) var(--space-xl);
        background-color: var(--color-bg-secondary);
        border-left: 1px solid var(--color-border);
        transform: translateX(100%);
        transition: transform var(--transition-base);
        z-index: calc(var(--z-overlay) + 1);
        overflow-y: auto;
        overflow-x: hidden;
        visibility: hidden;
        pointer-events: none;
    }

    .header__nav.open {
        transform: translateX(0);
        visibility: visible;
        pointer-events: auto;
    }

    .header__mobile-overlay {
        display: block;
    }

    .header__nav-list {
        flex-direction: column;
        gap: 0;
    }

    .header__nav-link {
        justify-content: center;
        padding: var(--space-md) 0;
        font-size: var(--fs-base);
        border-bottom: 1px solid var(--color-border);
        width: 100%;
    }

    .header__nav-link::after {
        bottom: -1px;
        left: 0;
        transform: scaleX(0);
        transform-origin: left;
        width: 100%;
    }

    .header__nav-link:hover::after,
    .header__nav-link.active::after {
        transform: scaleX(1);
    }

    .header__cta {
        margin: var(--space-xl) auto 0;
        justify-content: center;
        padding: 10px 24px;
        font-size: 0.85rem;
        width: max-content;
    }

    .header__dropdown {
        width: 100%;
    }

    .header__dropdown-trigger {
        display: grid;
        grid-template-columns: minmax(0, 1fr) auto;
        align-items: stretch;
    }

    .header__dropdown-menu {
        position: static;
        transform: none;
        min-width: 0;
        width: 100%;
        background: transparent;
        border: none;
        border-radius: 0;
        backdrop-filter: none;
        box-shadow: none;
        padding: 0;
        padding-inline-start: 0;
        margin: 0;
        max-height: 0;
        overflow: hidden;
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transition: max-height 0.3s ease;
    }

    .header__dropdown-menu[hidden] {
        display: none;
    }

    .header__dropdown.open .header__dropdown-menu {
        max-height: 500px;
    }

    .header__dropdown:hover .header__dropdown-menu {
        transform: none;
    }

    .header__dropdown-menu li a {
        display: block;
        padding: var(--space-sm) 0;
        font-size: 0.8rem;
        font-weight: 400;
        color: var(--color-text-secondary);
        letter-spacing: 0;
        text-transform: none;
        text-align: center;
        border-left: none;
        border-bottom: 1px solid var(--color-border);
        white-space: normal;
        overflow: hidden;
    }

    .header__dropdown-menu li a:hover {
        padding-left: 0;
        background: transparent;
        color: var(--color-accent-light);
    }

    .header__dropdown-toggle {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        min-width: 52px;
        border-left: 1px solid var(--color-border);
        border-bottom: 1px solid var(--color-border);
        color: var(--color-text-secondary);
    }

    .header__dropdown-toggle:hover,
    .header__dropdown-toggle:focus-visible,
    .header__dropdown.open .header__dropdown-toggle {
        color: var(--color-text-primary);
    }

    .header__dropdown-trigger .header__nav-link {
        border-bottom: 1px solid var(--color-border);
    }

    .header__dropdown-trigger .header__nav-link .header__dropdown-arrow {
        display: none;
    }

    .header__dropdown-arrow {
        position: absolute;
        right: 15px;
        margin-left: 0;
        vertical-align: middle;
    }

    .header__dropdown-toggle .header__dropdown-arrow {
        position: static;
        margin: 0;
    }

    .header__dropdown:not(.open) .header__dropdown-toggle .header__dropdown-arrow {
        transform: rotate(45deg);
    }

    .header__dropdown.open .header__dropdown-arrow {
        transform: rotate(-135deg);
    }
}