@media (max-width: 767px) {
    .header-navigation {
        position: absolute;
        top: 0;
        left: 0;
        z-index: 1;
        width: 100%;
        height: 100vh;
        height: 100dvh;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 0.5rem;
        padding: 6rem 1.5rem 2rem;
        overflow-y: auto;
        background:
            radial-gradient(ellipse at 100% 0%, rgba(0, 242, 255, 0.12), transparent 48%),
            radial-gradient(ellipse at 0% 100%, rgba(182, 0, 248, 0.1), transparent 45%),
            rgba(16, 20, 21, 0.99);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-top: 1px solid rgba(0, 242, 255, 0.35);
    }

    .header-navigation.is-open {
        display: flex;
        animation: mobile-menu-enter 180ms ease-out both;
    }

    .material-symbols-outlined {
        color: #00f2ff;
        font-size: 1rem;
    }

    .header-navigation-link {
        display: flex;
        align-items: center;
        gap: 0.85rem;
        width: min(100%, 34rem);
        min-height: 4rem;
        padding: 0.8rem 1rem;
        border: 1px solid transparent;
        border-radius: 0.85rem;
        font-weight: 500;
        font-size: 1.25rem;
        transition: color 180ms ease, background-color 180ms ease, border-color 180ms ease, transform 180ms ease;
    }

    .header-navigation-link::before {
        counter-increment: mobile-nav-item;
        content: "0" counter(mobile-nav-item);
        color: #00dbe7;
        font-family: "JetBrains Mono", monospace;
        font-size: 0.7rem;
        letter-spacing: 0.04em;
        opacity: 0.8;
        transition: color 180ms ease, opacity 180ms ease;
    }

    .header-navigation-link::after {
        content: "arrow_forward";
        margin-left: auto;
        color: #00f2ff;
        font-family: "Material Symbols Outlined";
        font-size: 1.25rem;
        opacity: 0;
        transform: translateX(-0.5rem);
        transition: opacity 180ms ease, transform 180ms ease;
    }

    .header-navigation {
        counter-reset: mobile-nav-item;
    }

    .header-navigation .header-navigation-link:hover,
    .header-navigation .header-navigation-link:focus-visible {
        color: #e1fdff;
        background: linear-gradient(100deg, rgba(0, 242, 255, 0.2), rgba(182, 0, 248, 0.12));
        border-color: rgba(0, 242, 255, 0.5);
        outline: none;
        transform: translateX(8px);
        box-shadow: 0 0 28px rgba(0, 242, 255, 0.14);
    }

    .header-navigation .header-navigation-link:hover::before,
    .header-navigation .header-navigation-link:focus-visible::before {
        color: #ebb2ff;
        opacity: 1;
    }

    .header-navigation .header-navigation-link:hover::after,
    .header-navigation .header-navigation-link:focus-visible::after {
        opacity: 1;
        transform: translateX(0);
    }

    .header-navigation-link:focus-visible {
        box-shadow: 0 0 0 2px rgba(0, 242, 255, 0.3);
    }

    .mobile-menu-toggle {
        position: relative;
        z-index: 2;
        display: grid;
        width: 2.75rem;
        height: 2.75rem;
        place-items: center;
        border: 1px solid rgba(0, 242, 255, 0.25);
        border-radius: 0.75rem;
        background: rgba(0, 242, 255, 0.06);
        transition: background-color 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
    }

    .mobile-menu-toggle:hover,
    .mobile-menu-toggle[aria-expanded="true"] {
        border-color: rgba(0, 242, 255, 0.65);
        background: rgba(0, 242, 255, 0.12);
        box-shadow: 0 0 18px rgba(0, 242, 255, 0.16);
    }

    .mobile-menu-toggle:focus-visible {
        outline: 2px solid #00f2ff;
        outline-offset: 3px;
    }

    .mobile-menu-toggle .material-symbols-outlined {
        font-size: 1.5rem;
        transition: transform 180ms ease;
    }

    .mobile-menu-toggle[aria-expanded="true"] .material-symbols-outlined {
        transform: rotate(90deg);
    }
}

@keyframes mobile-menu-enter {
    from {
        opacity: 0;
        transform: translateY(-0.4rem) scale(0.98);
        transform-origin: top right;
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
        transform-origin: top right;
    }
}

@media (prefers-reduced-motion: reduce) {
    .header-navigation.is-open {
        animation: none;
    }

    .header-navigation-link,
    .mobile-menu-toggle,
    .mobile-menu-toggle .material-symbols-outlined {
        transition: none;
    }
}