/* ===========================================================
   02 · NAVIGATION + MOBILE MENU
   =========================================================== */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 0 var(--gutter);
    background: rgba(255, 255, 255, 0);
    border-bottom: 1px solid transparent;
    transition: background var(--t-slow) var(--ease),
        border-color var(--t-slow) var(--ease),
        color var(--t-slow) var(--ease);
    color: var(--color-obsidian);
}

.nav__inner {
    width: 100%;
    max-width: var(--max-w);
    margin: 0 auto;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav.is-scrolled {
    background: var(--nav-scrolled-bg);
    backdrop-filter: blur(14px) saturate(1.2);
    -webkit-backdrop-filter: blur(14px) saturate(1.2);
    border-bottom-color: var(--color-obsidian-08);
}

.nav.is-on-dark {
    color: var(--color-canvas-white);
    border-bottom-color: var(--color-white-08);
}

.nav.is-on-dark.is-scrolled {
    background: var(--nav-scrolled-bg-dark);
    border-bottom-color: var(--color-white-08);
}

.nav__brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: var(--weight-bold);
    font-size: 17px;
    letter-spacing: -0.01em;
    color: inherit;
    position: relative;
}

.nav__mark {
    display: grid;
    place-items: center;
    width: 32px;
    height: 32px;
    background: var(--color-obsidian);
    color: var(--color-canvas-white);
    border-radius: var(--radius-pill);
    font-size: 13px;
    font-weight: var(--weight-extra);
    letter-spacing: -0.02em;
    transition: background var(--t-slow) var(--ease),
        color var(--t-slow) var(--ease),
        transform var(--t-base) var(--ease);
}

.nav.is-on-dark .nav__mark {
    background: var(--color-canvas-white);
    color: var(--color-obsidian);
}

.nav__brand:hover .nav__mark {
    transform: rotate(-8deg) scale(1.06);
}

.nav__word {
    font-weight: var(--weight-bold);
    letter-spacing: -0.01em;
    position: relative;
    overflow: hidden;
    display: inline-block;
    line-height: 1.2;
    height: 1.2em;
}

.nav__word::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 1.5px;
    background: var(--color-desert-sienna);
    transform: scaleX(0);
    transform-origin: right center;
    transition: transform var(--t-slow) var(--ease);
}

.nav__brand:hover .nav__word::after {
    transform: scaleX(1);
    transform-origin: left center;
}

.nav__links {
    display: flex;
    align-items: center;
    gap: 34px;
}

.nav__link {
    position: relative;
    display: inline-block;
    font-size: 17px;
    font-weight: var(--weight-regular);
    color: inherit;
    padding: 13px 0;
    transition: opacity var(--t-slow) var(--ease);
}

.nav__link::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    bottom: 8px;
    height: 1.5px;
    background: var(--color-desert-sienna);
    transform: scaleX(0);
    transform-origin: right center;
    transition: transform var(--t-base) var(--ease);
}

.nav__link:hover {
    opacity: 0.7;
}

.nav__link:hover::after,
.nav__link.is-active::after {
    transform: scaleX(1);
    transform-origin: left center;
}

.nav__cta {
    display: inline-flex;
    align-items: center;
    font-size: 17px;
    font-weight: var(--weight-bold);
    color: var(--color-canvas-white);
    background: var(--color-obsidian);
    padding: 13px 22px;
    border-radius: var(--radius-pill);
    transition: background var(--t-slow) var(--ease),
        color var(--t-slow) var(--ease),
        transform var(--t-base) var(--ease);
    letter-spacing: -0.005em;
    will-change: transform;
}

.nav__cta:hover {
    background: var(--color-desert-sienna);
}

.nav.is-on-dark .nav__cta {
    background: var(--color-canvas-white);
    color: var(--color-obsidian);
}

.nav.is-on-dark .nav__cta:hover {
    background: var(--color-desert-sienna);
    color: var(--color-canvas-white);
}

.nav__actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    cursor: none;
    padding: 8px;
    color: inherit;
    transition: color var(--t-base) var(--ease), transform var(--t-base) var(--ease);
    will-change: transform;
    position: relative;
    width: 38px;
    height: 38px;
}

.theme-toggle:hover {
    color: var(--color-desert-sienna);
    transform: scale(1.1);
}

.theme-toggle svg {
    position: absolute;
    display: block;
    pointer-events: none;
    transition: transform var(--t-slow) var(--ease), opacity var(--t-slow) var(--ease);
}

.theme-toggle__sun {
    opacity: 0;
    transform: rotate(-90deg) scale(0.6);
}

.theme-toggle__moon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.dark-mode .theme-toggle__sun {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.dark-mode .theme-toggle__moon {
    opacity: 0;
    transform: rotate(90deg) scale(0.6);
}

.nav__menu {
    display: none;
    width: 38px;
    height: 38px;
    position: relative;
    color: inherit;
}

.nav__menu span {
    position: absolute;
    left: 8px;
    right: 8px;
    height: 2px;
    background: currentColor;
    border-radius: 2px;
    transition: transform var(--t-base) var(--ease), opacity var(--t-base) var(--ease);
}

.nav__menu span:nth-child(1) {
    top: 13px;
}

.nav__menu span:nth-child(2) {
    top: 18px;
}

.nav__menu span:nth-child(3) {
    top: 23px;
}

.nav__menu.is-open span:nth-child(1) {
    transform: translateY(5px) rotate(45deg);
}

.nav__menu.is-open span:nth-child(2) {
    opacity: 0;
}

.nav__menu.is-open span:nth-child(3) {
    transform: translateY(-5px) rotate(-45deg);
}

/* ----- Mobile menu ----- */
.mobile-menu {
    position: fixed;
    inset: 0;
    z-index: 90;
    background: var(--surface-canvas-white);
    color: var(--color-obsidian);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 80px var(--gutter) 40px;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--t-slow) var(--ease);
    visibility: hidden;
}

.mobile-menu.is-open {
    opacity: 1;
    pointer-events: auto;
    visibility: visible;
}

.mobile-menu__nav {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
    max-width: 480px;
}

.mobile-menu__link {
    display: block;
    font-size: clamp(34px, 8vw, 56px);
    font-weight: var(--weight-bold);
    letter-spacing: -0.02em;
    padding: 16px 0;
    border-bottom: 1px solid var(--color-obsidian-08);
    color: var(--color-obsidian);
    transition: color var(--t-slow) var(--ease),
        padding-left var(--t-slow) var(--ease),
        border-color var(--t-slow) var(--ease);
    overflow: hidden;
    position: relative;
}

.mobile-menu__link:hover {
    color: var(--color-desert-sienna);
    padding-left: 8px;
    border-color: var(--color-desert-sienna);
}