/* Apple-Style Navbar - Gestura */

:root {
    --navbar-height: 72px;
    --navbar-bg: rgba(255, 255, 255, 0.8);
    --navbar-bg-scrolled: rgba(255, 255, 255, 0.95);
    --navbar-border: rgba(0, 0, 0, 0.08);
    --navbar-text: #1D1D1F;
    --navbar-text-hover: #007AFF;
    --navbar-text-active: #007AFF;
    --navbar-backdrop-blur: blur(20px);
    --navbar-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --navbar-shadow: 0 2px 16px rgba(0, 0, 0, 0.1);
    --navbar-mobile-bg: rgba(255, 255, 255, 0.98);
    --navbar-mobile-backdrop: blur(40px);
}

/* =========================
   MAIN NAVBAR CONTAINER
========================= */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--navbar-height);
    background: var(--navbar-bg);
    backdrop-filter: var(--navbar-backdrop-blur);
    -webkit-backdrop-filter: var(--navbar-backdrop-blur);
    border-bottom: 1px solid var(--navbar-border);
    z-index: 1000;
    transition: var(--navbar-transition);
    will-change: background-color, box-shadow;
    /* FIX: clip any hairline rendering at edges */
    overflow: hidden;
}

.navbar.scrolled {
    background: var(--navbar-bg-scrolled);
    box-shadow: var(--navbar-shadow);
    border-bottom-color: rgba(0, 0, 0, 0.12);
}

.navbar.hidden {
    transform: translateY(-100%);
}

.navbar-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
}

/* =========================
   NAVBAR LOGO
========================= */

.navbar-logo {
    flex-shrink: 0;
    z-index: 1001;
}

.navbar-logo a {
    display: flex;
    align-items: center;
    text-decoration: none;
    transition: var(--navbar-transition);
    padding: 8px;
    margin: -8px;
    border-radius: 8px;
}

.navbar-logo a:hover {
    background: rgba(0, 122, 255, 0.05);
}

/* FIX: show focus outline only when keyboarding */
.navbar-logo a:focus { outline: none; }
.navbar-logo a:focus-visible {
    outline: 2px solid var(--navbar-text-hover);
    outline-offset: 2px;
}

.navbar-logo-img {
    height: 32px;
    width: auto;
    transition: var(--navbar-transition);
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.1));
}

.navbar-logo a:hover .navbar-logo-img {
    transform: scale(1.05);
}

.navbar.scrolled .navbar-logo-img {
    height: 28px;
}

/* =========================
   DESKTOP NAVIGATION MENU
========================= */

.navbar-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 8px;
    align-items: center;
}

.navbar-item {
    position: relative;
}

.navbar-link {
    display: block;
    text-decoration: none;
    color: var(--navbar-text);
    font-weight: 500;
    font-size: 0.95rem;
    line-height: 1.2;
    padding: 10px 16px;
    border-radius: 8px;
    transition: var(--navbar-transition);
    position: relative;
    white-space: nowrap;
    -webkit-font-smoothing: antialiased;
}

.navbar-link:hover {
    color: var(--navbar-text-hover);
    background: rgba(0, 122, 255, 0.08);
    transform: translateY(-1px);
}

/* FIX: use focus-visible for outlines */
.navbar-link:focus { outline: none; }
.navbar-link:focus-visible {
    outline: 2px solid var(--navbar-text-hover);
    outline-offset: 2px;
}

.navbar-link.active {
    color: var(--navbar-text-active);
    background: rgba(0, 122, 255, 0.12);
    font-weight: 600;
}

.navbar-link.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 50%;
    transform: translateX(-50%);
    width: 24px;
    height: 2px;
    background: var(--navbar-text-active);
    border-radius: 1px;
    animation: activeIndicator 0.3s ease-out;
}

@keyframes activeIndicator {
    0% { width: 0; opacity: 0; }
    100% { width: 24px; opacity: 1; }
}

/* =========================
   MOBILE MENU BUTTON
========================= */

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    cursor: pointer;
    border-radius: 8px;
    transition: var(--navbar-transition);
    z-index: 1001;
    background: transparent;
    border: none;
    padding: 0;
}

.mobile-menu-btn:hover {
    background: rgba(0, 0, 0, 0.05);
}

/* FIX: focus-visible */
.mobile-menu-btn:focus { outline: none; }
.mobile-menu-btn:focus-visible {
    outline: 2px solid var(--navbar-text-hover);
    outline-offset: 2px;
}

.hamburger-line {
    width: 20px;
    height: 2px;
    background: var(--navbar-text);
    border-radius: 1px;
    transition: var(--navbar-transition);
    transform-origin: center center;
    margin: 2px 0;
}

.mobile-menu-btn.active .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(3px, 3px);
}

.mobile-menu-btn.active .hamburger-line:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.mobile-menu-btn.active .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(3px, -3px);
}

/* =========================
   MOBILE MENU OVERLAY
========================= */

.mobile-menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: var(--navbar-mobile-bg);
    backdrop-filter: var(--navbar-mobile-backdrop);
    -webkit-backdrop-filter: var(--navbar-mobile-backdrop);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

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

.mobile-menu {
    padding: 24px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    animation: slideInFromTop 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

@keyframes slideInFromTop {
    0% { opacity: 0; transform: translateY(-20px); }
    100% { opacity: 1; transform: translateY(0); }
}

.mobile-menu-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0 32px 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
    margin-bottom: 32px;
}

.mobile-logo {
    height: 32px;
    width: auto;
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.1));
}

.mobile-close-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--navbar-text);
    font-size: 1.25rem;
    cursor: pointer;
    transition: var(--navbar-transition);
}

.mobile-close-btn:hover {
    background: rgba(0, 0, 0, 0.05);
    color: var(--navbar-text-hover);
}

/* FIX: focus-visible */
.mobile-close-btn:focus { outline: none; }
.mobile-close-btn:focus-visible {
    outline: 2px solid var(--navbar-text-hover);
    outline-offset: 2px;
}

/* =========================
   MOBILE MENU NAVIGATION
========================= */

.mobile-menu-list {
    list-style: none;
    margin: 0;
    padding: 0;
    flex-grow: 1;
}

.mobile-menu-item {
    opacity: 0;
    transform: translateY(20px);
    animation: slideInMenuItem 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94) forwards;
}

.mobile-menu-overlay.active .mobile-menu-item:nth-child(1) { animation-delay: 0.1s; }
.mobile-menu-overlay.active .mobile-menu-item:nth-child(2) { animation-delay: 0.15s; }
.mobile-menu-overlay.active .mobile-menu-item:nth-child(3) { animation-delay: 0.2s; }
.mobile-menu-overlay.active .mobile-menu-item:nth-child(4) { animation-delay: 0.25s; }
.mobile-menu-overlay.active .mobile-menu-item:nth-child(5) { animation-delay: 0.3s; }

@keyframes slideInMenuItem {
    0% { opacity: 0; transform: translateY(20px); }
    100% { opacity: 1; transform: translateY(0); }
}

.mobile-menu-link {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--navbar-text);
    font-weight: 500;
    font-size: 1.25rem;
    line-height: 1.3;
    padding: 20px 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    transition: var(--navbar-transition);
    position: relative;
    -webkit-font-smoothing: antialiased;
}

.mobile-menu-link:hover {
    color: var(--navbar-text-hover);
    padding-left: 8px;
}

.mobile-menu-link.active {
    color: var(--navbar-text-active);
    font-weight: 600;
}

.mobile-menu-link.active::before {
    content: '';
    position: absolute;
    left: -24px;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 24px;
    background: var(--navbar-text-active);
    border-radius: 2px;
    animation: activeIndicatorMobile 0.3s ease-out;
}

@keyframes activeIndicatorMobile {
    0% { height: 0; opacity: 0; }
    100% { height: 24px; opacity: 1; }
}

/* =========================
   SCROLL PROGRESS INDICATOR
========================= */

/* FIXES:
   - Do not paint the gradient by default (prevents 1px sliver at x=0).
   - Avoid forcing GPU transform here to prevent subpixel bleed.
*/
.scroll-progress {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 2px;
    width: 100%;
    background: transparent;              /* was gradient */
    transform-origin: left center;
    transform: scaleX(0);
    transition: transform 0.1s ease-out;
    opacity: 0;
    visibility: hidden;
}

.navbar.scrolled .scroll-progress {
    opacity: 1;
    visibility: visible;
    background: linear-gradient(90deg, var(--navbar-text-hover), #0051D5);
}

/* =========================
   RESPONSIVE BREAKPOINTS
========================= */

@media (max-width: 1024px) {
    .navbar-container { padding: 0 20px; }
    .navbar-menu { gap: 4px; }
    .navbar-link { padding: 8px 12px; font-size: 0.9rem; }
}

@media (max-width: 768px) {
    .navbar-menu { display: none; }
    .mobile-menu-btn { display: flex; }
    .navbar-container { padding: 0 16px; }
}

@media (max-width: 480px) {
    .navbar-container { padding: 0 12px; }
    .navbar-logo-img { height: 28px; }
    .navbar.scrolled .navbar-logo-img { height: 24px; }
    .mobile-menu { padding: 16px; }
    .mobile-menu-header { padding: 12px 0 24px 0; margin-bottom: 24px; }
    .mobile-menu-link { font-size: 1.125rem; padding: 16px 0; }
}

/* =========================
   ACCESSIBILITY & FOCUS STATES
========================= */

.keyboard-navigation .navbar-link:focus,
.keyboard-navigation .mobile-menu-link:focus,
.keyboard-navigation .mobile-menu-btn:focus,
.keyboard-navigation .mobile-close-btn:focus {
    outline: 2px solid var(--navbar-text-hover);
    outline-offset: 2px;
    border-radius: 4px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .navbar { border-bottom-width: 2px; }
    .navbar-link.active::after { height: 3px; }
    .hamburger-line { height: 3px; }
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
    .navbar,
    .navbar-link,
    .navbar-logo-img,
    .mobile-menu-btn,
    .hamburger-line,
    .mobile-menu-overlay,
    .mobile-menu,
    .mobile-menu-link {
        transition: none !important;
        animation: none !important;
    }
    .mobile-menu-item {
        opacity: 1 !important;
        transform: none !important;
    }
}

/* Dark mode support (for future use) */
@media (prefers-color-scheme: dark) {
    :root {
        --navbar-bg: rgba(28, 28, 30, 0.8);
        --navbar-bg-scrolled: rgba(28, 28, 30, 0.95);
        --navbar-border: rgba(255, 255, 255, 0.1);
        --navbar-text: #F2F2F7;
        --navbar-mobile-bg: rgba(28, 28, 30, 0.98);
    }
}

/* =========================
   PERFORMANCE OPTIMIZATIONS
========================= */

.navbar {
    contain: layout style paint;
    will-change: background-color, transform;
}

.navbar-logo-img { will-change: transform; }

.hamburger-line { will-change: transform, opacity; }

.mobile-menu-overlay { contain: layout style paint; }

/* GPU acceleration for smooth animations */
/* FIX: exclude .scroll-progress to avoid subpixel gradient bleed */
.navbar,
.mobile-menu-overlay,
.hamburger-line {
    transform: translateZ(0);
    backface-visibility: hidden;
    perspective: 1000px;
}