/* ═══════════════════════════════════════════════════════════════════════════════
   Glassmorphic Sticky Navbar - Python Essentials Curriculum
   Non-invasive global navigation component
   ═══════════════════════════════════════════════════════════════════════════════ */

/* CSS Variables for Navbar */
:root {
    --navbar-height: 60px;
    --navbar-bg: rgba(10, 14, 39, 0.85);
    --navbar-blur: 20px;
    --navbar-border: rgba(0, 240, 255, 0.2);
    --navbar-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
    --nav-link-color: #e0e0e0;
    --nav-link-hover: #00f0ff;
    --nav-link-active: #ff00ff;
    --dropdown-bg: rgba(26, 31, 58, 0.95);
}

/* Body padding to account for fixed navbar */
body.has-navbar {
    padding-top: var(--navbar-height);
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Main Navbar Container
   ═══════════════════════════════════════════════════════════════════════════════ */
.global-navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    z-index: 9999;
    
    /* Glassmorphic Effect */
    background: var(--navbar-bg);
    backdrop-filter: blur(var(--navbar-blur));
    -webkit-backdrop-filter: blur(var(--navbar-blur));
    
    /* Border & Shadow */
    border-bottom: 1px solid var(--navbar-border);
    box-shadow: var(--navbar-shadow);
    
    /* Transitions */
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Navbar shrinks slightly on scroll */
.global-navbar.scrolled {
    --navbar-height: 50px;
    background: rgba(10, 14, 39, 0.95);
    box-shadow: 0 4px 40px rgba(0, 240, 255, 0.15);
}

/* Inner container */
.navbar-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1400px;
    height: 100%;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Logo / Brand
   ═══════════════════════════════════════════════════════════════════════════════ */
.navbar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    transition: transform 0.3s ease;
}

.navbar-brand:hover {
    transform: scale(1.02);
}

.navbar-logo {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.navbar-brand:hover .navbar-logo {
    filter: drop-shadow(0 0 8px rgba(0, 240, 255, 0.5));
}

.navbar-title {
    font-family: 'IBM Plex Mono', 'Space Mono', monospace;
    font-size: 1.1rem;
    font-weight: 700;
    background: linear-gradient(45deg, #00f0ff, #ff00ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 0.5px;
}

/* Hide title on very small screens */
@media (max-width: 480px) {
    .navbar-title {
        display: none;
    }
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Navigation Links
   ═══════════════════════════════════════════════════════════════════════════════ */
.navbar-nav {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    color: var(--nav-link-color);
    text-decoration: none;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 0.85rem;
    font-weight: 500;
    border-radius: 6px;
    transition: all 0.2s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--nav-link-hover);
    background: rgba(0, 240, 255, 0.1);
}

.nav-link.active {
    color: var(--nav-link-active);
    background: rgba(255, 0, 255, 0.15);
}

/* Underline indicator */
.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #00f0ff, #ff00ff);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 80%;
}

/* Nav icons */
.nav-icon {
    width: 16px;
    height: 16px;
    opacity: 0.8;
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Dropdown Menu (for Weeks)
   ═══════════════════════════════════════════════════════════════════════════════ */
.nav-dropdown {
    position: relative;
}

.dropdown-toggle {
    cursor: pointer;
}

.dropdown-toggle::after {
    content: '▼';
    font-size: 0.6rem;
    margin-left: 0.25rem;
    transition: transform 0.3s ease;
}

.nav-dropdown:hover .dropdown-toggle::after {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(10px);
    min-width: 280px;
    max-height: 400px;
    overflow-y: auto;
    
    /* Glassmorphic dropdown */
    background: var(--dropdown-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--navbar-border);
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
    
    /* Hidden by default */
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    
    padding: 0.5rem;
    z-index: 10000;
}

.nav-dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

/* Dropdown items */
.dropdown-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    color: var(--nav-link-color);
    text-decoration: none;
    font-size: 0.85rem;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.dropdown-item:hover {
    background: rgba(0, 240, 255, 0.15);
    color: var(--nav-link-hover);
    transform: translateX(4px);
}

.dropdown-item.active {
    background: rgba(255, 0, 255, 0.2);
    color: var(--nav-link-active);
}

/* Week number badge in dropdown */
.week-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 28px;
    height: 24px;
    background: linear-gradient(135deg, #00f0ff, #ff00ff);
    color: #0a0e27;
    font-size: 0.75rem;
    font-weight: 700;
    border-radius: 6px;
}

/* Dropdown section divider */
.dropdown-divider {
    height: 1px;
    background: var(--navbar-border);
    margin: 0.5rem 0;
}

.dropdown-header {
    padding: 0.5rem 1rem;
    font-size: 0.7rem;
    font-weight: 700;
    color: #00ff41;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Colab Notebook Links - Premium Styling
   ═══════════════════════════════════════════════════════════════════════════════ */
.colab-link {
    position: relative;
    border-left: 3px solid transparent;
    transition: all 0.3s ease;
}

.colab-link:hover {
    border-left-color: #f9ab00;
    background: rgba(249, 171, 0, 0.1) !important;
}

.colab-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    background: linear-gradient(135deg, #f9ab00, #ff6f00);
    color: #000;
    font-size: 0.7rem;
    font-weight: 700;
    border-radius: 50%;
    margin-right: 0.25rem;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(249, 171, 0, 0.3);
}

.colab-link:hover .colab-badge {
    transform: scale(1.15);
    box-shadow: 0 4px 15px rgba(249, 171, 0, 0.5);
}

/* Notebooks mega dropdown - wider for better UX */
.nav-dropdown:has(.colab-link) .dropdown-menu {
    min-width: 320px;
    max-height: 500px;
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Mobile Menu Toggle
   ═══════════════════════════════════════════════════════════════════════════════ */
.navbar-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 0.5rem;
    background: transparent;
    border: none;
    cursor: pointer;
    z-index: 10001;
}

.navbar-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: #00f0ff;
    border-radius: 2px;
    transition: all 0.3s ease;
}

.navbar-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

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

.navbar-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Mobile Responsive
   ═══════════════════════════════════════════════════════════════════════════════ */
@media (max-width: 900px) {
    .navbar-toggle {
        display: flex;
    }
    
    .navbar-nav {
        position: fixed;
        top: var(--navbar-height);
        left: 0;
        right: 0;
        bottom: 0;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        padding: 1rem;
        background: var(--dropdown-bg);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        
        /* Hidden by default */
        transform: translateX(100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        overflow-y: auto;
    }
    
    .navbar-nav.open {
        transform: translateX(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-link {
        padding: 1rem;
        font-size: 1rem;
        border-bottom: 1px solid rgba(0, 240, 255, 0.1);
    }
    
    .nav-dropdown .dropdown-menu {
        position: static;
        transform: none;
        min-width: 100%;
        max-height: none;
        opacity: 1;
        visibility: visible;
        background: rgba(0, 0, 0, 0.2);
        box-shadow: none;
        border: none;
        margin-top: 0.5rem;
        display: none;
    }
    
    .nav-dropdown.open .dropdown-menu {
        display: block;
    }
    
    .dropdown-item {
        padding-left: 2rem;
    }
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Scrollbar Styling for Dropdown
   ═══════════════════════════════════════════════════════════════════════════════ */
.dropdown-menu::-webkit-scrollbar {
    width: 6px;
}

.dropdown-menu::-webkit-scrollbar-track {
    background: transparent;
}

.dropdown-menu::-webkit-scrollbar-thumb {
    background: rgba(0, 240, 255, 0.3);
    border-radius: 3px;
}

.dropdown-menu::-webkit-scrollbar-thumb:hover {
    background: rgba(0, 240, 255, 0.5);
}

/* ═══════════════════════════════════════════════════════════════════════════════
   Accessibility
   ═══════════════════════════════════════════════════════════════════════════════ */
.nav-link:focus,
.dropdown-item:focus,
.navbar-toggle:focus {
    outline: 2px solid #00f0ff;
    outline-offset: 2px;
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    .global-navbar,
    .nav-link,
    .dropdown-menu,
    .dropdown-item,
    .navbar-toggle span {
        transition: none;
    }
}