/* CSS Variables for easier theme management */
:root {
    --font-family-sans: 'Inter', sans-serif;
    --color-primary: #4f46e5; /* indigo-600 */
    --color-primary-hover: #4338ca; /* indigo-700 */
    --color-secondary: #e5e7eb; /* gray-200 */
    --color-secondary-hover: #d1d5db; /* gray-300 */
    --color-text-dark: #1f2937; /* gray-800 */
    --color-text-medium: #4b5563; /* gray-600 */
    --color-text-light: #ffffff;
    --color-violet-100: #ede9fe;
    --color-violet-200: #ddd6fe;
    --color-violet-600: #7c3aed;
    --color-violet-700: #6d28d9;
    --color-violet-800: #5b21b6;
    /* Course Card Colors */
    --color-html-bg: #f97316; /* orange-500 */
    --color-css-bg: #8b5cf6;  /* A nice purple (violet-500 equivalent) */
    --color-js-bg: #facc15;   /* yellow-400 */
    --color-php-bg: #3b82f6;  /* blue-500 */
    --color-sql-bg: #ef4444;  /* red-500 */

    --border-radius-lg: 0.5rem; /* rounded-lg */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
}

/* Basic Reset and Body Styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html {
    scroll-behavior: smooth;
    font-size: 16px; /* Base font size */
}
body {
    font-family: var(--font-family-sans);
    background-color: #f9fafb; /* gray-50 */
    color: var(--color-text-medium);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}
a {
    text-decoration: none;
    color: inherit;
}
img {
    max-width: 100%;
    height: auto;
    display: block;
}
button, input, textarea {
    font-family: inherit;
}

/* Container */
.container {
    width: 90%;
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

/* Header & Navigation */
.site-header {
    background-color: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 50;
    padding-top: 1rem;
    padding-bottom: 1rem;
    transition: padding 0.3s ease-in-out, box-shadow 0.3s ease-in-out, background-color 0.3s ease-in-out;
}
.site-header.scrolled {
    padding-top: 0.5rem;
    padding-bottom: 0.5rem;
    background-color: rgba(255, 255, 255, 1);
    box-shadow: var(--shadow-lg);
}
.main-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
    display: flex;
    align-items: center;
}
.logo i {
    margin-right: 0.5rem;
}
.nav-links-desktop {
    display: none;
    align-items: center;
}
.nav-links-desktop a, #mobile-menu a.nav-link-mobile {
    color: var(--color-text-dark);
    padding: 0.5rem 0.75rem;
    border-radius: var(--border-radius-lg);
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.3s ease-in-out;
    position: relative;
    margin-left: 0.25rem;
    margin-right: 0.25rem;
}
.nav-links-desktop a::after, #mobile-menu a.nav-link-mobile::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-primary);
    transition: width 0.3s ease-in-out;
}
.nav-links-desktop a:hover, #mobile-menu a.nav-link-mobile:hover {
    color: var(--color-primary);
}
.nav-links-desktop a:hover::after, #mobile-menu a.nav-link-mobile:hover::after {
    width: 100%;
}
.nav-links-desktop a.active, #mobile-menu a.nav-link-mobile.active {
    color: var(--color-primary);
    font-weight: 600;
}
.nav-links-desktop a.active::after, #mobile-menu a.nav-link-mobile.active::after {
    width: 100%;
}
.auth-buttons-desktop {
    display: none;
    align-items: center;
}
.nav-button {
    margin-left: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    transition: all 0.2s ease-in-out;
    border: 2px solid transparent;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    line-height: 1.25;
}
.nav-button:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(var(--color-primary-rgb, 79, 70, 229), 0.4);
}
.nav-button-login {
    background-color: transparent;
    color: var(--color-violet-700);
    border-color: var(--color-violet-600);
    box-shadow: none;
}
.nav-button-login:hover {
    background-color: var(--color-violet-100);
    border-color: var(--color-violet-700);
    color: var(--color-violet-800);
    box-shadow: var(--shadow-sm);
}
.nav-button-login:focus {
     box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.4);
}
.nav-button-register {
    background-color: var(--color-violet-800);
    color: var(--color-text-light);
    box-shadow: var(--shadow-sm);
}
.nav-button-register:hover {
    background-color: var(--color-violet-700);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}
 .nav-button-register:focus {
     box-shadow: 0 0 0 3px rgba(91, 33, 182, 0.4);
}
.nav-button-register .icon {
    margin-left: 0.5rem;
    font-size: 0.8em;
}

.mobile-menu-button {
    display: block;
    background: none;
    border: none;
    color: var(--color-text-dark);
    font-size: 1.5rem;
    cursor: pointer;
}
.mobile-menu-button:hover {
    color: var(--color-primary);
}
#mobile-menu {
    display: none;
    background-color: var(--color-text-light);
    box-shadow: var(--shadow-lg);
}
#mobile-menu.open {
    display: block;
}
#mobile-menu a.nav-link-mobile {
    display: block;
    padding: 0.75rem 1.5rem;
    border-bottom: 1px solid #e5e7eb;
}
#mobile-menu .auth-buttons-mobile {
    padding: 1rem 1.5rem;
    border-top: 1px solid #e5e7eb;
}
#mobile-menu .auth-buttons-mobile .nav-button {
    display: block;
    width: 100%;
    text-align: center;
    margin-left: 0;
    padding: 0.75rem 1rem;
}
#mobile-menu .auth-buttons-mobile .nav-button:first-child {
    margin-bottom: 0.75rem;
}

/* Hero Section */
.hero-section {
    position: relative;
    height: 600px;
    width: 100%;
    background-size: cover;
    background-position: center;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
    background-image: var(--current-hero-bg);
}
.hero-section::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1;
}
.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-image: var(--hero-bg-next);
    z-index: 0;
    opacity: 0;
    transition: opacity 1.5s ease-in-out;
}
.hero-section.is-fading::before {
    opacity: 1;
}
.hero-section .container {
    position: relative;
    z-index: 2;
}
.hero-section h1 {
    font-size: 3em;
    margin-bottom: 20px;
}
.hero-section p {
    font-size: 1.2em;
    margin-bottom: 30px;
}

/* Buttons (Primary & Secondary) */
.btn {
    display: inline-block;
    font-weight: 600;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease-in-out;
    text-decoration: none;
    border: none;
    cursor: pointer;
}
.btn:hover {
    transform: translateY(-2px) scale(1.05);
}
.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-text-light);
}
.btn-primary:hover {
    background-color: var(--color-primary-hover);
    box-shadow: 0 0 15px rgba(79, 70, 229, 0.5);
}
.btn-secondary {
    background-color: var(--color-secondary);
    color: var(--color-text-dark);
}
.btn-secondary:hover {
    background-color: var(--color-secondary-hover);
}

/* Section Title */
.section-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text-dark);
    margin-bottom: 2rem;
    text-align: center;
}

/* Features Section */
.features-section {
    padding: 4rem 0;
    background-color: #f3f4f6;
}
.features-grid {
    display: grid;
    gap: 2rem;
}
.feature-card {
    background-color: var(--color-text-light);
    padding: 1.5rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
}
.feature-card .icon {
    color: var(--color-primary);
    font-size: 3rem;
    margin-bottom: 1rem;
}
.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-dark);
    margin-bottom: 0.5rem;
}

/* About Us Section */
.about-section {
    padding: 4rem 0;
}
.about-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
}
.about-image img {
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 500px;
    height: auto;
    object-fit: cover;
}
.about-text h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text-dark);
    margin-bottom: 1rem;
}
.about-text p {
    margin-bottom: 1rem;
    line-height: 1.7;
}
.about-text .btn {
    margin-top: 1.5rem;
}

/* Courses Section */
.courses-section {
    padding: 4rem 0;
    background-color: #f3f4f6;
}
.courses-grid {
    display: grid;
    gap: 2rem;
}
.course-card-new {
    background-color: var(--color-text-light);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}
.course-card-new .card-image-container {
    height: 10rem;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}
.course-card-new .card-image-container img {
    max-height: 100%;
    max-width: 60%;
    object-fit: contain;
}
.course-card-new .bg-html { background-color: var(--color-html-bg); }
.course-card-new .bg-css { background-color: var(--color-css-bg); }
.course-card-new .bg-js { background-color: var(--color-js-bg); }
.course-card-new .bg-php { background-color: var(--color-php-bg); }
.course-card-new .bg-sql { background-color: var(--color-sql-bg); }

.course-card-new .card-content {
    padding: 1.5rem;
}
.course-card-new .card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-dark);
    margin-bottom: 0.5rem;
}
.course-card-new .card-description {
    font-size: 0.875rem;
    color: var(--color-text-medium);
    margin-bottom: 1rem;
}
.course-card-new .card-link {
    color: var(--color-primary);
    font-weight: 600;
}
.course-card-new .card-link:hover {
    text-decoration: underline;
}
.view-all-courses-container {
    text-align: center;
    margin-top: 3rem;
}
.hidden {
    display: none !important;
}

/* Footer */
.site-footer {
    background-color: #111827;
    color: #d1d5db;
    padding: 3rem 0;
}
.footer-grid {
    display: grid;
    gap: 2rem;
    margin-bottom: 2rem;
}
.footer-grid h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-light);
    margin-bottom: 1rem;
}
.footer-grid ul {
    list-style: none;
    padding: 0;
}
.footer-grid ul li {
    margin-bottom: 0.5rem;
}
.footer-link {
    color: #9ca3af;
    font-size: 0.875rem;
    transition: color 0.15s ease-in-out;
}
.footer-link:hover {
    color: var(--color-primary);
}
.social-icons a {
    color: #9ca3af;
    font-size: 1.5rem;
    margin-right: 1rem;
}
.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    text-align: center;
    font-size: 0.875rem;
}
.footer-bottom .fa-heart {
    color: var(--color-primary);
}

/* === Interaction & Animation Enhancements === */

/* --- On-Scroll Fade-In Animation --- */
.fade-in-element {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.fade-in-element.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Enhanced Card Hover Effects --- */
.feature-card, .course-card-new {
    transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
}
.feature-card:hover, .course-card-new:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

/* --- Footer Social Icon Hover --- */
.social-icons a {
    transition: color 0.3s ease-in-out, transform 0.3s ease-in-out;
}
.social-icons a:hover {
    color: var(--color-text-light);
    transform: scale(1.1);
}
/* === Authentication Prompt Modal Styles (Final Version) === */

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(17, 24, 39, 0.7); /* A darker, more modern overlay (gray-900 at 70%) */
    display: flex; 
    align-items: center;
    justify-content: center;
    z-index: 9999; /* Set a very high z-index to ensure it's on top */
    
    /* Default hidden state */
    opacity: 0; 
    visibility: hidden;
    
    /* Transition for fade-in effect */
    transition: opacity 0.3s ease, visibility 0s linear 0.3s;
}

.modal-overlay.visible {
    opacity: 1;
    visibility: visible;
    transition: opacity 0.3s ease, visibility 0s linear 0s;
}

.modal-content {
    background-color: var(--color-text-light);
    padding: 2rem 2.5rem;
    border-radius: 0.75rem;
    box-shadow: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1); /* Equivalent to shadow-xl */
    text-align: center;
    max-width: 460px; 
    width: 90%; 
    position: relative; 
    
    /* Pop-in animation */
    transform: scale(0.95);
    opacity: 0;
    transition: transform 0.3s cubic-bezier(0.25, 0.8, 0.25, 1), opacity 0.3s ease;
}

.modal-overlay.visible .modal-content {
    transform: scale(1);
    opacity: 1;
}

.modal-close-btn {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    background: transparent;
    border: none;
    font-size: 1.75rem;
    color: #9ca3af; /* gray-400 */
    cursor: pointer;
    line-height: 1;
    padding: 0.25rem;
    transition: color 0.2s ease, transform 0.2s ease;
}
.modal-close-btn:hover {
    color: #1f2937; /* gray-800 */
    transform: rotate(90deg);
}

.modal-icon {
    font-size: 2.75rem;
    color: var(--color-primary);
    margin-bottom: 1.25rem;
}

.modal-content h2 {
    font-size: 1.75rem;
    color: var(--color-text-dark);
    margin-bottom: 0.75rem;
}

.modal-content p {
    font-size: 1rem;
    color: var(--color-text-medium);
    margin-bottom: 2rem;
    line-height: 1.6;
}

.modal-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.modal-actions .modal-btn {
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
    font-weight: 500;
    width: auto;
    min-width: 150px;
}


/* Responsive Styles */
@media (min-width: 768px) { /* md breakpoint */
    .nav-links-desktop, .auth-buttons-desktop {
        display: flex;
    }
    .mobile-menu-button, #mobile-menu {
        display: none;
    }
    .hero-section h1 {
        font-size: 3.75rem;
    }
    .hero-section p {
        font-size: 1.25rem;
    }
    .section-title {
        font-size: 2.25rem;
    }
    .features-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .about-content {
        flex-direction: row;
        text-align: left;
    }
    .about-image {
        width: 50%;
        padding-right: 2.5rem;
    }
    .about-text {
        width: 50%;
    }
    .courses-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .footer-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}



@media (min-width: 1024px) { /* lg breakpoint */
    .courses-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}