/* AI Agents Course - Main CSS */
/* Sophisticated Design System with Black, Red, White Theme */

:root {
    /* Color Palette - Dark Theme (Default) */
    --primary-color: #dc2626; /* Red-600 */
    --primary-hover: #b91c1c; /* Red-700 */
    --primary-light: #fca5a5; /* Red-300 */
    --secondary-color: #f8fafc; /* Slate-50 */
    --accent-color: #ef4444; /* Red-500 */

    /* Dark Theme Colors */
    --bg-primary: #0f0f0f; /* Almost black */
    --bg-secondary: #1a1a1a; /* Dark gray */
    --bg-tertiary: #262626; /* Medium dark */
    --bg-card: #1f1f1f; /* Card background */
    --bg-modal: rgba(0, 0, 0, 0.9); /* Modal overlay */

    --text-primary: #ffffff; /* Pure white */
    --text-secondary: #d1d5db; /* Light gray */
    --text-muted: #9ca3af; /* Muted gray */
    --text-inverse: #0f0f0f; /* Black for light backgrounds */

    --border-color: #374151; /* Gray-700 */
    --border-light: #4b5563; /* Gray-600 */
    --border-dark: #111827; /* Gray-900 */

    --shadow-sm: 0 1px 2px rgba(220, 38, 38, 0.1);
    --shadow-md: 0 4px 6px rgba(220, 38, 38, 0.15);
    --shadow-lg: 0 10px 15px rgba(220, 38, 38, 0.2);
    --shadow-xl: 0 20px 25px rgba(220, 38, 38, 0.25);

    /* Light Theme Colors */
    --light-bg-primary: #ffffff;
    --light-bg-secondary: #f8fafc;
    --light-bg-tertiary: #f1f5f9;
    --light-bg-card: #ffffff;
    --light-text-primary: #0f0f0f;
    --light-text-secondary: #374151;
    --light-text-muted: #6b7280;
    --light-border-color: #e5e7eb;

    /* Typography */
    --font-heading: "Montserrat", sans-serif;
    --font-body: "Montserrat", sans-serif;
    --font-mono: "JetBrains Mono", monospace;
    --font-brand: "Montserrat", sans-serif;
    --font-display: "Montserrat", sans-serif;

    /* Spacing Scale */
    --space-xs: 0.25rem; /* 4px */
    --space-sm: 0.5rem; /* 8px */
    --space-md: 0.75rem; /* 12px */
    --space-lg: 1rem; /* 16px */
    --space-xl: 1.5rem; /* 24px */
    --space-2xl: 2rem; /* 32px */
    --space-3xl: 3rem; /* 48px */
    --space-4xl: 4rem; /* 64px */
    --space-5xl: 6rem; /* 96px */

    /* Typography Scale */
    --text-xs: 0.75rem; /* 12px */
    --text-sm: 0.875rem; /* 14px */
    --text-base: 1rem; /* 16px */
    --text-lg: 1.125rem; /* 18px */
    --text-xl: 1.25rem; /* 20px */
    --text-2xl: 1.5rem; /* 24px */
    --text-3xl: 1.875rem; /* 30px */
    --text-4xl: 2.25rem; /* 36px */
    --text-5xl: 3rem; /* 48px */
    --text-6xl: 3.75rem; /* 60px */

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;

    /* Z-Index Scale */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
    --z-toast: 1080;
}

/* Light Theme Override */
.light-theme {
    --bg-primary: var(--light-bg-primary);
    --bg-secondary: var(--light-bg-secondary);
    --bg-tertiary: var(--light-bg-tertiary);
    --bg-card: var(--light-bg-card);
    --text-primary: var(--light-text-primary);
    --text-secondary: var(--light-text-secondary);
    --text-muted: var(--light-text-muted);
    --border-color: var(--light-border-color);
    --bg-modal: rgba(255, 255, 255, 0.9);
}

.light-theme .main-header {
    background: rgba(255, 255, 255, 0.95);
}

.light-theme .logo,
.light-theme .nav-link,
.light-theme .mobile-nav-link {
    color: var(--light-text-primary) !important;
}

.light-theme .nav-link:hover,
.light-theme .nav-link.active {
    color: var(--primary-color) !important;
}

/* CSS Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    font-weight: 400;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--space-lg);
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

h1 {
    font-size: var(--text-4xl);
}
h2 {
    font-size: var(--text-3xl);
}
h3 {
    font-size: var(--text-2xl);
}
h4 {
    font-size: var(--text-xl);
}
h5 {
    font-size: var(--text-lg);
}
h6 {
    font-size: var(--text-base);
}

p {
    margin-bottom: var(--space-lg);
    color: var(--text-secondary);
    max-width: 65ch;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition-fast);
}

a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Utility Classes */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.text-center {
    text-align: center;
}
.text-left {
    text-align: left;
}
.text-right {
    text-align: right;
}

.font-heading {
    font-family: var(--font-heading);
}
.font-body {
    font-family: var(--font-body);
}
.font-mono {
    font-family: var(--font-mono);
}

.text-primary {
    color: var(--text-primary);
}
.text-secondary {
    color: var(--text-secondary);
}
.text-muted {
    color: var(--text-muted);
}
.text-accent {
    color: var(--primary-color);
}

.bg-card {
    background-color: var(--bg-card);
}
.bg-secondary {
    background-color: var(--bg-secondary);
}

/* Layout */
.section {
    padding: var(--space-5xl) 0;
    position: relative;
}

.section:nth-child(even) {
    background-color: var(--bg-secondary);
}

/* Ensure sections are always visible */
.hero-section,
.hero-content,
.hero-title,
.hero-description,
.hero-stats,
.hero-actions,
.stat-card,
.modules-section,
.career-section,
.portfolio-section {
    opacity: 1 !important;
    visibility: visible !important;
}

.hero-title,
.subtitle,
.hero-description,
.stat-card,
.module-card,
.career-track,
.portfolio-card {
    opacity: 1 !important;
    visibility: visible !important;
    transform: none !important;
}

.hero-stats,
.hero-actions,
.modules-grid,
.career-grid,
.portfolio-grid {
    opacity: 1 !important;
    visibility: visible !important;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-4xl);
}

.section-title {
    font-size: var(--text-4xl);
    font-weight: 700;
    margin-bottom: var(--space-lg);
    position: relative;
}

.section-title::after {
    content: "";
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(
        90deg,
        var(--primary-color),
        var(--accent-color)
    );
    border-radius: var(--radius-sm);
}

.section-subtitle {
    font-size: var(--text-lg);
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
}

/* Header */
.main-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 15, 15, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: var(--z-fixed);
    transition: var(--transition-normal);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-lg) var(--space-xl);
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    font-family: var(--font-brand);
    font-size: var(--text-2xl);
    font-weight: 800;
    color: var(--text-primary);
    margin: 0;
    letter-spacing: 0.8px;
    text-transform: uppercase;
}

.logo i {
    color: var(--primary-color);
    margin-right: var(--space-sm);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    position: relative;
    transition: var(--transition-fast);
}

.registration-link {
    background: linear-gradient(
        135deg,
        var(--primary-color),
        var(--accent-color)
    );
    color: white !important;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-lg);
    font-weight: 600;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.registration-link:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    color: white !important;
    text-decoration: none;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
    text-decoration: none;
}

.nav-link.active::after {
    content: "";
    position: absolute;
    bottom: -8px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
    border-radius: var(--radius-sm);
}

/* Dropdown */
.nav-dropdown {
    position: relative;
}

.dropdown-trigger {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    cursor: pointer;
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: var(--space-md);
    min-width: 160px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--transition-normal);
    z-index: var(--z-dropdown);
}

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

.dropdown-item {
    display: block;
    padding: var(--space-sm) var(--space-md);
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    transition: var(--transition-fast);
}

.dropdown-item:hover {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    text-decoration: none;
}

/* Mobile Menu */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
    padding: var(--space-sm);
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition-fast);
}

.mobile-nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--bg-card);
    border-left: 1px solid var(--border-color);
    z-index: var(--z-modal);
    transition: var(--transition-normal);
    overflow-y: auto;
}

.mobile-nav.active {
    right: 0;
}

.mobile-nav-content {
    padding: var(--space-3xl) var(--space-xl);
}

.mobile-nav-link {
    display: block;
    padding: var(--space-lg);
    color: var(--text-secondary);
    font-weight: 500;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition-fast);
}

.mobile-nav-link:hover {
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    text-decoration: none;
}

/* Progress Bar */
.progress-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--border-color);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(
        90deg,
        var(--primary-color),
        var(--accent-color)
    );
    width: 0%;
    transition: var(--transition-fast);
}

/* Breadcrumb */
.breadcrumb {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-lg) 0;
    margin-top: 80px;
}

.breadcrumb-item {
    color: var(--text-muted);
    font-size: var(--text-sm);
}

.breadcrumb-item.active {
    color: var(--text-primary);
    font-weight: 500;
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 50%;
    right: var(--space-xl);
    transform: translateY(-50%);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: var(--text-lg);
    color: var(--text-primary);
    transition: var(--transition-normal);
    z-index: var(--z-fixed);
    box-shadow: var(--shadow-md);
}

.theme-toggle:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
    transform: translateY(-50%) scale(1.1);
}

.light-theme .theme-toggle .light-icon,
.dark-theme .theme-toggle .dark-icon {
    display: inline;
}

.light-theme .theme-toggle .dark-icon,
.dark-theme .theme-toggle .light-icon {
    display: none;
}

/* Hero Section */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    background: linear-gradient(
        135deg,
        var(--bg-primary) 0%,
        var(--bg-secondary) 100%
    );
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
}

.geometric-shapes {
    position: relative;
    width: 100%;
    height: 100%;
}

.shape {
    position: absolute;
    border-radius: 50%;
    background: linear-gradient(
        135deg,
        var(--primary-color),
        var(--accent-color)
    );
    opacity: 0.1;
    animation: float 20s ease-in-out infinite;
}

.shape-1 {
    width: 300px;
    height: 300px;
    top: 10%;
    right: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 200px;
    height: 200px;
    bottom: 20%;
    left: 5%;
    animation-delay: -7s;
}

.shape-3 {
    width: 150px;
    height: 150px;
    top: 60%;
    right: 30%;
    animation-delay: -14s;
}

@keyframes float {
    0%,
    100% {
        transform: translateY(0) rotate(0deg);
    }
    33% {
        transform: translateY(-30px) rotate(120deg);
    }
    66% {
        transform: translateY(15px) rotate(240deg);
    }
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
    padding: var(--space-3xl);
    opacity: 1 !important;
    visibility: visible !important;
    z-index: 10;
    position: relative;
}

.hero-title {
    font-family: var(--font-display);
    font-size: var(--text-6xl);
    font-weight: 800;
    margin-bottom: var(--space-xl);
    background: linear-gradient(
        135deg,
        var(--text-primary),
        var(--primary-color)
    );
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.04em;
    line-height: 1.1;
    text-transform: uppercase;
}

.subtitle {
    display: block;
    font-size: var(--text-2xl);
    font-weight: 600;
    color: var(--primary-color);
    margin-top: var(--space-md);
    letter-spacing: -0.01em;
}

.hero-description {
    font-size: var(--text-xl);
    color: var(--text-secondary);
    margin: var(--space-2xl) auto;
    max-width: 700px;
    line-height: 1.8;
}

.hero-stats {
    display: grid !important;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--space-xl);
    margin: var(--space-3xl) 0;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    opacity: 1 !important;
    visibility: visible !important;
}

.stat-card {
    text-align: center;
    padding: var(--space-xl);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: var(--transition-normal);
    opacity: 1 !important;
    visibility: visible !important;
    display: block !important;
}

.stat-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--space-sm);
}

.stat-label {
    font-size: var(--text-sm);
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.hero-actions {
    display: flex !important;
    gap: var(--space-lg);
    justify-content: center;
    margin-top: var(--space-3xl);
    flex-wrap: wrap;
    opacity: 1 !important;
    visibility: visible !important;
}

/* Back to Top */
.back-to-top {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: var(--text-lg);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-normal);
    z-index: var(--z-fixed);
    box-shadow: var(--shadow-md);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--primary-hover);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* Footer */
.main-footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--space-4xl) 0 var(--space-xl);
    margin-top: var(--space-5xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-2xl);
    margin-bottom: var(--space-2xl);
}

.footer-title {
    font-size: var(--text-xl);
    margin-bottom: var(--space-lg);
    color: var(--text-primary);
}

.footer-subtitle {
    font-size: var(--text-lg);
    margin-bottom: var(--space-lg);
    color: var(--text-primary);
}

.footer-description {
    color: var(--text-muted);
    line-height: 1.7;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--space-sm);
}

.footer-links a {
    color: var(--text-muted);
    transition: var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary-color);
}

.contact-info p {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    color: var(--text-muted);
    margin-bottom: var(--space-sm);
}

.contact-info i {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: var(--text-sm);
}