/* ================================================
   DIANA CYBER PLATFORM - MODERN CSS
   Clean, Professional, Attractive Design
   ================================================ */

/* === RESET & BASE === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors - Cyber Theme */
    --primary: #0a0e27;
    --secondary: #1a2332;
    --accent: #00f0ff;
    --accent-purple: #a855f7;
    --accent-pink: #ec4899;

    /* Text */
    --text-light: #ffffff;
    --text-gray: #94a3b8;
    --text-dark: #1e293b;

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;
    --space-xl: 6rem;

    /* Border */
    --radius: 1rem;
    --radius-sm: 0.5rem;

    /* Shadow */
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 30px rgba(0, 240, 255, 0.3);
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--primary);
    color: var(--text-light);
    line-height: 1.6;
    overflow-x: hidden;
}

/* === TYPOGRAPHY === */
h1,
h2,
h3,
h4 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--space-md);
}

h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-purple) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

p {
    font-size: 1.125rem;
    color: var(--text-gray);
    margin-bottom: var(--space-sm);
}

/* === NAVIGATION === */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(10, 14, 39, 0.9);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 240, 255, 0.1);
    padding: 1.5rem 0;
    z-index: 1000;
}

nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

nav ul {
    display: flex;
    gap: 2.5rem;
    list-style: none;
}

nav a {
    color: var(--text-gray);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

nav a:hover {
    color: var(--accent);
}

nav a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width 0.3s ease;
}

nav a:hover::after {
    width: 100%;
}

/* === CONTAINER === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

/* === HERO SECTION === */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: var(--space-xl) var(--space-md);
    background:
        radial-gradient(circle at 20% 30%, rgba(0, 240, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(168, 85, 247, 0.1) 0%, transparent 50%),
        var(--primary);
    position: relative;
}

.hero-content {
    max-width: 900px;
    animation: fadeInUp 1s ease-out;
}

.hero h1 {
    margin-bottom: var(--space-md);
}

.hero p {
    font-size: 1.35rem;
    color: var(--text-gray);
    margin-bottom: var(--space-lg);
    line-height: 1.8;
}

/* === BUTTONS === */
.btn {
    display: inline-block;
    padding: 1rem 2.5rem;
    font-size: 1.125rem;
    font-weight: 600;
    border-radius: var(--radius);
    text-decoration: none;
    transition: all 0.4s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-purple) 100%);
    color: var(--text-light);
    box-shadow: 0 10px 30px rgba(0, 240, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(0, 240, 255, 0.5);
}

.btn-outline {
    background: transparent;
    color: var(--accent);
    border: 2px solid var(--accent);
}

.btn-outline:hover {
    background: var(--accent);
    color: var(--primary);
}

.btn-group {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* === SECTION === */
section {
    padding: var(--space-xl) 0;
}

.section-dark {
    background: var(--secondary);
}

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

.section-header h2 {
    margin-bottom: var(--space-sm);
}

.section-header p {
    font-size: 1.25rem;
    max-width: 700px;
    margin: 0 auto;
}

/* === CARDS === */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-lg);
}

.card {
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius);
    padding: var(--space-md);
    border: 1px solid rgba(0, 240, 255, 0.1);
    transition: all 0.4s ease;
    backdrop-filter: blur(10px);
}

.card:hover {
    transform: translateY(-10px);
    border-color: var(--accent);
    box-shadow: var(--shadow-glow);
}

.card-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    margin-bottom: var(--space-md);
}

.card h3 {
    margin-bottom: var(--space-sm);
}

.card p {
    color: var(--text-gray);
    line-height: 1.7;
}

/* === STATS === */
.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    text-align: center;
}

.stat-box {
    padding: var(--space-md);
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius);
    border: 1px solid rgba(0, 240, 255, 0.1);
    transition: all 0.3s ease;
}

.stat-box:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--accent);
}

.stat-number {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: var(--space-sm);
}

.stat-label {
    color: var(--text-gray);
    font-size: 1.125rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* === FOOTER === */
footer {
    background: var(--secondary);
    border-top: 1px solid rgba(0, 240, 255, 0.1);
    padding: var(--space-lg) 0 var(--space-md);
}

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

.footer-col h4 {
    color: var(--accent);
    margin-bottom: var(--space-md);
    font-size: 1.25rem;
}

.footer-col ul {
    list-style: none;
}

.footer-col a {
    color: var(--text-gray);
    text-decoration: none;
    display: block;
    margin-bottom: var(--space-xs);
    transition: all 0.3s ease;
}

.footer-col a:hover {
    color: var(--accent);
    padding-left: 5px;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--space-md);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--text-gray);
}

/* === ANIMATIONS === */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeInUp 0.8s ease-out;
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
    nav ul {
        display: none;
    }

    .hero {
        min-height: 80vh;
        padding: var(--space-lg) var(--space-md);
    }

    .btn-group {
        flex-direction: column;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }
}

/* === UTILITY CLASSES === */
.text-center {
    text-align: center;
}

.mt-1 {
    margin-top: var(--space-sm);
}

.mt-2 {
    margin-top: var(--space-md);
}

.mt-3 {
    margin-top: var(--space-lg);
}

.mb-1 {
    margin-bottom: var(--space-sm);
}

.mb-2 {
    margin-bottom: var(--space-md);
}

.mb-3 {
    margin-bottom: var(--space-lg);
}

/* === BREADCRUMB NAVIGATION === */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.95rem;
    color: var(--text-gray);
    padding: 0.5rem 0;
}

.breadcrumb a {
    color: var(--text-gray);
    text-decoration: none;
    transition: color 0.3s ease;
}

.breadcrumb a:hover {
    color: var(--accent);
}

.breadcrumb .separator {
    color: var(--text-gray);
    opacity: 0.5;
}

.breadcrumb .current {
    color: var(--accent);
    font-weight: 600;
}

/* === COURSE DETAIL PAGE === */
.course-header {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.course-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    color: var(--text-light);
    padding: 0.5rem 1.5rem;
    border-radius: 2rem;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: var(--space-md);
}

.course-subtitle {
    font-size: 1.35rem;
    color: var(--text-gray);
    margin-bottom: var(--space-lg);
}

.course-meta {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-lg);
    padding: var(--space-md);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--radius);
    border: 1px solid rgba(0, 240, 255, 0.1);
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.meta-item .icon {
    font-size: 2rem;
}

.meta-item strong {
    display: block;
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
}

.meta-item p {
    color: var(--text-gray);
    font-size: 0.95rem;
    margin: 0;
}

/* Course Content Grid */
.course-content-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--space-lg);
    margin-top: var(--space-lg);
}

.course-main {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.course-sidebar {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

/* Learning Outcomes */
.learning-outcomes {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.outcome-item {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.check-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: var(--accent);
    color: var(--primary);
    border-radius: 50%;
    font-weight: 800;
    flex-shrink: 0;
    margin-top: 2px;
}

.outcome-item p {
    margin: 0;
    color: var(--text-gray);
}

/* Curriculum Sections */
.curriculum-section {
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.curriculum-section:last-child {
    border-bottom: none;
}

.curriculum-section h3 {
    color: var(--accent);
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
}

.curriculum-list {
    list-style: none;
    padding-left: 0;
}

.curriculum-list li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-gray);
}

.curriculum-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--accent);
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-md);
}

.feature-item {
    text-align: center;
}

.feature-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: var(--space-sm);
}

.feature-item h4 {
    color: var(--text-light);
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.feature-item p {
    font-size: 0.95rem;
    margin: 0;
}

/* Enrollment Card */
.price-tag {
    text-align: center;
    padding: var(--space-md);
    background: rgba(0, 240, 255, 0.05);
    border-radius: var(--radius-sm);
    margin: var(--space-md) 0;
}

.price {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.price-note {
    display: block;
    color: var(--text-gray);
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

.enrollment-benefits {
    list-style: none;
    padding: 0;
    margin: var(--space-md) 0;
}

.enrollment-benefits li {
    padding: 0.5rem 0;
    color: var(--text-gray);
    font-size: 0.95rem;
}

.prereq-list {
    list-style: none;
    padding: 0;
}

.prereq-list li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-gray);
    font-size: 0.95rem;
}

.prereq-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--accent);
    font-size: 1.5rem;
    line-height: 1;
}

/* Instructor Mini Card */
.instructor-mini {
    text-align: center;
}

.instructor-avatar {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-sm);
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
}

.instructor-mini h4 {
    margin-bottom: 0.5rem;
    font-size: 1.125rem;
}

/* Responsive for Course Pages */
@media (max-width: 968px) {
    .course-content-grid {
        grid-template-columns: 1fr;
    }

    .course-sidebar {
        order: -1;
    }

    .course-meta {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .course-meta {
        grid-template-columns: 1fr;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }
}