/* ===== CSS Variables ===== */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    --background-dark: #0f172a;
    --background-medium: #1e293b;
    --background-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: #475569;
    --success-color: #22c55e;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-secondary: linear-gradient(135deg, #10b981 0%, #14b8a6 100%);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.4);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.5);
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

/* ===== Reset & Base ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--background-dark);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    text-align: center;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.5);
}

.btn-secondary {
    background: var(--background-light);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.1rem;
}

/* ===== Header ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 1.8rem;
}

.logo-text {
    font-size: 1.4rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav {
    display: flex;
    gap: 30px;
}

.nav a {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s ease;
}

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

/* ===== Hero Section ===== */
.hero {
    padding: 150px 0 100px;
    text-align: center;
    background: linear-gradient(180deg, var(--background-dark) 0%, var(--background-medium) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%);
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 16px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.hero-features span {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ===== Courses Section ===== */
.courses {
    padding: 100px 0;
    background: var(--background-medium);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 60px;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.course-card {
    background: var(--background-dark);
    border-radius: var(--radius-lg);
    padding: 40px 30px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
}

.course-card:hover {
    transform: translateY(-10px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-xl);
}

.course-card.featured {
    border-color: var(--primary-color);
    background: linear-gradient(180deg, var(--background-dark) 0%, rgba(99, 102, 241, 0.1) 100%);
}

.course-badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--gradient-primary);
    color: white;
    padding: 6px 20px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.course-icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.course-name {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.course-desc {
    color: var(--text-secondary);
    margin-bottom: 25px;
    font-size: 1.1rem;
}

.course-features {
    text-align: left;
    margin-bottom: 30px;
}

.course-features li {
    padding: 10px 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.course-features li:last-child {
    border-bottom: none;
}

.course-card .btn {
    width: 100%;
}

/* ===== Features Section ===== */
.features {
    padding: 100px 0;
    background: var(--background-dark);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    background: var(--background-medium);
    border-radius: var(--radius-md);
    padding: 30px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.feature-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* ===== Curriculum Section ===== */
.curriculum {
    padding: 100px 0;
    background: var(--background-medium);
}

.curriculum-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 25px;
}

.curriculum-item {
    background: var(--background-dark);
    border-radius: var(--radius-md);
    padding: 25px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.curriculum-item:hover {
    border-color: var(--primary-color);
}

.curriculum-number {
    display: inline-block;
    background: var(--gradient-primary);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    line-height: 40px;
    text-align: center;
    font-weight: 700;
    margin-bottom: 15px;
}

.curriculum-item h4 {
    font-size: 1.1rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.curriculum-item p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ===== FAQ Section ===== */
.faq {
    padding: 100px 0;
    background: var(--background-dark);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 15px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 20px 25px;
    background: var(--background-medium);
    border: none;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
}

.faq-question:hover {
    background: var(--background-light);
}

.faq-icon {
    font-size: 1.5rem;
    color: var(--primary-color);
    transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
    max-height: 200px;
}

.faq-answer p {
    padding: 20px 25px;
    color: var(--text-secondary);
    background: var(--background-dark);
}

/* ===== CTA Section ===== */
.cta {
    padding: 80px 0;
    background: var(--gradient-primary);
    text-align: center;
}

.cta h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
}

.cta p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.cta .btn {
    background: white;
    color: var(--primary-color);
}

.cta .btn:hover {
    background: var(--background-dark);
    color: white;
}

/* ===== Footer ===== */
.footer {
    padding: 60px 0 30px;
    background: var(--background-dark);
    border-top: 1px solid var(--border-color);
}

.footer-content {
    text-align: center;
    margin-bottom: 30px;
}

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
}

.footer-disclaimer {
    max-width: 700px;
    margin: 0 auto;
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.7;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
}

.footer-bottom p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .courses-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

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

@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-features {
        flex-direction: column;
        gap: 15px;
    }

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

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

    .section-title {
        font-size: 2rem;
    }

    .nav {
        display: none;
    }

    .cta h2 {
        font-size: 1.8rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .btn-large {
        padding: 14px 24px;
        font-size: 1rem;
    }

    .course-card {
        padding: 30px 20px;
    }
}