* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-dark: #121212;
    --bg-darker: #0a0a0a;
    --bg-card: #1a1a1a;
    --primary-purple: #a78bfa;
    --purple-bright: #d8b4fe;
    --purple-accent: #9333ea;
    --text-primary: #ffffff;
    --text-secondary: #a3a3a3;
    --border-color: #2a2a2a;
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

html {
    scroll-behavior: smooth;
}

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

/* ========== TOP NAVIGATION ========== */
nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: rgba(18, 18, 18, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
}

nav .container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 3rem;
}

.logo {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--primary-purple);
    text-decoration: none;
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: opacity 0.3s ease;
}

.logo:hover {
    opacity: 0.8;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    list-style: none;
    align-items: center;
    flex: 1;
}

.nav-links a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-purple);
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

.profile-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-purple), var(--purple-bright));
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--bg-dark);
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.3s ease;
    font-size: 0.85rem;
}

.profile-icon:hover {
    transform: scale(1.1);
}

/* ========== WELCOME SECTION ========== */
.welcome-section {
    background-color: var(--bg-dark);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border-color);
}

.welcome-section .container {
    max-width: 1400px;
    margin: 0 auto;
    font-size: 0.95rem;
    color: var(--text-secondary);
}

/* ========== CONTAINER ========== */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ========== HERO SECTION ========== */
.hero {
    padding: 6rem 2rem;
    background: linear-gradient(135deg, var(--bg-darker) 0%, var(--bg-dark) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(167, 139, 250, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
    max-width: 900px;
}

.hero h1 {
    font-size: clamp(2.5rem, 8vw, 4rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.hero p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin-bottom: 2rem;
}

.hero .highlight {
    color: var(--primary-purple);
}

/* ========== SECTION HEADING ========== */
.section-heading {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 800;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.section-subtext {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 2rem;
    max-width: 600px;
}

/* ========== BUTTON ========== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.75rem;
    background-color: var(--primary-purple);
    color: var(--bg-dark);
    border: none;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
}

.btn:hover {
    background-color: var(--purple-bright);
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(167, 139, 250, 0.3);
}

.btn:active {
    transform: translateY(0);
}

/* ========== LEARNING TOOLS CAROUSEL ========== */
.learning-tools {
    padding: 5rem 2rem;
    background-color: var(--bg-dark);
}

.learning-tools .section-heading {
    margin-bottom: 3rem;
}

.carousel-container {
    position: relative;
    margin-bottom: 2rem;
}

.carousel {
    display: flex;
    gap: 1.5rem;
    overflow-x: auto;
    padding-bottom: 1rem;
    scroll-behavior: smooth;
}

.carousel::-webkit-scrollbar {
    height: 6px;
}

.carousel::-webkit-scrollbar-track {
    background: var(--bg-card);
    border-radius: 10px;
}

.carousel::-webkit-scrollbar-thumb {
    background: var(--primary-purple);
    border-radius: 10px;
    opacity: 0.6;
}

.carousel::-webkit-scrollbar-thumb:hover {
    opacity: 1;
}

.tool-card {
    min-width: 300px;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.tool-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-purple), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.tool-card:hover {
    border-color: var(--primary-purple);
    background-color: rgba(167, 139, 250, 0.05);
    transform: translateY(-8px);
    box-shadow: var(--shadow);
}

.tool-card:hover::before {
    opacity: 1;
}

.tool-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.tool-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ========== ENROLL GRID ========== */
.enroll-section {
    padding: 5rem 2rem;
    background-color: var(--bg-darker);
}

.enroll-header {
    margin-bottom: 3rem;
}

.enroll-header h2 {
    margin-bottom: 0.5rem;
}

.enroll-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.enroll-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2.5rem 2rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.enroll-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-purple), var(--purple-bright));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

.enroll-card:hover::before {
    transform: scaleX(1);
}

.enroll-card:hover {
    border-color: var(--primary-purple);
    background-color: rgba(167, 139, 250, 0.05);
    transform: translateY(-8px);
}

.card-number {
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary-purple);
    line-height: 1;
    margin-bottom: 1rem;
}

.enroll-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.card-meta {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ========== AUTHOR SECTION ========== */
.author-section {
    padding: 5rem 2rem;
    background-color: var(--bg-dark);
}

.author-section .container {
    max-width: 900px;
}

.author-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 3rem;
    margin-top: 3rem;
}

.author-item {
    padding: 2rem;
    border-left: 3px solid var(--primary-purple);
    background-color: var(--bg-card);
    border-radius: 8px;
    transition: all 0.3s ease;
}

.author-item:hover {
    background-color: rgba(167, 139, 250, 0.08);
    transform: translateX(8px);
}

.author-item h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

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

/* ========== FOOTER ========== */
footer {
    background-color: var(--bg-darker);
    border-top: 1px solid var(--border-color);
    padding: 3rem 2rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
    nav .container {
        flex-direction: column;
        gap: 1.5rem;
    }

    .nav-links {
        gap: 1.5rem;
        width: 100%;
        flex-wrap: wrap;
        justify-content: center;
    }

    .hero {
        padding: 3rem 1rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .tool-card {
        min-width: 250px;
    }

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

    .author-list {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}

@media (max-width: 480px) {
    nav {
        padding: 0.75rem 1rem;
    }

    .logo {
        font-size: 1.25rem;
    }

    .nav-links {
        gap: 1rem;
        font-size: 0.85rem;
    }

    .hero {
        padding: 2rem 1rem;
    }

    .hero h1 {
        font-size: 1.5rem;
    }

    .hero p {
        font-size: 0.95rem;
    }

    .section-heading {
        font-size: 1.5rem;
    }

    .tool-card {
        min-width: 100%;
        padding: 1.5rem;
    }

    .carousel {
        gap: 1rem;
    }

    .card-number {
        font-size: 2rem;
    }

    .btn {
        padding: 0.6rem 1.25rem;
        font-size: 0.85rem;
    }
}

/* ========== ANIMATIONS ========== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeInUp 0.6s ease-out forwards;
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }