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

:root {
    --bg-primary: #0a0a0a;
    --bg-secondary: #111111;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --accent-1: #00d4ff;
    --accent-2: #7c3aed;
    --accent-3: #f59e0b;
    --accent-4: #10b981;
}

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

/* Navigation Bar */
.navbar {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 10, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background: rgba(10, 10, 10, 0.95);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 16px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
}

/* Logo Section */
.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 1.25rem;
    transition: opacity 0.3s ease;
}

.nav-logo:hover {
    opacity: 0.8;
}

.logo-icon {
    width: 32px;
    height: 32px;
    color: var(--accent-1);
    filter: drop-shadow(0 0 8px rgba(0, 212, 255, 0.4));
}

.logo-text {
    background: linear-gradient(135deg, #ffffff 0%, #b0b0b0 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Navigation Links */
.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
    flex: 1;
    justify-content: center;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    position: relative;
    padding: 4px 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-1), var(--accent-2));
    transition: width 0.3s ease;
}

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

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

/* Action Buttons */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.btn-login {
    padding: 10px 20px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    border-radius: 8px;
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.1);
    background: rgba(255, 255, 255, 0.03);
}

.btn-login:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

.btn-signup {
    padding: 10px 24px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    border-radius: 8px;
    background: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 100%);
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.2);
}

.btn-signup:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 212, 255, 0.3);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1001;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all 0.3s ease;
    border-radius: 2px;
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* Mobile Menu */
.mobile-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(10, 10, 10, 0.98);
    backdrop-filter: blur(20px);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    padding: 24px;
    flex-direction: column;
    gap: 20px;
    animation: slideDown 0.3s ease;
}

.mobile-menu.active {
    display: flex;
}

.mobile-menu .nav-link {
    padding: 12px 0;
    font-size: 1.1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.mobile-menu .nav-link:last-child {
    border-bottom: none;
}

.mobile-menu .nav-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 8px;
}

.mobile-menu .btn-login,
.mobile-menu .btn-signup {
    width: 100%;
    text-align: center;
    padding: 12px 20px;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.container {
    min-height: 100vh;
    position: relative;
}

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(124, 58, 237, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(245, 158, 11, 0.05) 0%, transparent 50%);
    z-index: -1;
    animation: backgroundShift 20s ease-in-out infinite;
}

@keyframes backgroundShift {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.8;
    }
}

/* Hero Section */
.hero {
    padding: 120px 20px 80px;
    max-width: 1400px;
    margin: 0 auto;
    position: relative;
}

.hero-content {
    text-align: center;
    margin-bottom: 80px;
    animation: fadeInUp 1s ease-out;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #ffffff 0%, #b0b0b0 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.hero-description {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.8;
}

/* Social Proof Section */
.social-proof {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 80px;
    animation: fadeInUp 1s ease-out 0.5s backwards;
}

.avatar-stack {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 20px;
    position: relative;
    height: 60px;
}

.avatar {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    border: 3px solid var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-primary);
    position: relative;
    transition: transform 0.3s ease, z-index 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.avatar:not(:first-child) {
    margin-left: -20px;
}

.avatar:hover {
    transform: translateY(-4px) scale(1.1);
    z-index: 10;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

.avatar span {
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}

.social-proof-text {
    font-size: clamp(0.95rem, 1.5vw, 1.1rem);
    color: var(--text-secondary);
    text-align: center;
    font-weight: 500;
}

.student-count {
    color: var(--text-primary);
    font-weight: 700;
    font-size: 1.1em;
    background: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Course Boxes Grid */
.course-boxes {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    max-width: 1200px;
    margin: 0 auto;
}

.course-box {
    position: relative;
    padding: 32px;
    border-radius: 20px;
    min-height: 280px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.05);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.03) 0%, rgba(255, 255, 255, 0.01) 100%);
    backdrop-filter: blur(10px);
    animation: fadeInUp 1s ease-out backwards;
}

.course-box:nth-child(1) {
    animation-delay: 0.1s;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.15) 0%, rgba(0, 212, 255, 0.05) 100%);
}

.course-box:nth-child(2) {
    animation-delay: 0.2s;
    background: linear-gradient(135deg, rgba(124, 58, 237, 0.15) 0%, rgba(124, 58, 237, 0.05) 100%);
}

.course-box:nth-child(3) {
    animation-delay: 0.3s;
    background: linear-gradient(135deg, rgba(245, 158, 11, 0.15) 0%, rgba(245, 158, 11, 0.05) 100%);
}

.course-box:nth-child(4) {
    animation-delay: 0.4s;
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.15) 0%, rgba(16, 185, 129, 0.05) 100%);
}

.course-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, transparent 0%, rgba(255, 255, 255, 0.05) 100%);
    opacity: 0;
    transition: opacity 0.4s ease;
    z-index: 0;
}

.course-box:hover {
    transform: translateY(-8px);
    border-color: rgba(255, 255, 255, 0.1);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.course-box:hover::before {
    opacity: 1;
}

.course-box:nth-child(1):hover {
    box-shadow: 0 20px 40px rgba(0, 212, 255, 0.2);
}

.course-box:nth-child(2):hover {
    box-shadow: 0 20px 40px rgba(124, 58, 237, 0.2);
}

.course-box:nth-child(3):hover {
    box-shadow: 0 20px 40px rgba(245, 158, 11, 0.2);
}

.course-box:nth-child(4):hover {
    box-shadow: 0 20px 40px rgba(16, 185, 129, 0.2);
}

/* Box Icon */
.box-icon {
    width: 56px;
    height: 56px;
    margin-bottom: 24px;
    position: relative;
    z-index: 1;
    transition: transform 0.4s ease;
}

.box-icon svg {
    width: 100%;
    height: 100%;
    color: var(--text-primary);
    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.3));
}

.course-box:nth-child(1) .box-icon svg {
    color: var(--accent-1);
}

.course-box:nth-child(2) .box-icon svg {
    color: var(--accent-2);
}

.course-box:nth-child(3) .box-icon svg {
    color: var(--accent-3);
}

.course-box:nth-child(4) .box-icon svg {
    color: var(--accent-4);
}

.course-box:hover .box-icon {
    transform: scale(1.1) rotate(5deg);
}

/* Box Title */
.box-title {
    font-size: clamp(1.5rem, 2.5vw, 1.75rem);
    font-weight: 700;
    margin-bottom: auto;
    position: relative;
    z-index: 1;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

/* Box Link */
.box-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    margin-top: auto;
    position: relative;
    z-index: 1;
    transition: all 0.3s ease;
    padding: 8px 0;
}

.box-link svg {
    transition: transform 0.3s ease;
}

.course-box:hover .box-link {
    gap: 12px;
}

.course-box:hover .box-link svg {
    transform: translateX(4px);
}

.course-box:nth-child(1) .box-link {
    color: var(--accent-1);
}

.course-box:nth-child(2) .box-link {
    color: var(--accent-2);
}

.course-box:nth-child(3) .box-link {
    color: var(--accent-3);
}

.course-box:nth-child(4) .box-link {
    color: var(--accent-4);
}

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

/* Responsive Design */
@media (max-width: 968px) {
    .nav-links {
        display: none;
    }

    .nav-actions {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .nav-container {
        padding: 16px 20px;
    }
}

@media (max-width: 768px) {
    .nav-container {
        padding: 12px 16px;
    }

    .logo-text {
        font-size: 1.1rem;
    }

    .logo-icon {
        width: 28px;
        height: 28px;
    }

    .hero {
        padding: 80px 20px 60px;
    }

    .hero-content {
        margin-bottom: 60px;
    }

    .social-proof {
        margin-bottom: 60px;
    }

    .avatar {
        width: 48px;
        height: 48px;
        font-size: 1.1rem;
    }

    .avatar:not(:first-child) {
        margin-left: -16px;
    }

    .course-boxes {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .course-box {
        min-height: 240px;
        padding: 24px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 60px 16px 40px;
    }

    .social-proof {
        margin-bottom: 40px;
    }

    .avatar-stack {
        height: 52px;
    }

    .avatar {
        width: 44px;
        height: 44px;
        font-size: 1rem;
        border-width: 2px;
    }

    .avatar:not(:first-child) {
        margin-left: -14px;
    }

    .course-box {
        min-height: 220px;
        padding: 20px;
    }

    .box-icon {
        width: 48px;
        height: 48px;
        margin-bottom: 20px;
    }
}

/* Smooth Scroll */
html {
    scroll-behavior: smooth;
}