/* Reset and Base Styles */
:root {
    --accent-color: #2E8B57;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: #333;
    overflow-x: hidden;
}

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

/* Navigation Styles */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo h2 {
    color: #2E8B57;
    font-weight: 700;
    font-size: 1.8rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #2E8B57;
}

.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -5px;
    left: 0;
    background-color: #2E8B57;
    transition: width 0.3s ease;
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: #333;
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #E8F5E8 0%, #F0F8F0 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 100px 0 50px;
    position: relative;
    overflow: hidden;
}

.hero-content {
    flex: 1;
    z-index: 2;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.highlight {
    color: #2E8B57;
    position: relative;
}

.hero-subtitle {
    font-size: 1.3rem;
    color: #666;
    margin-bottom: 2.5rem;
    max-width: 600px;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    padding: 15px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
    text-align: center;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #2E8B57;
    color: white;
    box-shadow: 0 4px 15px rgba(46, 139, 87, 0.3);
}

.btn-primary:hover {
    background: #228B22;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(46, 139, 87, 0.4);
}

.btn-secondary {
    background: transparent;
    color: #2E8B57;
    border: 2px solid #2E8B57;
}

.btn-secondary:hover {
    background: #2E8B57;
    color: white;
    transform: translateY(-2px);
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-visual {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, #2E8B57, #228B22);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 20px 40px rgba(46, 139, 87, 0.3);
    animation: float 6s ease-in-out infinite;
}

.hero-visual i {
    font-size: 8rem;
    color: white;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* Section Styles */
section {
    padding: 80px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.8rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1rem;
}

.section-header p {
    font-size: 1.2rem;
    color: #666;
    max-width: 600px;
    margin: 0 auto;
}

/* About Section */
.about {
    background: #f8f9fa;
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.about-card {
    background: white;
    padding: 2.5rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.about-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.card-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #2E8B57, #228B22);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
}

.card-icon i {
    font-size: 2.5rem;
    color: white;
}

.about-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 1rem;
}

.about-card p {
    color: #666;
    line-height: 1.6;
}

/* Mission Section */
.mission {
    background: white;
}

.mission-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
    align-items: center;
}

.mission-text h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1.5rem;
}

.mission-statement {
    font-size: 1.2rem;
    color: #666;
    margin-bottom: 2rem;
    line-height: 1.7;
    font-style: italic;
    border-left: 4px solid #2E8B57;
    padding-left: 1.5rem;
}

.mission-features {
    display: grid;
    gap: 1rem;
}

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

.feature i {
    color: #2E8B57;
    font-size: 1.2rem;
}

.feature span {
    color: #666;
    font-weight: 500;
}

.mission-visual {
    display: flex;
    justify-content: center;
}

.mission-stats {
    display: grid;
    gap: 1.5rem;
}

.stat {
    text-align: center;
    padding: 1.5rem;
    background: linear-gradient(135deg, #E8F5E8, #F0F8F0);
    border-radius: 15px;
    border: 2px solid #2E8B57;
}

.stat h3 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #2E8B57;
    margin-bottom: 0.5rem;
}

.stat p {
    color: #666;
    font-weight: 500;
}

/* Products Section */
.products {
    background: #f8f9fa;
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.product-card {
    background: white;
    padding: 2.5rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
}

.product-card.featured {
    border: 3px solid #2E8B57;
    transform: scale(1.02);
}

.product-badge {
    position: absolute;
    top: -10px;
    left: 50%;
    transform: translateX(-50%);
    background: #2E8B57;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.product-card.featured:hover {
    transform: scale(1.02) translateY(-5px);
}

.product-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #2E8B57, #228B22);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
}

.product-icon i {
    font-size: 2.5rem;
    color: white;
}

.product-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 1.5rem;
}

.product-features {
    list-style: none;
    margin-bottom: 1.5rem;
}

.product-features li {
    padding: 0.5rem 0;
    color: #666;
    border-bottom: 1px solid #eee;
}

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

.product-features li::before {
    content: "✓";
    color: #2E8B57;
    font-weight: bold;
    margin-right: 0.5rem;
}

.product-description {
    color: #666;
    line-height: 1.6;
}

/* Benefits Section */
.benefits {
    background: white;
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.benefit-item {
    padding: 2rem;
    border-radius: 15px;
    background: linear-gradient(135deg, #E8F5E8, #F0F8F0);
    text-align: center;
    border: 1px solid rgba(46, 139, 87, 0.2);
    transition: transform 0.3s ease;
}

.benefit-item:hover {
    transform: translateY(-5px);
}

.benefit-icon {
    width: 70px;
    height: 70px;
    background: #2E8B57;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
}

.benefit-icon i {
    font-size: 2rem;
    color: white;
}

.benefit-item h3 {
    font-size: 1.3rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 1rem;
}

.benefit-item p {
    color: #666;
    line-height: 1.6;
}

/* Business Section */
.business {
    background: #f8f9fa;
}

.business-content {
    margin-top: 3rem;
}

.business-problem,
.business-solution {
    margin-bottom: 4rem;
}

.business-problem h3,
.business-solution h3 {
    font-size: 2rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 2rem;
    text-align: center;
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.problem-item {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    border-left: 4px solid #dc3545;
}

.problem-item i {
    font-size: 2.5rem;
    color: #dc3545;
    margin-bottom: 1rem;
}

.problem-item h4 {
    font-size: 1.3rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 1rem;
}

.problem-item p {
    color: #666;
    line-height: 1.6;
}

.solution-details {
    display: grid;
    gap: 2rem;
    margin-top: 2rem;
}

.solution-item {
    display: flex;
    gap: 2rem;
    align-items: center;
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.solution-number {
    width: 60px;
    height: 60px;
    background: #2E8B57;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    flex-shrink: 0;
}

.solution-content h4 {
    font-size: 1.3rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.5rem;
}

.solution-content p {
    color: #666;
    line-height: 1.6;
}

.partnership-details {
    margin-top: 4rem;
}

.partnership-details h3 {
    font-size: 2rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 2rem;
    text-align: center;
}

.investment-card {
    background: white;
    padding: 3rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    border: 3px solid #2E8B57;
}

.investment-amount {
    font-size: 3rem;
    font-weight: 700;
    color: #2E8B57;
    margin-bottom: 1rem;
}

.investment-description {
    font-size: 1.2rem;
    color: #666;
    margin-bottom: 2rem;
}

.target-cities h4 {
    font-size: 1.3rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 1rem;
}

.target-cities ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.5rem;
}

.target-cities li {
    color: #666;
    padding: 0.5rem;
    background: #f8f9fa;
    border-radius: 5px;
}

/* CEO Section */
.ceo {
    background: white;
}

.ceo-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 4rem;
    align-items: center;
}

.ceo-image {
    text-align: center;
}

.ceo-photo {
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, #2E8B57, #228B22);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    box-shadow: 0 15px 35px rgba(46, 139, 87, 0.3);
}

.ceo-photo i {
    font-size: 8rem;
    color: white;
}

.ceo-info h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 0.5rem;
}

.ceo-info h3 {
    font-size: 2rem;
    font-weight: 600;
    color: #2E8B57;
    margin-bottom: 0.5rem;
}

.ceo-title {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 2rem;
    font-style: italic;
}

.ceo-story p {
    color: #666;
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.ceo-story blockquote {
    background: #f8f9fa;
    border-left: 4px solid #2E8B57;
    padding: 1.5rem;
    margin: 2rem 0;
    font-style: italic;
    font-size: 1.1rem;
    color: #555;
}

.ceo-achievements {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}

.achievement {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: #f8f9fa;
    border-radius: 10px;
    border: 1px solid rgba(46, 139, 87, 0.2);
}

.achievement i {
    color: #2E8B57;
    font-size: 1.5rem;
}

.achievement span {
    color: #666;
    font-weight: 500;
}

/* Contact Section */
.contact {
    background: #f8f9fa;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
}

.contact-info {
    display: grid;
    gap: 2rem;
}

.contact-item {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.contact-icon {
    width: 60px;
    height: 60px;
    background: #2E8B57;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.contact-icon i {
    font-size: 1.5rem;
    color: white;
}

.contact-details h3 {
    font-size: 1.3rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.5rem;
}

.contact-details a,
.contact-details p {
    color: #292929;
    text-decoration: none;
    line-height: 1.6;
}

.contact-details a:hover {
    color: #2E8B57;
}

.contact-form {
    background: white;
    padding: 2.5rem;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid #e9ecef;
    border-radius: 10px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
    font-family: 'Inter', sans-serif;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #2E8B57;
}

.form-group textarea {
    resize: vertical;
}

/* Footer */
.footer {
    background: #333;
    color: white;
    padding: 3rem 0 1rem;
}

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

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: #2E8B57;
}

.footer-section p,
.footer-section li {
    color: #ccc;
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

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

.footer-section a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: #2E8B57;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.social-links a {
    width: 40px;
    height: 40px;
    background: #2E8B57;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.3s ease;
}

.social-links a:hover {
    background: #228B22;
}

.footer-bottom {
    border-top: 1px solid #555;
    padding-top: 1rem;
    text-align: center;
    color: #ccc;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero {
        flex-direction: column;
        text-align: center;
        padding: 120px 0 50px;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-visual {
        width: 200px;
        height: 200px;
        margin-top: 2rem;
    }

    .hero-visual i {
        font-size: 5rem;
    }

    .mission-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .ceo-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .solution-item {
        flex-direction: column;
        text-align: center;
    }

    .section-header h2 {
        font-size: 2.2rem;
    }

    .about-grid,
    .products-grid,
    .benefits-grid {
        grid-template-columns: 1fr;
    }

    .hero-buttons {
        justify-content: center;
    }

    .btn {
        padding: 12px 25px;
        font-size: 0.95rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

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

    .hero-subtitle {
        font-size: 1rem;
    }

    .section-header h2 {
        font-size: 1.8rem;
    }

    .about-card,
    .product-card {
        padding: 2rem 1.5rem;
    }

    .ceo-photo {
        width: 200px;
        height: 200px;
    }

    .ceo-photo i {
        font-size: 6rem;
    }

    .investment-amount {
        font-size: 2.5rem;
    }

    .target-cities ul {
        grid-template-columns: 1fr;
    }
}

/* Smooth scrolling for all browsers */
@media (prefers-reduced-motion: no-preference) {
    * {
        scroll-behavior: smooth;
    }
}

/* Focus styles for accessibility */
button:focus,
input:focus,
textarea:focus,
select:focus,
a:focus {
    outline: 2px solid #2E8B57;
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .navbar,
    .footer {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    h1, h2, h3 {
        page-break-after: avoid;
    }
}

/* Email Protection Styles */
.reveal-email-btn {
    background: linear-gradient(135deg, var(--accent-color), #2563eb);
    color: #666666 !important;
    border: 2px solid black;
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    text-shadow: 1px 1px 1px black;
}

.reveal-email-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    background: linear-gradient(135deg, #2563eb, var(--accent-color));
}

.reveal-email-btn i {
    font-size: 16px;
}

/* Footer email button specific styles */
.footer-email-btn {
    padding: 8px 12px;
    font-size: 12px;
    display: inline-flex;
    margin-left: 8px;
    /* Better mobile touch targets */
    min-height: 36px;
    min-width: 120px;
}

.footer-email-btn i {
    font-size: 12px;
}

/* Touch device improvements */
@media (hover: none) and (pointer: coarse) {
    .reveal-email-btn {
        /* Larger touch targets for mobile */
        min-height: 48px;
        padding: 15px 20px;
        font-size: 15px;
    }
    
    .footer-email-btn {
        min-height: 40px;
        padding: 10px 15px;
        font-size: 13px;
    }
}

/* Protected email styles */
.protected-email {
    color: var(--accent-color);
    font-weight: 500;
}

/* Challenge Modal Styles */
.challenge-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    /* Ensure modal is always on top and clickable */
    pointer-events: auto;
    /* Prevent scrolling behind modal */
    overflow: hidden;
}

.challenge-modal.show {
    display: flex !important;
    animation: fadeIn 0.3s ease;
    /* Ensure visibility on all devices */
    visibility: visible !important;
    opacity: 1 !important;
}

.challenge-content {
    background: white;
    border-radius: 16px;
    padding: 30px;
    max-width: 450px;
    width: 90%;
    max-height: 85vh;
    overflow-y: auto;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.4);
    animation: slideUp 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    margin: 20px;
    position: relative;
    /* Ensure it's above everything */
    z-index: 10000;
    /* Better mobile handling */
    -webkit-overflow-scrolling: touch;
}

.challenge-header {
    text-align: center;
    margin-bottom: 25px;
}

.challenge-header h3 {
    color: var(--primary-color);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.challenge-header h3 i {
    color: var(--accent-color);
}

.challenge-header p {
    color: #666;
    margin: 0;
}

.challenge-body {
    margin-bottom: 25px;
}

.math-problem {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 12px;
    text-align: center;
    margin-bottom: 20px;
    border: 2px solid #e9ecef;
}

.math-problem span {
    font-size: 24px;
    font-weight: 600;
    color: var(--primary-color);
}

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

.answer-input input {
    flex: 1;
    padding: 12px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 16px;
    text-align: center;
    transition: border-color 0.3s ease;
}

.answer-input input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.answer-input button {
    padding: 12px 20px;
    font-size: 14px;
    white-space: nowrap;
}

.challenge-error {
    color: #dc2626;
    text-align: center;
    margin-top: 10px;
    padding: 8px;
    background: #fef2f2;
    border-radius: 6px;
    border: 1px solid #fecaca;
}

.challenge-footer {
    text-align: center;
}

.challenge-footer button {
    padding: 10px 20px;
    font-size: 14px;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { 
        opacity: 0;
        transform: translateY(30px) scale(0.95);
    }
    to { 
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Success Animation */
.challenge-success {
    animation: successPulse 0.6s ease;
}

@keyframes successPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .challenge-modal {
        padding: 15px;
        /* Ensure full viewport coverage on mobile */
        width: 100vw;
        height: 100vh;
        position: fixed;
        top: 0;
        left: 0;
    }
    
    .challenge-content {
        padding: 25px;
        margin: 15px;
        max-width: calc(100vw - 30px);
        width: calc(100% - 30px);
        border-radius: 12px;
        max-height: 90vh;
        /* Better mobile positioning */
        transform: none;
        /* Ensure touch scrolling works */
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    .challenge-header h3 {
        font-size: 1.3rem;
        margin-bottom: 15px;
    }
    
    .challenge-header p {
        font-size: 15px;
    }
    
    .math-problem {
        padding: 20px;
        margin-bottom: 20px;
        border-radius: 10px;
    }
    
    .math-problem span {
        font-size: 22px;
        font-weight: 700;
    }
    
    .answer-input {
        flex-direction: column;
        gap: 15px;
    }
    
    .answer-input input {
        padding: 18px;
        font-size: 18px;
        border-radius: 10px;
        /* Better mobile input handling */
        -webkit-appearance: none;
        appearance: none;
    }
    
    .answer-input button {
        width: 100%;
        padding: 18px;
        font-size: 16px;
        border-radius: 10px;
        /* Better touch target */
        min-height: 50px;
    }
    
    .challenge-footer button {
        width: 100%;
        padding: 15px;
        font-size: 16px;
        border-radius: 8px;
        min-height: 48px;
    }
}

/* Extra small screens */
@media (max-width: 480px) {
    .challenge-content {
        padding: 15px;
        margin: 5px;
        width: calc(100% - 10px);
        max-height: 98vh;
    }
    
    .challenge-header {
        margin-bottom: 20px;
    }
    
    .challenge-header h3 {
        font-size: 1.1rem;
    }
    
    .challenge-header p {
        font-size: 14px;
    }
    
    .math-problem {
        padding: 12px;
    }
    
    .math-problem span {
        font-size: 18px;
    }
}

/* Screen reader only utility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}