body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #121212;
    color: #ffffff;
}

.navbar { 
    background-color: #1f1f1f;
    overflow: visible;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 15px;
    position: relative;
    z-index: 1000;
}

.menu-toggle {
    display: none;
    font-size: 20px;
    cursor: pointer;
    color: white;
    position: absolute;
    left: 15px;
}

.nav-links {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.nav-links a {
    color: white;
    text-decoration: none;
    padding: 10px 15px;
}

.nav-links a:hover {
    background-color: #333;
}

.language-switch {
    position: absolute;
    right: 15px;
}

.language-switch .lang-btn {
    background-color: #007bff;
    color: white;
    border: none;
    padding: 5px 10px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
}

.language-switch .lang-btn:hover {
    background-color: #0056b3;
}

.container {
    text-align: center;
    padding: 50px;
}

.fade-in {
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.feature-item {
    transition: transform 0.3s ease, background 0.3s ease;
    padding: 10px;
    border-radius: 8px;
}

.feature-item:hover {
    transform: scale(1.05);
    background: rgba(255,255,255,0.1);
}

.testimonial-card {
    transition: transform 0.3s ease;
    background: #1f1f1f;
    padding: 20px;
    border-radius: 10px;
    text-align: left;
}

.testimonial-card:hover {
    transform: translateY(-5px);
}

.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: #007bff;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-decoration: none;
    opacity: 0;
    transition: opacity 0.3s;
    cursor: pointer;
}

.back-to-top.visible {
    opacity: 1;
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.7);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 5px solid #f3f3f3;
    border-top: 5px solid #007bff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }
    
    .nav-links {
        display: none;
        flex-direction: column;
        background-color: #1f1f1f;
        width: 100%;
        text-align: center;
        position: absolute;
        top: 100%;
        left: 0;
        z-index: 1000;
        padding: 10px 0;
        box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    }
    
    .nav-links.active {
        display: flex !important;
    }
    
    .nav-links a {
        padding: 15px;
        display: block;
        width: 100%;
        box-sizing: border-box;
    }
    
    .menu-toggle {
        display: block;
        position: absolute;
        left: 15px;
        z-index: 1001;
    }
    
    .language-switch {
        z-index: 1001;
    }
}

/* Stats container */
.stats-container {
    display: flex;
    justify-content: space-around;
    margin: 30px 0;
    flex-wrap: wrap;
    gap: 20px;
}

.stat-item {
    text-align: center;
    padding: 20px;
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
    min-width: 200px;
}

.stat-item div:first-child {
    font-size: 2em;
    font-weight: bold;
    color: #007bff;
}

/* Feature list */
.feature-list {
    margin: 30px 0;
}

.feature-item {
    margin: 10px 0;
}

.show-more {
    color: #007bff;
    cursor: pointer;
}

.more-features-container {
    display: none;
    text-align: left;
    margin-top: 20px;
    padding: 20px;
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
}

/* Pricing table */
.pricing-table {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin: 30px 0;
    flex-wrap: wrap;
}

.price-card {
    background: #1f1f1f;
    padding: 30px;
    border-radius: 15px;
    min-width: 250px;
    text-align: left;
}

.price-card.premium {
    border: 2px solid #007bff;
}

.price-card h3 {
    color: #007bff;
    margin-bottom: 20px;
}

.price-card .price {
    font-size: 1.5em;
    margin-bottom: 20px;
}

.price-card ul {
    list-style: none;
    padding: 0;
}

.price-card li {
    margin: 10px 0;
}

/* Guarantees */
.guarantees {
    margin-top: 40px;
    text-align: left;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.guarantees h3 {
    color: #007bff;
    margin-bottom: 20px;
}

.guarantees ul {
    list-style: none;
    padding: 0;
}

.guarantees li {
    margin: 15px 0;
}

/* Certifications */
.certifications {
    margin: 30px 0;
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

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

.cert-item div {
    margin-top: 10px;
}

/* Achievements */
.achievements {
    margin: 30px 0;
    padding: 20px;
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
}

.achievements h3 {
    color: #007bff;
    margin-bottom: 20px;
}

.achievements ul {
    list-style: none;
    padding: 0;
    text-align: left;
}

.achievements li {
    margin: 10px 0;
}

/* Community links */
.community-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    margin-top: 20px;
}

.community-link {
    text-decoration: none;
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.community-link.zalo {
    background: #0068ff;
}

.community-link.facebook {
    background: #1877f2;
}

.community-link.telegram {
    background: #0088cc;
}

.community-link.forum {
    background: #ff4500;
}

/* Testimonials */
.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.rating {
    font-size: 24px;
    margin-bottom: 10px;
}

.testimonial-text {
    font-style: italic;
}

.testimonial-author {
    color: #888;
    margin-top: 10px;
}

/* Download button */
.download-btn {
    display: inline-block;
    padding: 10px 20px;
    background-color: #007bff;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
}