/* YDS AI Website - Clean & Simple Design */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    min-height: 100vh;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
}

.header {
    background: #7B2CBF;
    color: white;
    padding: 40px 30px;
    text-align: center;
}

.header h1 {
    font-size: 2.2rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.nav {
    background: #f8f9fa;
    padding: 15px 30px;
    border-bottom: 1px solid #e9ecef;
}

.nav ul {
    list-style: none;
    display: flex;
    gap: 25px;
    flex-wrap: wrap;
}

.nav a {
    text-decoration: none;
    color: #7B2CBF;
    font-weight: 500;
    padding: 8px 0;
    border-bottom: 2px solid transparent;
    transition: border-color 0.3s ease;
}

.nav a:hover {
    border-bottom-color: #7B2CBF;
}

.content {
    padding: 40px 30px;
}

.content h1 {
    color: #7B2CBF;
    font-size: 2rem;
    margin-bottom: 30px;
    border-bottom: 3px solid #7B2CBF;
    padding-bottom: 10px;
}

.content h2 {
    color: #333;
    font-size: 1.4rem;
    margin-top: 30px;
    margin-bottom: 15px;
}

.content h3 {
    color: #555;
    font-size: 1.2rem;
    margin-top: 20px;
    margin-bottom: 10px;
}

.content p {
    margin-bottom: 15px;
    text-align: justify;
}

.content ul, .content ol {
    margin-bottom: 20px;
    padding-left: 25px;
}

.content li {
    margin-bottom: 8px;
}

.highlight {
    background: #f8f9ff;
    border: 1px solid #e6e9ff;
    border-left: 4px solid #7B2CBF;
    padding: 20px;
    margin: 20px 0;
    border-radius: 0 5px 5px 0;
}

.highlight h4 {
    color: #7B2CBF;
    margin-bottom: 10px;
    font-weight: 600;
}

.contact-info {
    background: #7B2CBF;
    color: white;
    padding: 25px;
    margin: 30px 0;
    border-radius: 5px;
    text-align: center;
}

.contact-info h3 {
    margin-bottom: 15px;
    color: white;
}

.contact-info a {
    color: white;
    text-decoration: none;
    font-weight: 500;
}

.contact-info a:hover {
    text-decoration: underline;
}

.footer {
    background: #f8f9fa;
    padding: 25px 30px;
    text-align: center;
    border-top: 1px solid #e9ecef;
    color: #666;
}

.footer a {
    color: #7B2CBF;
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

/* Mobile responsive */
@media (max-width: 768px) {
    .container {
        margin: 0;
        box-shadow: none;
    }
    
    .header {
        padding: 30px 20px;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .nav {
        padding: 15px 20px;
    }
    
    .nav ul {
        gap: 15px;
    }
    
    .content {
        padding: 30px 20px;
    }
    
    .content h1 {
        font-size: 1.7rem;
    }
}

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

.content {
    animation: fadeIn 0.6s ease-out;
}

/* Back to top */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: linear-gradient(135deg, #7B2CBF, #9A42C7);
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    box-shadow: 0 4px 20px rgba(123, 44, 191, 0.3);
    transition: all 0.3s ease;
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 25px rgba(123, 44, 191, 0.4);
}