:root {
    --primary-color: #4361ee;
    --secondary-color: #3a0ca3;
    --accent-color: #7209b7;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --success-color: #4cc9f0;
    --warning-color: #f72585;
    --border-radius: 12px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
}

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

.header-main {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 2rem 0;
    text-align: center;
    box-shadow: var(--box-shadow);
}

.site-title {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

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

.main-nav {
    background-color: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    margin-top: 1.5rem;
}

.nav-menu {
    display: flex;
    justify-content: center;
    list-style: none;
    padding: 1rem 0;
    flex-wrap: wrap;
}

.nav-menu li {
    margin: 0 1rem;
}

.nav-menu a {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    transition: var(--transition);
    font-weight: 500;
}

.nav-menu a:hover {
    background-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.section {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    margin: 2rem 0;
    box-shadow: var(--box-shadow);
}

.section h2 {
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--accent-color);
    font-size: 1.8rem;
}

.presentation-card {
    display: flex;
    align-items: center;
    gap: 2rem;
    background: linear-gradient(135deg, #f0f4ff, #e6f0ff);
    padding: 2rem;
    border-radius: var(--border-radius);
    margin-top: 1rem;
}

.tech-icons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.tech-icon {
    background-color: var(--primary-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.skills-grid, .tp-grid, .demo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.skill-card, .tp-card, .demo-card {
    background: var(--light-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    border-left: 4px solid var(--accent-color);
    transition: var(--transition);
}

.skill-card:hover, .tp-card:hover, .demo-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.skill-card h3, .tp-card h3, .demo-card h4 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.skill-card ul, .tp-card ul {
    list-style-position: inside;
}

.tp-card a {
    color: var(--primary-color);
    text-decoration: none;
    display: block;
    padding: 0.3rem 0;
    transition: var(--transition);
}

.tp-card a:hover {
    color: var(--accent-color);
    padding-left: 0.5rem;
}

.demo-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.7rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    margin: 0.5rem 0;
}

.demo-btn:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

.demo-result {
    margin-top: 1rem;
    padding: 1rem;
    background-color: #f8f9fa;
    border-radius: var(--border-radius);
    min-height: 100px;
    border: 1px solid #dee2e6;
}

.chart-container {
    height: 200px;
    margin: 1rem 0;
}

.student-form {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin: 1rem 0;
}

.student-form input {
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
}

.footer {
    background-color: var(--dark-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

.footer-links {
    margin-top: 1rem;
}

.footer-links a {
    color: var(--success-color);
    text-decoration: none;
    margin: 0 0.5rem;
}

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

@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        align-items: center;
    }
    
    .nav-menu li {
        margin: 0.3rem 0;
    }
    
    .presentation-card {
        flex-direction: column;
        text-align: center;
    }
    
    .skills-grid, .tp-grid, .demo-grid {
        grid-template-columns: 1fr;
    }
    
    .site-title {
        font-size: 2rem;
    }
}

.tp-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

.tp-nav {
    background-color: var(--light-color);
    padding: 1rem;
    border-radius: var(--border-radius);
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.tp-nav a {
    color: var(--primary-color);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    background-color: white;
    transition: var(--transition);
}

.tp-nav a:hover {
    background-color: var(--primary-color);
    color: white;
}

.tp-content {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--box-shadow);
}

.code-block {
    background-color: #f8f9fa;
    border: 1px solid #dee2e6;
    border-radius: var(--border-radius);
    padding: 1rem;
    margin: 1rem 0;
    font-family: 'Courier New', monospace;
    overflow-x: auto;
}

.result-display {
    background-color: #e8f4fd;
    border: 2px solid var(--primary-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin: 1.5rem 0;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--dark-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.1);
}

.form-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transition);
}

.form-btn:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
}

.data-table th {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem;
    text-align: left;
}

.data-table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid #dee2e6;
}

.data-table tr:hover {
    background-color: #f8f9fa;
}

.data-table tr:last-child td {
    border-bottom: none;
}

.alert {
    padding: 1rem;
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert-info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

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

.section {
    animation: fadeIn 0.5s ease-out;
}