/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --light-gray: #f8f9fa;
    --border-color: #ddd;
    --sidebar-width: 280px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #fff;
}

/* Left Sidebar Navigation */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: linear-gradient(180deg, var(--primary-color) 0%, #34495e 100%);
    color: white;
    padding: 2rem 0;
    overflow-y: auto;
    z-index: 1000;
    box-shadow: 2px 0 10px rgba(0,0,0,0.1);
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.3);
    border-radius: 3px;
}

.profile {
    text-align: center;
    padding: 0 1.5rem 2rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.profile-img {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    object-position: center 15%;
    border: 4px solid rgba(255,255,255,0.4);
    margin: 0 auto 1rem auto;
    display: block;
    background-color: #e8edf2;
    box-shadow: 0 6px 16px rgba(0,0,0,0.3);
}

.profile h2 {
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.profile .title {
    font-size: 0.9rem;
    color: rgba(255,255,255,0.8);
}

.nav-links {
    list-style: none;
    padding: 1.5rem 0;
}

.nav-links li {
    margin: 0;
}

.nav-link {
    display: flex;
    align-items: center;
    padding: 0.9rem 1.5rem;
    color: rgba(255,255,255,0.9);
    text-decoration: none;
    transition: all 0.3s ease;
    border-left: 3px solid transparent;
}

.nav-link i {
    margin-right: 0.8rem;
    font-size: 1.1rem;
    width: 20px;
}

.nav-link:hover {
    background: rgba(255,255,255,0.1);
    color: white;
    border-left-color: var(--secondary-color);
}

.nav-link.active {
    background: rgba(52, 152, 219, 0.2);
    color: white;
    border-left-color: var(--secondary-color);
    font-weight: 500;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
    padding: 1.5rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    margin-top: auto;
}

.social-links a {
    color: rgba(255,255,255,0.8);
    font-size: 1.3rem;
    transition: all 0.3s ease;
}

.social-links a:hover {
    color: var(--secondary-color);
    transform: translateY(-2px);
}

/* Main Content */
.content {
    margin-left: var(--sidebar-width);
    padding: 3rem 4rem;
    max-width: 1200px;
}

.section {
    margin-bottom: 4rem;
    animation: fadeIn 0.6s ease-in;
}

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

.section h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    border-bottom: 3px solid var(--secondary-color);
    padding-bottom: 0.5rem;
}

.section h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.section h3 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

/* About Section */
.about-content p {
    margin-bottom: 1rem;
    text-align: justify;
    font-size: 1.05rem;
}

.contact-info {
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: var(--light-gray);
    border-left: 4px solid var(--secondary-color);
    border-radius: 4px;
}

.contact-info p {
    margin-bottom: 0.5rem;
}

/* News Section */
.news-list {
    margin-bottom: 1.5rem;
}

.news-item {
    display: flex;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
}

.news-item:last-child {
    border-bottom: none;
}

.news-item .date {
    font-weight: 600;
    color: var(--secondary-color);
    min-width: 100px;
    margin-right: 1rem;
}

.news-item .news-content {
    flex: 1;
}

/* Publications Section */
.note {
    font-style: italic;
    color: #666;
    margin-bottom: 1.5rem;
}

.publication {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--light-gray);
    border-radius: 8px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.publication:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.publication h3 {
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.publication .authors {
    margin-bottom: 0.5rem;
    color: #555;
}

.publication .venue {
    margin-bottom: 1rem;
    color: #666;
}

.pub-links {
    display: flex;
    gap: 0.8rem;
    flex-wrap: wrap;
}

.pub-link {
    padding: 0.4rem 1rem;
    background: var(--secondary-color);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-size: 0.9rem;
    transition: background 0.3s ease;
}

.pub-link:hover {
    background: #2980b9;
}

/* Research Group Section */
.group-intro {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 8px;
}

.group-section {
    margin-bottom: 2.5rem;
}

.member-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.member-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    text-align: center;
    transition: all 0.3s ease;
}

.member-card:hover {
    box-shadow: 0 6px 16px rgba(0,0,0,0.1);
    transform: translateY(-4px);
}

.member-img {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1rem;
    border: 3px solid var(--secondary-color);
    background-color: var(--light-gray);
}

.member-card h4 {
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.member-role {
    color: var(--secondary-color);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.member-info {
    color: #666;
    font-size: 0.9rem;
}

.alumni-list {
    list-style: none;
    padding: 0;
}

.alumni-list li {
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--border-color);
}

.alumni-list li:last-child {
    border-bottom: none;
}

/* Talks Section */
.talk {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.talk:last-child {
    border-bottom: none;
}

.talk h3 {
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.talk-info {
    margin-bottom: 1rem;
    color: #666;
}

/* Awards Section */
.awards-list {
    list-style: none;
    padding: 0;
}

.awards-list li {
    padding: 1rem;
    margin-bottom: 1rem;
    background: var(--light-gray);
    border-left: 4px solid var(--secondary-color);
    border-radius: 4px;
}

/* Services Section */
.service-category {
    margin-bottom: 2rem;
}

.service-category h3 {
    color: var(--primary-color);
    margin-bottom: 0.8rem;
}

.service-category p {
    margin-bottom: 0.5rem;
    color: #555;
    line-height: 1.8;
}

/* Buttons */
.load-more {
    padding: 0.6rem 1.5rem;
    background: white;
    color: var(--secondary-color);
    border: 2px solid var(--secondary-color);
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    font-weight: 500;
}

.load-more:hover {
    background: var(--secondary-color);
    color: white;
}

/* Footer */
footer {
    margin-top: 4rem;
    padding: 2rem 0;
    text-align: center;
    color: #666;
    border-top: 1px solid var(--border-color);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .content {
        padding: 2rem 3rem;
    }
}

@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }
    
    .content {
        margin-left: 0;
        padding: 2rem 1.5rem;
    }
    
    .nav-links {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .nav-link {
        flex: 0 0 auto;
    }
    
    .member-grid {
        grid-template-columns: 1fr;
    }
    
    .section h1 {
        font-size: 2rem;
    }
    
    .section h2 {
        font-size: 1.6rem;
    }
}

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

/* Selection Color */
::selection {
    background: var(--secondary-color);
    color: white;
}

::-moz-selection {
    background: var(--secondary-color);
    color: white;
}