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

:root {
    --primary: #1e40af;
    --secondary: #3b82f6;
    --accent: #60a5fa;
    --dark: #1e293b;
    --light: #f8fafc;
    --green: #10b981;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    overflow-x: hidden;
}

/* Navigation */
nav {
    position: fixed;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0,0,0,0.1);
    z-index: 1000;
    transition: all 0.3s ease;
}

nav.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 30px rgba(0,0,0,0.15);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
}

.logo span {
    color: var(--secondary);
}

.nav-links {
    display: flex;
    gap: 0.5rem;
    list-style: none;
    align-items: center;
}

.nav-links > li {
    position: relative;
}

.nav-links a {
    text-decoration: none;
    color: var(--dark);
    font-weight: 500;
    padding: 0.7rem 1.2rem;
    display: block;
    transition: all 0.3s ease;
    border-radius: 8px;
}

.nav-links > li > a:hover {
    background: rgba(59, 130, 246, 0.1);
    color: var(--secondary);
}

/* Dropdown Menu */
.dropdown {
    position: relative;
}

.dropdown-toggle::after {
    content: '▼';
    font-size: 0.7rem;
    margin-left: 0.4rem;
    transition: transform 0.3s ease;
}

.dropdown:hover .dropdown-toggle::after {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: white;
    min-width: 220px;
    border-radius: 10px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.15);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    padding: 0.5rem 0;
    margin-top: 0.5rem;
}

.dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu li {
	list-style: none;
}

.dropdown-menu a {
    padding: 0.8rem 1.5rem;
    color: var(--dark);
	border-radius: 0;
	display: flex;
	align-items: center;
	gap: 0.7rem;
}

.dropdown-menu a:hover {
    background: rgba(59, 130, 246, 0.1);
    color: var(--secondary);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 0.5rem;
    z-index: 1001;
}

.mobile-menu-toggle span {
    width: 28px;
    height: 3px;
    background: var(--primary);
    border-radius: 3px;
    transition: all 0.3s ease-in-out;
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(7px, 7px);
}

.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* Hero Section */
.hero {
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 6rem 2rem 3rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    top: -200px;
    right: -200px;
    animation: float 6s ease-in-out infinite;
}

.hero::after {
    content: '';
    position: absolute;
    width: 300px;
    height: 300px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    bottom: -100px;
    left: -100px;
    animation: float 8s ease-in-out infinite;
}

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

.hero-content {
    max-width: 900px;
    z-index: 1;
    animation: fadeInUp 1s ease;
}

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

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    font-weight: 800;
}

/* Section Styles */
section {
    padding: 5rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.bg-white { background: white; }
.bg-light { background: var(--light); }

.about-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 3rem;
    align-items: center;
}

/* Research Areas */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.research-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    border-top: 4px solid var(--secondary);
}

.research-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.2);
}

.research-card h3 {
    color: var(--primary);
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

/* Footer */
footer {
    background: var(--dark);
    color: white;
    text-align: center;
    padding: 2rem;
}

/* Responsive */
@media (max-width: 968px) {
    .mobile-menu-toggle {
        display: flex;
    }
    .nav-container {
        padding: 1rem;
    }
    .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--light);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 2rem;
        transform: translateX(100%);
        transition: transform 0.3s ease-in-out;
    }
    .nav-links.active {
        transform: translateX(0);
    }
    .nav-links a {
        font-size: 1.5rem;
    }
    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: transparent;
        margin: 0;
        padding: 0;
        min-width: auto;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.4s ease;
        text-align: center;
    }
    .dropdown-menu a {
        font-size: 1.1rem;
        padding: 0.8rem 1.5rem;
        color: var(--secondary);
    }
    .dropdown.active .dropdown-menu {
        max-height: 500px;
        margin-top: 1rem;
    }
    .dropdown-toggle::after {
        display: inline-block;
    }
    .hero {
        padding-top: 6rem;
    }
    .hero h1 { font-size: 2.2rem; }
    .hero h2 { font-size: 1.1rem; }
    .about-content { grid-template-columns: 1fr; }
}