:root {
    --primary: #2c3e50;
    --secondary: #3498db;
    --accent: #e74c3c;
    --light: #ecf0f1;
    --dark: #1a252f;
    --success: #2ecc71;
    --warning: #f39c12;
    --gradient-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-2: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-3: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.15);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.2);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: #333;
    line-height: 1.6;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header Styles */
header {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 1rem 0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo img {
    height: 50px;
    width: auto;
    transition: transform 0.3s;
}

.logo img:hover {
    transform: scale(1.1);
}

.logo h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: white;
    margin: 0;
}

/* Desktop Navigation */
nav {
    display: flex;
    align-items: center;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
    margin: 0;
    padding: 0;
}

nav ul li {
    margin: 0;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
    font-size: 1.1rem;
}

nav a:hover, 
nav a.active {
    background-color: rgba(255, 255, 255, 0.2);
}

/* Hamburger Menu - Hidden on Desktop */
.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.8rem;
    color: white;
    background: none;
    border: none;
    padding: 5px;
    z-index: 1001;
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(44, 62, 80, 0.8), rgba(52, 152, 219, 0.8)), url('https://images.unsplash.com/photo-1558494949-ef010cbdcc31?ixlib=rb-4.0.3&auto=format&fit=crop&w=1350&q=80');
    background-size: cover;
    background-position: center;
    color: white;
    padding: 5rem 0;
    text-align: center;
    margin-bottom: 3rem;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto 2rem;
}

.btn {
    display: inline-block;
    background-color: var(--accent);
    color: white;
    padding: 0.8rem 1.5rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn:hover {
    background-color: #c0392b;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* Labs Section */
.section-title {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--primary);
    position: relative;
}

.section-title:after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background-color: var(--secondary);
    margin: 10px auto;
}

.labs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.lab-card {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.lab-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}

.lab-card-header {
    background-color: var(--primary);
    color: white;
    padding: 1.5rem;
    text-align: center;
}

.lab-card-body {
    padding: 1.5rem;
}

.lab-card-body h3 {
    color: var(--primary);
    margin-bottom: 1rem;
}

.lab-card-body p {
    color: #666;
    margin-bottom: 1.5rem;
}

.lab-card-footer {
    padding: 1rem 1.5rem;
    background-color: #f8f9fa;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Footer */
footer {
    background-color: var(--dark);
    color: white;
    padding: 3rem 0 1.5rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3 {
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
}

.footer-section h3:after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 50px;
    height: 2px;
    background-color: var(--secondary);
}

.footer-section p {
    margin-bottom: 1rem;
}

.footer-section a {
    color: white;
    text-decoration: none;
}

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

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    color: white;
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.social-links a {
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
}

.social-links a:hover {
    color: white;
    background: var(--secondary);
    transform: translateY(-5px) scale(1.1);
    box-shadow: var(--shadow-md);
}

.completion-badge {
    color: var(--success);
    font-size: 1.2rem;
    margin-left: 0.5rem;
    animation: bounceIn 0.5s ease-out;
}

@keyframes bounceIn {
    0% { transform: scale(0); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}

.quick-tool-btn {
    transition: all 0.3s ease;
}

.quick-tool-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

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

/* ========== MOBILE STYLES ========== */
@media (max-width: 768px) {
    .header-content {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }

    /* Show hamburger on mobile */
    .hamburger {
        display: block;
        z-index: 1001;
    }

    /* Hide regular nav links on mobile */
    .navbar {
        position: static;
    }

    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--dark);
        flex-direction: column;
        padding: 80px 30px 30px;
        transition: right 0.3s ease-in-out;
        box-shadow: -5px 0 15px rgba(0, 0, 0, 0.1);
        z-index: 999;
    }

    .nav-links.active {
        right: 0;
    }

    .nav-links li {
        margin-bottom: 20px;
        text-align: left;
    }

    .nav-links li:last-child {
        margin-bottom: 0;
    }

    .nav-links a {
        color: white;
        display: block;
        padding: 12px 15px;
        border-radius: 6px;
        font-size: 1.1rem;
        text-align: left;
        border: none;
    }

    .nav-links a:hover,
    .nav-links a.active {
        background-color: var(--secondary);
        color: white;
    }

    /* Logo adjustments for mobile */
    .logo img {
        height: 40px;
    }

    .logo h1 {
        font-size: 1.4rem;
    }

    /* Hero adjustments */
    .hero {
        padding: 4rem 0;
    }
    
    .hero h2 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .lab-card-footer {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .logo {
        flex-direction: row;
        gap: 8px;
    }

    .logo h1 {
        font-size: 1.2rem;
    }
    
    .nav-links {
        width: 250px;
    }
    
    .hero {
        padding: 3rem 0;
    }
    
    .hero h2 {
        font-size: 1.8rem;
    }
}