header {
    background: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
}
/* Animated gradient border bottom */
header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 5px;
    background: linear-gradient(
        90deg,
        #4a90e2 0%,    /* Blue */
        #48bb78 33%,   /* Green */
        #4a90e2 66%,   /* Blue */
        #48bb78 100%   /* Green */
    );
    background-size: 300% 100%;
    animation: gradient-shift 8s linear infinite;
}

@keyframes gradient-shift {
    0% { background-position: 100% 0; }
    100% { background-position: 0 0; }
}
h1 {
    color: #ecf0f1;
    font-size: 1.2rem;
    margin: 0;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
    letter-spacing: 0.5px;
}

.nav-menu {
    position: relative;
}

.hamburger {
    color: #ecf0f1;
    font-size: 1.5rem;
    cursor: pointer;
    transition: color 0.3s ease;
}

.hamburger:hover {
    color: #e74c3c;
}

.menu-items {
    position: absolute;
    top: 150%;
    right: 0;
    background: #fff;
    padding: 1rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    display: none;
    flex-direction: column;
    gap: 1rem;
    min-width: 120px;
}

.menu-items.show {
    display: flex;
}

.menu-items a {
    color: #2c3e50;
    text-decoration: none;
    font-size: 1.2rem;
    padding: 0.5rem;
    border-radius: 4px;
    transition: background-color 0.3s ease;
    text-align: center;
}

.menu-items a:hover {
    background-color: #f5f6fa;
    color: #e74c3c;
}

@media screen and (max-width: 768px) {
    header {
        padding: 0.8rem 1rem;
    }
    
    h1 {
        font-size: 1rem;
    }
    
    .hamburger {
        font-size: 1.2rem;
    }
    
    .menu-items {
        min-width: 100px;
    }
    
    .menu-items a {
        font-size: 1rem;
    }
}