.top-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 30px;
    height: 60px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.15);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.top-nav select option {
    background: #667eea;
    color: white;
}

.nav-subject-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
}

.nav-subject-wrapper select {
    max-width: 250px;
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-link {
    color: rgba(255, 255, 255, 0.85);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 6px;
    transition: all 0.2s ease;
    font-size: 14px;
    font-weight: 500;
}

.nav-link:hover {
    color: white;
    background: rgba(255, 255, 255, 0.15);
}

.nav-link.active {
    color: white;
    background: rgba(255, 255, 255, 0.25);
    font-weight: 600;
}

.nav-user {
    display: flex;
    align-items: center;
    gap: 15px;
}

.nav-username {
    font-size: 14px;
    font-weight: 500;
}

.nav-logout-btn {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    padding: 6px 14px;
    border-radius: 4px;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.nav-logout-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}