/* Header and Navigation */
header {
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    background: linear-gradient(to bottom, 
        rgba(20, 20, 20, 0.95) 0%,
        var(--bg-primary) 100%
    );
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

/* Light theme gradient override */
.light-theme header {
    background: linear-gradient(to bottom, 
        rgba(255, 255, 255, 0.95) 0%,
        var(--bg-primary) 100%
    );
}

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

.logo {
    font-size: 2rem;
    font-weight: bold;
    color: var(--accent-color);
}

#theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    transition: var(--transition);
}

#theme-toggle:hover {
    color: var(--accent-color);
    transform: scale(1.1);
}

#theme-toggle:focus {
    outline: 2px solid var(--accent-color);
    border-radius: 4px;
}