.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 15px 20px;
    background: rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

.theme-toggle {
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    background: var(--card-background);
    border: 1px solid var(--border-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.theme-toggle:hover {
    background: var(--primary-color);
    color: white;
}

.menu-toggle {
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.hamburger {
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.mobile-menu {
    position: fixed;
    top: 70px;
    right: 20px;
    background: rgba(20, 20, 35, 0.75);
    backdrop-filter: blur(6px);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 20px;
    min-width: 200px;
    transform: translateY(-20px);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.25s ease, opacity 0.25s ease, visibility 0.25s ease;
    will-change: transform, opacity;
    z-index: 999;
}

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

body.light-theme .mobile-menu {
    background: rgba(44, 62, 80, 0.85);
}

.mobile-menu a {
    display: block;
    color: var(--text-primary);
    text-decoration: none;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
    transition: color 0.3s ease;
}

.mobile-menu a:last-child {
    border-bottom: none;
}

.mobile-menu a:hover {
    color: var(--primary-color);
}