.header {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-primary);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
    z-index: 1001;
}

.header-logo-link {
    display: flex;
    align-items: center;
    transition: opacity 0.2s ease;
    border-radius: 8px;
}

.header-logo-link:hover {
    opacity: 0.8;
}

.header-logo {
    width: 40px;
    height: 40px;
    border-radius: 8px;
    object-fit: cover;
    display: block;
}

.header-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

.header-title-link {
    color: var(--text-hover);
    text-decoration: none;
    transition: color 0.2s ease;
    white-space: nowrap;
}

.header-title-link:hover {
    color: var(--text-secondary);
}

.nav {
    position: relative;
    display: flex;
    align-items: center;
}

.nav-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 6px;
    transition: all 0.2s ease;
    position: relative;
    z-index: 1002;
    width: 44px;
    height: 44px;
    align-items: center;
    justify-content: center;
}

.nav-menu-toggle:hover {
    background-color: var(--border-primary);
}

.nav-menu-toggle:focus {
    outline: 2px solid var(--text-hover);
    outline-offset: 2px;
}

.nav-menu-icon {
    width: 24px;
    height: 24px;
    color: var(--text-hover);
    transition: transform 0.3s ease;
}

.nav-menu-toggle.active .nav-menu-icon {
    transform: rotate(180deg);
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
    margin: 0;
}

.nav-item {
    margin: 0;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 400;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: all 0.2s ease;
    font-size: 0.95rem;
    display: block;
}

.nav-link:hover {
    color: var(--text-hover);
    background-color: var(--bg-tertiary);
}

.nav-link:focus {
    outline: 2px solid var(--text-hover);
    outline-offset: 2px;
}

.nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-color: var(--overlay-bg);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

.nav-overlay.active {
    opacity: 1;
    visibility: visible;
}

@media (max-width: 768px) {
    .nav-menu-toggle {
        display: flex;
    }

    .nav-list {
        position: fixed;
        top: 0;
        right: -100%;
        width: min(300px, 80vw);
        height: 100vh;
        background-color: var(--bg-secondary);
        border-left: 1px solid var(--border-primary);
        padding: 80px 0 2rem 0;
        flex-direction: column;
        gap: 0;
        align-items: stretch;
        transition: right 0.3s ease, background-color 0.3s ease;
        overflow-y: auto;
        z-index: 1000;
    }

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

    .nav-item {
        width: 100%;
        border-bottom: 1px solid var(--border-primary);
    }

    .nav-item:last-child {
        border-bottom: none;
    }

    .nav-link {
        width: 100%;
        padding: 1rem 1.5rem;
        text-align: left;
        font-size: 1rem;
        border-radius: 0;
        transition: all 0.2s ease;
    }

    .nav-link:hover {
        background-color: var(--bg-tertiary);
        padding-left: 2rem;
    }

    .header-container {
        padding: 0 1rem;
        height: 65px;
    }

    .header-title {
        font-size: 1.3rem;
    }

    .header-logo {
        width: 36px;
        height: 36px;
    }
}

@media (max-width: 480px) {
    .header-container {
        padding: 0 0.75rem;
        height: 60px;
    }

    .header-brand {
        gap: 0.5rem;
    }

    .header-title {
        font-size: 1.2rem;
    }

    .header-logo {
        width: 32px;
        height: 32px;
    }

    .nav-list {
        width: min(280px, 85vw);
        padding-top: 70px;
    }

    .nav-menu-toggle {
        width: 40px;
        height: 40px;
        padding: 0.4rem;
    }

    .nav-menu-icon {
        width: 20px;
        height: 20px;
    }
}

@media (min-width: 1400px) {
    .header-container {
        max-width: 1400px;
    }
}

@media (prefers-reduced-motion: reduce) {
    .nav-menu-toggle,
    .nav-list,
    .nav-link,
    .nav-overlay,
    .nav-menu-icon {
        transition: none;
    }
}