.topbar {
    background: var(--header-bg, rgba(255, 255, 255, 0.95));
    border-bottom: 1px solid var(--border-color, #e2e8f0);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    backdrop-filter: blur(10px);
    transition: background 0.3s ease;
}

.topbar .container {
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 0 20px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    z-index: 1001;
}

.brand-name {
    font-weight: 600;
    color: var(--header-text, #0f172a);
    transition: color 0.3s ease;
}

.logo {
    display: block;
    width: 30px;
    background: transparent;
    border: none;
    outline: none;
}

[data-theme="dark"] .logo {
    filter: brightness(0) invert(1);
}

.mainnav {
    display: flex;
    gap: 36px;
    margin-inline: auto;
}

.mainnav a {
    color: var(--header-text, #222);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.3s ease;
}

.mainnav a:hover, .login-btn:hover {
    color: var(--accent-primary, #0b6e4f);
}

.mainnav a.current {
    color: var(--accent-primary, #0b6e4f);
    font-weight: bold;
    text-decoration: none;
}

.login-btn {
    color: var(--header-text, #222);
    text-decoration: none;
    font-size: 14px;
    font-weight: 400;
    transition: color 0.3s ease;
}

button.login-btn,
button.nav-login {
    background: none;
    border: none;
    padding: 0;
    margin: 0;
    font: inherit;
    color: inherit;
    cursor: pointer;
    line-height: inherit;
    vertical-align: baseline;
}

button.login-btn:hover,
button.nav-login:hover {
    color: var(--accent-primary, #0b6e4f);
}

.nav-login {
    display: none;
}

.burger-menu {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1001;
}

.burger-menu span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--header-text, #222);
    transition: all 0.3s ease;
}

.burger-menu.active span:nth-child(1) {
    transform: rotate(45deg) translate(7px, 7px);
}

.burger-menu.active span:nth-child(2) {
    opacity: 0;
}

.burger-menu.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

@media (max-width: 768px) {
    .login-btn {
        display: none;
    }

    .burger-menu {
        display: flex;
    }

    .mainnav {
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        height: calc(100vh - 64px);
        background: var(--bg-primary, #fff);
        flex-direction: column;
        gap: 0;
        margin: 0;
        padding: 20px;
        transform: translateX(-105%); 
        transition: transform 0.28s cubic-bezier(.2,.9,.2,1);
        box-shadow: 2px 0 10px rgba(0,0,0,0.3);
        z-index: 1100; 
    }

    .mainnav.active {
        transform: translateX(0);
    }

    .mainnav a {
        padding: 15px 0;
        border-bottom: 1px solid var(--border-color, #eee);
        font-size: 16px;
        color: var(--text-primary, #222);
        font-weight: 500;
    }

    .nav-login {
        display: block;
        font-weight: 600;
        color: var(--accent-primary, #0b6e4f);
    }
    
    
    [data-theme="dark"] .mainnav a {
        color: #f1f5f9;
        font-weight: 500;
    }
    
    [data-theme="dark"] .mainnav a.current {
        color: var(--accent-primary, #10b981);
        font-weight: 700;
    }
    
    [data-theme="dark"] .nav-login {
        color: var(--accent-primary, #10b981);
        font-weight: 700;
    }
    
    [data-theme="dark"] .burger-menu span {
        background: #f1f5f9;
    }
}

.mainnav a:focus,
.burger-menu:focus,
.login-btn:focus,
button.login-btn:focus,
button.nav-login:focus,
.nav-login:focus {
    outline: 3px solid rgba(18,201,212,0.18);
    outline-offset: 2px;
}