/* ══════════════════════════════════════════
   Top Navigation Bar
   Replaces sidebar — horizontal tabs, always visible
   ══════════════════════════════════════════ */

.topnav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--topnav-height);
    background: var(--bg-base);
    border-bottom: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    padding: 0 1.25rem;
    gap: 0;
    z-index: 200;
    user-select: none;
}

/* ── Ecosystem Switcher ── */
.system-switcher {
    position: relative;
    cursor: pointer;
    border-right: 1px solid rgba(255, 255, 255, 0.06);
    padding-right: 1rem;
    margin-right: 0.75rem;
    border-radius: var(--radius-sm);
    transition: background 0.2s;
    user-select: none;
    flex-shrink: 0;
}

.system-switcher:hover, .system-switcher.active {
    background: rgba(255, 255, 255, 0.04);
}

.logo-content {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.25rem 0.5rem;
}

.switcher-caret {
    color: var(--gold-light);
    transition: transform 0.2s;
    margin-left: 0.25rem;
    opacity: 0.7;
}

.system-switcher.active .switcher-caret {
    transform: rotate(180deg);
}

.system-dropdown {
    position: absolute;
    top: calc(100% + 0.5rem);
    left: 0;
    background: var(--bg-surface);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    box-shadow: var(--glass-shadow);
    min-width: 220px;
    padding: 0.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.system-switcher.active .system-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    pointer-events: auto;
}

.system-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.2s;
}

.system-link:hover, .system-link:focus-visible {
    background: var(--bg-hover);
    outline: none;
}

.system-link.active {
    background: rgba(212, 160, 23, 0.08); /* --tool-accent-bg */
    border: 1px solid rgba(212, 160, 23, 0.15);
}

.system-icon {
    font-size: 1.5rem;
}

.system-info strong {
    display: block;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1rem;
    line-height: 1.1;
    color: var(--gold-light);
}

.system-info span {
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 400;
    color: var(--text-secondary);
}

/* Typography elements */
.topnav-logo-icon {
    font-size: 1.4rem;
    line-height: 1;
}

.topnav-logo-text {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 700;
    color: var(--gold-light);
    line-height: 1.15;
}

.topnav-logo-text small {
    display: block;
    font-size: 0.6rem;
    font-weight: 400;
    color: var(--text-muted);
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

/* ── Tab buttons ── */
.topnav-tabs {
    display: flex;
    align-items: center;
    gap: 0.15rem;
    flex: 1;
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
    position: relative;
    /* for .topnav-indicator */
}

.topnav-tabs::-webkit-scrollbar {
    display: none;
}

/* ── Animated sliding underline ── */
.topnav-indicator {
    position: absolute;
    bottom: -1px;
    height: 2px;
    border-radius: 2px 2px 0 0;
    background: var(--tool-accent, var(--gold));
    pointer-events: none;
    transition:
        left 0.32s cubic-bezier(0.16, 1, 0.3, 1),
        width 0.32s cubic-bezier(0.16, 1, 0.3, 1),
        background 0.2s ease;
    will-change: left, width;
}

.topnav-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.55rem 1rem;
    min-height: 44px;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-muted);
    white-space: nowrap;
    transition:
        background var(--transition-fast),
        color var(--transition-fast),
        transform 120ms cubic-bezier(0.16, 1, 0.3, 1);
}

.topnav-btn:hover {
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-primary);
}

.topnav-btn:active {
    transform: scale(0.94);
}

.topnav-btn:focus-visible {
    outline: 2px solid var(--tool-accent);
    outline-offset: 2px;
    background: rgba(255, 255, 255, 0.04);
}

.topnav-btn.active {
    color: var(--tool-accent, var(--gold-light));
    background: rgba(255, 255, 255, 0.04);
}

/* ::after underline replaced by .topnav-indicator element */
.topnav-btn::after {
    display: none;
}

.topnav-icon {
    font-size: 1rem;
    line-height: 1;
    transition: transform 200ms cubic-bezier(0.22, 1, 0.36, 1);
}

.topnav-btn:hover .topnav-icon {
    transform: translateY(-1px);
}

/* ── Version badge ── */
.topnav-version {
    font-size: 0.7rem;
    color: var(--text-muted);
    padding-left: 1rem;
    border-left: 1px solid rgba(255, 255, 255, 0.06);
    flex-shrink: 0;
}

/* ── Mobile: collapse labels, keep icons ── */
@media (max-width: 640px) {
    .topnav {
        padding: 0 0.75rem;
    }

    .topnav-logo-text {
        display: none;
    }

    .topnav-logo {
        padding-right: 0.75rem;
        margin-right: 0.5rem;
    }

    .topnav-btn-label {
        display: none;
    }

    .topnav-btn {
        padding: 0.55rem 0.75rem;
    }

    .topnav-version {
        display: none;
    }
}