/* ============================================================
   ToolZen — Tools Shell Layout
   Sidebar navigation + content layout for tool pages.
   Requires the same CSS custom properties defined in each
   tool page's :root block.
   ============================================================ */

/* Skip link (accessibility) */
.skip-link {
    position: absolute; top: -100%; left: 16px;
    background: var(--primary-500); color: white;
    padding: 8px 16px; border-radius: var(--radius-md);
    z-index: 10000; font-weight: 600;
    transition: top var(--transition-fast);
}
.skip-link:focus { top: 8px; }

/* ────────────────────────────────────────────────────────────
   App Shell Wrapper
   ──────────────────────────────────────────────────────────── */
.app-shell {
    display: flex;
    flex: 1;
    min-height: 0;
    position: relative;
}

/* ────────────────────────────────────────────────────────────
   Sidebar
   ──────────────────────────────────────────────────────────── */
:root {
    --sidebar-width: 220px;
    --sidebar-collapsed-width: 52px;
    --sidebar-bg: var(--bg-primary, #ffffff);
    --sidebar-border: var(--border-default, #E4E8EC);
    --sidebar-active-bg: var(--primary-50, #EBF3FA);
    --sidebar-active-color: var(--primary-500, #2E75B6);
    --sidebar-hover-bg: var(--surface-hover, #F0F4F8);
    --sidebar-group-color: var(--text-tertiary, #9AA5B1);
    --sidebar-item-color: var(--text-secondary, #666666);
    --sidebar-transition: 250ms ease;
}

.sidebar {
    width: var(--sidebar-width);
    flex-shrink: 0;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--sidebar-border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: width var(--sidebar-transition), background-color var(--sidebar-transition);
    position: sticky;
    top: 64px; /* matches header height */
    height: calc(100vh - 64px);
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--sidebar-border) transparent;
    z-index: 100;
}

.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }
.sidebar::-webkit-scrollbar-thumb { background: var(--sidebar-border); border-radius: 4px; }

/* Collapsed state */
.sidebar.collapsed {
    width: var(--sidebar-collapsed-width);
}

/* Sidebar toggle button */
.sidebar-toggle {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding: 10px 12px;
    border-bottom: 1px solid var(--sidebar-border);
    gap: 8px;
    flex-shrink: 0;
}

.sidebar-toggle-btn {
    width: 28px;
    height: 28px;
    border-radius: 6px;
    border: 1px solid var(--sidebar-border);
    background: transparent;
    color: var(--sidebar-group-color);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background var(--sidebar-transition), color var(--sidebar-transition);
    flex-shrink: 0;
}
.sidebar-toggle-btn:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary, #333);
}

/* Sidebar label (hidden when collapsed) */
.sidebar-label {
    font-size: 11px;
    font-weight: 700;
    color: var(--sidebar-group-color);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    white-space: nowrap;
    flex: 1;
    overflow: hidden;
    transition: opacity var(--sidebar-transition), width var(--sidebar-transition);
}
.sidebar.collapsed .sidebar-label {
    opacity: 0;
    width: 0;
    flex: 0;
}

/* Group */
.sidebar-group {
    padding: 8px 0 4px;
}
.sidebar-group + .sidebar-group {
    border-top: 1px solid var(--sidebar-border);
}

.sidebar-group-title {
    padding: 6px 14px 4px;
    font-size: 10px;
    font-weight: 700;
    color: var(--sidebar-group-color);
    letter-spacing: 0.07em;
    text-transform: uppercase;
    white-space: nowrap;
    overflow: hidden;
    transition: opacity var(--sidebar-transition);
}
.sidebar.collapsed .sidebar-group-title {
    opacity: 0;
    padding: 6px 0 4px;
}

/* Tool item */
.sidebar-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 7px 14px;
    font-size: 13px;
    font-weight: 500;
    color: var(--sidebar-item-color);
    text-decoration: none;
    border-radius: 0;
    cursor: pointer;
    transition: background var(--sidebar-transition), color var(--sidebar-transition);
    white-space: nowrap;
    overflow: hidden;
    border-left: 3px solid transparent;
    position: relative;
}
.sidebar-item:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary, #333);
    text-decoration: none;
}
.sidebar-item.active {
    background: var(--sidebar-active-bg);
    color: var(--sidebar-active-color);
    font-weight: 600;
    border-left-color: var(--sidebar-active-color);
}

.sidebar-item-icon {
    width: 26px;
    height: 26px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    font-size: 15px;
    transition: background var(--sidebar-transition);
}

.sidebar-item-name {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: opacity var(--sidebar-transition), width var(--sidebar-transition);
}
.sidebar.collapsed .sidebar-item-name {
    opacity: 0;
    width: 0;
    flex: 0;
    overflow: hidden;
}

/* Tooltip when collapsed */
.sidebar.collapsed .sidebar-item {
    justify-content: center;
    padding: 7px 0;
}
.sidebar.collapsed .sidebar-item::after {
    content: attr(data-tooltip);
    position: absolute;
    left: calc(var(--sidebar-collapsed-width) + 8px);
    top: 50%;
    transform: translateY(-50%);
    background: var(--gray-800, #222);
    color: white;
    font-size: 12px;
    padding: 4px 10px;
    border-radius: 6px;
    white-space: nowrap;
    pointer-events: none;
    opacity: 0;
    transition: opacity 150ms ease;
    z-index: 200;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}
.sidebar.collapsed .sidebar-item:hover::after {
    opacity: 1;
}

/* ────────────────────────────────────────────────────────────
   Content Area
   ──────────────────────────────────────────────────────────── */
.shell-content {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.shell-main {
    flex: 1;
    max-width: 860px;
    margin: 0 auto;
    padding: 32px 24px;
    width: 100%;
}

/* ────────────────────────────────────────────────────────────
   Mobile Overlay
   ──────────────────────────────────────────────────────────── */
.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    z-index: 99;
}
.sidebar-overlay.visible {
    display: block;
}

/* ────────────────────────────────────────────────────────────
   Mobile Hamburger (in header)
   ──────────────────────────────────────────────────────────── */
.hamburger-btn {
    display: none;
    width: 38px;
    height: 38px;
    border-radius: 8px;
    border: 1px solid rgba(255,255,255,0.2);
    background: rgba(255,255,255,0.1);
    color: white;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 18px;
    transition: background 150ms ease;
}
.hamburger-btn:hover { background: rgba(255,255,255,0.2); }

/* ────────────────────────────────────────────────────────────
   Responsive
   ──────────────────────────────────────────────────────────── */

/* Tablet: auto-collapse sidebar */
@media (max-width: 1024px) {
    .sidebar { width: var(--sidebar-collapsed-width); }
    .sidebar.collapsed { width: var(--sidebar-collapsed-width); }
    .sidebar.mobile-open {
        width: var(--sidebar-width);
    }
    .sidebar.mobile-open .sidebar-item-name { opacity: 1; width: auto; flex: 1; }
    .sidebar.mobile-open .sidebar-group-title { opacity: 1; }
    .sidebar.mobile-open .sidebar-label { opacity: 1; width: auto; flex: 1; }
    .sidebar.mobile-open .sidebar-item { justify-content: flex-start; padding: 7px 14px; }
    .sidebar.mobile-open .sidebar-item::after { display: none; }
}

/* Mobile: sidebar off-canvas */
@media (max-width: 768px) {
    .hamburger-btn { display: flex; }

    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        height: 100vh;
        width: var(--sidebar-width) !important;
        transform: translateX(-100%);
        transition: transform var(--sidebar-transition);
        z-index: 200;
        padding-top: 64px; /* below header */
    }
    .sidebar.mobile-open {
        transform: translateX(0);
    }

    .shell-main {
        padding: 24px 16px;
    }

    /* Restore item layout on mobile open */
    .sidebar .sidebar-item-name { opacity: 1 !important; width: auto !important; flex: 1 !important; }
    .sidebar .sidebar-group-title { opacity: 1 !important; }
    .sidebar .sidebar-item { justify-content: flex-start !important; padding: 7px 14px !important; }
    .sidebar .sidebar-item::after { display: none !important; }
    .sidebar .sidebar-label { opacity: 1 !important; width: auto !important; flex: 1 !important; }
}

@media (max-width: 480px) {
    .shell-main { padding: 16px 12px; }
}

/* Print */
@media print {
    .sidebar, .sidebar-overlay, .hamburger-btn { display: none !important; }
    .app-shell { display: block; }
}