/* ── layout.css ── Page structure, nav, grid, containers ── */

/* ── App Shell ── */
.app-layout {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.app-content {
    flex: 1;
    padding: var(--space-lg);
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
}

/* ── Nav Bar ── */
.app-nav {
    background: var(--color-bg);
    border-bottom: var(--border);
    padding: 0 var(--space-lg);
    display: flex;
    align-items: center;
    height: 48px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-nav .nav-brand {
    font-weight: 600;
    font-size: var(--text-lg);
    color: var(--color-text);
    text-decoration: none;
    margin-right: var(--space-xl);
    white-space: nowrap;
}
.app-nav .nav-brand:hover {
    text-decoration: none;
    color: var(--color-text);
}

.app-nav .nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    height: 100%;
}

.app-nav .nav-link {
    text-decoration: none;
    color: var(--color-text-muted);
    font-size: var(--text-base);
    font-weight: 500;
    padding: 0 var(--space-md);
    height: 100%;
    display: flex;
    align-items: center;
    border-bottom: 2px solid transparent;
    transition: color 0.15s, border-color 0.15s;
}
.app-nav .nav-link:hover {
    color: var(--color-text);
    text-decoration: none;
}
.app-nav .nav-link.active {
    color: var(--color-accent);
    border-bottom-color: var(--color-accent);
}

/* ── Page Header ── */
.page-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
    flex-wrap: wrap;
}

.page-header h1 {
    margin: 0;
}

.page-header .back-link {
    color: var(--color-text-muted);
    font-size: var(--text-sm);
    text-decoration: none;
}
.page-header .back-link:hover {
    color: var(--color-accent);
    text-decoration: none;
}

.header-actions {
    margin-left: auto;
    display: flex;
    gap: var(--space-sm);
    align-items: center;
}

/* ── Grid ── */
.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
}

.grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: var(--space-lg);
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-md);
}

.grid-auto {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-md);
}

/* ── Split View (for editors) ── */
.split-view {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0;
    border: var(--border);
    min-height: 500px;
}

.split-view .split-left,
.split-view .split-right {
    padding: var(--space-md);
    overflow: auto;
}

.split-view .split-left {
    border-right: var(--border);
    background: var(--color-surface);
}

.split-view .split-right {
    background: var(--color-bg);
}

.split-view-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-sm) var(--space-md);
    background: var(--color-surface);
    border-bottom: var(--border);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-muted);
}

/* ── Empty State ── */
.empty-state {
    text-align: center;
    padding: var(--space-2xl);
    color: var(--color-text-faint);
}

.empty-state p {
    color: var(--color-text-faint);
    margin-bottom: var(--space-md);
}

/* ── Loading ── */
.loading {
    text-align: center;
    padding: var(--space-lg);
    color: var(--color-text-faint);
}

.loading-spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ── Responsive ── */
@media (max-width: 768px) {
    .app-content {
        padding: var(--space-md);
    }
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
    .split-view {
        grid-template-columns: 1fr;
    }
    .split-view .split-left {
        border-right: none;
        border-bottom: var(--border);
    }
    .header-actions {
        width: 100%;
    }
}