:root {
    --shell-bg: #f3f5f9;
    --shell-surface: #ffffff;
    --shell-surface-muted: #f8fafc;
    --shell-border: #d9e1ec;
    --shell-border-strong: #c8d3e1;
    --shell-text: #1f2937;
    --shell-text-muted: #6b7280;
    --shell-text-soft: #94a3b8;
    --shell-primary: #2563eb;
    --shell-primary-strong: #1d4ed8;
    --shell-primary-soft: #dbeafe;
    --shell-success: #16a34a;
    --shell-danger: #dc2626;
    --shell-warning: #d97706;
    --shell-shadow: 0 12px 30px rgba(15, 23, 42, 0.06);
    --shell-shadow-soft: 0 4px 14px rgba(15, 23, 42, 0.04);
    --shell-radius-xl: 18px;
    --shell-radius-lg: 14px;
    --shell-radius-md: 12px;
    --shell-header-height: 58px;
    --shell-sidebar-width: 58px;
    --shell-gap: 14px;
    --shell-transition: 180ms ease;
}

[data-theme="dark"] {
    --shell-bg: #0f172a;
    --shell-surface: #111827;
    --shell-surface-muted: #172033;
    --shell-border: #243043;
    --shell-border-strong: #314155;
    --shell-text: #e5eef9;
    --shell-text-muted: #93a4ba;
    --shell-text-soft: #64748b;
    --shell-primary: #60a5fa;
    --shell-primary-strong: #3b82f6;
    --shell-primary-soft: rgba(59, 130, 246, 0.2);
    --shell-success: #4ade80;
    --shell-danger: #f87171;
    --shell-warning: #f59e0b;
    --shell-shadow: 0 16px 34px rgba(2, 6, 23, 0.24);
    --shell-shadow-soft: 0 8px 18px rgba(2, 6, 23, 0.18);
}