:root {
    color-scheme: light;
    --color-primary: #4f46e5;
    --color-primary-hover: #4338ca;
    --color-primary-soft: #eef2ff;
    --color-secondary: #0ea5e9;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-bg: #f8fafc;
    --color-surface: #ffffff;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-border: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --sidebar-width: 260px;
    --header-height: 64px;
    --transition: 0.2s ease;
}

/* Dark mode – applied via data-theme="dark" on <html> */
[data-theme="dark"] {
    color-scheme: dark;
    --color-primary: #6366f1;
    --color-primary-hover: #818cf8;
    --color-primary-soft: rgba(99, 102, 241, 0.18);
    --color-secondary: #38bdf8;
    --color-success: #34d399;
    --color-warning: #fbbf24;
    --color-danger: #f87171;
    --color-bg: #0f172a;
    --color-surface: #1e293b;
    --color-text: #e2e8f0;
    --color-text-light: #94a3b8;
    --color-border: #334155;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5);
}

/* Smooth theme transition on supported browsers */
html[data-theme] body,
html[data-theme] .sidebar,
html[data-theme] .header,
html[data-theme] .card,
html[data-theme] .modal,
html[data-theme] input,
html[data-theme] select,
html[data-theme] textarea {
    transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease;
}