:root{
/* Rules, not boxes. No shadows. Square corners. */
--radius-0:0px;            /* default everywhere */
--radius-field:0px;        /* form fields are underlined or 1px-ruled, square */
--border-rule:1px solid var(--rule);
--border-strong:1px solid var(--rule-strong);
--border-accent:1px solid var(--accent);
--shadow-none:none;        /* the shadow system is: none */
}