/* ── make marks fill the rail (what you already had) ───────────── */
.week-slider .rc-slider-mark       { width:100% !important; left:0 !important; }
.week-slider .rc-slider-mark-text  { flex:1; text-align:center; white-space:nowrap; }

/* ── centre the dots (optional) ────────────────────────────────── */
.week-slider .rc-slider-dot  { margin-left:-4px; }

/* ──────────────────────────────────────────────────────────────── */
/* NEW 1 ▸ let the outer component stretch (flex-grow)            */
.week-slider{             flex:1 1 0;  min-width:0; }

/* NEW 2 ▸ and force the inner rc-slider rail to use all that room */
.week-slider .rc-slider{  width:100% !important; }