truncate.css

* ── Resize handle ──────────────────────────────── */
.resize-box {
  resize: horizontal;
  overflow: hidden;
  width: 100%;
  max-width: 100%;
  min-width: 4ch;
  border: 1px solid hsl(0 0% 20%);
  border-radius: 6px;
  padding: 12px 16px;
  background: hsl(0 0% 6%);
  cursor: col-resize;
}

/* ── 01  Standard truncation ────────────────────── */
.standard-truncate {
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

/* ── 02  RTL truncation ─────────────────────────── */
.rtl-truncate {
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
  direction: rtl;
  text-align: left;            /* keep visual alignment LTR */
}

/* ── 03  Center truncation ──────────────────────── */

/*
 * The UUID is 36 chars. In monospace 1ch = 1 character, so
 * 36ch is the exact width of the full string.
 *
 * >= 36ch  → full string, no truncation, ::after + ::before hidden
 * <  36ch  → two halves (each max 50%), LTR left + RTL right,
 *            both use text-overflow: clip.
 *            ::before sits in the center with "..." content and
 *            a gradient bg that fades from transparent → bg → transparent,
 *            smoothly masking the junction.
 */

.center-truncate {
  --_bg: hsl(0 0% 6%);
  container-type: inline-size;
  display: flex;
  overflow: hidden;
  position: relative;
}

/* ── shared base for both text layers ── */

.center-truncate > span {
  flex: 0 1 auto;
  overflow: hidden;
  white-space: nowrap;
}

.center-truncate::after {
  content: attr(data-string);
  flex: 0 1 auto;
  overflow: hidden;
  white-space: nowrap;
}

/* ── the "..." overlay ── */

.center-truncate::before {
  content: "\2026";             /* … unicode ellipsis */
  position: absolute;
  left: 50%;
  top: 0;
  transform: translateX(-50%);
  z-index: 1;
  white-space: nowrap;
  /* gradient: transparent → bg → bg → transparent */
  background: linear-gradient(
    to right,
    transparent,
    var(--_bg) 2ch,
    var(--_bg) calc(100% - 2ch),
    transparent
  );
  /* 3ch for "..." + 2ch fade each side = ~7ch total */
  padding: 0 2ch;
  pointer-events: none;
  display: none;
}

/* ── wide: full string fits ── */

@container (min-width: 36ch) {
  .center-truncate > span {
    max-width: 100%;
    text-overflow: clip;
  }
  .center-truncate::after {
    display: none;
  }
  .center-truncate::before {
    display: none;
  }
}

/* ── narrow: center-truncate ── */

@container (max-width: calc(36ch - 1px)) {
  .center-truncate > span {
    min-width: 3ch;
    max-width: 50%;
    text-overflow: clip;
  }
  .center-truncate::after {
    min-width: 3ch;
    max-width: 50%;
    text-overflow: clip;
    direction: rtl;
    text-align: right;
  }
  .center-truncate::before {
    display: block;
  }
}