/* ==========================================================================
   MathMaster – tiesinės funkcijos tyriklis (linearfn.js)
   ==========================================================================
   Išdėstymas: plokštuma, po ja šliaužikliai, po jų analitinis skydelis.
   Plačiame ekrane plokštuma ir valdikliai stoja greta, kad traukiant
   šliaužiklį grafikas liktų akyse, o ne nuslinktų žemiau.
   ========================================================================== */

.lf-host {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 8px 0 4px;
}

.lf-stage {
  max-width: 420px;
  width: 100%;
  margin: 0 auto;
}

.lf-svg {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1 / 1;
  border: 1px solid var(--border, #E2E8F0);
  border-radius: 12px;
  background: #FFFFFF;
  font-family: inherit;
}

.lf-caption {
  text-align: center;
  font-size: 1.02rem;
  color: var(--text, #0F172A);
}

/* ------------------------------ Valdikliai ------------------------------ */

.lf-controls {
  display: grid;
  gap: 10px;
}

.lf-group {
  display: grid;
  gap: 10px;
  padding: 12px;
  border: 1px solid var(--border, #E2E8F0);
  border-radius: 12px;
  background: var(--surface-2, #F8FAFC);
}

.lf-group-2 {
  border-color: #99F6E4;
  background: #F0FDFA;
}

/* `linearfn.js` slepia antrosios tiesės grupę per `second.hidden = !showSecond`,
   bet `.lf-group{display:grid}` nugali naršyklės `[hidden]{display:none}` – k₂/b₂
   šliaužikliai buvo matomi net išjungus „Antra tiesė", ir mokinys juos sukiodavo
   be jokio pokyčio brėžinyje. */
.lf-group[hidden] {
  display: none;
}

.lf-ctrl-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 4px;
}

.lf-ctrl-name { font-size: 0.95rem; color: var(--text-muted, #475569); }

.lf-ctrl-val {
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 1.05rem;
  color: #4F46E5;
  min-width: 3.2em;
  text-align: right;
}

.lf-ctrl-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.lf-range {
  flex: 1 1 auto;
  min-width: 0;
  height: 28px;
  accent-color: #4F46E5;
  cursor: pointer;
}

.lf-num {
  flex: 0 0 5.2em;
  min-height: 40px;
  padding: 6px 8px;
  font: inherit;
  font-variant-numeric: tabular-nums;
  text-align: center;
  border: 1px solid var(--border, #CBD5E1);
  border-radius: 8px;
  background: #FFFFFF;
  color: var(--text, #0F172A);
}

.lf-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.lf-toggle {
  min-height: 44px;
  padding: 8px 14px;
  font: inherit;
  font-weight: 600;
  color: var(--text, #0F172A);
  background: #FFFFFF;
  border: 1px solid var(--border, #CBD5E1);
  border-radius: 999px;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.lf-toggle:hover { border-color: #A5B4FC; }

.lf-toggle.is-on {
  background: #4F46E5;
  border-color: #4F46E5;
  color: #FFFFFF;
}

.lf-toggle:focus-visible,
.lf-range:focus-visible,
.lf-num:focus-visible {
  outline: 3px solid #A5B4FC;
  outline-offset: 2px;
}

/* --------------------------- Analitinis skydelis ------------------------ */

.lf-panel {
  padding: 12px 14px;
  border: 1px solid var(--border, #E2E8F0);
  border-radius: 12px;
  background: var(--surface, #FFFFFF);
}

.lf-panel-title {
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  color: var(--text-muted, #64748B);
  margin-bottom: 8px;
}

.lf-rows {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 6px 14px;
  margin: 0;
}

.lf-rows dt {
  color: var(--text-muted, #475569);
  font-size: 0.95rem;
}

.lf-rows dd {
  margin: 0;
  color: var(--text, #0F172A);
}

.lf-rel {
  margin-top: 10px;
  padding: 9px 12px;
  border-radius: 10px;
  border: 1px solid transparent;
  font-weight: 600;
}

.lf-rel.is-par   { background: #DCFCE7; border-color: #86EFAC; color: #14532D; }
.lf-rel.is-perp  { background: #EDE9FE; border-color: #C4B5FD; color: #4C1D95; }
.lf-rel.is-same  { background: #FEF9C3; border-color: #FDE68A; color: #713F12; }
.lf-rel.is-cross { background: var(--surface-2, #F1F5F9); border-color: var(--border, #E2E8F0); }

.lf-second-eq {
  margin-top: 6px;
  color: #0D9488;
  font-size: 0.98rem;
}

@media (min-width: 900px) {
  .lf-host {
    grid-template-columns: minmax(0, 420px) minmax(0, 1fr);
    align-items: start;
  }
  .lf-stage { grid-row: span 2; }
}

@media (max-width: 420px) {
  .lf-ctrl-row { gap: 8px; }
  .lf-num { flex-basis: 4.6em; }
}