/* ── Sales Tax & VAT Calculator — tool-specific styles ─────────────────────────
   Global styles are inherited from /css/style.css.
   Pattern mirrors discount-markup-calculator's dmc- component set, renamed
   with an stc- prefix, plus a rate-preset chip row.
   All colours reference CSS custom properties where possible.
   ─────────────────────────────────────────────────────────────────────────── */

/* ── Tabs ─────────────────────────────────────────────────────────────────── */
.stc-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  border-bottom: 2px solid var(--border-color);
  margin-bottom: 1.25rem;
}

.stc-tab {
  padding: 0.55rem 1.1rem;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-control, 6px) var(--radius-control, 6px) 0 0;
  transition: color 0.15s, border-color 0.15s;
  white-space: nowrap;
}

.stc-tab:hover {
  color: var(--text-primary);
}

.stc-tab.is-active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ── Rate presets ─────────────────────────────────────────────────────────── */
.stc-rate-presets {
  margin-bottom: 1.25rem;
}

.stc-rate-presets__label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.stc-rate-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.stc-rate-chip {
  padding: 5px 12px;
  border: 1px solid var(--border-color);
  border-radius: 14px;
  background: var(--bg-secondary, #f5f5f5);
  color: var(--text-primary);
  cursor: pointer;
  font-size: 0.8rem;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.stc-rate-chip:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.stc-rate-chip.is-active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ── Panel / Card ─────────────────────────────────────────────────────────── */
.stc-panel {
  animation: stc-fade-in 0.15s ease;
}

@keyframes stc-fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}

.stc-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card, 8px);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

/* ── Fields ───────────────────────────────────────────────────────────────── */
.stc-fields {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

@media (max-width: 520px) {
  .stc-fields {
    grid-template-columns: 1fr;
  }
}

.stc-field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.stc-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
}

.stc-input {
  width: 100%;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-control, 6px);
  background: var(--bg-input, var(--bg-card));
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.stc-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--focus-ring, rgba(37, 99, 235, 0.12));
}

/* ── Error ────────────────────────────────────────────────────────────────── */
.stc-error {
  font-size: 0.875rem;
  color: var(--color-danger, #dc2626);
  margin: 0;
}

/* ── Output ───────────────────────────────────────────────────────────────── */
.stc-output {
  background: var(--bg-secondary, var(--bg-card));
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card, 8px);
  padding: 1.1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.stc-output__primary {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.stc-output__label-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.stc-output__label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}

.stc-output__value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.02em;
}

/* ── Secondary stats ──────────────────────────────────────────────────────── */
.stc-output__secondary {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
}

.stc-stat {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.stc-stat__label {
  font-size: 0.775rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.stc-stat__value {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* ── Copy button ──────────────────────────────────────────────────────────── */
.stc-copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.25rem 0.6rem;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-control, 6px);
  font-size: 0.8rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background 0.12s, color 0.12s;
  white-space: nowrap;
}

.stc-copy-btn:hover {
  background: var(--bg-hover, rgba(0,0,0,0.04));
  color: var(--text-primary);
}

.stc-copy-btn.is-copied {
  color: var(--color-success, #16a34a);
  border-color: var(--color-success, #16a34a);
}

/* ── Formula ──────────────────────────────────────────────────────────────── */
.stc-formula-wrap {
  border-top: 1px solid var(--border-color);
  padding-top: 0.75rem;
}

.stc-formula__label {
  font-size: 0.775rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
  display: block;
  margin-bottom: 0.3rem;
}

.stc-formula {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  margin: 0;
  word-break: break-all;
}

/* ── Reset button ─────────────────────────────────────────────────────────── */
.stc-reset-btn {
  align-self: flex-start;
  padding: 0.4rem 0.9rem;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-control, 6px);
  font-size: 0.85rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background 0.12s, color 0.12s;
}

.stc-reset-btn:hover {
  background: var(--bg-hover, rgba(0,0,0,0.04));
  color: var(--text-primary);
}