/* ============================================================
   Pipe Flow & Pump Calculator — pipe-flow-calculator.css
   Namespace: .pf-*
   ============================================================ */

/* --- Section headings ---------------------------------------- */
.pf-section {
  margin: 1.4rem 0 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--md-default-fg-color--light);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  border-bottom: 1px solid var(--md-default-fg-color--lightest);
  padding-bottom: 0.3rem;
}

/* --- Input grid ---------------------------------------------- */
.pf-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem 1.25rem;
}

.pf-grid-4 {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  gap: 0.75rem 1rem;
}

/* --- Input group (label + input) ----------------------------- */
.pf-group {
  display: flex;
  flex-direction: column;
  margin-bottom: 0.2rem;
}

.pf-group label {
  font-size: 0.78rem;
  margin-bottom: 0.18rem;
  color: var(--md-default-fg-color--light);
  line-height: 1.3;
}

.pf-group .pf-unit {
  font-size: 0.72rem;
  color: var(--md-default-fg-color--lighter);
}

.pf-group input[type="number"] {
  padding: 0.38rem 0.55rem;
  font-size: 0.92rem;
  font-family: var(--md-code-font-family);
  background: var(--md-code-bg-color);
  color: var(--md-default-fg-color);
  border: 1px solid var(--md-default-fg-color--lightest);
  border-radius: 3px;
  width: 100%;
  box-sizing: border-box;
}

.pf-group input[type="number"]:focus {
  border-color: var(--md-primary-fg-color);
  outline: none;
}

/* --- Calculate button ---------------------------------------- */
.pf-btn {
  margin-top: 1.25rem;
  background: var(--md-primary-fg-color);
  color: var(--md-primary-bg-color);
  border: none;
  border-radius: 3px;
  padding: 0.5rem 1.4rem;
  font-size: 0.92rem;
  cursor: pointer;
  font-family: var(--md-text-font-family);
}

.pf-btn:hover {
  opacity: 0.88;
}

/* --- Error --------------------------------------------------- */
.pf-error {
  color: #e53935;
  font-size: 0.88rem;
  padding: 0.5rem 0;
  margin-top: 0.5rem;
}

.pf-notice {
  font-size: 0.88rem;
  padding: 0.55rem 0.8rem;
  margin-top: 0.5rem;
  background: color-mix(in srgb, var(--md-code-bg-color) 82%, #ffc107 18%);
  border-left: 3px solid #ffc107;
  border-radius: 0.25rem;
  color: var(--md-default-fg-color);
  line-height: 1.55;
}

/* --- Results area -------------------------------------------- */
.pf-results {
  margin-top: 1.5rem;
}

.pf-divider {
  border: none;
  border-top: 1px solid var(--md-default-fg-color--lightest);
  margin: 1.1rem 0 0.8rem;
}

.pf-result-heading {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--md-default-fg-color--light);
  margin: 1.1rem 0 0.55rem;
}

/* Primary KV grid — larger, highlighted */
.pf-kv-primary {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 0.6rem;
  margin-bottom: 1rem;
}

.pf-kv {
  background: var(--md-code-bg-color);
  border: 1px solid var(--md-default-fg-color--lightest);
  border-radius: 3px;
  padding: 0.55rem 0.8rem;
}

.pf-kv.pf-kv-accent {
  border-color: var(--md-accent-fg-color);
}

.pf-kv-label {
  font-size: 0.7rem;
  color: var(--md-default-fg-color--light);
  margin-bottom: 0.12rem;
}

.pf-kv-value {
  font-size: 1.05rem;
  font-family: var(--md-code-font-family);
  color: var(--md-accent-fg-color);
}

.pf-kv-value.pf-kv-normal {
  color: var(--md-default-fg-color);
}

/* Secondary KV grid — smaller */
.pf-kv-secondary {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.pf-kv-secondary .pf-kv-value {
  font-size: 0.92rem;
}

/* --- Assumptions note --------------------------------------- */
.pf-assumptions {
  font-size: 0.75rem;
  color: var(--md-default-fg-color--light);
  margin-top: 1.4rem;
  padding: 0.6rem 0.9rem;
  border-left: 3px solid var(--md-default-fg-color--lightest);
  line-height: 1.7;
}

/* --- Responsive -------------------------------------------- */
@media (max-width: 760px) {
  .pf-grid-4 {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 520px) {
  .pf-grid-2,
  .pf-grid-4 {
    grid-template-columns: 1fr;
  }
}