/* ---------- Calculator page (builds on style.css) ---------- */
:root {
  --c-point: #c0392b;
  --c-udl: #2980b9;
  --c-moment: #27ae60;
  --c-error: #b3261e;
}

button.btn { border: 1px solid transparent; cursor: pointer; font-family: inherit; }
button.btn-outline { border-color: var(--border); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; box-shadow: none; }
.btn-small { padding: 9px 18px; font-size: 0.88rem; }
.btn-block { display: block; width: 100%; text-align: center; }
.muted { color: var(--text-muted); font-weight: 400; }

/* Intro strip */
.calc-intro {
  background: var(--steel-light);
  border-bottom: 1px solid var(--border);
  padding: 28px 24px 18px;
}
.calc-intro-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  gap: 20px;
  align-items: flex-end;
  justify-content: space-between;
  flex-wrap: wrap;
}
.calc-intro h1 { margin: 0 0 6px; font-size: 1.7rem; color: var(--navy); }
.calc-intro p { margin: 0; color: var(--text-muted); }
.calc-disclaimer {
  max-width: 1280px;
  margin: 14px auto 0 !important;
  font-size: 0.85rem;
}

/* Two-column layout */
.calc-layout {
  max-width: 1280px;
  margin: 0 auto;
  padding: 28px 24px 64px;
  display: grid;
  grid-template-columns: minmax(300px, 360px) minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}
.calc-panel {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
}
.calc-inputs { position: sticky; top: 86px; max-height: calc(100vh - 100px); overflow-y: auto; }
.calc-results { display: flex; flex-direction: column; gap: 20px; min-width: 0; }

.panel-title {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--steel);
  margin: 0 0 12px;
}
.calc-inputs .panel-title:not(:first-child) { margin-top: 22px; }

/* Fields */
.field { margin-bottom: 12px; }
.field label { display: block; font-size: 0.85rem; font-weight: 600; margin-bottom: 4px; }
.input-unit { display: flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; background: var(--white); }
.input-unit:focus-within { border-color: var(--navy); box-shadow: 0 0 0 3px rgba(15, 39, 67, 0.12); }
.input-unit input {
  flex: 1; min-width: 0; border: 0; padding: 9px 10px;
  font: inherit; font-size: 0.95rem; color: var(--text); background: transparent;
}
.input-unit input:focus { outline: none; }
.input-unit span {
  padding: 9px 10px; background: var(--steel-light); color: var(--text-muted);
  font-size: 0.85rem; border-left: 1px solid var(--border); white-space: nowrap;
}
.input-unit.invalid { border-color: var(--c-error); }
.field-row { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 10px; }
.input-unit input { width: 100%; }

/* White halo behind diagram labels so lines never obscure them */
#beam-svg text { paint-order: stroke; stroke: #ffffff; stroke-width: 4px; stroke-linejoin: round; }

.section-props { border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; margin-top: 4px; }
.section-props summary { cursor: pointer; font-size: 0.9rem; font-weight: 600; }
.section-props[open] summary { margin-bottom: 12px; }

/* Load cards */
.load-card {
  border: 1px solid var(--border);
  border-left: 4px solid var(--load-color);
  border-radius: 8px;
  padding: 10px 12px 2px;
  margin-bottom: 10px;
}
.load-card.point { --load-color: var(--c-point); }
.load-card.udl { --load-color: var(--c-udl); }
.load-card.moment { --load-color: var(--c-moment); }
.load-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 8px; }
.load-name { font-weight: 700; font-size: 0.92rem; }
.load-name b { color: var(--load-color); }
.remove-btn {
  border: 0; background: none; color: var(--text-muted); cursor: pointer;
  font-size: 1.1rem; line-height: 1; padding: 4px 6px; border-radius: 6px;
}
.remove-btn:hover { background: var(--steel-light); color: var(--c-error); }

.add-load { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.add-btn {
  border: 1px dashed var(--border); background: var(--white); border-radius: 8px;
  padding: 8px 4px; font: inherit; font-size: 0.85rem; font-weight: 600; cursor: pointer;
}
.add-point { color: var(--c-point); }
.add-udl { color: var(--c-udl); }
.add-moment { color: var(--c-moment); }
.add-btn:hover:not(:disabled) { border-style: solid; border-color: currentColor; }
.add-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.hint { font-size: 0.8rem; color: var(--text-muted); margin: 10px 0 16px; }

.input-errors {
  background: #fdecea; border: 1px solid #f5c2bd; color: var(--c-error);
  border-radius: 8px; padding: 10px 12px; font-size: 0.85rem; margin-bottom: 14px;
}
.input-errors ul { margin: 0; padding-left: 18px; }
.calc-status { font-size: 0.85rem; color: var(--text-muted); margin: 10px 0 0; text-align: center; }

/* Results */
.results-notice {
  background: #fff8e6; border: 1px solid #f0dca8; color: #6b5210;
  border-radius: var(--radius); padding: 12px 16px; font-size: 0.9rem;
}
.results-notice.error { background: #fdecea; border-color: #f5c2bd; color: var(--c-error); }
.results-notice ul { margin: 4px 0 0; padding-left: 18px; }
.calc-results.stale .result-tiles,
.calc-results.stale .chart { opacity: 0.45; transition: opacity 0.2s; }
.result-tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; }
.tile { background: var(--white); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; }
.tile-label { font-size: 0.75rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.04em; }
.tile-value { font-size: 1.35rem; font-weight: 700; color: var(--navy); margin-top: 4px; }
.tile-value small { font-size: 0.8rem; font-weight: 500; color: var(--text-muted); }
.tile-sub { font-size: 0.78rem; color: var(--text-muted); margin-top: 2px; }

.diagram-box { overflow-x: auto; }
#beam-svg { display: block; width: 100%; min-width: 520px; height: auto; font-family: inherit; }
.chart { width: 100%; height: 300px; }

.export-row { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.export-row p { margin: 0; font-size: 0.9rem; }

@media (max-width: 900px) {
  .calc-layout { grid-template-columns: minmax(0, 1fr); }
  .calc-inputs { position: static; max-height: none; }
}
@media (max-width: 480px) {
  .calc-layout { padding: 20px 16px 48px; }
  .calc-intro { padding: 22px 16px 14px; }
  .calc-panel { padding: 16px; }
  .chart { height: 260px; }
}