.check-intro {
  padding: 86px max(24px, calc((100vw - var(--max)) / 2)) 54px;
  background: linear-gradient(115deg, #f8fafb 0 70%, #eef3f4 70%);
}

.check-intro h1 {
  max-width: 980px;
  margin-bottom: 24px;
  font-size: clamp(3rem, 6vw, 6rem);
}

.check-intro h1 em { color: var(--blue); font-style: normal; }
.check-intro > p:last-child { max-width: 760px; margin: 0; color: var(--muted); font-size: 1.12rem; }

.checker-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(340px, .65fr);
  max-width: var(--max);
  margin: 0 auto 110px;
  border: 1px solid var(--line);
  background: #fff;
  box-shadow: 24px 24px 0 rgba(0, 99, 125, .10);
}

.checker-view-column { min-width: 0; border-right: 1px solid var(--line); }

.stl-drop-zone {
  display: grid;
  grid-template-columns: 62px 1fr;
  column-gap: 18px;
  align-items: center;
  min-height: 116px;
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
  background: #fff;
  cursor: pointer;
  transition: background-color .18s ease, box-shadow .18s ease;
}

.stl-drop-zone:hover,
.stl-drop-zone.dragging { background: #eef9fb; box-shadow: inset 0 0 0 3px #79c7d8; }
.stl-drop-zone:focus-within { outline: 3px solid #79c7d8; outline-offset: -3px; }
.stl-drop-zone strong { font-size: 1.03rem; line-height: 1.3; }
.stl-drop-zone small { grid-column: 2; color: var(--muted); }

.drop-icon {
  grid-row: 1 / span 2;
  display: grid;
  place-items: center;
  width: 62px;
  height: 62px;
  background: var(--blue);
  color: #fff;
  font-family: monospace;
  font-weight: 900;
  letter-spacing: .08em;
}

.check-stage {
  position: relative;
  min-height: 520px;
  overflow: hidden;
  background-color: #111a1f;
  background-image:
    linear-gradient(rgba(121, 199, 216, .08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(121, 199, 216, .08) 1px, transparent 1px);
  background-size: 38px 38px;
  touch-action: none;
}

.check-stage canvas { display: block; width: 100%; height: 100%; min-height: 520px; cursor: grab; outline: none; }
.check-stage canvas:active { cursor: grabbing; }
.check-stage canvas:focus-visible { outline: 3px solid #79c7d8; outline-offset: -5px; }

.check-status {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 30px;
  background: rgba(17, 26, 31, .72);
  color: #d7eef3;
  text-align: center;
  font-weight: 800;
  pointer-events: none;
}

.check-status.hidden { opacity: 0; }
.check-status.error { color: #fff; background: rgba(92, 24, 24, .86); }

.check-help {
  position: absolute;
  left: 16px;
  bottom: 14px;
  margin: 0;
  padding: 8px 11px;
  background: rgba(17, 26, 31, .84);
  color: #c5dce1;
  font-size: .76rem;
  pointer-events: none;
}

.viewer-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  min-height: 72px;
  padding: 14px 24px;
  background: #fff;
}

.viewer-toolbar span { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--muted); font-size: .84rem; }
.viewer-toolbar button { flex: 0 0 auto; min-height: 42px; border: 1px solid var(--blue); background: #fff; padding: 8px 14px; color: var(--ink); font: inherit; font-weight: 800; cursor: pointer; }
.viewer-toolbar button:hover:not(:disabled) { background: var(--blue); color: #fff; }
.viewer-toolbar button:disabled { opacity: .45; cursor: not-allowed; }

.check-panel { padding: 42px 34px; }
.check-panel h2 { margin-bottom: 18px; font-size: clamp(1.8rem, 3vw, 2.65rem); }
.check-panel-lead { margin: 0 0 28px; color: var(--muted); }

.dimension-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-left: 1px solid var(--line); margin-bottom: 28px; }
.dimension-grid div { display: grid; gap: 5px; padding: 15px 10px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.dimension-grid span { color: var(--muted); font-size: .72rem; }
.dimension-grid strong { color: var(--blue); font-size: 1rem; font-variant-numeric: tabular-nums; white-space: nowrap; }

.check-form { display: grid; gap: 16px; }
.check-form label { display: grid; gap: 6px; font-size: .8rem; font-weight: 800; }
.check-form select,
.check-form input,
.check-form textarea { border-color: #cbd3d7; }
.check-email { width: 100%; border: 0; background: var(--blue); color: #fff; }
.check-email:disabled { opacity: .45; cursor: not-allowed; }

.local-privacy { margin-top: 28px; padding: 18px; border-left: 4px solid var(--blue); background: #eef3f4; }
.local-privacy strong { display: block; margin-bottom: 5px; }
.local-privacy p { margin: 0 0 8px; color: var(--muted); font-size: .8rem; }
.local-privacy a { color: var(--blue); font-size: .78rem; font-weight: 800; }

@media (max-width: 920px) {
  .checker-wrap { grid-template-columns: 1fr; margin-right: 24px; margin-left: 24px; }
  .checker-view-column { border-right: 0; border-bottom: 1px solid var(--line); }
}

@media (max-width: 620px) {
  .check-intro { padding-top: 62px; }
  .check-intro h1 { font-size: 3rem; }
  .checker-wrap { margin-right: 16px; margin-bottom: 80px; margin-left: 16px; box-shadow: 12px 12px 0 rgba(0, 99, 125, .10); }
  .stl-drop-zone { grid-template-columns: 50px 1fr; padding: 16px; column-gap: 12px; }
  .drop-icon { width: 50px; height: 50px; }
  .check-stage, .check-stage canvas { min-height: 390px; }
  .check-help { right: 10px; left: 10px; bottom: 10px; text-align: center; }
  .viewer-toolbar { align-items: stretch; flex-direction: column; gap: 10px; }
  .viewer-toolbar button { width: 100%; }
  .check-panel { padding: 34px 22px; }
  .dimension-grid { grid-template-columns: 1fr; }
}