:root {
  --bg: #f3f5f8;
  --card: #fff;
  --accent: #1f4e79;
  --muted: #5e6a78;
  --line: #d5dce5;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: #1c2430;
}
header {
  background: var(--accent);
  color: #fff;
  padding: 1rem 1.5rem;
}
header p { margin: 0.25rem 0 0; opacity: 0.85; font-size: 0.9rem; }
.layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 1rem;
  max-width: 1100px;
  margin: 1rem auto;
  padding: 0 1rem 2rem;
}
nav steps {
  display: block;
}
.step-nav button {
  display: block;
  width: 100%;
  text-align: left;
  border: none;
  background: #e7edf4;
  padding: 0.65rem 0.75rem;
  margin-bottom: 0.35rem;
  border-radius: 6px;
  cursor: pointer;
}
.step-nav button.active { background: var(--card); font-weight: 600; color: var(--accent); }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
}
.field { margin-bottom: 0.85rem; }
.field label { display: block; font-size: 0.85rem; margin-bottom: 0.25rem; }
.field input, .field select, .field textarea {
  width: 100%;
  padding: 0.45rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 4px;
  font: inherit;
}
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.75rem; }
.hidden { display: none; }
.actions {
  display: flex;
  gap: 0.5rem;
  justify-content: flex-end;
  margin-top: 1rem;
  flex-wrap: wrap;
}
.btn {
  border: none;
  border-radius: 6px;
  padding: 0.55rem 1rem;
  cursor: pointer;
  font: inherit;
}
.btn-primary { background: var(--accent); color: #fff; font-weight: 600; }
.btn-ghost { background: #eef2f7; }
#estimate-json { font-family: ui-monospace, monospace; font-size: 0.8rem; min-height: 160px; }
.hint { color: var(--muted); font-size: 0.8rem; }
@media (max-width: 800px) {
  .layout { grid-template-columns: 1fr; }
  .grid2, .grid3 { grid-template-columns: 1fr; }
}