:root {
  --bg: #eef1f4;
  --card: #ffffff;
  --ink: #263238;
  --ink-soft: #5b6b76;
  --line: #d5dde3;
  --primary: #4a7ea1;
  --primary-ink: #ffffff;
  --accent: #b8562f;
  --warn-bg: #fff4e2;
  --warn-line: #e6b26a;
  --error: #b3261e;
  --ok: #2e7d4f;
  --radius: 12px;
  --shadow: 0 2px 10px rgba(38, 50, 56, 0.08);
  --gap: 18px;

  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color: var(--ink);
  line-height: 1.5;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
}

.topbar {
  padding: 22px 24px 16px;
  text-align: center;
}
.topbar h1 { margin: 0; font-size: 1.7rem; }
.tagline { margin: 4px 0 0; color: var(--ink-soft); }

.wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 20px 60px;
  display: flex;
  flex-direction: column;
  gap: var(--gap);
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px 24px;
}
.card h2 { margin: 0 0 16px; font-size: 1.2rem; }
.card h3 { margin: 0 0 10px; font-size: 1rem; }

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  margin-right: 8px;
  border-radius: 50%;
  background: var(--primary);
  color: var(--primary-ink);
  font-size: 0.9rem;
}

.hidden { display: none !important; }

/* Buttons — one base, colour variants only */
.btn {
  display: inline-block;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 10px 18px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: filter 0.15s ease;
}
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn:not(:disabled):hover { filter: brightness(1.06); }
.btn-primary { background: var(--primary); color: var(--primary-ink); }
.btn-accent { background: var(--accent); color: #fff; }
.btn-ghost { background: transparent; border-color: var(--line); color: var(--ink-soft); }

/* Banner */
.banner {
  border-radius: var(--radius);
  padding: 14px 18px;
}
.banner-warn { background: var(--warn-bg); border: 1px solid var(--warn-line); }
.banner code {
  background: rgba(0, 0, 0, 0.06);
  padding: 1px 6px;
  border-radius: 4px;
}

/* Step 1 */
.import-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}
.file-drop {
  flex: 1 1 240px;
  border: 2px dashed var(--line);
  border-radius: 8px;
  padding: 12px 16px;
  color: var(--ink-soft);
  cursor: pointer;
  text-align: center;
}
.file-drop:hover { border-color: var(--primary); }
.upload-preview {
  margin-top: 16px;
  max-width: 260px;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

/* Step 2 */
.position-grid {
  display: grid;
  grid-template-columns: minmax(220px, 320px) 1fr;
  gap: 24px;
  align-items: start;
}
.board-preview {
  width: 100%;
  border-radius: 8px;
  box-shadow: var(--shadow);
}
.position-controls { display: flex; flex-direction: column; gap: 14px; }

.field { display: flex; flex-direction: column; gap: 6px; border: 0; padding: 0; margin: 0; }
.field > span, .field legend { font-size: 0.85rem; color: var(--ink-soft); font-weight: 600; }
.field-inline { flex-direction: row; align-items: center; gap: 10px; }
.field input[type="text"], .field textarea, select {
  font: inherit;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
}
fieldset.field label { font-weight: 400; margin-right: 14px; }
.checkbox { font-size: 0.9rem; color: var(--ink-soft); }

/* Step 3 */
.choose-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
.choice {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.line-out {
  margin-top: 20px;
  padding: 16px;
  border-radius: 10px;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.line-label { margin: 0; font-size: 0.8rem; font-weight: 700; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.04em; }
.solution-list {
  margin: 0;
  padding-left: 22px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 1.1rem;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
}
.solution-list.single { list-style: none; padding-left: 0; }

/* Step 4 — one figure per generated solution */
.result-gallery {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}
.result-item {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-start;
  max-width: 420px;
}
.result-item figcaption {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.95rem;
  color: var(--ink);
}
.result-gif {
  display: block;
  max-width: 100%;
  width: 420px;
  border-radius: 10px;
  box-shadow: var(--shadow);
}

/* Status text */
.status { margin: 12px 0 0; font-size: 0.9rem; min-height: 1.2em; }
.status.error { color: var(--error); }
.status.ok { color: var(--ok); }
.status.busy { color: var(--ink-soft); }

@media (max-width: 620px) {
  .position-grid, .choose-grid { grid-template-columns: 1fr; }
}