:root {
  --bg: #0f1220;
  --card: #1a1f33;
  --ink: #e8ecff;
  --muted: #9aa3c7;
  --accent: #7aa2ff;
  --accent2: #ffb86b;
  --line: #2a3354;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Noto Sans SC", sans-serif;
  background: radial-gradient(1200px 600px at 10% -10%, #243056 0%, var(--bg) 55%);
  color: var(--ink);
  min-height: 100vh;
}
.wrap { max-width: 880px; margin: 0 auto; padding: 28px 18px 48px; }
header h1 { margin: 0 0 6px; font-size: 1.7rem; letter-spacing: 0.02em; }
.sub { margin: 0 0 22px; color: var(--muted); }
.panel {
  background: color-mix(in srgb, var(--card) 92%, black);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px;
  box-shadow: 0 12px 40px rgba(0,0,0,.35);
}
label { display: block; font-size: 0.9rem; margin: 10px 0 6px; color: var(--muted); }
.hint { opacity: 0.75; font-size: 0.8rem; }
textarea, input[type="number"] {
  width: 100%;
  background: #12172a;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 1rem;
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px 16px;
  margin-top: 8px;
}
.row { display: flex; flex-wrap: wrap; gap: 12px; }
.radio, .check { color: var(--ink); display: inline-flex; align-items: center; gap: 6px; }
.val { color: var(--accent); margin-left: 6px; font-variant-numeric: tabular-nums; }
.actions { display: flex; gap: 10px; margin-top: 16px; flex-wrap: wrap; }
button {
  appearance: none;
  border: 0;
  border-radius: 999px;
  padding: 10px 18px;
  font-weight: 600;
  cursor: pointer;
  background: linear-gradient(135deg, var(--accent), #9b7bff);
  color: #0b1020;
}
button:disabled { opacity: 0.45; cursor: not-allowed; }
#dl { background: linear-gradient(135deg, var(--accent2), #ff8f6b); }
.status { margin-top: 12px; min-height: 1.4em; color: var(--muted); font-size: 0.92rem; }
.preview-wrap { margin-top: 18px; }
.checker {
  border-radius: 16px;
  border: 1px solid var(--line);
  overflow: auto;
  background-image:
    linear-gradient(45deg, #2a3148 25%, transparent 25%),
    linear-gradient(-45deg, #2a3148 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #2a3148 75%),
    linear-gradient(-45deg, transparent 75%, #2a3148 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
  background-color: #1c2238;
  min-height: 160px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}
#preview { max-width: 100%; height: auto; background: transparent; }
.hidden { display: none; }
footer { margin-top: 22px; color: var(--muted); font-size: 0.85rem; line-height: 1.5; }