* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #f4f6f8;
  color: #172033;
}
.topbar {
  position: sticky;
  top: 0;
  z-index: 2;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
  padding: 18px 20px;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #e6e8ef;
}
h1 { margin: 0 0 6px; font-size: 22px; }
p { margin: 0; color: #687086; }
.layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  padding: 18px;
  max-width: 1280px;
  margin: 0 auto;
}
.card {
  background: #fff;
  border: 1px solid #e6e8ef;
  border-radius: 18px;
  padding: 18px;
  box-shadow: 0 8px 28px rgba(23,32,51,.06);
}
.card.wide { grid-column: 1 / -1; }
h2 { margin: 0 0 10px; font-size: 18px; }
h3 { margin: 14px 0 8px; font-size: 15px; }
.tip {
  padding: 10px 12px;
  background: #f7f8fb;
  border-radius: 12px;
  margin-bottom: 14px;
  line-height: 1.5;
}
.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
label {
  display: flex;
  flex-direction: column;
  gap: 7px;
  font-size: 13px;
  color: #4b5568;
}
input, select, textarea {
  width: 100%;
  border: 1px solid #d9deea;
  border-radius: 12px;
  padding: 11px 12px;
  font-size: 14px;
  outline: none;
  background: #fff;
}
textarea {
  min-height: 150px;
  resize: vertical;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 12px;
}
input:focus, select:focus, textarea:focus { border-color: #4f7cff; }
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}
button {
  border: 0;
  border-radius: 12px;
  padding: 11px 14px;
  font-weight: 700;
  color: #fff;
  background: #246bfe;
  cursor: pointer;
}
button.secondary { background: #172033; }
button.danger { background: #d92d20; }
button:disabled { opacity: .45; cursor: not-allowed; }
.result input { margin-top: 8px; }
.pre {
  min-height: 120px;
  max-height: 460px;
  overflow: auto;
  padding: 14px;
  border-radius: 12px;
  background: #0e1320;
  color: #d7e0ff;
  white-space: pre-wrap;
  word-break: break-all;
  font-size: 12px;
}
code {
  padding: 2px 5px;
  border-radius: 6px;
  background: #eef2ff;
  color: #1f3fb5;
}
@media (max-width: 820px) {
  .topbar { align-items: flex-start; flex-direction: column; }
  .layout { grid-template-columns: 1fr; padding: 12px; }
  .grid { grid-template-columns: 1fr; }
  .card { border-radius: 14px; padding: 14px; }
}