:root {
  --bg: #0f1115;
  --panel: #161a22;
  --panel-2: #1d222c;
  --line: #2a3140;
  --text: #e6e9ef;
  --muted: #8a93a6;
  --accent: #4f8cff;
  --accent-2: #6aa3ff;
  --ok: #2ecc71;
  --warn: #f39c12;
  --err: #ff5c5c;
  --radius: 10px;
}

* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font-family: -apple-system, "Segoe UI", "Sarabun", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.45;
}

.muted { color: var(--muted); font-weight: normal; font-size: .9em; }

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  padding: 12px 16px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 10;
}
.brand { font-weight: 600; letter-spacing: .3px; }
.conn { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
@media (max-width: 540px) {
  .topbar { padding: 10px 12px; }
  .brand { font-size: .95rem; }
  .conn { width: 100%; justify-content: flex-end; }
  .badge { order: -1; }
}

.badge {
  font-size: .8rem; padding: 3px 10px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--panel-2);
}
.badge-off { color: var(--muted); }
.badge-on { color: var(--ok); border-color: rgba(46,204,113,.3); background: rgba(46,204,113,.08); }
.badge-busy { color: var(--warn); border-color: rgba(243,156,18,.3); background: rgba(243,156,18,.08); }
.badge-err { color: var(--err); border-color: rgba(255,92,92,.3); background: rgba(255,92,92,.08); }

.btn {
  appearance: none; border: 1px solid var(--line); background: var(--panel-2);
  color: var(--text); padding: 8px 14px; border-radius: 8px; cursor: pointer;
  font: inherit; transition: .15s;
}
.btn:hover:not(:disabled) { border-color: var(--accent); }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-primary:hover:not(:disabled) { background: var(--accent-2); }
.btn-ghost { background: transparent; }
.btn-sm { padding: 4px 10px; font-size: .85rem; }

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 20px;
  padding: 20px;
  max-width: 1400px;
  margin: 0 auto;
}
@media (max-width: 980px) {
  .layout { grid-template-columns: 1fr; gap: 14px; padding: 14px; }
}
@media (max-width: 540px) {
  .layout { padding: 10px; gap: 10px; }
}

.form-pane, .preview-pane {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}
@media (max-width: 540px) {
  .form-pane, .preview-pane { padding: 12px; }
}
h2 { margin: 0 0 14px; font-size: 1.1rem; }
h3 { margin: 18px 0 8px; font-size: .95rem; color: var(--muted); }

.row { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 12px; }
@media (max-width: 540px) { .row { grid-template-columns: 1fr; } }

fieldset {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 14px 14px;
  margin: 0 0 14px;
}
legend { padding: 0 8px; color: var(--accent-2); font-size: .9rem; }

label { display: block; font-size: .85rem; color: var(--muted); margin-bottom: 10px; }
label:last-child { margin-bottom: 0; }

input, textarea, select {
  width: 100%;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 10px 12px;
  font: inherit;
  font-size: 16px; /* prevent iOS Safari zoom-on-focus */
  margin-top: 4px;
}
input:focus, textarea:focus, select:focus { outline: none; border-color: var(--accent); }
textarea { resize: vertical; }

.actions {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-top: 14px;
  flex-wrap: wrap;
}
.actions .spacer { flex: 1 1 auto; }
@media (max-width: 540px) {
  .actions { gap: 8px; }
  .actions .spacer { display: none; }
  .actions .btn { flex: 1 1 calc(50% - 4px); }
  .actions .btn-primary { flex: 1 1 100%; order: 99; padding: 12px; font-size: 1rem; }
}
.btn { min-height: 40px; }
@media (max-width: 540px) {
  .btn { min-height: 44px; } /* touch target */
}

.preview-wrap {
  background: #f5f5f5;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  overflow: auto;
  max-height: 60vh;
}
@media (max-width: 540px) {
  .preview-wrap { padding: 8px; max-height: 50vh; }
}
.preview-canvas {
  background: #fff;
  box-shadow: 0 2px 10px rgba(0,0,0,.15);
  image-rendering: pixelated;
  max-width: 100%;
  height: auto;
  display: block;
}

.log {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 12px;
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: .82rem;
  max-height: 220px;
  overflow: auto;
  white-space: pre-wrap;
}
.log .l { padding: 2px 0; }
.log .l-info { color: var(--text); }
.log .l-ok { color: var(--ok); }
.log .l-warn { color: var(--warn); }
.log .l-err { color: var(--err); }
.log .l-time { color: var(--muted); margin-right: 6px; }