:root {
  --bg: #0b0f14;
  --card: #111827;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --accent: #38bdf8;
  --accent-2: #0ea5e9;
  --danger: #f87171;
  --border: #1f2937;
}

* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: radial-gradient(ellipse at top, #1e293b 0%, var(--bg) 60%);
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 24px;
}

.card {
  position: relative;
  width: 100%;
  max-width: 420px;
  background: rgba(17, 24, 39, 0.85);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
  text-align: center;
}

.help-btn {
  position: absolute;
  top: 14px;
  right: 14px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--muted);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  line-height: 1;
}
.help-btn:hover { color: var(--text); border-color: var(--accent); }

h1 { margin: 0 0 4px; font-size: 24px; font-weight: 700; }
.sub { margin: 0 0 24px; color: var(--muted); font-size: 14px; }

.row { display: flex; gap: 10px; margin-bottom: 20px; }
.btn {
  flex: 1;
  padding: 12px 14px;
  border: none;
  border-radius: 10px;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: transform 0.1s, opacity 0.15s;
}
.btn:disabled { opacity: 0.4; cursor: not-allowed; }
.btn:active:not(:disabled) { transform: scale(0.97); }
.btn-primary { background: var(--accent); color: #082f49; }
.btn-accent { background: var(--accent-2); color: #fff; }
.btn-ghost { background: transparent; color: var(--muted); border: 1px solid var(--border); }
/* Device connected + firmware picked = green go. Pulse keeps the
   state obvious without being a strobe. */
.btn-ready {
  background: #22c55e;
  color: #052e16;
  box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.55);
  animation: ready-pulse 1.8s ease-out infinite;
}
.btn-ready:hover:not(:disabled) { background: #16a34a; }
@keyframes ready-pulse {
  0%   { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.55); }
  70%  { box-shadow: 0 0 0 10px rgba(34, 197, 94, 0); }
  100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0); }
}

.status {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--muted);
  border-top: 1px solid var(--border);
  padding-top: 14px;
}
.status .label { color: var(--muted); }

.firmware {
  text-align: left;
  border-top: 1px solid var(--border);
  padding-top: 14px;
}
.firmware .status { border-top: none; padding-top: 0; }
.adv { margin-top: 8px; }
.adv summary {
  color: var(--muted);
  font-size: 12px;
  cursor: pointer;
}
.adv-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px 12px;
  align-items: center;
  margin-top: 8px;
}
.sel {
  width: 100%;
  background: #0f172a;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 13px;
  font-family: inherit;
}
.sel:disabled { opacity: 0.55; }

.warning {
  background: rgba(248, 113, 113, 0.12);
  color: var(--danger);
  border: 1px solid rgba(248, 113, 113, 0.35);
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 13px;
  margin-bottom: 16px;
  text-align: left;
}
.warning ul { margin: 6px 0 4px; padding-left: 18px; }
.warning li { margin: 2px 0; }
.warn-env {
  margin-top: 8px;
  font-size: 11px;
  color: var(--muted);
}
.req {
  margin: 12px 0 0;
  padding: 10px 0 0 18px;
  border-top: 1px solid var(--border);
  font-size: 12px;
  color: var(--muted);
  line-height: 1.6;
}

progress {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 16px;
  appearance: none;
  border: none;
}
progress::-webkit-progress-bar { background: var(--border); }
progress::-webkit-progress-value { background: var(--accent); }
progress::-moz-progress-bar { background: var(--accent); }

.guide {
  position: absolute;
  top: 48px;
  right: 14px;
  z-index: 10;
  width: min(360px, calc(100% - 28px));
  text-align: left;
  background: #0f172a;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.55);
}
.guide-body { display: flex; gap: 14px; align-items: flex-start; }
.board { width: 46%; flex-shrink: 0; }
.steps { font-size: 13px; color: var(--muted); }
.steps-title { margin: 0 0 8px; color: var(--text); font-weight: 600; }
.steps ol { margin: 0 0 10px; padding-left: 18px; line-height: 1.9; }
.steps b { color: var(--text); }
.steps-note { font-size: 12px; margin: 0; }
.b-boot { color: #f59e0b; }
.b-rst { color: var(--accent); }
.board .lbl { fill: var(--muted); font-size: 9.5px; font-weight: 600; font-family: inherit; }
.board .lbl-accent { fill: var(--accent); }
.board .lbl-boot { fill: #f59e0b; }
.board .lead { stroke: #334155; stroke-width: 1; }
.board .lead-accent { stroke: var(--accent); }
.board .lead-boot { stroke: #f59e0b; }
.board .pcb-txt { fill: #64748b; font-size: 8.5px; font-family: inherit; }

.notice {
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.35);
  color: var(--accent);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 13px;
  margin-bottom: 16px;
  text-align: left;
}
.notice.ok {
  background: rgba(34, 197, 94, 0.12);
  border-color: rgba(34, 197, 94, 0.5);
  color: #4ade80;
}
.notice.bad {
  background: rgba(248, 113, 113, 0.12);
  border-color: rgba(248, 113, 113, 0.5);
  color: var(--danger);
}

.log-wrap { text-align: left; }
.log-wrap summary { color: var(--muted); font-size: 13px; cursor: pointer; padding: 6px 0; }
.log-wrap pre {
  background: #0f172a;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px;
  font-size: 12px;
  color: var(--muted);
  max-height: 140px;
  overflow: auto;
  margin: 8px 0 0;
  white-space: pre-wrap;
}