:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface2: #21262d;
  --surface3: #2d333b;
  --accent: #58a6ff;
  --accent-hover: #79b8ff;
  --green: #3fb950;
  --yellow: #e3b341;
  --red: #f85149;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --border: #30363d;
  --radius: 8px;
  --radius-sm: 4px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.5;
  min-height: 100vh;
}

/* ── Header ──────────────────────────────────────────────── */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 10px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

header h1 {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.5px;
  color: var(--text);
  flex-shrink: 0;
}

.conn-status {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--text-muted);
}

.conn-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-muted);
  flex-shrink: 0;
  transition: background 0.3s;
}
.conn-dot.connected { background: var(--green); box-shadow: 0 0 6px var(--green); }
.conn-dot.reconnecting { background: var(--yellow); box-shadow: 0 0 6px var(--yellow); animation: conn-pulse 1s ease-in-out infinite; }
.conn-dot.error { background: var(--red); }
@keyframes conn-pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }

.header-spacer { flex: 1; }

.conn-controls { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }

/* ── Buttons ─────────────────────────────────────────────── */
button {
  cursor: pointer;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface2);
  color: var(--text);
  font-family: var(--font);
  font-size: 13px;
  padding: 6px 14px;
  transition: background 0.15s, border-color 0.15s;
  white-space: nowrap;
}
button:hover:not(:disabled) { background: var(--surface3); border-color: var(--accent); }
button:active:not(:disabled) { transform: scale(0.97); }
button:disabled { opacity: 0.4; cursor: not-allowed; }

button.primary {
  background: var(--accent);
  color: #0d1117;
  border-color: var(--accent);
  font-weight: 600;
}
button.primary:hover:not(:disabled) { background: var(--accent-hover); border-color: var(--accent-hover); }

button.danger {
  background: rgba(248,81,73,0.15);
  border-color: var(--red);
  color: var(--red);
}
button.danger:hover:not(:disabled) { background: rgba(248,81,73,0.25); }

/* ── Tabs ────────────────────────────────────────────────── */
.tab-bar {
  display: flex;
  gap: 0;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
  scrollbar-width: none;
}
.tab-bar::-webkit-scrollbar { display: none; }

.tab-btn {
  border: none;
  border-bottom: 2px solid transparent;
  border-radius: 0;
  background: transparent;
  color: var(--text-muted);
  padding: 10px 20px;
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  transition: color 0.15s, border-color 0.15s;
}
.tab-btn:hover:not(:disabled) { color: var(--text); background: transparent; border-color: transparent; }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-btn:disabled { opacity: 0.35; }

.tab-pane { display: none; padding: 20px 16px; }
.tab-pane.active { display: block; }

/* ── Toast / status bar ──────────────────────────────────── */
#toast-area {
  position: fixed;
  bottom: 16px;
  right: 16px;
  z-index: 200;
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: min(360px, calc(100vw - 32px));
}
.toast {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 14px;
  font-size: 13px;
  animation: slideIn 0.2s ease;
}
.toast.error { border-color: var(--red); color: var(--red); }
.toast.success { border-color: var(--green); color: var(--green); }
@keyframes slideIn { from { opacity: 0; transform: translateX(20px); } to { opacity: 1; transform: none; } }

/* ── Config tab ──────────────────────────────────────────── */
.param-list { display: flex; flex-direction: column; gap: 12px; max-width: 520px; }

.param-row {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.param-label {
  flex: 1;
  min-width: 140px;
  font-weight: 500;
}
.param-row.param-disabled { opacity: 0.4; pointer-events: none; }

.param-ctrl { display: flex; align-items: center; gap: 6px; flex-shrink: 0; }

/* Integer control */
.int-ctrl { display: flex; align-items: center; gap: 4px; }
.int-ctrl button { padding: 4px 10px; font-size: 16px; line-height: 1; }
.int-ctrl input[type=number],
.int-ctrl input[type=text] {
  width: 80px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 5px 8px;
  text-align: center;
  -moz-appearance: textfield;
}
.int-ctrl input[type=number]::-webkit-inner-spin-button,
.int-ctrl input[type=number]::-webkit-outer-spin-button { -webkit-appearance: none; }
.int-ctrl input:focus { outline: none; border-color: var(--accent); }
.unit-label { color: var(--text-muted); font-size: 12px; min-width: 24px; }

/* Toggle switch */
.toggle { position: relative; display: inline-block; width: 44px; height: 24px; flex-shrink: 0; }
.toggle input { opacity: 0; width: 0; height: 0; }
.toggle-track {
  position: absolute; inset: 0;
  background: var(--surface3);
  border: 1px solid var(--border);
  border-radius: 12px;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}
.toggle input:checked + .toggle-track { background: var(--accent); border-color: var(--accent); }
.toggle-track::after {
  content: '';
  position: absolute;
  left: 3px; top: 3px;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--text-muted);
  transition: transform 0.2s, background 0.2s;
}
.toggle input:checked + .toggle-track::after { transform: translateX(20px); background: #0d1117; }

/* Enum control */
.param-ctrl select {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 13px;
  padding: 5px 30px 5px 10px;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238b949e' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  cursor: pointer;
  min-width: 160px;
}
.param-ctrl select:focus { outline: none; border-color: var(--accent); }

.config-actions { margin-top: 20px; display: flex; gap: 10px; }

/* Export/Import dropdown */
.dropdown { position: relative; }
.dropdown .caret { font-size: 9px; margin-left: 2px; }
.dropdown-menu {
  display: none;
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  min-width: 150px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px;
  z-index: 10;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}
.dropdown.open .dropdown-menu { display: flex; flex-direction: column; }
.dropdown.drop-up .dropdown-menu { top: auto; bottom: calc(100% + 4px); }
.dropdown-menu button {
  background: none;
  border: none;
  text-align: left;
  padding: 6px 10px;
  width: 100%;
  white-space: nowrap;
}
.dropdown-menu button:hover:not(:disabled) { background: var(--surface3); }

/* Preset controls */
.preset-controls { display: flex; align-items: center; gap: 10px; margin-bottom: 20px; }
.preset-select {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 13px;
  padding: 5px 30px 5px 10px;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238b949e' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  cursor: pointer;
  min-width: 160px;
}
.preset-select:focus { outline: none; border-color: var(--accent); }

#transport-select {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 13px;
  padding: 5px 30px 5px 10px;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238b949e' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  cursor: pointer;
  min-width: 110px;
}
#transport-select:focus { outline: none; border-color: var(--accent); }
#transport-select:disabled { opacity: 0.5; cursor: default; }

/* ── Frame Buffer tab ────────────────────────────────────── */
.fb-controls { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 16px; }

.auto-reload-ctrl { display: flex; align-items: center; gap: 8px; }
.auto-reload-ctrl label { font-size: 13px; color: var(--text-muted); cursor: pointer; display: flex; align-items: center; gap: 6px; }
#auto-reload-interval {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 13px;
  padding: 5px 28px 5px 10px;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238b949e' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  cursor: pointer;
  min-width: 70px;
}
#auto-reload-interval:focus { outline: none; border-color: var(--accent); }

.fb-container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  display: inline-block;
  max-width: 100%;
}

#fb-canvas {
  display: block;
  image-rendering: pixelated;
  image-rendering: crisp-edges;
  max-width: min(640px, calc(100vw - 56px));
  height: auto;
  background: #000;
  border-radius: 2px;
}

.fb-info { margin-top: 8px; font-size: 11px; color: var(--text-muted); font-family: var(--font-mono); }

/* Character LCD text buffer readout (shown below the captured image) */
.fb-text {
  display: block;
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 21px;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  white-space: pre;
  overflow: hidden;
  resize: none;
  max-width: 100%;
}
.fb-text:focus { outline: none; border-color: var(--accent); }

.fb-text-copy { margin-top: 8px; }

/* ── Command Dump tab ────────────────────────────────────── */
.dump-controls { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 16px; }

.dump-status-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px 14px;
  font-size: 12px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.status-badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 10px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.5px;
  background: var(--surface3);
  color: var(--text-muted);
}
.status-badge.WAIT { background: rgba(139,148,158,0.2); color: var(--text-muted); }
.status-badge.ACTIVE { background: rgba(63,185,80,0.2); color: var(--green); }
.status-badge.COMPLETE { background: rgba(88,166,255,0.2); color: var(--accent); }

#dump-byte-count { color: var(--text-muted); font-family: var(--font-mono); }

.dump-view-wrapper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  overflow-x: auto;
}

#dump-view {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1;
}

.dump-row { display: flex; align-items: center; gap: 2px; margin-bottom: 2px; }
.dump-row-addr {
  color: var(--text-muted);
  width: 40px;
  flex-shrink: 0;
  user-select: none;
  font-size: 11px;
}

.dump-cell {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 20px;
  border-radius: 2px;
  font-size: 11px;
  letter-spacing: 0.5px;
  user-select: all;
}
/* Command byte: cyan */
.dump-cell.cmd { background: #00c3ff; color: #000; }
/* Data byte: alternating dark */
.dump-cell.dat0 { background: #000; color: #e6edf3; }
.dump-cell.dat1 { background: #1a1a1a; color: #e6edf3; }
/* HW Reset: yellow */
.dump-cell.evt-rst { background: #ffe300; color: #000; font-size: 9px; font-weight: 700; }
/* Unknown event: red */
.dump-cell.evt-unk { background: #ff0042; color: #000; }

/* ── Statistics tab ──────────────────────────────────────── */
.stats-controls { display: flex; align-items: center; gap: 10px; margin-bottom: 16px; }

.stats-table {
  border-collapse: collapse;
  min-width: 320px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.stats-table td { padding: 8px 14px; border-bottom: 1px solid var(--border); font-size: 13px; }
.stats-table tr:last-child td { border-bottom: none; }
.stats-name { color: var(--text); }
.stats-value { font-family: var(--font-mono); text-align: right; color: var(--accent); white-space: nowrap; }

/* ── Utility ──────────────────────────────────────────────── */
.section-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.8px;
  margin-bottom: 14px;
}

@media (max-width: 480px) {
  header { padding: 8px 12px; }
  .tab-btn { padding: 10px 14px; }
  .tab-pane { padding: 14px 12px; }
}