:root {
  --bg: #14181f;
  --panel: #1d242e;
  --fg: #e6edf3;
  --muted: #8b949e;
  --accent: #ff7a18;
  --accent-fg: #14181f;
  --error: #f85149;
  --border: #30363d;

  /* iOS safe areas */
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior-y: contain;
}

main {
  max-width: 640px;
  margin: 0 auto;
  padding: calc(16px + var(--safe-top)) 16px calc(32px + var(--safe-bottom));
}

h1 {
  font-size: 1.25rem;
  margin: 0 0 16px;
  letter-spacing: 0.02em;
}

section {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px;
  margin-bottom: 14px;
}

button {
  appearance: none;
  -webkit-appearance: none;
  background: var(--accent);
  color: var(--accent-fg);
  border: 0;
  padding: 12px 18px;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  font-size: 1rem;
  min-height: 44px;
  touch-action: manipulation;
}

button:disabled {
  background: var(--border);
  color: var(--muted);
  cursor: not-allowed;
}

.status {
  display: block;
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 8px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  white-space: pre-wrap;
  word-break: break-word;
}

.status:empty {
  display: none;
}

.status.error {
  color: var(--error);
}

#device {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.device-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

#device .status {
  margin-top: 0;
  flex: 1 1 auto;
  min-width: 0;
}

.link-btn {
  background: transparent;
  color: var(--muted);
  border: 0;
  padding: 6px 0;
  font-size: 0.8rem;
  font-weight: 400;
  text-decoration: underline;
  min-height: auto;
  align-self: flex-start;
  cursor: pointer;
}

.link-btn:hover { color: var(--accent); }
.link-btn:disabled { color: var(--border); text-decoration: none; cursor: not-allowed; }

#brightness-row {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.slider-label {
  color: var(--muted);
  font-size: 0.85rem;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}

.slider-label > span {
  color: var(--fg);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-weight: 600;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 36px; /* generous touch target */
  background: transparent;
  margin: 0;
  padding: 0;
}

input[type="range"]:focus { outline: none; }

input[type="range"]::-webkit-slider-runnable-track {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
}

input[type="range"]::-moz-range-track {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent);
  border: 0;
  margin-top: -11px;
  cursor: pointer;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.4);
}

input[type="range"]::-moz-range-thumb {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent);
  border: 0;
  cursor: pointer;
}

input[type="range"]:disabled {
  opacity: 0.5;
}

.file-drop {
  display: block;
  border: 2px dashed var(--border);
  border-radius: 10px;
  padding: 28px 12px;
  text-align: center;
  color: var(--muted);
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
  font-size: 0.95rem;
  min-height: 96px;
  user-select: none;
  -webkit-user-select: none;
}

.file-drop:hover, .file-drop.drag {
  border-color: var(--accent);
  color: var(--fg);
}

.previews {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 14px 0;
}

.previews figure {
  margin: 0;
  text-align: center;
}

.previews figcaption {
  color: var(--muted);
  font-size: 0.75rem;
  margin-bottom: 4px;
}

.previews img {
  width: 100%;
  height: auto;
  aspect-ratio: 1 / 1;
  object-fit: contain;
  image-rendering: pixelated;
  background: #000;
  border: 1px solid var(--border);
  border-radius: 4px;
}

#send-btn {
  width: 100%;
  margin-top: 4px;
}

.note {
  color: var(--muted);
  font-size: 0.8rem;
  margin: 12px 0 0;
  line-height: 1.45;
}

.note a {
  color: var(--accent);
}

/* Tighter spacing on very narrow phones */
@media (max-width: 380px) {
  main { padding-left: 12px; padding-right: 12px; }
  section { padding: 12px; }
  h1 { font-size: 1.1rem; }
  #connect-btn { width: 100%; }
  #device { flex-direction: column; align-items: stretch; }
  #device .status { text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}