:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #1a1a1a;
  --muted: #6b6b6b;
  --accent: #2563eb;
  --border: #d0d0d0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --fg: #f0f0f0;
    --muted: #a0a0a0;
    --accent: #60a5fa;
    --border: #3a3a3a;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

main {
  max-width: 1000px;
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
}

h1 {
  font-size: 1.5rem;
  margin-bottom: 0.25rem;
}

.intro {
  color: var(--muted);
  margin-top: 0;
}

.drop-zone {
  position: relative;
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 2.5rem 1rem;
  text-align: center;
  cursor: pointer;
  margin: 1.5rem 0;
}

.drop-zone.dragover {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, transparent);
}

.drop-zone input[type="file"] {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

.or-divider {
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0;
}

.dual-drop-row {
  display: flex;
  gap: 1rem;
}

.drop-zone-small {
  flex: 1;
  padding: 1.25rem 1rem;
  margin: 0.75rem 0 1.5rem;
}

.drop-zone-small p {
  margin: 0;
}

.drop-zone-small .file-name {
  display: inline-block;
  margin-top: 0.25rem;
  font-size: 0.85rem;
  color: var(--accent);
  word-break: break-all;
}

.drop-zone-small.has-file {
  border-style: solid;
  border-color: var(--accent);
}

.control-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 1.5rem 0;
}

.control-row label {
  white-space: nowrap;
}

.control-row input[type="range"] {
  flex: 1;
}

.control-row .value-input {
  width: 4.5rem;
  padding: 0.3rem 0.4rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--fg);
  font: inherit;
}

.control-row .unit {
  color: var(--muted);
  white-space: nowrap;
}

.color-mode-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 1.25rem;
  margin: 1.5rem 0;
  padding: 0;
  border: 0;
}

.color-mode-group legend {
  width: 100%;
  padding: 0;
  margin-bottom: 0.25rem;
  font-weight: 600;
}

.color-mode-group label {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  white-space: nowrap;
  cursor: pointer;
}

.hint-inline {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--muted);
}

#status {
  min-height: 1.5em;
  color: var(--muted);
}

#status.error {
  color: #dc2626;
}

#editor h2, .output h2 {
  font-size: 1rem;
  margin: 1.5rem 0 0.4rem;
}

.hint {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0 0 0.75rem;
}

#align-canvas, #preview-canvas, #magnifier-canvas {
  max-width: 100%;
  display: block;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #000;
  touch-action: none;
}

#align-canvas { cursor: grab; }
#align-canvas:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
#preview-canvas { cursor: default; }

.align-row {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 1rem;
}

.align-main {
  flex: 1 1 480px;
  min-width: 280px;
}

.align-magnifier {
  flex: 0 0 auto;
  width: 320px;
  max-width: 100%;
}

#align-offset-label {
  margin: 0.5rem 0 0;
}

#reset-align-btn, #generate-gif-btn, #generate-webp-btn {
  padding: 0.5rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--fg);
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

#reset-align-btn {
  margin-top: 0.75rem;
  font-weight: 400;
}

#reset-align-btn:hover, #generate-gif-btn:hover, #generate-webp-btn:hover {
  border-color: var(--accent);
}

#generate-gif-btn:disabled, #generate-webp-btn:disabled {
  opacity: 0.6;
  cursor: default;
}

.button-row {
  display: flex;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.output {
  margin-top: 2rem;
}

.output img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  border: 1px solid var(--border);
  display: block;
}

#download-link {
  display: inline-block;
  margin-top: 0.75rem;
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}

#download-link:hover {
  text-decoration: underline;
}