:root {
  --bg: #0f0f1a;
  --panel: #1a1a2e;
  --text: #e8e8f0;
  --muted: #9aa0b5;
  --accent: #5b8cff;
  --ok: #3dba7a;
  --err: #e35d6a;
  --line: #2c2c44;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  background:
    radial-gradient(1200px 600px at 10% -10%, #243056 0%, transparent 55%),
    radial-gradient(900px 500px at 100% 0%, #2a1f3d 0%, transparent 50%),
    var(--bg);
  color: var(--text);
  min-height: 100vh;
}

main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
}

h1 {
  font-size: 1.55rem;
  margin: 0 0 0.35rem;
  letter-spacing: -0.02em;
}

.sub {
  color: var(--muted);
  margin-bottom: 1.25rem;
  line-height: 1.45;
}

.tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.tab {
  background: #2a3350;
  color: #c9d0e8;
  border: 0;
  border-radius: 999px;
  padding: 0.45rem 0.95rem;
  font-weight: 600;
  cursor: pointer;
}

.tab.active {
  background: var(--accent);
  color: #fff;
}

section {
  background: color-mix(in srgb, var(--panel) 92%, black);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1.1rem 1.2rem 1.25rem;
  margin-bottom: 1rem;
}

.panel { display: none; }
.panel.active { display: block; }

h2 {
  font-size: 1.05rem;
  margin: 0 0 0.35rem;
}

.section-lead {
  color: var(--muted);
  font-size: 0.88rem;
  margin: 0 0 0.9rem;
  line-height: 1.45;
}

.badge {
  display: inline-block;
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: 999px;
  background: #2a3350;
  color: #b8c4ea;
  margin-left: 0.35rem;
}

.row {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  align-items: center;
  margin-top: 0.75rem;
}

.grid2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.85rem;
}

@media (max-width: 800px) {
  .grid2 { grid-template-columns: 1fr; }
}

button {
  background: var(--accent);
  color: white;
  border: 0;
  border-radius: 8px;
  padding: 0.55rem 0.95rem;
  font-weight: 600;
  cursor: pointer;
}

button.secondary { background: #3a4160; }
button.ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--text);
}
button:disabled { opacity: 0.45; cursor: not-allowed; }

pre {
  background: #12121f;
  border-radius: 8px;
  padding: 0.75rem;
  overflow: auto;
  font-size: 0.78rem;
  color: #c9d0e8;
  min-height: 3.5rem;
  max-height: 180px;
  margin: 0.75rem 0 0;
}

.ok { color: var(--ok); }
.err { color: var(--err); }
a { color: #8eb0ff; }
.hint { font-size: 0.78rem; color: var(--muted); }

/* Upload component */
.upload {
  border: 1.5px dashed #3a4468;
  border-radius: 12px;
  background: #12121f;
  padding: 0.9rem;
  transition: border-color 0.15s, background 0.15s;
}

.upload.dragover {
  border-color: var(--accent);
  background: #161b2e;
}

.upload-head {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  align-items: flex-start;
  margin-bottom: 0.65rem;
}

.upload-title {
  font-size: 0.92rem;
  font-weight: 600;
  margin: 0 0 0.2rem;
}

.upload-help {
  margin: 0;
  color: var(--muted);
  font-size: 0.8rem;
  line-height: 1.4;
}

.upload input[type="file"] { display: none; }

.thumbs {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(88px, 1fr));
  gap: 0.5rem;
  min-height: 72px;
}

.thumb {
  position: relative;
  border-radius: 8px;
  overflow: hidden;
  background: #000;
  aspect-ratio: 1;
  border: 1px solid var(--line);
}

.thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.thumb .name {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 0.2rem 0.3rem;
  font-size: 0.65rem;
  background: linear-gradient(transparent, rgba(0,0,0,.85));
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.thumb .remove {
  position: absolute;
  top: 4px;
  right: 4px;
  width: 22px;
  height: 22px;
  border-radius: 999px;
  border: 0;
  background: rgba(0,0,0,.7);
  color: #fff;
  font-size: 12px;
  padding: 0;
  line-height: 22px;
}

.upload-empty {
  color: var(--muted);
  font-size: 0.82rem;
  padding: 1.1rem 0.5rem;
  text-align: center;
}

/* Alignment docs */
.method-list {
  display: grid;
  gap: 0.55rem;
  margin: 0.75rem 0;
}

.method {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.7rem 0.8rem;
  background: #12121f;
  cursor: pointer;
}

.method:has(input:checked) {
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
}

.method-top {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
}

.method input { margin-top: 0.2rem; }

.method h3 {
  margin: 0 0 0.25rem;
  font-size: 0.9rem;
}

.method p {
  margin: 0;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.4;
}

.method .when {
  margin-top: 0.35rem;
  color: #b8c4ea;
  font-size: 0.74rem;
}

/* Viewer + free transform */
.viewer-wrap {
  display: grid;
  gap: 0.75rem;
}

.viewer {
  position: relative;
  width: 100%;
  aspect-ratio: 3 / 2;
  background: #0a0a12;
  border-radius: 10px;
  overflow: hidden;
  user-select: none;
  touch-action: none;
  border: 1px solid var(--line);
}

.viewer img.base-layer,
.viewer img.compare-top {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  pointer-events: none;
}

.viewer .divider {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: #fff;
  box-shadow: 0 0 0 1px rgba(0,0,0,.4);
  pointer-events: none;
  display: none;
}

.viewer.mode-compare .divider { display: block; }
.viewer.mode-compare .compare-top {
  clip-path: inset(0 50% 0 0);
}

.viewer.mode-transform .compare-top,
.viewer.mode-transform .divider {
  display: none !important;
}

.transform-stage {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  display: none;
  overflow: visible;
}

.viewer.mode-transform .transform-stage,
.viewer.mode-distort .transform-stage {
  display: block;
}

.viewer.mode-distort .compare-top,
.viewer.mode-distort .divider,
.viewer.mode-transform .compare-top,
.viewer.mode-transform .divider {
  display: none !important;
}

.transform-layer {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  object-fit: fill;
  pointer-events: none;
  transform-origin: 0 0;
}

.transform-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
  pointer-events: none;
}

.transform-poly {
  fill: rgba(94, 140, 255, 0.08);
  stroke: #7eb0ff;
  stroke-width: 1.5;
  pointer-events: fill;
  cursor: move;
}

.rotate-stem-line {
  stroke: #7eb0ff;
  stroke-width: 1.5;
  pointer-events: none;
}

.svg-handle {
  fill: #fff;
  stroke: var(--accent);
  stroke-width: 2;
  pointer-events: auto;
  cursor: nwse-resize;
}

.svg-handle.rotate {
  fill: #ffd27a;
  stroke: #c98a20;
  cursor: grab;
}

.viewer.mode-distort .svg-handle.corner {
  fill: #ff8e8e;
  stroke: #d45555;
  cursor: move;
}

.viewer.mode-distort .svg-handle.rotate {
  display: none;
}

.viewer.mode-distort .rotate-stem-line {
  display: none;
}

.viewer-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.viewer-toolbar label {
  font-size: 0.8rem;
  color: var(--muted);
}

.viewer-toolbar input[type="range"] {
  width: 140px;
}

.nudge-readout {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.78rem;
  color: #b8c4ea;
  background: #12121f;
  border-radius: 8px;
  padding: 0.45rem 0.65rem;
  border: 1px solid var(--line);
}

.mosaic-preview {
  margin-top: 0.75rem;
  background: #12121f;
  border-radius: 8px;
  padding: 0.5rem;
  border: 1px solid var(--line);
}

.mosaic-preview img {
  width: 100%;
  border-radius: 6px;
  background: #000;
  min-height: 80px;
  display: block;
}