:root {
  color-scheme: light dark;
}

* { box-sizing: border-box; }

body {
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  margin: 0;
  padding: 2rem 1rem;
  max-width: 1600px;
  margin-inline: auto;
  line-height: 1.5;
}

header, .intake, .controls {
  max-width: 900px;
  margin-inline: auto;
}

header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.5rem;
}

header p {
  margin: 0 0 1.5rem;
  color: #666;
  font-size: 0.95rem;
}

.dropzone {
  border: 2px dashed #aaa;
  border-radius: 12px;
  padding: 2.5rem 1rem;
  text-align: center;
  cursor: pointer;
  color: #666;
  transition: border-color 0.15s, background-color 0.15s;
}

.dropzone:hover { border-color: #555; }

.dropzone.dragover {
  border-color: #2a7;
  background-color: rgba(34, 170, 119, 0.08);
  color: #2a7;
}

.dropzone:focus-visible {
  outline: 2px solid #2a7;
  outline-offset: 2px;
}

.dropzone-error {
  margin: 0.5rem 0 0;
  color: #c33;
  font-size: 0.9rem;
  min-height: 1.2em;
}

.dropzone-error:empty { display: none; }

.privacy-note {
  max-width: 900px;
  margin: 0.5rem auto 0;
  text-align: center;
  font-size: 0.8rem;
  color: #888;
}

.stage {
  margin-top: 1.5rem;
  text-align: center;
}

.stage.hidden { display: none; }

.image-area {
  position: relative;
  display: inline-block;
  vertical-align: top;
  max-width: 100%;
}

.image-wrap {
  max-width: 100%;
  max-height: 70vh;
  overflow: auto;
  border-radius: 8px;
  display: inline-block;
  vertical-align: top;
}

.grid-overlay {
  position: absolute;
  inset: 0;
  pointer-events: none;
  display: none;
  mix-blend-mode: difference;
}

.image-area.grid-thirds .grid-overlay,
.image-area.grid-cross .grid-overlay { display: block; }

.image-area.grid-thirds .grid-overlay {
  background-image:
    linear-gradient(#fff, #fff),
    linear-gradient(#fff, #fff),
    linear-gradient(#fff, #fff),
    linear-gradient(#fff, #fff);
  background-size: 100% 1px, 100% 1px, 1px 100%, 1px 100%;
  background-position: 0 33.333%, 0 66.667%, 33.333% 0, 66.667% 0;
  background-repeat: no-repeat;
}

.image-area.grid-cross .grid-overlay {
  background-image:
    linear-gradient(#fff, #fff),
    linear-gradient(#fff, #fff);
  background-size: 100% 1px, 1px 100%;
  background-position: 0 50%, 50% 0;
  background-repeat: no-repeat;
}

#image {
  max-width: 100%;
  max-height: 70vh;
  border-radius: 8px;
  filter: url(#squintFilter);
  display: block;
}

#image.actual-size {
  max-width: none;
  max-height: none;
  cursor: grab;
}

.image-wrap.panning #image { cursor: grabbing; }

#image:not(.actual-size):hover,
.stage.show-original #image {
  filter: none;
}

.view-status {
  margin: 0.75rem 0 0;
  text-align: center;
  font-size: 0.9rem;
  color: #666;
}

.view-status.original { color: #2a7; font-weight: 600; }

.stage-buttons {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

#toggleBtn, #flipBtn, #zoomBtn, #gridThirdsBtn, #gridCrossBtn {
  padding: 0.5rem 1rem;
  border: 1px solid #888;
  background: #fff;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
}

#toggleBtn:hover, #flipBtn:hover, #zoomBtn:hover,
#gridThirdsBtn:hover, #gridCrossBtn:hover { background: #f0f0f0; }

#flipBtn.active, #zoomBtn.active,
#gridThirdsBtn.active, #gridCrossBtn.active {
  background: #2a7;
  color: #fff;
  border-color: #2a7;
}

#image.flipped { transform: scaleX(-1); }

.controls {
  display: grid;
  gap: 0.75rem;
  margin-top: 2rem;
  padding: 1rem;
  border: 1px solid #ddd;
  border-radius: 8px;
}

.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid #ddd;
}

.presets button {
  padding: 0.4rem 0.8rem;
  border: 1px solid #888;
  background: #fff;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
}

.presets button:hover { background: #f0f0f0; }

.presets button.active {
  background: #2a7;
  color: #fff;
  border-color: #2a7;
}

.presets button.reset { margin-left: auto; }

.controls label {
  display: grid;
  grid-template-columns: 12rem 1fr 5rem;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.9rem;
}

.controls output {
  font-variant-numeric: tabular-nums;
  color: #555;
  text-align: right;
}

@media (max-width: 600px) {
  .controls label {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }
  .controls output { text-align: left; }
}

@media (min-width: 900px) {
  main:has(#stage:not(.hidden)) {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 20rem;
    grid-template-areas:
      "stage dropzone"
      "stage controls";
    gap: 1.5rem;
    align-items: start;
  }
  main:has(#stage:not(.hidden)) .intake { grid-area: dropzone; }
  main:has(#stage:not(.hidden)) #dropzone { padding: 1.25rem 1rem; }
  main:has(#stage:not(.hidden)) #stage {
    grid-area: stage;
    position: sticky;
    top: 1rem;
    margin-top: 0;
  }
  main:has(#stage:not(.hidden)) .controls { grid-area: controls; margin-top: 0; }
  main:has(#stage:not(.hidden)) .controls label {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }
  main:has(#stage:not(.hidden)) .controls output { text-align: left; }
}

@media (prefers-color-scheme: dark) {
  body { background: #1a1a1a; color: #eee; }
  header p { color: #aaa; }
  .dropzone { border-color: #555; color: #aaa; }
  .dropzone:hover { border-color: #888; }
  .controls { border-color: #444; }
  .controls output { color: #bbb; }
  #toggleBtn, #flipBtn, #zoomBtn,
  #gridThirdsBtn, #gridCrossBtn { background: #2a2a2a; color: #eee; border-color: #555; }
  #toggleBtn:hover, #flipBtn:hover, #zoomBtn:hover,
  #gridThirdsBtn:hover, #gridCrossBtn:hover { background: #3a3a3a; }
  .view-status { color: #aaa; }
  .presets { border-bottom-color: #444; }
  .presets button { background: #2a2a2a; color: #eee; border-color: #555; }
  .presets button:hover { background: #3a3a3a; }
}