* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: sans-serif;
  background: #f0f0f0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  padding: 1rem 2rem;
  background: #111827;
  color: #f9fafb;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  font-size: 1.5rem;
}

header .back-arrow {
  margin-right: auto;
  color: inherit;
  text-decoration: none;
  font-size: 1.25rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem;
}

header h1 {
  margin: 0;
}

main {
  flex: 1;
  padding: 1rem 2rem;
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 1rem;
}

main.no-preview {
  grid-template-columns: 1fr;
}

#original-wrapper,
#preview-wrapper {
  background: #fff;
  border-radius: 0.75rem;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
}

#intro {
  margin-top: 0;
  margin-bottom: 1rem;
  text-align: center;
  font-size: 0.9rem;
  color: #333;
}

main:not(.no-preview) #intro {
  display: none;
}

#upload-area {
  cursor: pointer;
  width: 100%;
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 2px dashed #ccc;
  text-align: center;
  padding: 1rem;
}

#preview-wrapper.hidden {
  display: none;
}

#original-image {
  display: none;
  max-width: 100%;
  image-rendering: pixelated;
}

#drop-message {
  color: #666;
  margin: 0.5rem 0;
  font-size: 0.8rem;
}

#settings {
  margin-top: 1rem;
  width: 100%;
}

main.no-preview #settings {
  display: none;
}

main.no-preview #download-wrapper {
  display: none;
}

.setting {
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.setting label {
  flex: 1;
  font-size: 0.9rem;
}

.setting label small {
  display: block;
  margin-top: 0.25rem;
  font-size: 0.75rem;
  color: #666;
}

.setting input[type="range"] {
  flex: 2;
}

#preset-buttons button {
  flex: 1;
}

canvas {
  max-width: 100%;
  max-height: 80vh;
  height: auto;
}

footer {
  text-align: center;
  padding: 0.5rem;
  background: #e5e7eb;
  font-size: 0.8rem;
}

#file-input {
  display: none;
}

#upload-area.dragover {
  border-color: #000;
}

#download-wrapper {
  flex-direction: column;
  align-items: stretch;
  gap: 0.5rem;
  width: 100%;
}

#download-btn {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1rem;
}