:root {
  color-scheme: light;
  --bg: #f6f7f9;
  --panel: #ffffff;
  --line: #d8dde6;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #0b6ecf;
  --ok: #147d3f;
  --error: #b91c1c;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Noto Sans KR", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
  color: var(--text);
  background: radial-gradient(circle at 10% 10%, #e9f2ff 0%, var(--bg) 50%);
}

.page-header {
  border-bottom: 1px solid var(--line);
  background: linear-gradient(140deg, #123a67, #1d6db3);
  color: #fff;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.2rem 1rem;
}

.header-inner h1 {
  margin: 0;
  font-size: 1.55rem;
}

.header-inner p {
  margin: 0.45rem 0 0;
  opacity: 0.9;
}

.layout {
  max-width: 1200px;
  margin: 1rem auto;
  padding: 0 1rem 1rem;
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 1rem;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1rem;
  box-shadow: 0 3px 14px rgba(9, 26, 46, 0.07);
}

.panel h2 {
  margin: 0 0 0.8rem;
  font-size: 1.15rem;
}

.field-label {
  display: block;
  margin-bottom: 0.4rem;
  font-weight: 600;
}

input[type="file"] {
  width: 100%;
  margin-bottom: 0.75rem;
}

fieldset {
  margin: 0 0 0.85rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.6rem;
}

legend {
  padding: 0 0.2rem;
  font-weight: 600;
}

fieldset label,
.checks label {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin: 0.25rem 0.7rem 0.25rem 0;
}

.actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

button {
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 0.55rem 0.8rem;
  font-weight: 600;
  cursor: pointer;
}

#convert {
  background: var(--accent);
  color: #fff;
}

#download {
  background: #e8edf5;
  color: #1f2937;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.status {
  margin-top: 0.9rem;
  font-size: 0.95rem;
  color: var(--muted);
}

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

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

.notes h3,
.preview h3 {
  margin: 0.75rem 0 0.45rem;
  font-size: 1rem;
}

.notes ul {
  margin: 0;
  padding-left: 1.2rem;
  color: var(--muted);
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
}

#original-preview,
#result-canvas {
  width: 100%;
  max-height: 70vh;
  object-fit: contain;
  border: 1px dashed var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

#result-canvas {
  image-rendering: pixelated;
}

.palette {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.color-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.25rem 0.55rem 0.25rem 0.25rem;
  font-size: 0.84rem;
}

.color-dot {
  width: 1.1rem;
  height: 1.1rem;
  border-radius: 50%;
  border: 1px solid rgba(0, 0, 0, 0.12);
}

@media (max-width: 980px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .preview-grid {
    grid-template-columns: 1fr;
  }
}