* { box-sizing: border-box; }

body {
  font-family: -apple-system, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f6f8;
  color: #1f2933;
}

header {
  padding: 24px 32px 8px;
}

h1 { margin: 0 0 4px; font-size: 22px; }
.subtitle { margin: 0; color: #52606d; font-size: 14px; }

main {
  padding: 16px 32px 32px;
  max-width: 1200px;
  margin: 0 auto;
}

.input-panel {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

textarea {
  width: 100%;
  font-size: 14px;
  padding: 12px;
  border: 1px solid #cbd2d9;
  border-radius: 6px;
  resize: vertical;
}

.input-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

#char-count { font-size: 12px; color: #7b8794; }

button {
  cursor: pointer;
  border: 1px solid #3e4c59;
  background: #1f2933;
  color: #fff;
  padding: 8px 16px;
  border-radius: 6px;
  font-size: 14px;
}

button:disabled {
  background: #cbd2d9;
  border-color: #cbd2d9;
  cursor: not-allowed;
}

.warning-banner {
  background: #fff3cd;
  border: 1px solid #f0c419;
  color: #7a5c00;
  padding: 12px 16px;
  border-radius: 6px;
  margin-bottom: 16px;
  font-size: 13px;
  white-space: pre-wrap;
}

.preview-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.column {
  background: #fff;
  border: 1px solid #e4e7eb;
  border-radius: 8px;
  padding: 12px 16px;
  min-height: 320px;
}

.column h2 { font-size: 15px; margin: 0 0 8px; }

#original-view {
  white-space: pre-wrap;
  word-break: break-word;
  font-size: 13px;
  line-height: 1.6;
}

.preview-toggle {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
}

.preview-toggle button {
  background: #fff;
  color: #1f2933;
  font-size: 12px;
  padding: 4px 10px;
}

.rendered-view h1 { font-size: 18px; }
.rendered-view h2 { font-size: 16px; }
.rendered-view h3 { font-size: 14px; }
.rendered-view { font-size: 13px; line-height: 1.7; }

.source-view {
  white-space: pre-wrap;
  word-break: break-word;
  font-size: 13px;
  line-height: 1.6;
}

.highlight-missing {
  background: #ffe3e3;
}

footer {
  padding: 16px 32px 32px;
  font-size: 12px;
  color: #7b8794;
  border-top: 1px solid #e4e7eb;
  max-width: 1200px;
  margin: 0 auto;
}