* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; background: #f5f7fa; color: #333; line-height: 1.6; padding: 20px; }
.container { max-width: 1400px; margin: 0 auto; }
header { text-align: center; margin-bottom: 24px; padding: 20px; background: #ffffff; border-radius: 12px; box-shadow: 0 2px 8px rgba(0,0,0,0.06); }
header h1 { font-size: 1.5rem; margin-bottom: 8px; color: #2563eb; }
header p { color: #666; font-size: 0.9rem; }
.toolbar { display: flex; gap: 10px; margin-bottom: 20px; align-items: flex-end; background: #fff; padding: 16px; border-radius: 12px; box-shadow: 0 2px 8px rgba(0,0,0,0.06); flex-wrap: wrap; }
.toolbar textarea { flex: 1 1 300px; min-height: 60px; padding: 10px; border: 1px solid #d1d5db; border-radius: 8px; font-family: inherit; font-size: 0.95rem; resize: vertical; }
.toolbar button, .code-actions button { padding: 10px 20px; border: none; border-radius: 8px; background: #2563eb; color: #fff; font-size: 0.95rem; cursor: pointer; font-weight: 600; }
.toolbar button:hover, .code-actions button:hover { background: #1d4ed8; }
.toolbar select { padding: 10px 14px; border: 1px solid #d1d5db; border-radius: 8px; background: #fff; font-size: 0.9rem; }
.split-view { display: grid; grid-template-columns: 460px 1fr; gap: 20px; align-items: start; }
@media (max-width: 900px) { .split-view { grid-template-columns: 1fr; } .toolbar { flex-direction: column; align-items: stretch; } }
.panel { background: #fff; border-radius: 12px; box-shadow: 0 2px 8px rgba(0,0,0,0.06); display: flex; flex-direction: column; }
.panel h3 { padding: 16px 16px 8px; font-size: 1rem; color: #374151; border-bottom: 1px solid #f3f4f6; margin-bottom: 0; }
.panel textarea { flex: 1; width: 100%; padding: 16px; font-family: ui-monospace, SFMono-Regular, "SF Mono", Consolas, monospace; font-size: 0.9rem; border: none; border-top: 1px solid #f3f4f6; resize: vertical; min-height: 300px; outline: none; }
.panel textarea:focus { box-shadow: inset 0 0 0 2px #2563eb; }
.code-actions { padding: 12px 16px; display: flex; gap: 10px; border-top: 1px solid #f3f4f6; flex-wrap: wrap; }
.preview-panel { min-height: 500px; }
#mermaidChart { padding: 20px; min-height: 400px; display: flex; align-items: center; justify-content: center; }
#mermaidChart svg { max-width: 100%; height: auto; }
#loading { padding: 20px; color: #666; font-size: 0.95rem; }
#status { margin-top: 12px; padding: 10px 16px; border-radius: 8px; background: #eff6ff; color: #1e40af; font-size: 0.9rem; display: none; }
#status.show { display: block; }
.input-hint { color: #666; font-size: 0.85rem; margin-top: 8px; }

.hint { background: #fff; border-radius: 12px; box-shadow: 0 2px 8px rgba(0,0,0,0.06); padding: 20px; margin-top: 24px; }
.hint h3 { margin-bottom: 12px; color: #2563eb; font-size: 1.1rem; }
.hint ol { margin-left: 20px; color: #4b5563; }
.hint li { margin-bottom: 8px; }