* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  background: #fff;
  color: #222;
  min-height: 100vh;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 32px 20px 40px;
}

header {
  margin-bottom: 28px;
  padding-bottom: 16px;
  border-bottom: 1px solid #ddd;
}

header h1 {
  font-size: 22px;
  font-weight: 500;
  color: #111;
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 14px;
}

.toolbar-left {
  display: flex;
  gap: 16px;
  align-items: center;
}

.toolbar label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: #555;
}

.toolbar select {
  padding: 5px 8px;
  background: #fff;
  border: 1px solid #ccc;
  border-radius: 4px;
  color: #222;
  font-size: 13px;
  cursor: pointer;
}

.toolbar select:focus {
  outline: none;
  border-color: #888;
}

.toolbar-right {
  display: flex;
  gap: 8px;
}

button {
  padding: 6px 16px;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 13px;
  cursor: pointer;
  background: #fff;
  color: #222;
}

button:hover {
  background: #f5f5f5;
}

.btn-primary {
  background: #222;
  color: #fff;
  border-color: #222;
}

.btn-primary:hover {
  background: #444;
  border-color: #444;
}

.panel-header {
  font-size: 12px;
  color: #888;
  margin-bottom: 4px;
}

.editor-panel,
.input-panel,
.output-panel {
  margin-bottom: 14px;
}

#source-editor {
  width: 100%;
  min-height: 200px;
  padding: 12px;
  background: #fafafa;
  border: 1px solid #ddd;
  border-radius: 4px;
  color: #222;
  font-family: "SF Mono", "Cascadia Code", "Consolas", monospace;
  font-size: 13px;
  line-height: 1.5;
  resize: vertical;
}

#source-editor:focus {
  outline: none;
  border-color: #888;
}

#source-editor::placeholder {
  color: #bbb;
}

#input-editor {
  width: 100%;
  padding: 10px 12px;
  background: #fafafa;
  border: 1px solid #ddd;
  border-radius: 4px;
  color: #222;
  font-family: "SF Mono", "Cascadia Code", "Consolas", monospace;
  font-size: 13px;
  resize: vertical;
}

#input-editor:focus {
  outline: none;
  border-color: #888;
}

#input-editor::placeholder {
  color: #bbb;
}

.output-area {
  min-height: 40px;
  padding: 12px;
  background: #fafafa;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-family: "SF Mono", "Cascadia Code", "Consolas", monospace;
  font-size: 13px;
  white-space: pre-wrap;
  word-break: break-all;
  color: #222;
}

.output-area:empty::before {
  content: "No output";
  color: #bbb;
}

.error-area {
  margin-top: 6px;
  padding: 10px 12px;
  background: #fff5f5;
  border: 1px solid #ecc;
  border-radius: 4px;
  color: #c33;
  font-family: "SF Mono", "Cascadia Code", "Consolas", monospace;
  font-size: 13px;
  white-space: pre-wrap;
}

footer {
  text-align: center;
  margin-top: 28px;
  padding-top: 12px;
  border-top: 1px solid #eee;
  font-size: 11px;
  color: #aaa;
}

footer a {
  color: #555;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}