body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background: #f8fafc;
  color: #1e293b;
}

#html-viewer-wrapper * {
  box-sizing: border-box;
}

#html-viewer-wrapper {
  max-width: 1600px;
  margin: auto;
}

/* Navbar */
.navbar {
  background-color: #6366f1;
  color: white;
  padding: 16px 28px;
  font-size: 24px;
  font-weight: bold;
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Main container */
.main {
  display: flex;
  justify-content: center;
  padding: 30px 20px;
}

/* Three-column layout */
.editor-group {
  display: flex;
  flex-direction: row;
  gap: 20px;
  flex-wrap: nowrap;
  justify-content: center;
  align-items: flex-start;
  width: 100%;
  max-width: 1400px;
}

/* Input + Output boxes */
textarea,
iframe {
  background: white;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  padding: 16px;
  width: 100%;
  max-width: 480px;
  height: 70vh;
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
  resize: vertical;
  font-size: 14px;
}

/* Button Panel */
.control-panel {
  display: flex;
  flex-direction: column;
  gap: 12px;
  justify-content: center;
  align-items: center;
  padding: 20px 12px;
  background: #f1f5f9;
  border-radius: 12px;
  box-shadow: 0 6px 18px rgba(0,0,0,0.08);
  height: fit-content;
  min-width: 150px;
}

button {
  background-color: #6366f1;
  color: white;
  font-weight: bold;
  border: none;
  padding: 10px 20px;
  border-radius: 10px;
  font-size: 15px;
  cursor: pointer;
  transition: background 0.2s ease;
  width: 130px;
}

button:hover {
  background-color: #4f46e5;
}

/* Footer */
.status-bar {
  text-align: center;
  font-size: 13px;
  color: #475569;
  padding: 16px;
  background-color: #e2e8f0;
  margin-top: 40px;
}