* {
  box-sizing: border-box;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

body {
  margin: 0;
  background: #f9fafb;
  color: #1f2937;
}

header {
  background: #ffffff;
  border-bottom: 1px solid #e5e7eb;
  padding: 15px;
}

nav {
  max-width: 1000px;
  margin: auto;
  display: flex;
  justify-content: space-between;
}

nav a {
  text-decoration: none;
  color: #111827;
  margin-right: 15px;
  font-weight: 500;
}

.container {
  max-width: 900px;
  margin: auto;
  padding: 30px 15px;
}

h1, h2 {
  color: #111827;
}

.tool-box {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  padding: 20px;
  border-radius: 8px;
  margin-bottom: 20px;
}

textarea, input {
  width: 100%;
  padding: 10px;
  border: 1px solid #d1d5db;
  border-radius: 6px;
  font-size: 16px;
}

button {
  background: #2563eb;
  color: white;
  border: none;
  padding: 10px 15px;
  border-radius: 6px;
  cursor: pointer;
}

button:hover {
  background: #1d4ed8;
}

footer {
  text-align: center;
  padding: 20px;
  color: #6b7280;
  font-size: 14px;
}