body {
  font-family: Arial, sans-serif;
  background: #f3f4f6;
  color: #111827;
  margin: 0;
  padding: 0;
}

header {
  background: white;
  border-bottom: 1px solid #e5e7eb;
  padding: 18px 24px;
}

.logo {
  font-size: 26px;
  font-weight: 800;
  color: #111827;
  text-decoration: none;
}

.logo span {
  color: #22c55e;
}

main {
  max-width: 720px;
  margin: 50px auto;
  padding: 0 20px;
}

.card {
  background: white;
  padding: 28px;
  border-radius: 16px;
  box-shadow: 0 10px 24px rgba(0,0,0,0.06);
}

h1 {
  margin-top: 0;
}

label {
  display: block;
  margin-top: 15px;
  color: #374151;
}

input,
button {
  width: 100%;
  box-sizing: border-box;
  padding: 12px;
  margin-top: 8px;
  border-radius: 10px;
  font-size: 16px;
}

input {
  border: 1px solid #d1d5db;
}

button {
  margin-top: 20px;
  background: #22c55e;
  color: white;
  border: 0;
  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background: #16a34a;
}

.result {
  margin-top: 20px;
  font-size: 20px;
  font-weight: bold;
}

.tool-list a {
  display: block;
  background: white;
  padding: 18px;
  border-radius: 12px;
  margin: 12px 0;
  text-decoration: none;
  color: #111827;
  border: 1px solid #e5e7eb;
}

.tool-list a:hover {
  border-color: #22c55e;
}

textarea {
  width: 100%;
  box-sizing: border-box;
  min-height: 180px;
  padding: 12px;
  margin-top: 8px;
  border-radius: 10px;
  font-size: 16px;
  border: 1px solid #d1d5db;
  font-family: Arial, sans-serif;
}