:root {
  --bg: #f2f5f9;
  --panel: #ffffff;
  --text: #0e1a2b;
  --muted: #4f5f75;
  --accent: #0b6bcb;
  --border: #d8e0ea;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top, #e4eefb, var(--bg));
}

.container {
  max-width: 880px;
  margin: 40px auto;
  padding: 24px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
}

h1,
h2 {
  margin: 0 0 12px;
}

.intro {
  margin: 0 0 20px;
  color: var(--muted);
}

section {
  margin-bottom: 24px;
}

.grid-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 8px;
}

label {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.hint {
  font-size: 0.9rem;
  color: var(--muted);
}

button {
  border: none;
  background: var(--accent);
  color: white;
  padding: 12px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
}

button:hover {
  opacity: 0.92;
}

.result {
  margin-top: 8px;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #f6f9fe;
}

.hidden {
  display: none;
}