* {
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont,
               "Segoe UI", Roboto, "Noto Sans", sans-serif;
  margin: 0;
  padding: 2rem;
  background: #f9fafb;
  color: #111827;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ===== レイアウト ===== */
.container {
  max-width: 960px;
}

.mx-auto {
  margin-left: auto;
  margin-right: auto;
}

.flex {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* ===== タイポグラフィ ===== */
.text-6xl {
  font-size: 3.75rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 1rem;
}

.text-xl {
  font-size: 1.25rem;
  font-weight: 600;
}

.font-mono {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas,
               "Liberation Mono", "Courier New", monospace;
}

.text-blue-600 {
  color: #2563eb;
}

.text-gray-700 {
  color: #374151;
}

/* ===== マージン系 ===== */
.mt-2 {
  margin-top: 0.5rem;
}

.mt-8 {
  margin-top: 2rem;
}

.ml-4 {
  margin-left: 1rem;
}

/* ===== フォーム ===== */
textarea {
  width: 100%;
  resize: vertical;
  padding: 0.75rem;
  border-radius: 0.5rem;
  border: 1px solid #d1d5db;
  font-family: ui-monospace, monospace;
  font-size: 0.9rem;
  background: white;
}

textarea:focus {
  outline: none;
  border-color: #2563eb;
  box-shadow: 0 0 0 1px #2563eb;
}

input[type="number"] {
  font-size: 0.9rem;
}

input[type="text"] {
  display: block;
  width: 100%;
  padding: 0.75rem;
  border-radius: 0.5rem;
  border: 1px solid #d1d5db;
  font-family: ui-monospace, monospace;
  font-size: 0.9rem;
  background: white;
}

/* ===== input utility ===== */
.appearance-none {
  appearance: none;
}

.border {
  border: 1px solid #d1d5db;
}

.rounded {
  border-radius: 0.375rem;
}

.w-20 {
  width: 5rem;
}

.py-1 {
  padding-top: 0.25rem;
  padding-bottom: 0.25rem;
}

.px-2 {
  padding-left: 0.5rem;
  padding-right: 0.5rem;
}

.leading-tight {
  line-height: 1.25;
}

/* ===== エンコードセレクタ ===== */
.encode-selector label {
  cursor: pointer;
  font-size: 0.9rem;
}

/* ===== Fancy radio ===== */
.fancy-radio {
  appearance: none;
  width: 1rem;
  height: 1rem;
  border-radius: 9999px;
  border: 2px solid #9ca3af;
  position: relative;
  cursor: pointer;
}

.fancy-radio:checked {
  border-color: #2563eb;
}

.fancy-radio:checked::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0.5rem;
  height: 0.5rem;
  background: #2563eb;
  border-radius: 9999px;
  transform: translate(-50%, -50%);
}

.my-4  { margin: 1rem 0; }
.my-6  { margin: 1.5rem 0; }
.my-8  { margin: 2rem 0; }
.my-10 { margin: 2.5rem 0; }
.my-12 { margin: 3rem 0; }