:root {
  --bg: #f7f8fc;
  --panel: #ffffff;
  --text: #1b1f2a;
  --subtle: #5e667a;
  --line: #d6dbe7;
  --accent: #1f6feb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  background: linear-gradient(140deg, #eef2ff 0%, var(--bg) 45%, #f0fff7 100%);
  color: var(--text);
}

.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 32px 20px 40px;
}

h1 {
  margin: 0;
  font-size: clamp(1.5rem, 2.5vw, 2rem);
}

.note {
  margin: 8px 0 20px;
  color: var(--subtle);
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.panel {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--panel);
  box-shadow: 0 8px 22px rgba(26, 39, 84, 0.06);
}

.panel span {
  font-weight: 700;
}

.panelHead {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}

.copyBtn {
  border: 1px solid #c6cfde;
  border-radius: 8px;
  background: #f4f7ff;
  color: var(--text);
  font-size: 0.9rem;
  padding: 6px 10px;
  cursor: pointer;
}

.copyBtn:hover {
  background: #eaf0ff;
}

.copyBtn:focus-visible {
  outline: 2px solid color-mix(in srgb, var(--accent), #ffffff 65%);
}

textarea {
  width: 100%;
  min-height: 230px;
  resize: vertical;
  border: 1px solid #c7cfdf;
  border-radius: 10px;
  padding: 12px;
  font-size: 1rem;
  line-height: 1.6;
  font-family: ui-monospace, "SFMono-Regular", "Menlo", "Consolas", monospace;
  background: #fbfcff;
}

textarea:focus {
  outline: 2px solid color-mix(in srgb, var(--accent), #ffffff 65%);
  border-color: var(--accent);
}

@media (max-width: 760px) {
  .grid {
    grid-template-columns: 1fr;
  }
}