:root {
  --webview-bg-start: #f7f1e7;
  --webview-bg-end: #edf4ff;
  --webview-text: #1f2933;
  --webview-muted: #5f6b7a;
  --webview-accent: #2f6f8f;
  --webview-border: #e3e7ef;
}

body.webview {
  margin: 0;
  min-height: 100vh;
  font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  color: var(--webview-text);
  background:
    radial-gradient(circle at top left, rgba(47, 111, 143, 0.18), transparent 45%),
    radial-gradient(circle at bottom right, rgba(73, 129, 176, 0.12), transparent 50%),
    linear-gradient(160deg, var(--webview-bg-start), var(--webview-bg-end));
}

.webview-container {
  max-width: 920px;
  margin: 0 auto;
  padding: 32px 20px 48px;
}

.webview-card {
  background: #ffffff;
  border-radius: 20px;
  padding: 28px;
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
  border: 1px solid var(--webview-border);
}

.webview-card h1 {
  margin: 0 0 20px;
  font-size: 1.8rem;
  color: var(--webview-accent);
  letter-spacing: 0.02em;
}

.webview-card h2 {
  margin: 28px 0 12px;
  font-size: 1.1rem;
  color: var(--webview-accent);
}

.webview-card p,
.webview-card li {
  line-height: 1.8;
  font-size: 0.98rem;
}

.webview-card ul,
.webview-card ol {
  padding-left: 1.4rem;
  margin: 12px 0 0;
}

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

.webview-section + .webview-section {
  border-top: 1px solid var(--webview-border);
  margin-top: 24px;
  padding-top: 24px;
}

.webview-highlight {
  background: #f5f9ff;
  border-radius: 12px;
  padding: 16px;
  margin-top: 16px;
}

@media (max-width: 640px) {
  .webview-container {
    padding: 20px 16px 32px;
  }

  .webview-card {
    padding: 22px;
    border-radius: 16px;
  }

  .webview-card h1 {
    font-size: 1.5rem;
  }
}