:root {
  --bg: #f3f5ef;
  --paper: #ffffff;
  --ink: #17201d;
  --muted: #5f6b65;
  --line: #d9e0da;
  --brand: #0f5b44;
  --brand-strong: #0b4534;
  --accent: #dbeee6;
  --max: 860px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  color: var(--ink);
  background: radial-gradient(circle at top right, #eaf3ee 0%, var(--bg) 45%, #eef2e9 100%);
  line-height: 1.55;
}

main {
  width: min(var(--max), calc(100% - 2rem));
  margin: 2rem auto 3rem;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 1.5rem;
  box-shadow: 0 8px 22px rgba(18, 41, 33, 0.08);
}

header {
  margin-bottom: 1.25rem;
}

h1 {
  margin: 0;
  font-size: clamp(1.3rem, 2.7vw, 2rem);
  line-height: 1.2;
}

h2 {
  margin-top: 1.4rem;
  font-size: 1.05rem;
  border-left: 4px solid var(--accent);
  padding-left: 0.5rem;
}

p,
li {
  color: var(--ink);
}

small,
.muted {
  color: var(--muted);
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.8rem;
}

nav a,
.link-button {
  display: inline-block;
  text-decoration: none;
  padding: 0.45rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--brand-strong);
  background: #f8fbf9;
  font-size: 0.9rem;
}

nav a:hover,
.link-button:hover {
  border-color: #bfcec5;
  background: #eef5f1;
}

.notice {
  padding: 0.7rem 0.8rem;
  border-left: 4px solid var(--brand);
  background: #f1f8f4;
  border-radius: 6px;
}

footer {
  margin-top: 1.5rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
}

code {
  font-family: "IBM Plex Mono", "SFMono-Regular", monospace;
  font-size: 0.9em;
  background: #f3f6f4;
  border: 1px solid #e1e8e3;
  border-radius: 5px;
  padding: 0.1rem 0.28rem;
}