:root {
  color-scheme: light;
  --bg: #f7f5f2;
  --paper: #ffffff;
  --text: #1f2328;
  --muted: #5b6068;
  --accent: #0057b8;
  --border: #e5e1da;
}

.theme-dark {
  color-scheme: dark;
  --bg: #0f1115;
  --paper: #171a21;
  --text: #f2f3f5;
  --muted: #b3b9c4;
  --accent: #6aa6ff;
  --border: #2a2f3a;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Source Serif 4", "Iowan Old Style", "Times New Roman", serif;
  background: linear-gradient(180deg, var(--bg) 0%, var(--paper) 100%);
  color: var(--text);
}

.page {
  max-width: 1000px;
  margin: 56px auto 80px;
  padding: 0 20px;
}

.md {
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 40px 44px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.08);
  line-height: 1.7;
  font-size: 1.05rem;
}

.theme-dark .md {
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.4);
}

.avatar {
  width: 180px;
  height: 180px;
  border-radius: 24px;
  object-fit: cover;
  border: 1px solid var(--border);
  box-shadow: 0 14px 28px rgba(0, 0, 0, 0.12);
  float: right;
  margin: 4px 0 16px 20px;
}

.md-body {
  min-width: 0;
}

.md h1,
.md h2,
.md h3 {
  font-weight: 600;
  margin-top: 28px;
}

.md h1 {
  margin-top: 0;
  font-size: 2.1rem;
}

.md h2 {
  font-size: 1.5rem;
}

.md details > summary {
  cursor: pointer;
  list-style: none;
  margin: 0;
}

.md details > summary strong {
  display: inline-block;
  font-weight: 600;
  font-size: 1.5rem;
  line-height: 1.2;
  margin-top: 28px;
}

.md details[open] > summary {
  margin-bottom: 12px;
}

.md details > summary::-webkit-details-marker {
  display: none;
}

.md details > summary::before {
  content: "▸";
  display: inline-block;
  margin-right: 8px;
  transform: translateY(-1px);
  color: var(--muted);
}

.md details[open] > summary::before {
  content: "▾";
}

.theme-toggle {
  position: fixed;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 10;
}

.theme-toggle button {
  border: 1px solid var(--border);
  background: var(--paper);
  color: var(--text);
  font-size: 0.85rem;
  padding: 8px 12px;
  border-radius: 999px;
  cursor: pointer;
}

.theme-toggle button:hover {
  background: var(--bg);
}

.md p {
  color: var(--text);
}

.md a {
  color: var(--accent);
  text-decoration: none;
}

.md a:hover {
  text-decoration: underline;
}

.md ul {
  padding-left: 22px;
}

.md li {
  margin: 6px 0;
}

.md hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 28px 0;
}

@media (max-width: 640px) {
  .page {
    margin: 32px auto 60px;
  }

  .md {
    padding: 28px 24px;
  }

  .avatar {
    width: 160px;
    height: 160px;
    float: none;
    display: block;
    margin: 0 auto 16px;
  }
}