:root {
  --ink: #111;
  --paper: #f5f5f5;
  --card: #fff;
  --text: #333;
  --muted: #555;
  --heading: #2c3e50;
  --link: #4f46a3;
  --soft: #fafafa;
}

* {
  box-sizing: border-box;
}

body {
  background-color: var(--paper);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  margin: 0 auto;
  max-width: 800px;
  padding: 20px;
}

.container {
  background-color: var(--card);
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  padding: 40px;
}

h1 {
  border-bottom: 3px solid var(--ink);
  color: var(--heading);
  padding-bottom: 10px;
}

h2 {
  color: var(--heading);
  margin-bottom: 15px;
  margin-top: 30px;
}

p {
  color: var(--text);
  margin-bottom: 15px;
}

em {
  color: #7f8c8d;
  font-style: italic;
}

a {
  background-color: var(--link);
  border-radius: 2px;
  color: #fff;
  display: inline-block;
  line-height: 1.35;
  padding: 1px 6px 2px;
  text-decoration: none;
}

a:hover {
  background-color: #fff;
  color: #2f2a72;
  outline: 1px solid #2f2a72;
  text-decoration: none;
}

code {
  background-color: #f4f4f4;
  border-radius: 3px;
  color: #e74c3c;
  font-family: "Courier New", monospace;
  padding: 2px 6px;
}

pre {
  background-color: #2c3e50;
  border-radius: 5px;
  color: #ecf0f1;
  overflow-x: auto;
  padding: 15px;
  white-space: pre-wrap;
  word-wrap: break-word;
}

pre code {
  background-color: transparent;
  border: 0;
  color: #ecf0f1;
  display: inline;
  padding: 0;
}

ul {
  color: var(--text);
}

li {
  margin-bottom: 10px;
}

img {
  height: auto;
  max-width: 100%;
}

table {
  border-collapse: collapse;
  display: block;
  margin: 20px 0 30px;
  overflow-x: auto;
  width: 100%;
}

th,
td {
  border: 1px solid #ddd;
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

th {
  background-color: #f4f4f4;
  color: var(--heading);
}

.note,
.highlight,
.architecture-box {
  background-color: var(--soft);
  border-left: 4px solid var(--ink);
  border-radius: 4px;
  color: var(--muted);
  font-size: 0.95em;
  margin-bottom: 20px;
  padding: 15px;
}

.back {
  margin-bottom: 20px;
}

.year {
  color: #999;
  font-size: 0.85em;
  margin-right: 10px;
  white-space: nowrap;
}

.row {
  display: flex;
  gap: 20px;
}

.column-2 {
  flex: 1;
}

.references,
.resources {
  margin-top: 30px;
}

.app-link {
  background-color: var(--link);
  border-radius: 3px;
  color: #fff;
  display: inline-block;
  font-weight: 600;
  line-height: 1.2;
  margin-top: 10px;
  padding: 10px 14px;
  text-decoration: none;
}

.app-link:hover {
  background-color: #fff;
  color: #2f2a72;
  outline: 1px solid #2f2a72;
}

.article-index a,
.archive-index a {
  text-decoration: none;
}

.article-index ul,
.archive-index ul {
  color: var(--text);
  list-style-type: none;
  padding-left: 0;
}

.article-index li,
.archive-index li {
  margin-bottom: 10px;
  padding-left: 20px;
  position: relative;
}

.article-index li::before,
.archive-index li::before {
  color: var(--ink);
  content: "→";
  left: 0;
  position: absolute;
}

.article-index li a,
.archive-index li a {
  background-color: var(--ink);
  border-radius: 2px;
  color: #fff;
  display: inline-block;
  line-height: 1.35;
  padding: 1px 6px 2px;
}

.article-index li a:hover,
.archive-index li a:hover {
  background-color: #fff;
  color: var(--ink);
  outline: 1px solid var(--ink);
}

.article-index .note a,
.archive-index .note a {
  background: none;
  color: var(--link);
  display: inline;
  padding: 0;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.site-footer {
  border-top: 1px solid #e5e5e5;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  font-size: 0.8em;
  gap: 10px;
  justify-content: space-between;
  margin-top: 40px;
  padding-top: 15px;
}

.site-footer a {
  background: none;
  color: var(--link);
  display: inline;
  padding: 0;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.site-footer a:hover {
  background: none;
  color: var(--heading);
  outline: none;
}

@media (max-width: 680px) {
  body {
    padding: 12px;
  }

  .container {
    padding: 24px;
  }

  .row {
    display: block;
  }
}