:root {
  --bg: #f8fafc;
  --surface: #fff;
  --text: #172033;
  --muted: #526072;
  --line: #dbe3ee;
  --link: #075985;
  --focus: #f59e0b;
  --space: 1.25rem;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font:
    16px/1.65 system-ui,
    sans-serif;
}

header,
main,
footer {
  max-width: 72rem;
  margin: auto;
  padding: var(--space);
}

header {
  display: flex;
  gap: var(--space);
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.brand {
  font-weight: 700;
}

nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.categories {
  position: relative;
}

.categories summary {
  color: var(--link);
  cursor: pointer;
}

.categories[open] {
  background: var(--surface);
  border: 1px solid var(--line);
  padding: 0.25rem 0.5rem;
}

.categories a,
.footer-tags a {
  margin-inline: 0.5rem;
}

.categories[open] a {
  display: block;
  margin-block: 0.25rem;
}

.footer-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-block-end: 0.75rem;
}

.footer-tags a {
  margin: 0;
}

a {
  color: var(--link);
}

main {
  min-height: 70vh;
  background: var(--surface);
}

article {
  border-block-end: 1px solid var(--line);
  padding-block: 1.5rem;
}

h1,
h2 {
  line-height: 1.2;
}

time {
  color: var(--muted);
}

pre {
  overflow: auto;
  padding: 1rem;
  background: #eaf0f6;
  border-radius: 0.25rem;
}

form {
  display: grid;
  gap: 1rem;
  max-width: 36rem;
}

label {
  display: grid;
  gap: 0.25rem;
}

input,
textarea,
button {
  font: inherit;
  padding: 0.6rem;
}

textarea {
  min-height: 10rem;
}

button {
  cursor: pointer;
  background: var(--link);
  color: #fff;
  border: 0;
  border-radius: 0.25rem;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

@media (max-width: 40rem) {
  header {
    align-items: flex-start;
    flex-direction: column;
  }

  nav {
    gap: 0.75rem;
  }
}