/* light-dark(a, b) picks a in light mode and b in dark mode, based on color-scheme */
:root {
  color-scheme: light dark;

  --bg: light-dark(#ffffff, #242424);
  --fg: light-dark(#242424, #ededed);
  --muted: light-dark(#666666, #a0a0a0);
  --line: light-dark(#e2e2e2, #333333);
  --subtle: light-dark(#f4f4f4, #1e1e1e);
  --yellow: #ffd21f;
  --on-yellow: #242424;

  --serif: Charter, "Bitstream Charter", "Sitka Text", Cambria, Georgia, serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --measure: 67ch; /* line length of the reading column */
}

[data-theme="light"] {
  color-scheme: light;
}
[data-theme="dark"] {
  color-scheme: dark;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 115%;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0 auto;
  padding: 0 1.25rem;
  max-width: var(--measure);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--serif);
  line-height: 1.65;
  overflow-wrap: break-word;
}

main {
  flex: 1;
}

::selection {
  background: var(--yellow);
  color: var(--on-yellow);
}

:focus-visible {
  outline: 2px solid var(--yellow);
  outline-offset: 2px;
}

/* Yellow text is unreadable on white, so yellow marks links rather than coloring them */
a {
  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--yellow);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

a:hover {
  /* increase margin of the highlighted link */
  margin: -0.1rem -0.2rem;
  padding: 0.1rem 0.2rem;
  background: var(--yellow);
  color: var(--on-yellow);
}

/* ---------- site header and footer ---------- */

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 1rem;
  padding: 1.5rem 0;
  font-family: var(--sans);
  font-size: 1rem;
}

.site-title {
  font-weight: 700;
  text-decoration: none;
}

.site-header nav {
  display: flex;
  gap: 0.75rem;
}

.site-header nav a {
  color: var(--muted);
  text-decoration: none;
}
.site-header nav a:hover {
  color: var(--on-yellow);
}

.search {
  position: relative;
  flex: 1 1 8rem;
  min-width: 8rem;
}

#search-input {
  width: 100%;
  padding: 0.3rem 0.6rem;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg);
  color: var(--fg);
  font: inherit;
}

#search-results {
  position: absolute;
  z-index: 10;
  top: calc(100% + 0.25rem);
  right: 0;
  width: min(30rem, calc(100vw - 2.5rem));
  max-height: 70vh;
  margin: 0;
  padding: 0;
  overflow-y: auto;
  list-style: none;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--bg);
}

#search-results a,
#search-results .empty {
  display: block;
  padding: 0.5rem 0.75rem;
  text-decoration: none;
}

#search-results li + li {
  border-top: 1px solid var(--line);
}
#search-results a:hover,
#search-results a:focus {
  background: var(--subtle);
  color: var(--fg);
}
#search-results strong {
  display: block;
}
#search-results span {
  color: var(--muted);
}
#search-results mark {
  background: var(--yellow);
  color: var(--on-yellow);
}

#theme-toggle {
  display: flex;
  padding: 0.25rem;
  border: 0;
  background: none;
  color: var(--fg);
  cursor: pointer;
}

.site-footer {
  display: flex;
  gap: 0.75rem;
  padding: 3rem 0 1.5rem;
  color: var(--muted);
  font-family: var(--sans);
  font-size: 0.8rem;
}

/* ---------- lists ---------- */

.post-list,
.tag-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.post-list li {
  display: flex;
  gap: 1rem;
  padding: 0.2rem 0;
}

time,
.count {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.8rem;
  white-space: nowrap;
}

.post-list time {
  flex: none;
  padding-top: 0.2rem;
}

.intro {
  margin-bottom: 2rem;
}

.tag {
  font-family: var(--sans);
  font-size: 0.8rem;
}

/* ---------- article ---------- */

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 2em 0 0.5em;
  font-family: var(--sans);
  line-height: 1.25;
}

h1 {
  margin-top: 0.5em;
  font-size: 1.6rem;
}
h2 {
  font-size: 1.25rem;
}
h3 {
  font-size: 1.05rem;
}
h4,
h5,
h6 {
  font-size: 1rem;
}

.post-header {
  margin-bottom: 2rem;
}
.post-meta {
  margin: 0;
}
.post-meta .tag {
  margin-left: 0.5rem;
}

blockquote {
  margin: 1.5em 0;
  padding-left: 1rem;
  border-left: 3px solid var(--yellow);
  color: var(--muted);
}

.callout {
  margin: 1.5em 0;
  padding: 0.75rem 1rem;
  border-left: 3px solid var(--yellow);
  background: var(--subtle);
}

.callout > :last-child {
  margin-bottom: 0;
}

.callout-title {
  margin: 0 0 0.25rem;
  font-family: var(--sans);
  font-size: 0.85rem;
  font-weight: 700;
}

code,
pre {
  font-family: var(--mono);
  font-size: 0.82rem;
}

code {
  padding: 0.1em 0.3em;
  border-radius: 3px;
  background: var(--subtle);
}

pre {
  padding: 0.75rem 1rem;
  overflow-x: auto;
  border-radius: 4px;
  background: var(--subtle);
  line-height: 1.5;
}

pre code {
  padding: 0;
  background: none;
}

li:has(> input[type="checkbox"]) {
  list-style: none;
  margin-left: -1.25rem;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 1.5em auto;
}

hr {
  margin: 2.5em 0;
  border: 0;
  border-top: 1px solid var(--line);
}

table {
  display: block;
  max-width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 0.85rem;
}

th,
td {
  padding: 0.35rem 0.75rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

/* Wide equations scroll inside the column instead of widening the page */
.katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 0.25em 0;
}

@media (max-width: 30rem) {
  .post-list li {
    flex-direction: column;
    gap: 0;
    padding: 0.4rem 0;
  }
  .post-list time {
    padding-top: 0;
  }
  .search {
    flex-basis: 100%;
    order: 1;
  }
  #theme-toggle {
    margin-left: auto;
  }
}

/* ---------- votes ---------- */

/* Takes up its space from the start, so the page doesn't jump once the count loads */
.vote {
  display: block;
  margin-top: 2.5rem;
  padding: 0.25rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: none;
  color: var(--muted);
  font-family: var(--sans);
  font-size: 0.85rem;
  cursor: pointer;
}

.vote:not(.ready) {
  visibility: hidden;
}

.vote:hover {
  border-color: var(--yellow);
}

.vote[aria-pressed="true"] {
  border-color: var(--yellow);
  background: var(--yellow);
  color: var(--on-yellow);
}