:root {
  --border: #c2c2c2;
  --header-bg: #1b2a4a;
  --header-fg: #f4f4f4;
  --link: #1b4fa0;
}

* { box-sizing: border-box; }

body {
  font-family: -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  margin: 0;
  color: #1a1a1a;
  background: #fff;
}

.site-title {
  text-align: center;
  margin: 0;
  padding: 1rem 1.25rem 0.5rem;
  font-size: 1.75rem;
  letter-spacing: 0.03em;
}

.static-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1.5rem;
  padding: 0 1.25rem 0.75rem;
}

.static-links a {
  color: var(--link);
  text-decoration: none;
  font-size: 0.9rem;
}

.static-links a:hover { text-decoration: underline; }

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

nav.problem-tabs {
  display: flex;
  overflow-x: auto;
  border-bottom: 1px solid var(--border);
  padding: 0 1.25rem;
}

nav.problem-tabs button {
  font: inherit;
  font-size: 0.92rem;
  font-weight: 600;
  padding: 0.7rem 1rem;
  border: 0;
  border-bottom: 3px solid transparent;
  background: none;
  color: #555;
  cursor: pointer;
  white-space: nowrap;
}

/* centered, but still scrollable from the first tab when narrower than the tabs */
nav.problem-tabs button:first-child { margin-left: auto; }
nav.problem-tabs button:last-child { margin-right: auto; }

nav.problem-tabs button:hover { color: #1a1a1a; }
nav.problem-tabs button[aria-pressed="true"] { color: #1a1a1a; border-bottom-color: var(--link); }

form.selectors {
  display: grid;
  gap: 0.7rem;
  padding: 0.9rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: #f7f8fa;
}

.selector-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.6rem 1.75rem;
}

form.selectors label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.selector-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #555;
}

.selector-label.kq { text-transform: none; letter-spacing: 0; font-size: 0.9rem; }

form.selectors select {
  padding: 0.25rem 0.35rem;
  font: inherit;
  font-size: 0.9rem;
}

.segmented {
  display: inline-flex;
  flex-wrap: wrap;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.segmented button {
  font: inherit;
  font-size: 0.88rem;
  padding: 0.3rem 0.75rem;
  border: 0;
  border-right: 1px solid var(--border);
  background: #fff;
  cursor: pointer;
}

.segmented button:last-child { border-right: 0; }
.segmented button[aria-pressed="true"] { background: var(--link); color: #fff; }

p.subject { color: #444; margin-top: -0.5rem; }

main {
  padding: 1.25rem;
  max-width: 1100px;
  margin: 0 auto;
}

h1 { font-size: 1.4rem; }
h2 { font-size: 1.1rem; margin-top: 2rem; }
h3 { font-size: 0.95rem; color: #444; margin-top: 1.25rem; }

table {
  border-collapse: collapse;
  border: 1px solid var(--border);
  width: 100%;
  margin-top: 0.5rem;
  font-size: 0.9rem;
}

th, td {
  border: 1px solid var(--border);
  padding: 0.4rem 0.6rem;
  text-align: left;
  vertical-align: top;
}

th { background: #eef1f6; }

td.fn { font-family: "Cambria Math", Cambria, Georgia, serif; }

p.empty { color: #777; font-style: italic; }
p.stub-note { color: #8a5a00; background: #fff6e0; padding: 0.6rem 0.9rem; border: 1px solid #f0d18a; }

main ul { margin: 0.25rem 0; padding-left: 1.5rem; }
main li { margin: 0.15rem 0; }

ul.bibliography { list-style: none; padding-left: 0; }
ul.bibliography li { margin: 0.5rem 0; scroll-margin-top: 1rem; }
ul.bibliography li:target { background: #fff6e0; }

.site-footer {
  text-align: center;
  color: #888;
  font-size: 0.8rem;
  padding: 1.5rem;
}

table.status-table { width: auto; }
table.status-table th, table.status-table td { text-align: center; }
table.status-table td { min-width: 7rem; }

.status-proven       { background: #d9f0dc; color: #1e5b27; }
.status-conjectural  { background: #dde8f7; color: #1b3f73; }
.status-experimental { background: #fff1d1; color: #7a5200; }
.status-open         { background: #f4f4f4; color: #888; }
.status-uncomputed   { background: #ece8f6; color: #4b3d7a; }
span.map-count { display: block; font-size: 0.75rem; opacity: 0.8; }
span.status-cites { display: block; font-size: 0.7rem; }
span.status-cites a { color: inherit; }
table.with-subproblems th.subproblem-label { font-weight: normal; font-size: 0.8rem; text-align: left; white-space: nowrap; }
table.with-subproblems td { padding-top: 0.15rem; padding-bottom: 0.15rem; font-size: 0.8rem; }
table.with-subproblems tr.degree-start > * { border-top: 2px solid #8a93a6; }

.prose { max-width: 46rem; line-height: 1.55; }
.prose h2 { margin-top: 2.25rem; }
.nowrap { white-space: nowrap; }

.statement {
  border-left: 3px solid var(--header-bg);
  background: #f7f8fa;
  padding: 0.1rem 1rem;
  margin: 1rem 0;
}
.statement p { margin: 0.6rem 0; }

.problem-list {
  background: #f4f6fa;
  border: 1px solid var(--border);
  border-left: 4px solid var(--header-bg);
  padding: 0.25rem 1.25rem 0.75rem;
  margin: 1.5rem 0;
}
.problem-list h2 { margin-top: 0.75rem; }
.problem-list > ol > li { margin: 0.6rem 0; }

nav.jump-links {
  background: #f4f6fa;
  border: 1px solid var(--border);
  padding: 0.6rem 1rem;
  margin: 1rem 0 1.5rem;
  line-height: 1.7;
}
nav.jump-links ul { list-style: none; margin: 0; padding-left: 0; }
nav.jump-links ul ul { padding-left: 1.5rem; }
nav.jump-links li { margin: 0; }
section[id], h3[id] { scroll-margin-top: 1rem; }
h3.subproblem { font-size: 1.05rem; color: #1a1a1a; margin-top: 1.75rem; }
h4 { font-size: 0.9rem; color: #444; margin: 1.25rem 0 0.25rem; }

a.sage-export {
  font-size: 0.75rem;
  font-weight: normal;
  margin-left: 0.6rem;
  padding: 0.1rem 0.45rem;
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--link);
  text-decoration: none;
  white-space: nowrap;
  vertical-align: middle;
}
a.sage-export:hover { background: #eef1f6; }

a.footnote-ref { text-decoration: none; margin-left: 0.1rem; }
p.table-footnote { font-size: 0.85rem; color: #555; margin-top: 0.5rem; scroll-margin-top: 1rem; }
p.table-footnote:target { background: #fff6e0; }

iframe.comments-form {
  width: 100%;
  max-width: 46rem;
  height: 900px;
  border: 1px solid var(--border);
}
p.form-fallback { font-size: 0.85rem; color: #555; }
a.form-button {
  display: inline-block;
  padding: 0.5rem 1.1rem;
  background: var(--header-bg);
  color: var(--header-fg);
  text-decoration: none;
  border-radius: 3px;
}

.site-footer .footnote { font-size: 0.75rem; margin-top: 0.25rem; }

.qbar { text-decoration: overline; }
.intro { max-width: 60rem; }