:root {
  --accent: #1772d0;
  --accent-hover: #f09228;
  --ink: #202020;
  --muted: #5f6b76;
  --line: #d9e4ee;
  --soft: #f7fafc;
  --card: #fbfdff;
  --teal: #0f766e;
  --green: #15803d;
  --orange: #c2410c;
  --title-font-size: 22px;
  --text-font-size: 15px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: #ffffff;
  color: var(--ink);
  font-family: 'Poppins', Verdana, Helvetica, sans-serif;
  font-size: var(--text-font-size);
  line-height: 1.58;
}

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

a:hover,
a:focus {
  color: var(--accent-hover);
}

.page-shell {
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
  padding: 34px 0 54px;
}

.hero {
  padding: 18px 0 22px;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  line-height: 1.25;
  font-weight: 600;
}

h1 {
  max-width: 760px;
  font-size: 38px;
}

.hero h1 {
  max-width: 100%;
  font-size: 35px;
  white-space: nowrap;
}

h2 { font-size: var(--title-font-size); }
h3 { margin-top: 28px; font-size: 18px; }
h4 { margin-top: 20px; font-size: 16px; }

.hero-copy {
  max-width: 760px;
  margin: 14px 0 0;
  color: #38434f;
  font-size: 17px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.hero-actions a,
.reader-tab {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 5px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  color: #354452;
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.hero-actions a:hover,
.reader-tab:hover {
  border-color: #a0b4c8;
  color: var(--accent);
}

.section {
  padding: 28px 0;
  border-bottom: 1px solid #e9eef3;
}

.intro-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.intro-grid article {
  min-height: 148px;
  padding: 15px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--soft);
}

.intro-grid h2 {
  font-size: 16px;
}

.intro-grid p,
.section-heading p,
.contribute-panel p {
  margin: 8px 0 0;
  color: var(--muted);
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 14px;
}

.topic-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.topic-tab {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 34px;
  padding: 5px 13px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  color: #354452;
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.topic-tab small {
  min-width: 20px;
  padding: 1px 6px;
  border-radius: 999px;
  background: #eef4fa;
  color: #4f6172;
  font-size: 11px;
}

.topic-tab:hover,
.topic-tab:focus,
.topic-tab.active {
  border-color: var(--accent);
  outline: none;
}

.topic-tab.active {
  color: var(--accent);
}

.topic-summary {
  max-width: 720px;
  margin-bottom: 14px;
}

.topic-summary p {
  margin: 0;
  color: var(--muted);
}

.topic-summary p + p {
  margin-top: 3px;
}

.seed-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.seed-card {
  display: flex;
  width: 100%;
  flex-direction: column;
  gap: 7px;
  padding: 13px 15px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  font-family: inherit;
  text-align: left;
  cursor: pointer;
}

.seed-card:hover,
.seed-card:focus,
.seed-card.active {
  border-color: var(--accent);
  outline: none;
}

.seed-title-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.seed-badges {
  display: inline-flex;
  flex: 0 0 auto;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
}

.seed-ramp {
  flex: 0 0 auto;
  padding: 2px 8px;
  border-radius: 999px;
  background: #eef4fa;
  color: #4f6172;
  font-size: 12px;
  font-weight: 600;
}

.seed-difficulty {
  --difficulty-color: #15803d;
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 6px;
  padding: 2px 8px;
  border-radius: 999px;
  background: #ffffff;
  box-shadow: inset 0 0 0 1px #dce6ef;
  color: #4f6172;
  font-size: 12px;
  font-weight: 600;
}

.difficulty-1 { --difficulty-color: #15803d; }
.difficulty-2 { --difficulty-color: #65a30d; }
.difficulty-3 { --difficulty-color: #ca8a04; }
.difficulty-4 { --difficulty-color: #ea580c; }
.difficulty-5 { --difficulty-color: #dc2626; }

.difficulty-scale {
  display: inline-grid;
  grid-template-columns: repeat(5, 5px);
  gap: 2px;
}

.difficulty-scale span {
  width: 5px;
  height: 12px;
  border-radius: 999px;
  background: #dce6ef;
}

.difficulty-scale span.active {
  background: var(--difficulty-color);
}

.seed-card strong {
  font-size: 16px;
  line-height: 1.35;
}

.seed-hook {
  color: #38434f;
  font-size: 14px;
}

.seed-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  color: var(--muted);
  font-size: 13px;
}

.seed-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
}

.seed-tags span {
  padding: 1px 7px;
  border-radius: 999px;
  background: #edf7f6;
  color: var(--teal);
  font-size: 11px;
  font-weight: 600;
}

.empty-topic {
  padding: 16px;
  border: 1px dashed var(--line);
  border-radius: 8px;
  background: var(--soft);
}

.empty-topic strong,
.empty-topic span {
  display: block;
}

.empty-topic span {
  margin-top: 4px;
  color: var(--muted);
}

.seed-reader {
  scroll-margin-top: 24px;
}

.seed-reader.is-folded {
  display: none;
}

.reader-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.reader-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.reader-tab.active {
  border-color: var(--accent);
  background: var(--accent);
  color: #ffffff;
}

.markdown-body {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.markdown-body h1 {
  font-size: 25px;
}

.markdown-body h2 {
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid #e9eef3;
}

.markdown-body p,
.markdown-body li,
.markdown-body blockquote {
  color: #2f3740;
}

.markdown-body blockquote {
  margin: 16px 0;
  padding: 12px 14px;
  border-left: 3px solid var(--accent);
  background: #f5f8fb;
}

.markdown-body code {
  padding: 1px 5px;
  border-radius: 5px;
  background: #eef4fa;
  font-size: 13px;
}

.markdown-body pre {
  overflow-x: auto;
  padding: 14px;
  border-radius: 8px;
  background: #18222d;
}

.markdown-body pre code {
  padding: 0;
  background: transparent;
  color: #f5f8fb;
}

.markdown-body hr {
  height: 1px;
  margin: 26px 0;
  border: 0;
  background: #e9eef3;
}

.contribute-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.9fr);
  gap: 26px;
}

.contribute-panel ol {
  margin: 0;
  padding-left: 22px;
}

.contribute-panel code {
  color: var(--orange);
  font-size: 13px;
}

.loading-note,
.error-note {
  color: var(--muted);
}

@media (max-width: 860px) {
  .hero h1 {
    white-space: normal;
  }
}

@media (max-width: 720px) {
  .page-shell {
    width: min(100% - 22px, 920px);
    padding-top: 20px;
  }

  h1 {
    font-size: 30px;
  }

  .intro-grid,
  .contribute-panel {
    grid-template-columns: 1fr;
  }

  .seed-title-line,
  .seed-meta {
    align-items: flex-start;
    flex-direction: column;
    gap: 6px;
  }

  .seed-badges {
    justify-content: flex-start;
  }

  .reader-topline {
    align-items: flex-start;
    flex-direction: column;
  }

  .markdown-body {
    padding: 16px;
  }
}