:root {
  color-scheme: light;
  --bg: #f4f4f5;
  --surface: #ffffff;
  --ink: #18181b;
  --muted: #71717a;
  --line: #e4e4e7;
  --accent: #0f766e;
  --font: ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.55;
}

body {
  min-height: 100%;
}

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 48px;
  padding: 8px 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--ink);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
  white-space: nowrap;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex-wrap: wrap;
  gap: 14px;
}

.site-nav a {
  color: var(--accent);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.open-planner,
.site-nav a.open-planner {
  background: var(--accent);
  color: #ffffff;
  text-decoration: none;
  border-radius: 8px;
  padding: 8px 14px;
  font-weight: 600;
}

.site-nav a.open-planner:hover {
  background: #0d9488;
  color: #ffffff;
}

.guide-column,
.about-column {
  width: min(680px, 100%);
  margin: 24px auto 48px;
  padding: 8px 20px 32px;
}

.about-column h1,
.guide-column h1 {
  margin: 8px 0 12px;
  font-size: 32px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.about-intro p,
.guide-column p,
.about-column > p {
  margin: 0 0 16px;
}

.about-column h2,
.guide-column h2 {
  margin: 28px 0 8px;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.3;
}

.about-column h3 {
  margin: 20px 0 4px;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.3;
}

.guide-column ul,
.about-column ul {
  margin: 0 0 16px;
  padding-left: 1.25rem;
}

.guide-column li,
.about-column li {
  margin: 6px 0;
}

.guide-column a,
.about-column a {
  color: var(--accent);
}

.breadcrumb {
  margin: 12px 0 4px;
  color: var(--muted);
  font-size: 14px;
}

.breadcrumb a {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}

.summary {
  color: var(--muted);
  font-size: 18px;
}

.example-plan {
  display: inline-block;
  margin: 4px 0 8px;
  padding: 8px 14px;
  background: var(--accent);
  color: #ffffff;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 600;
}

.guide-column a.example-plan {
  color: #ffffff;
}

.guide-index-list {
  list-style: none;
  padding: 0;
}

.guide-index-list a {
  font-weight: 600;
  text-decoration: none;
}

.guide-summary {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-weight: 400;
}

.planner-bar {
  display: none;
  width: 100%;
  min-height: 44px;
  height: 44px;
  background: var(--accent);
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  align-items: center;
  justify-content: center;
}

.changelog-page {
  position: static;
  z-index: auto;
  overflow: visible;
  background: var(--bg);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.5;
}

.changelog-column {
  width: min(40rem, 100%);
  margin: 0 auto;
  padding: 28px 16px 64px;
}

.changelog-back {
  margin: 0;
}

.changelog-back a {
  color: var(--muted);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.changelog-back a:hover {
  color: var(--accent);
}

.changelog-app {
  margin: 22px 0 0;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.changelog-subtitle,
.changelog-subline {
  margin: 4px 0 0;
  color: var(--muted);
  line-height: 1.35;
}

.changelog-subtitle {
  font-size: 14px;
}

.changelog-subline {
  font-size: 13px;
}

.changelog-page h1 {
  margin: 18px 0 0;
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.changelog-page article {
  margin: 0;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.changelog-page h1 + article {
  margin-top: 22px;
}

.changelog-page article + article {
  margin-top: 8px;
}

.changelog-page h2 {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.3;
}

.changelog-date {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.changelog-headline {
  margin: 8px 0 0;
  font-size: 16px;
}

.changelog-page ul {
  margin: 10px 0 0;
  padding-left: 1.15rem;
}

.changelog-page li {
  margin: 6px 0;
}

@media (max-width: 767px) {
  .guide-column {
    width: 100%;
    margin-top: 0;
  }

  .about-column {
    width: 100%;
  }

  .site-header .open-planner {
    display: none;
  }

  .planner-bar {
    display: flex;
    position: sticky;
    bottom: 0;
    z-index: 1;
  }
}

@media (min-width: 768px) {
  .planner-bar {
    display: none;
  }
}