:root {
  color-scheme: light;
  --bg: #f4f6f8;
  --surface: #fff;
  --ink: #17242d;
  --muted: #52636e;
  --line: #d9e1e5;
  --accent: #176b63;
  --accent-strong: #10544e;
  --soft: #e7f2ef;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #111a1e;
  --surface: #19262b;
  --ink: #eff5f4;
  --muted: #b4c4c7;
  --line: #35474d;
  --accent: #8bd3c6;
  --accent-strong: #a8e3d9;
  --soft: #203b38;
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); line-height: 1.6; }
a { color: var(--accent-strong); text-underline-offset: .18em; }
a:hover { text-decoration-thickness: 2px; }
button, a { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 3px solid #d28436; outline-offset: 3px; }
.skip-link { position: absolute; top: .75rem; left: .75rem; z-index: 2; padding: .65rem 1rem; transform: translateY(-160%); background: var(--surface); color: var(--ink); border-radius: .5rem; }
.skip-link:focus { transform: translateY(0); }
.site-header, .site-footer { display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; width: min(1120px, calc(100% - 3rem)); margin: auto; }
.site-header { min-height: 88px; border-bottom: 1px solid var(--line); }
.brand { display: flex; align-items: center; gap: .75rem; color: var(--ink); text-decoration: none; }
.brand > span:last-child { display: grid; line-height: 1.25; }
.brand-mark { display: grid; place-items: center; width: 42px; height: 42px; border-radius: 13px; background: var(--accent); color: #fff; font-size: 1.25rem; font-weight: 800; }
.brand-caption { margin-top: .18rem; color: var(--muted); font-size: .78rem; }
nav { display: flex; align-items: center; gap: 1.5rem; }
nav a { color: var(--muted); text-decoration: none; font-size: .94rem; }
nav a[aria-current="page"] { color: var(--ink); font-weight: 700; }
.theme-toggle, .button { min-height: 44px; border: 1px solid var(--line); border-radius: .65rem; padding: .7rem 1rem; background: var(--surface); color: var(--ink); font: inherit; font-size: .92rem; font-weight: 650; text-decoration: none; cursor: pointer; }
.theme-toggle:hover, .button-secondary:hover { border-color: var(--accent); }
.page-shell { width: min(960px, calc(100% - 3rem)); margin: 0 auto; padding: 5.5rem 0 4rem; }
.intro { max-width: 750px; }
.eyebrow { margin: 0 0 .8rem; color: var(--accent-strong); font-size: .78rem; font-weight: 750; letter-spacing: .13em; text-transform: uppercase; }
h1 { margin: 0; font-size: clamp(2.6rem, 6vw, 4.9rem); line-height: 1.05; letter-spacing: -.055em; }
.lead { max-width: 640px; margin: 1.4rem 0 0; color: var(--muted); font-size: clamp(1.08rem, 2vw, 1.25rem); }
.actions { display: flex; flex-wrap: wrap; gap: .8rem; margin-top: 2rem; }
.button-primary { display: inline-flex; align-items: center; justify-content: center; gap: .65rem; border-color: var(--accent); background: var(--accent); color: #fff; }
.button-primary:hover { background: var(--accent-strong); }
:root[data-theme="dark"] .button-primary { color: #10201e; }
.check-card { display: flex; align-items: flex-start; gap: 1.1rem; margin: 5rem 0 4rem; padding: 1.6rem; border: 1px solid var(--line); border-radius: 1rem; background: var(--surface); }
.check-icon { display: grid; flex: 0 0 44px; place-items: center; height: 44px; border-radius: 50%; background: var(--soft); color: var(--accent-strong); font-size: 1.2rem; font-weight: 800; }
h2 { margin: 0; font-size: 1.15rem; line-height: 1.35; }
.check-card p { margin: .45rem 0 1rem; color: var(--muted); }
.check-card .result { min-height: 1.6em; margin: .6rem 0 0; font-size: .9rem; }
.details { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.details article { padding-top: 1.1rem; border-top: 1px solid var(--line); }
.detail-number { display: block; margin-bottom: 1.2rem; color: var(--accent-strong); font-size: .78rem; font-weight: 750; }
.details h2 { font-size: 1rem; }
.details p { margin: .5rem 0 0; color: var(--muted); font-size: .93rem; }
.site-footer { min-height: 80px; border-top: 1px solid var(--line); color: var(--muted); font-size: .85rem; }
.site-footer a { color: var(--muted); }
.about-page { min-height: calc(100vh - 170px); }
.about-page .lead { margin-bottom: 2rem; }
.about-note { max-width: 680px; margin: 0 0 2rem; padding: 1.5rem; border: 1px solid var(--line); border-radius: 1rem; background: var(--surface); }
.about-note ul { margin: 1rem 0 0; padding-left: 1.2rem; color: var(--muted); }
.about-note li + li { margin-top: .5rem; }
code { color: var(--ink); font-size: .9em; }

@media (max-width: 700px) {
  .site-header { width: min(100% - 2rem, 1120px); min-height: 76px; flex-wrap: wrap; padding: .8rem 0; gap: .8rem; }
  nav { order: 3; width: 100%; padding: .25rem 0; }
  .theme-toggle { margin-left: auto; padding-inline: .7rem; font-size: .82rem; }
  .page-shell { width: min(100% - 2rem, 960px); padding: 3.7rem 0 3rem; }
  .check-card { margin: 3.5rem 0; padding: 1.2rem; }
  .details { grid-template-columns: 1fr; gap: 1rem; }
  .details article { padding-top: .8rem; }
  .detail-number { margin-bottom: .5rem; }
  .site-footer { width: min(100% - 2rem, 1120px); }
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
  .button, .theme-toggle { transition: background-color .16s ease, border-color .16s ease, color .16s ease; }
}