:root {
  --ink: #0f172a;
  --body: #1e293b;
  --paper: #f0f1f3;
  --card: #ffffff;
  --line: #94a3b8;
  --link: #0f766e;
  --focus: #0d9488;
}

* { box-sizing: border-box; }

html { font-size: 100%; }

body {
  margin: 0;
  color: var(--body);
  background: var(--paper);
  font-family: system-ui, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-size: 1.3125rem;
  line-height: 1.5;
}

a { color: var(--link); }

.wrap {
  width: 880px;
  max-width: calc(100% - 2rem);
  margin: 0 auto;
  padding: 1.75rem 0 3.5rem;
}

.mark {
  margin: 0 0 1rem;
  color: var(--ink);
  font-size: 1.25rem;
  font-weight: 650;
}

.mark a { color: inherit; text-decoration: none; }

h1 {
  margin: 0 0 1rem;
  color: var(--ink);
  font-size: 2.125rem;
  line-height: 1.2;
  font-weight: 650;
}

.lead {
  margin: 0 0 0.85rem;
}

h2 {
  margin: 1.75rem 0 1rem;
  color: var(--ink);
  font-size: 1.5rem;
  line-height: 1.3;
  font-weight: 650;
}

.doors {
  display: grid;
  gap: 0.85rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.door {
  display: block;
  height: 100%;
  padding: 1.15rem 1.2rem 1.2rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--body);
  text-decoration: none;
}

.door strong {
  display: block;
  margin-bottom: 0.45rem;
  color: var(--ink);
  font-size: 1.35rem;
  line-height: 1.3;
}

.door span {
  display: block;
  font-size: 1.25rem;
  line-height: 1.45;
}

.door:hover,
.door:focus-visible {
  border-color: var(--link);
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.proof {
  margin: 1.5rem 0 0;
}

.back { margin-top: 1.75rem; font-size: 1.25rem; }

@media (min-width: 900px) {
  .doors { grid-template-columns: 1fr 1fr 1fr; }
}