:root {
  --bg: #f6f8fb;
  --fg: #1c2430;
  --muted: #5d6b7e;
  --accent: #2f6fed;
  --card: #ffffff;
  --line: #e3e8ef;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.top {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 1040px; margin: 0 auto; padding: 18px 20px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--fg); font-weight: 650; font-size: 18px; }
.brand:hover { text-decoration: none; }
.top nav { display: flex; align-items: center; gap: 22px; }
.top nav a:not(.btn) { color: var(--muted); }

.btn {
  display: inline-block; padding: 8px 16px; border-radius: 8px;
  border: 1px solid var(--accent); color: var(--accent); background: transparent;
  font: inherit; font-weight: 600; cursor: pointer;
}
.btn:hover { text-decoration: none; background: rgba(47, 111, 237, .08); }
.btn.big { padding: 11px 26px; background: var(--accent); color: #fff; }
.btn.big:hover { background: #2760d1; }

main { max-width: 1040px; margin: 0 auto; padding: 0 20px 40px; }
.hero { text-align: center; padding: 64px 0 40px; }
.hero h1 { font-size: 44px; line-height: 1.15; margin: 0 0 16px; letter-spacing: -0.02em; }
.hero p { max-width: 620px; margin: 0 auto 18px; color: var(--muted); font-size: 18px; }
.note { color: var(--muted); font-size: 14px; }

.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin: 24px 0; }
.grid article, .split > div {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 22px;
}
.grid h2, .split h2 { margin: 0 0 8px; font-size: 18px; }
.grid p, .split p { margin: 0; color: var(--muted); }
.split { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; margin-top: 18px; }

footer {
  max-width: 1040px; margin: 0 auto; padding: 24px 20px 40px;
  display: flex; justify-content: space-between; color: var(--muted); font-size: 14px;
  border-top: 1px solid var(--line);
}

body.auth { display: flex; min-height: 100vh; align-items: center; justify-content: center; padding: 20px; }
.card {
  width: 100%; max-width: 400px; background: var(--card); border: 1px solid var(--line);
  border-radius: 14px; padding: 28px; box-shadow: 0 6px 24px rgba(28, 36, 48, .06);
}
.card h1 { font-size: 24px; margin: 18px 0 14px; }
form label { display: block; margin-bottom: 14px; font-size: 14px; color: var(--muted); }
form input {
  display: block; width: 100%; margin-top: 6px; padding: 10px 12px; font: inherit; color: var(--fg);
  border: 1px solid var(--line); border-radius: 8px; background: #fff;
}
form input:focus { outline: 2px solid rgba(47, 111, 237, .35); border-color: var(--accent); }
.error { color: #b42318; font-size: 14px; margin: 0 0 12px; }

@media (max-width: 760px) {
  .grid, .split { grid-template-columns: 1fr; }
  .hero h1 { font-size: 34px; }
  .top nav a:not(.btn) { display: none; }
}