:root {
  color-scheme: light;
  --bg: #f5f6fb;
  --card: #ffffff;
  --text: #1f2430;
  --muted: #5d6571;
  --accent: #2f5cff;
  --border: #e3e7ef;
  --shadow: 0 18px 40px rgba(15, 23, 42, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", "SF Pro Text", "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

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

a:hover,
a:focus {
  text-decoration: underline;
}

header {
  background: #fff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-inner {
  max-width: 960px;
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.02em;
}

.app {
  color: var(--muted);
  font-weight: 600;
}

main {
  padding: 40px 24px 64px;
}

.container {
  max-width: 700px;
  margin: 0 auto;
  background: var(--card);
  padding: 40px 36px;
  border-radius: 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

h1 {
  font-size: clamp(2rem, 3vw, 2.6rem);
  margin-top: 0;
}

h2 {
  margin-top: 32px;
  font-size: 1.4rem;
}

h3 {
  margin-top: 24px;
  font-size: 1.15rem;
}

p {
  margin: 0 0 16px;
}

ul,
ol {
  padding-left: 22px;
  margin: 0 0 16px;
}

li {
  margin-bottom: 8px;
}

.subtitle {
  color: var(--muted);
  margin-top: 0;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 32px;
}

.card {
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px;
  background: #fff;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.06);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.card strong {
  font-size: 1.05rem;
}

.tag {
  display: inline-block;
  padding: 6px 12px;
  border-radius: 999px;
  background: #eef1ff;
  color: #3346c2;
  font-weight: 600;
  font-size: 0.9rem;
}

footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
  padding: 24px 24px 48px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

@media (max-width: 640px) {
  .container {
    padding: 28px 22px;
  }

  .header-inner {
    padding: 16px 18px;
  }
}