*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f5f6f8;
  color: #15171c;
}

.page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.9rem 1.25rem;
  background: rgba(245, 246, 248, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(15, 23, 42, 0.08);
}

.logo {
  font-weight: 700;
  letter-spacing: 0.03em;
  font-size: 1rem;
}

.logo span {
  color: #2563eb;
}

.nav {
  display: flex;
  gap: 0.9rem;
  font-size: 0.85rem;
}

.nav a {
  text-decoration: none;
  color: #4b5563;
}

.nav a:hover {
  color: #111827;
}

.main {
  max-width: 960px;
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
}

.hero {
  padding: 1.5rem 0 1rem;
}

.hero-text h1 {
  font-size: clamp(2.1rem, 4vw, 2.6rem);
  margin-bottom: 0.5rem;
}

.hero-text p {
  max-width: 34rem;
  font-size: 0.98rem;
  color: #4b5563;
}

#hero-start {
  margin-top: 1rem;
  padding: 0.7rem 1.5rem;
  border-radius: 999px;
  border: none;
  background: #111827;
  color: #f9fafb;
  font-size: 0.95rem;
  cursor: pointer;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.9rem;
  font-size: 0.75rem;
  color: #6b7280;
}

.hero-tags span {
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  background: #e5e7eb;
}

.card {
  background: #ffffff;
  border-radius: 1rem;
  padding: 1.5rem 1.25rem;
  margin-top: 1.5rem;
  box-shadow: 0 14px 35px rgba(15, 23, 42, 0.06);
  border: 1px solid rgba(15, 23, 42, 0.05);
}

.card h2 {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.card-sub {
  font-size: 0.9rem;
  color: #6b7280;
  margin-bottom: 1.1rem;
}

.status {
  font-size: 0.9rem;
  color: #2563eb;
  margin-bottom: 1rem;
}

.results {
  display: flex;
  gap: 0.9rem;
  margin-bottom: 1.1rem;
}

.result-box {
  flex: 1;
  background: #f9fafb;
  border-radius: 0.9rem;
  padding: 0.9rem;
  border: 1px solid #e5e7eb;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: #9ca3af;
}

.value {
  font-size: 1.7rem;
  font-weight: 600;
}

.unit {
  font-size: 0.75rem;
  color: #6b7280;
}

#retest {
  margin-top: 0.25rem;
  padding: 0.7rem 1.3rem;
  border-radius: 999px;
  border: none;
  background: #2563eb;
  color: #f9fafb;
  font-size: 0.9rem;
  cursor: pointer;
}

#retest:disabled {
  opacity: 0.65;
  cursor: default;
}

.info-card .info-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.9rem;
  font-size: 0.9rem;
  color: #4b5563;
  margin-top: 0.75rem;
}

.info-card h3 {
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
}

.faq-card {
  font-size: 0.9rem;
  color: #4b5563;
}

.faq-item + .faq-item {
  margin-top: 0.75rem;
}

.faq-item h3 {
  font-size: 0.95rem;
  margin-bottom: 0.1rem;
  color: #111827;
}

.footer {
  border-top: 1px solid rgba(15, 23, 42, 0.08);
  padding: 1rem 1.25rem 1.5rem;
  text-align: center;
  font-size: 0.75rem;
  color: #6b7280;
  margin-top: auto;
}

.footer-links a {
  color: #6b7280;
  text-decoration: none;
}

.footer-links a:hover {
  color: #111827;
}

@media (min-width: 768px) {
  .hero {
    padding-top: 2.2rem;
  }

  .info-card .info-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}