:root {
  --color-bg: #F5F7F8;
  --color-surface: #FFFFFF;
  --color-primary: #1F6F8B;
  --color-primary-dark: #184f63;
  --color-accent: #3BB273;
  --color-text: #2B2E2F;
  --color-muted: #7a8288;
  --shadow-soft: 0 10px 30px rgba(0,0,0,0.06);
  --radius-lg: 16px;
}

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

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Inter", sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(245,247,248,0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(0,0,0,0.04);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.5rem;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.logo-icon {
  width: 32px;
  height: 32px;
  border-radius: 999px;
  background: radial-gradient(circle at 30% 30%, #ffffff 0, #d9f3ea 35%, #1F6F8B 100%);
  position: relative;
  overflow: hidden;
}

.logo-icon::before {
  content: "";
  position: absolute;
  inset: 25% 20% 30% 20%;
  border-radius: 999px 999px 600px 600px;
  background: rgba(255,255,255,0.9);
}

.logo-icon::after {
  content: "";
  position: absolute;
  width: 38%;
  height: 38%;
  border-radius: 50%;
  background: rgba(255,255,255,0.95);
  top: 8%;
  left: 31%;
}

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

.logo-text span {
  color: var(--color-primary);
}

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.nav-link {
  text-decoration: none;
  color: var(--color-muted);
  font-size: 0.9rem;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  transition: background 0.15s ease, color 0.15s ease;
}

.nav-link:hover {
  background: rgba(31,111,139,0.06);
  color: var(--color-primary);
}

.nav-link.active {
  background: var(--color-primary);
  color: #ffffff;
}

.content {
  max-width: 960px;
  margin: 1.5rem auto 3rem;
  padding: 0 1rem;
}

.hero {
  background: radial-gradient(circle at 0 0, #ffffff 0, #E8F6F1 45%, #F5F7F8 100%);
  padding: 2.5rem 2rem;
  border-radius: 24px;
  box-shadow: var(--shadow-soft);
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
  gap: 2rem;
  align-items: center;
}

.hero-title {
  font-size: clamp(2rem, 3vw, 2.6rem);
  margin: 0 0 0.5rem;
}

.hero-sub {
  margin: 0 0 1.5rem;
  color: var(--color-muted);
  font-size: 1rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.3rem;
  border-radius: 999px;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.1s ease, box-shadow 0.1s ease, background 0.1s ease, color 0.1s ease;
}

.btn-primary {
  background: var(--color-primary);
  color: #ffffff;
  box-shadow: 0 10px 20px rgba(31,111,139,0.3);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 12px 24px rgba(31,111,139,0.35);
}

.btn-secondary {
  background: #ffffff;
  color: var(--color-primary);
  border: 1px solid rgba(31,111,139,0.2);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  background: rgba(59,178,115,0.12);
  color: var(--color-accent);
  font-size: 0.75rem;
  font-weight: 500;
  margin-bottom: 0.8rem;
}

.hero-stat {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.hero-visual {
  justify-self: end;
}

.hero-bubble {
  width: 210px;
  aspect-ratio: 1 / 1;
  border-radius: 40%;
  background: radial-gradient(circle at 30% 20%, #ffffff 0, #d9f3ea 36%, #1F6F8B 100%);
  position: relative;
  box-shadow: 0 18px 40px rgba(0,0,0,0.18);
  overflow: hidden;
}

.hero-bubble::before,
.hero-bubble::after {
  content: "";
  position: absolute;
  border-radius: 999px;
  background: rgba(255,255,255,0.85);
}

.hero-bubble::before {
  inset: 24% 26% 26% 24%;
}

.hero-bubble::after {
  width: 40%;
  aspect-ratio: 1 / 1;
  top: 9%;
  left: 31%;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
}

.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  padding: 1.3rem 1.4rem;
}

.card h2,
.card h3 {
  margin-top: 0;
}

.card p {
  margin: 0.3rem 0 0.4rem;
}

.card a {
  color: var(--color-primary);
  text-decoration: none;
  font-size: 0.9rem;
}

.card a:hover {
  text-decoration: underline;
}

.section-title {
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.1rem 0.6rem;
  border-radius: 999px;
  background: rgba(31,111,139,0.06);
  color: var(--color-primary);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.3rem;
}

.prose h1,
.prose h2,
.prose h3 {
  margin-top: 1.8rem;
}

.prose h1 {
  font-size: 1.9rem;
}

.prose h2 {
  font-size: 1.35rem;
}

.prose p {
  line-height: 1.7;
  margin: 0.6rem 0;
}

.prose ul {
  padding-left: 1.2rem;
}

.prose li {
  margin: 0.35rem 0;
}

.info-box {
  border-radius: 12px;
  padding: 0.9rem 1rem;
  margin: 1rem 0;
  font-size: 0.95rem;
}

.info-box.tip {
  background: #E8F6F1;
}

.info-box.warn {
  background: #FFF1E6;
}

.info-box.note {
  background: #EEF3F6;
}

.site-footer {
  border-top: 1px solid rgba(0,0,0,0.05);
  padding: 1.5rem 1rem 2rem;
  text-align: center;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 0.4rem;
}

.footer-links a {
  color: var(--color-muted);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--color-primary);
}

@media (max-width: 768px) {
  .site-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.4rem;
  }
  .hero {
    grid-template-columns: minmax(0, 1fr);
    padding: 1.8rem 1.4rem;
  }
  .hero-visual {
    justify-self: start;
  }
  .content {
    margin-top: 1rem;
  }
}