:root {
  --bg: #eff6ff;
  --bg-soft: #dbeafe;
  --card: #ffffff;
  --line: rgba(30, 64, 175, 0.12);
  --text: #1e3a8a;
  --muted: #475569;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --white: #ffffff;
  --shadow: 0 20px 40px rgba(30, 64, 175, 0.12);
  --radius: 22px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, Arial, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(147, 197, 253, 0.5), transparent 28%),
    linear-gradient(180deg, #dbeafe 0%, #eff6ff 18%, #ffffff 100%);
  color: var(--text);
  line-height: 1.75;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  width: min(920px, calc(100% - 2rem));
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(30, 64, 175, 0.96);
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 0;
  min-width: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: #ffffff;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--primary), #60a5fa);
  color: var(--white);
  box-shadow: var(--shadow);
}

.nav-scroll {
  margin-left: auto;
  min-width: 0;
  overflow: visible;
  position: relative;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.nav-scroll::-webkit-scrollbar {
  display: none;
}

.nav-links {
  display: flex;
  gap: 1.2rem;
  align-items: center;
  color: #dbeafe;
  font-size: 0.95rem;
  white-space: nowrap;
  width: max-content;
  min-width: max-content;
}

.nav-links > a,
.nav-dropdown-toggle {
  color: #dbeafe;
  font-weight: 600;
}

.nav-links > a:hover,
.nav-dropdown-toggle:hover {
  color: #ffffff;
  text-decoration: none;
}

.nav-dropdown {
  position: relative;
  padding-bottom: 0.45rem;
  margin-bottom: -0.45rem;
}

.nav-dropdown-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  background: transparent;
  border: 0;
  padding: 0;
  font: inherit;
  cursor: pointer;
}

.nav-dropdown-toggle::after,
.mobile-dropdown-toggle::after {
  content: '▾';
  font-size: 0.8rem;
  transition: transform 0.2s ease;
}

.nav-dropdown:hover .nav-dropdown-toggle::after,
.nav-dropdown:focus-within .nav-dropdown-toggle::after,
.nav-dropdown.is-open .nav-dropdown-toggle::after,
.nav-dropdown-toggle[aria-expanded="true"]::after {
  transform: rotate(180deg);
}

.dropdown-menu {
  position: absolute;
  top: calc(100% + 0.35rem);
  left: 0;
  min-width: 280px;
  display: grid;
  gap: 0.25rem;
  padding: 0.8rem;
  max-height: min(70vh, 420px);
  overflow-y: auto;
  background: rgba(30, 64, 175, 0.98);
  border-radius: 18px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  box-shadow: var(--shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
  z-index: 20;
}

.dropdown-menu a {
  padding: 0.7rem 0.85rem;
  border-radius: 12px;
  color: #eff6ff;
  font-weight: 600;
  white-space: nowrap;
}

.dropdown-menu a:hover,
.dropdown-menu a:focus-visible {
  background: rgba(255, 255, 255, 0.14);
  color: #ffffff;
  text-decoration: none;
}

.nav-dropdown:hover .dropdown-menu,
.nav-dropdown:focus-within .dropdown-menu,
.nav-dropdown.is-open .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

@media (max-width: 1100px) and (min-width: 641px) {
  .nav-scroll {
    overflow-x: auto;
    overflow-y: visible;
  }
}

.menu-toggle {
  display: none;
  background: transparent;
  border: 0;
  padding: 0;
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 0.28rem;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 3px;
  border-radius: 999px;
  background: #ffffff;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.menu-toggle.is-active span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.menu-toggle.is-active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.is-active span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.mobile-menu {
  display: none;
  padding: 0 0 1rem;
}

.mobile-menu.is-open {
  display: block;
}

.mobile-menu nav {
  display: grid;
  gap: 0.75rem;
  padding: 1rem;
  max-height: calc(100vh - 110px);
  overflow-y: auto;
  background: rgba(30, 64, 175, 0.96);
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  box-shadow: var(--shadow);
  scrollbar-width: thin;
}

.mobile-menu a {
  color: #eff6ff;
  font-weight: 600;
  padding: 0.7rem 0.8rem;
  border-radius: 12px;
  transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.mobile-menu a:hover {
  background: rgba(255, 255, 255, 0.14);
  color: #ffffff;
  transform: translateX(4px);
  text-decoration: none;
}

.mobile-dropdown {
  display: grid;
  gap: 0.5rem;
}

.mobile-dropdown-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  background: transparent;
  border: 0;
  padding: 0.7rem 0.8rem;
  border-radius: 12px;
  color: #eff6ff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.mobile-dropdown-toggle:hover {
  background: rgba(255, 255, 255, 0.14);
}

.mobile-dropdown.is-open .mobile-dropdown-toggle::after {
  transform: rotate(180deg);
}

.mobile-submenu {
  display: none;
  gap: 0.45rem;
  padding-left: 0.75rem;
}

.mobile-dropdown.is-open .mobile-submenu {
  display: grid;
}

.mobile-submenu a {
  font-size: 0.94rem;
  background: rgba(255, 255, 255, 0.06);
}

.article-card,
.list-card {
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.article-card {
  padding: 36px;
  margin: 16px 0 48px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 20px;
  color: var(--muted);
  font-size: 0.95rem;
}

.badge {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 999px;
  background: var(--bg-soft);
  color: var(--primary-dark);
  font-size: 0.92rem;
  font-weight: 700;
}

h1,
h2,
h3 {
  line-height: 1.25;
  margin-top: 0;
}

h1 {
  font-size: clamp(2rem, 3vw, 2.8rem);
  margin-bottom: 16px;
}

h2 {
  font-size: clamp(1.4rem, 2vw, 1.9rem);
  margin: 34px 0 14px;
}

h3 {
  font-size: 1.15rem;
  margin: 24px 0 10px;
}

p,
ul,
ol {
  margin: 0 0 16px;
  color: #334155;
}

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

.cta-box {
  margin-top: 34px;
  padding: 24px;
  border-radius: 18px;
  background: linear-gradient(135deg, #dbeafe, #eff6ff);
  border: 1px solid var(--line);
}

.cta-button {
  display: inline-block;
  margin-top: 10px;
  padding: 12px 18px;
  border-radius: 999px;
  background: var(--primary);
  color: var(--white);
  font-weight: 700;
}

.cta-button:hover {
  text-decoration: none;
  background: var(--primary-dark);
}

footer {
  padding: 0 0 48px;
  color: var(--muted);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.list-card {
  padding: 22px;
}

.list-card h2 {
  font-size: 1.15rem;
  margin: 0 0 10px;
}

.list-card p {
  font-size: 0.98rem;
}

@media (max-width: 640px) {
  .topbar-inner {
    padding: 0.9rem 0;
  }

  .nav-scroll {
    display: none;
  }

  .menu-toggle {
    display: inline-flex;
  }

  .article-card {
    padding: 24px;
  }
}