:root {
  --navy: #030213;
  --navy-mid: #0f0e2a;
  --navy-card: #16143a;
  --blue: #2563eb;
  --blue-light: #3b82f6;
  --blue-50: #eff6ff;
  --blue-100: #dbeafe;
  --teal: #0d9488;
  --teal-50: #f0fdfa;
  --teal-100: #ccfbf1;
  --amber: #d97706;
  --amber-50: #fffbeb;
  --amber-100: #fef3c7;
  --white: #ffffff;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-900: #111827;
  --font: "Noto Sans KR", sans-serif;
  --display: "Instrument Serif", serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--gray-900);
  background:
    radial-gradient(circle at top left, rgba(59, 130, 246, 0.11), transparent 24%),
    linear-gradient(180deg, #fafcff 0%, #ffffff 22%);
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
}

.article-shell {
  min-height: 100vh;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(16px);
  background: rgba(255, 255, 255, 0.88);
  border-bottom: 1px solid rgba(17, 24, 39, 0.06);
}

.topbar-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  color: var(--navy);
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--blue);
  color: var(--white);
  font-size: 16px;
}

.topbar-links {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.topbar-links a {
  font-size: 14px;
  color: var(--gray-600);
}

.topbar-links .primary-link {
  padding: 10px 16px;
  border-radius: 999px;
  background: var(--blue);
  color: var(--white);
  font-weight: 600;
}

.hero-article {
  padding: 72px 24px 28px;
}

.breadcrumb-wrap {
  max-width: 1120px;
  margin: 0 auto;
  padding: 24px 24px 0;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  font-size: 13px;
  color: var(--gray-500);
}

.breadcrumb span[aria-hidden="true"] {
  color: var(--gray-400);
}

.breadcrumb a:hover {
  color: var(--blue);
}

.hero-inner {
  max-width: 1120px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(280px, 0.9fr);
  gap: 28px;
  align-items: stretch;
}

.hero-copy {
  background:
    linear-gradient(145deg, rgba(3, 2, 19, 0.98), rgba(15, 14, 42, 0.94)),
    var(--navy);
  color: var(--white);
  border-radius: 28px;
  padding: 42px;
  position: relative;
  overflow: hidden;
}

.hero-copy::after {
  content: "";
  position: absolute;
  width: 320px;
  height: 320px;
  border-radius: 50%;
  right: -100px;
  top: -120px;
  background: rgba(59, 130, 246, 0.2);
  filter: blur(18px);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  color: var(--blue-100);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--blue-light);
}

.hero-copy h1 {
  margin: 18px 0 16px;
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.05;
  letter-spacing: -0.04em;
}

.hero-copy h1 .serif {
  font-family: var(--display);
  font-style: italic;
  font-weight: 400;
}

.hero-copy p {
  margin: 0;
  max-width: 700px;
  color: rgba(255, 255, 255, 0.8);
  font-size: 18px;
  line-height: 1.7;
}

.hero-meta {
  margin-top: 28px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.hero-meta span {
  padding: 10px 14px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.08);
  color: rgba(255, 255, 255, 0.84);
  font-size: 14px;
}

.hero-side {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(17, 24, 39, 0.06);
  border-radius: 28px;
  padding: 28px;
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.06);
}

.hero-side h2 {
  margin: 0 0 14px;
  font-size: 18px;
}

.hero-side ol,
.hero-side ul {
  margin: 0;
  padding-left: 18px;
  color: var(--gray-700);
  line-height: 1.8;
}

.hero-side li + li {
  margin-top: 8px;
}

.page-wrap {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px 88px;
  display: grid;
  grid-template-columns: minmax(0, 1.65fr) minmax(260px, 0.75fr);
  gap: 32px;
}

.content-column {
  min-width: 0;
}

.content-card {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(17, 24, 39, 0.06);
  border-radius: 24px;
  padding: 36px;
  box-shadow: 0 16px 36px rgba(15, 23, 42, 0.05);
}

.content-card + .content-card {
  margin-top: 20px;
}

.guides-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.guide-card {
  display: block;
  padding: 24px;
  border-radius: 22px;
  background: var(--white);
  border: 1px solid rgba(17, 24, 39, 0.08);
  box-shadow: 0 16px 36px rgba(15, 23, 42, 0.05);
}

.guide-card h3 {
  margin: 0 0 10px;
  font-size: 22px;
  line-height: 1.3;
  letter-spacing: -0.03em;
}

.guide-card p {
  margin: 0 0 16px;
}

.guide-card .guide-meta {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  font-size: 13px;
  color: var(--gray-500);
}

.guide-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--blue-50);
  color: var(--blue);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.content-card h2 {
  margin: 0 0 16px;
  font-size: 28px;
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.content-card h3 {
  margin: 24px 0 10px;
  font-size: 20px;
  line-height: 1.35;
}

.content-card p {
  margin: 0;
  color: var(--gray-700);
  line-height: 1.85;
  font-size: 17px;
}

.content-card p + p,
.content-card ul + p,
.content-card ol + p,
.content-card p + ul,
.content-card p + ol,
.content-card ul + ul,
.content-card ol + ol {
  margin-top: 14px;
}

.content-card ul,
.content-card ol {
  margin: 0;
  padding-left: 20px;
  color: var(--gray-700);
  line-height: 1.85;
  font-size: 17px;
}

.content-card li + li {
  margin-top: 8px;
}

.highlight-box {
  margin-top: 18px;
  padding: 18px 20px;
  border-radius: 20px;
  background: linear-gradient(180deg, var(--blue-50), #ffffff);
  border: 1px solid var(--blue-100);
}

.highlight-box strong {
  color: var(--navy);
}

.callout-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 18px;
}

.callout-card {
  padding: 18px;
  border-radius: 18px;
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
}

.callout-card p:first-child {
  margin-bottom: 8px;
  color: var(--gray-500);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.callout-card p:last-child {
  color: var(--gray-900);
  font-weight: 700;
  line-height: 1.5;
}

.sidebar {
  min-width: 0;
}

.sidebar-card {
  position: sticky;
  top: 86px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(239, 246, 255, 0.92));
  border: 1px solid rgba(37, 99, 235, 0.12);
  border-radius: 24px;
  padding: 24px;
  box-shadow: 0 16px 36px rgba(37, 99, 235, 0.08);
}

.sidebar-card + .sidebar-card {
  margin-top: 18px;
}

.sidebar-card h3 {
  margin: 0 0 10px;
  font-size: 18px;
}

.sidebar-card p,
.sidebar-card li {
  color: var(--gray-700);
  line-height: 1.75;
  font-size: 15px;
}

.sidebar-card ul {
  margin: 0;
  padding-left: 18px;
}

.sidebar-card .cta-button {
  display: inline-flex;
  margin-top: 16px;
  padding: 12px 16px;
  border-radius: 999px;
  background: var(--blue);
  color: var(--white);
  font-weight: 600;
}

.related-links {
  display: grid;
  gap: 10px;
  margin-top: 12px;
}

.related-links a {
  padding: 12px 14px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid rgba(17, 24, 39, 0.08);
  color: var(--gray-700);
  font-size: 14px;
}

.inline-cta {
  margin-top: 18px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.inline-cta a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 16px;
  border-radius: 999px;
  font-weight: 600;
}

.inline-cta .primary {
  background: var(--blue);
  color: var(--white);
}

.inline-cta .secondary {
  background: var(--gray-100);
  color: var(--gray-900);
}

.article-footer {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px 44px;
}

.article-footer-box {
  border-radius: 28px;
  background: linear-gradient(140deg, var(--navy), var(--navy-mid));
  color: var(--white);
  padding: 34px;
}

.article-footer-box h2 {
  margin: 0 0 10px;
  font-size: 30px;
}

.article-footer-box p {
  margin: 0;
  color: rgba(255, 255, 255, 0.8);
  line-height: 1.8;
}

.article-footer-actions {
  margin-top: 18px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.article-footer-actions a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 16px;
  border-radius: 999px;
  font-weight: 600;
}

.article-footer-actions .primary {
  background: var(--white);
  color: var(--navy);
}

.article-footer-actions .secondary {
  background: rgba(255, 255, 255, 0.08);
  color: var(--white);
}

.bottom-meta {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px 72px;
  color: var(--gray-500);
  font-size: 13px;
  line-height: 1.7;
}

@media (max-width: 980px) {
  .hero-inner,
  .page-wrap {
    grid-template-columns: 1fr;
  }

  .sidebar-card {
    position: static;
  }

  .topbar-inner {
    padding: 12px 18px;
  }

  .hero-article {
    padding: 60px 18px 24px;
  }

  .breadcrumb-wrap {
    padding: 18px 18px 0;
  }

  .hero-copy,
  .hero-side,
  .content-card {
    padding: 26px;
  }

  .page-wrap,
  .article-footer,
  .bottom-meta {
    padding-left: 18px;
    padding-right: 18px;
  }
}

@media (max-width: 640px) {
  .topbar-inner {
    flex-direction: column;
    align-items: stretch;
  }

  .topbar-links {
    justify-content: space-between;
  }

  .callout-grid {
    grid-template-columns: 1fr;
  }

  .guides-grid {
    grid-template-columns: 1fr;
  }

  .hero-copy h1 {
    font-size: 34px;
  }

  .content-card h2 {
    font-size: 24px;
  }

  .article-footer-box h2 {
    font-size: 24px;
  }
}