:root {
  --ink: #102421;
  --muted: #526965;
  --line: #d8e4df;
  --paper: #fbfdfb;
  --surface: #ffffff;
  --green: #0f8b8d;
  --blue: #2d6cdf;
  --amber: #d79512;
  --shadow: 0 18px 50px rgba(16, 36, 33, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Arial, "Noto Sans KR", sans-serif;
  letter-spacing: 0;
}

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

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 16px clamp(20px, 5vw, 72px);
  background: rgba(251, 253, 251, 0.9);
  border-bottom: 1px solid rgba(216, 228, 223, 0.9);
  backdrop-filter: blur(14px);
}

.brand,
.nav {
  display: flex;
  align-items: center;
}

.brand {
  gap: 10px;
  font-weight: 800;
  font-size: 18px;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  background: var(--ink);
  color: #fff;
  border-radius: 8px;
}

.nav {
  gap: 22px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.nav a:hover {
  color: var(--ink);
}

.admin-link {
  padding: 9px 12px;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.hero {
  position: relative;
  min-height: 78vh;
  display: grid;
  align-items: center;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.hero-backdrop {
  position: absolute;
  inset: 0;
}

.hero-backdrop svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-backdrop::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(251, 253, 251, 0.96) 0%, rgba(251, 253, 251, 0.8) 48%, rgba(251, 253, 251, 0.3) 100%);
}

.hero-content {
  position: relative;
  width: min(760px, calc(100% - 40px));
  margin-left: clamp(20px, 6vw, 82px);
  padding: 72px 0;
}

.hero h1 {
  max-width: 720px;
  margin: 0;
  font-size: clamp(42px, 6vw, 84px);
  line-height: 0.98;
  letter-spacing: 0;
}

.hero p {
  max-width: 650px;
  margin: 26px 0 0;
  color: var(--muted);
  font-size: 20px;
  line-height: 1.65;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border-radius: 8px;
  font-weight: 800;
}

.button.primary {
  background: var(--ink);
  color: #fff;
}

.button.secondary {
  background: var(--surface);
  border: 1px solid var(--line);
}

.summary-band {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border-bottom: 1px solid var(--line);
}

.summary-band div {
  min-height: 140px;
  padding: 30px clamp(20px, 4vw, 48px);
  background: var(--surface);
}

.summary-band strong {
  display: block;
  margin-bottom: 12px;
  font-size: 22px;
}

.summary-band span {
  color: var(--muted);
  line-height: 1.6;
}

.section {
  padding: 90px clamp(20px, 6vw, 82px);
  border-bottom: 1px solid var(--line);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 40px;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(32px, 4vw, 56px);
  line-height: 1.08;
}

.section-heading p {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.7;
}

.timeline {
  display: grid;
  gap: 18px;
  max-width: 980px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.timeline li {
  display: grid;
  grid-template-columns: 74px 1fr;
  gap: 22px;
  align-items: start;
  padding: 24px 0;
  border-top: 1px solid var(--line);
}

.timeline li:last-child {
  border-bottom: 1px solid var(--line);
}

.timeline span {
  color: var(--green);
  font-size: 18px;
  font-weight: 900;
}

.timeline h3,
.question-list h3,
.layer-grid h3 {
  margin: 0;
  font-size: 22px;
  line-height: 1.35;
}

.timeline p,
.layer-grid p {
  margin: 8px 0 0;
  color: var(--muted);
  line-height: 1.65;
}

.layer-section {
  background: #eef6f2;
}

.layer-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.layer-grid article {
  min-height: 230px;
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.layer-grid b {
  display: inline-flex;
  margin-bottom: 28px;
  color: var(--blue);
  font-size: 24px;
}

.question-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.question-list article {
  min-height: 150px;
  padding: 26px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.question-list article:nth-child(2n) {
  border-top: 5px solid var(--amber);
}

.question-list article:nth-child(2n + 1) {
  border-top: 5px solid var(--green);
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 28px clamp(20px, 6vw, 82px);
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 900px) {
  .topbar,
  .footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .summary-band,
  .layer-grid,
  .question-list {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: 72vh;
  }

  .hero-backdrop::after {
    background: rgba(251, 253, 251, 0.88);
  }

  .timeline li {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}