:root {
  --ink: #102a43;
  --muted: #627887;
  --line: #cad9d8;
  --paper: #f7f3ea;
  --teal: #0f8b8d;
  --green: #0b5260;
  --amber: #ffb454;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(15, 139, 141, 0.05) 1px, transparent 1px),
    linear-gradient(rgba(15, 139, 141, 0.05) 1px, transparent 1px),
    radial-gradient(circle at 85% 4%, rgba(255, 180, 84, 0.25), transparent 24%),
    linear-gradient(155deg, #fffdf7, #eef7f5);
  background-size: 28px 28px, 28px 28px, auto, auto;
  font-family: "Avenir Next", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
}

header {
  display: flex;
  width: min(1040px, calc(100% - 40px));
  margin: 0 auto;
  align-items: center;
  justify-content: space-between;
  padding: 22px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  position: relative;
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 13px 5px 13px 5px;
  color: #fff;
  background: linear-gradient(145deg, #102a43, #087f83);
  box-shadow: 0 8px 20px rgba(16, 42, 67, 0.2);
  font-size: 21px;
  font-weight: 800;
}

.brand-mark::after {
  position: absolute;
  top: 7px;
  right: 7px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--amber);
  content: "";
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 17px;
}

.brand small {
  margin-top: 2px;
  color: var(--muted);
  font-size: 9px;
  letter-spacing: 0.8px;
  text-transform: uppercase;
}

.updated {
  color: var(--muted);
  font-size: 11px;
}

main {
  width: min(1040px, calc(100% - 40px));
  margin: 0 auto;
  padding: 42px 0 80px;
}

.hero {
  max-width: 100%;
  padding: 50px 0 54px;
}

.hero > span {
  color: var(--teal);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.hero h1 {
  margin: 14px 0 20px;
  font-family: "Avenir Next", "Futura", "Apple SD Gothic Neo", sans-serif;
  max-width: 940px;
  font-size: clamp(36px, 5vw, 52px);
  letter-spacing: -2.4px;
  line-height: 1.08;
}

.hero p {
  max-width: 680px;
  margin: 0;
  color: #496474;
  font-size: 15px;
  line-height: 1.75;
}

nav {
  position: sticky;
  z-index: 2;
  top: 12px;
  display: flex;
  gap: 8px;
  padding: 10px;
  overflow-x: auto;
  border: 1px solid rgba(202, 217, 216, 0.9);
  border-radius: 15px 5px 15px 5px;
  background: rgba(255, 253, 247, 0.9);
  box-shadow: 0 12px 34px rgba(16, 42, 67, 0.08);
  backdrop-filter: blur(16px);
}

nav a {
  flex: 0 0 auto;
  padding: 8px 11px;
  border-radius: 8px 3px 8px 3px;
  color: #315565;
  font-size: 11px;
  font-weight: 750;
  text-decoration: none;
}

nav a:hover {
  color: #fff;
  background: var(--green);
}

article {
  margin-top: 34px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 28px 9px 28px 9px;
  background: rgba(255, 255, 255, 0.87);
  box-shadow: 0 24px 60px rgba(16, 42, 67, 0.1);
}

article section {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 20px;
  padding: 40px;
}

article section + section {
  border-top: 1px solid #dde7e5;
}

.number {
  color: var(--teal);
  font-family: "Avenir Next", "Futura", sans-serif;
  font-size: 14px;
  font-weight: 800;
}

h2 {
  margin: 0 0 18px;
  font-size: 23px;
  letter-spacing: -0.6px;
}

p,
li,
dd {
  color: #48616f;
  font-size: 13px;
  line-height: 1.75;
}

p {
  margin: 0;
}

p + p {
  margin-top: 12px;
}

ul {
  margin: 0 0 13px;
  padding-left: 20px;
}

li + li {
  margin-top: 5px;
}

dl {
  margin: 0;
}

dt {
  margin-top: 18px;
  color: #163e50;
  font-size: 13px;
  font-weight: 800;
}

dt:first-child {
  margin-top: 0;
}

dd {
  margin: 5px 0 0;
}

code {
  padding: 2px 5px;
  border-radius: 4px;
  color: #155c63;
  background: #e7f3f1;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.88em;
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px max(20px, calc((100% - 1040px) / 2));
  color: #dceeed;
  background: #102a43;
  font-size: 11px;
}

@media (max-width: 640px) {
  header {
    align-items: flex-start;
  }

  .updated {
    max-width: 90px;
    text-align: right;
  }

  main {
    padding-top: 12px;
  }

  .hero {
    padding: 32px 0 42px;
  }

  .hero h1 {
    font-size: 38px;
    letter-spacing: -1.6px;
  }

  article section {
    display: block;
    padding: 27px 22px;
  }

  .number {
    display: block;
    margin-bottom: 10px;
  }
}