:root {
  color-scheme: light;
  --ink: #10283a;
  --muted: #506777;
  --paper: #f4f8fb;
  --surface: #ffffff;
  --line: #bfd0da;
  --line-strong: #7893a2;
  --signal: #167f9c;
  --signal-dark: #075a71;
  --moss: #2f7057;
  --danger: #a33d45;
  --focus: #f0a61b;
  --button-bg: #10283a;
  --button-fg: #ffffff;
  --shadow: 0 18px 50px rgba(16, 40, 58, 0.1);
  --display: "Avenir Next", "Pretendard", "Noto Sans KR", sans-serif;
  --body: "Pretendard", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
  color: var(--ink);
  font-family: var(--body);
  line-height: 1.72;
}

a {
  color: var(--signal-dark);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--signal);
}

a:focus-visible {
  border-radius: 2px;
  outline: 3px solid var(--focus);
  outline-offset: 4px;
}

code {
  border: 1px solid #c5d6df;
  background: #e8f1f5;
  color: #174c62;
  font-family: var(--mono);
  font-size: 0.88em;
  overflow-wrap: anywhere;
  padding: 0.12em 0.35em;
}

.skip-link {
  position: fixed;
  z-index: 20;
  left: 16px;
  top: 12px;
  transform: translateY(-160%);
  background: var(--ink);
  color: #fff;
  padding: 10px 14px;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 82px;
  border-bottom: 1px solid var(--line-strong);
  background: rgba(244, 248, 251, 0.96);
  padding: 12px clamp(20px, 5vw, 72px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  text-decoration: none;
}

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

.brand strong {
  font-family: var(--display);
  font-size: 0.98rem;
  letter-spacing: -0.015em;
}

.brand small {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.brand-logo {
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  border-radius: 10px;
}

.site-nav {
  display: flex;
  gap: clamp(14px, 3vw, 34px);
}

.site-nav a {
  position: relative;
  color: var(--ink);
  font-size: 0.88rem;
  font-weight: 650;
  text-decoration: none;
}

.site-nav a[aria-current="page"]::after {
  position: absolute;
  right: 0;
  bottom: -10px;
  left: 0;
  height: 3px;
  background: var(--signal);
  content: "";
}

.configuration-notice {
  border-bottom: 1px solid #cf9f39;
  background: #fff3ce;
  color: #5c430d;
  font-size: 0.87rem;
  padding: 10px clamp(20px, 5vw, 72px);
}

main {
  min-height: 70vh;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(300px, 0.65fr);
  gap: clamp(36px, 7vw, 100px);
  align-items: end;
  max-width: 1320px;
  margin: 0 auto;
  padding: clamp(72px, 11vw, 150px) clamp(20px, 5vw, 72px) 88px;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--signal-dark);
  font-family: var(--mono);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.hero h1,
.document-header h1,
.support-hero h1,
.oauth-result h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2.8rem, 7vw, 6.6rem);
  font-weight: 730;
  letter-spacing: -0.065em;
  line-height: 0.98;
}

.hero-purpose {
  max-width: 760px;
  margin: 28px 0 0;
  border-left: 4px solid var(--signal);
  color: var(--ink);
  font-size: clamp(1.12rem, 2vw, 1.42rem);
  line-height: 1.58;
  padding-left: 18px;
}

.hero-summary {
  max-width: 720px;
  margin: 22px 0 0;
  color: #304d5f;
  font-size: clamp(1.05rem, 2vw, 1.28rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  align-items: center;
  margin-top: 36px;
}

.primary-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  border: 2px solid var(--ink);
  background: var(--button-bg);
  color: var(--button-fg);
  font-weight: 700;
  padding: 10px 18px;
  text-decoration: none;
}

.primary-link::after {
  margin-left: 16px;
  content: "→";
}

.primary-link:hover {
  background: var(--signal-dark);
  color: var(--button-fg);
}

.text-link {
  font-weight: 700;
}

.scope-card {
  border-top: 6px solid var(--signal);
  background: var(--surface);
  box-shadow: var(--shadow);
  padding: 28px;
}

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

.card-label {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
}

.scope-card h2 {
  font-family: var(--display);
  font-size: 1.7rem;
}

.scope-card dl {
  margin: 24px 0;
}

.scope-card dl div {
  border-top: 1px solid var(--line);
  padding: 18px 0;
}

.scope-card dt {
  font-weight: 750;
}

.scope-card dd {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 0.91rem;
}

.scope-note {
  margin: 0;
  color: var(--moss);
  font-size: 0.86rem;
  font-weight: 700;
}

.data-route,
.assurances,
.feature-overview,
.google-data-use,
.policy-callout,
.policy-document,
.support-page {
  max-width: 1320px;
  margin: 0 auto;
  padding-right: clamp(20px, 5vw, 72px);
  padding-left: clamp(20px, 5vw, 72px);
}

.data-route,
.assurances,
.feature-overview,
.google-data-use {
  padding-top: 96px;
  padding-bottom: 96px;
}

.feature-overview {
  border-top: 1px solid var(--line-strong);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  margin-top: 50px;
  border: 1px solid var(--line-strong);
  background: var(--line-strong);
}

.feature-grid article {
  min-height: 250px;
  background: var(--surface);
  padding: 28px;
}

.feature-index {
  color: var(--signal-dark);
  font-family: var(--mono);
  font-size: 0.76rem;
  font-weight: 750;
}

.feature-grid h3,
.data-use-grid h3 {
  margin: 34px 0 14px;
  font-family: var(--display);
  font-size: 1.24rem;
}

.feature-grid p,
.data-use-grid p {
  margin: 0;
  color: var(--muted);
}

.google-data-use {
  border-top: 1px solid var(--line-strong);
  background: rgba(255, 255, 255, 0.66);
  background-clip: content-box;
}

.data-use-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  margin-top: 50px;
  border: 1px solid var(--line-strong);
  background: var(--line-strong);
}

.data-use-grid article {
  min-height: 210px;
  background: var(--surface);
  padding: 28px;
}

.data-use-grid h3 {
  margin-top: 0;
}

.english-disclosure {
  margin: 28px 0 0;
  border-left: 4px solid var(--moss);
  background: var(--surface);
  color: var(--ink);
  font-size: 0.98rem;
  padding: 22px 24px;
}

.data-route {
  border-top: 1px solid var(--line-strong);
  background: rgba(255, 255, 255, 0.66);
  background-clip: content-box;
}

.section-heading {
  max-width: 620px;
}

.section-heading h2,
.policy-callout h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2rem, 4vw, 3.6rem);
  letter-spacing: -0.045em;
  line-height: 1.06;
}

.section-heading > p:last-child {
  color: var(--muted);
}

.route-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: 54px 0 0;
  padding: 0;
  list-style: none;
}

.route-steps li {
  position: relative;
  min-height: 270px;
  border-top: 4px solid var(--line-strong);
  border-right: 1px solid var(--line);
  background: var(--surface);
  padding: 26px 22px;
}

.route-steps li:last-child {
  border-top-color: var(--moss);
  border-right: 0;
}

.route-steps li:not(:last-child)::after {
  position: absolute;
  z-index: 1;
  top: -9px;
  right: -7px;
  width: 12px;
  height: 12px;
  border: 2px solid var(--surface);
  border-radius: 50%;
  background: var(--signal);
  content: "";
}

.route-index,
.support-label {
  color: var(--signal-dark);
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.08em;
}

.route-steps h3 {
  margin: 56px 0 12px;
  font-family: var(--display);
  font-size: 1.25rem;
}

.route-steps p {
  color: var(--muted);
  font-size: 0.9rem;
}

.assurance-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  margin-top: 50px;
  border: 1px solid var(--line-strong);
  background: var(--line-strong);
}

.assurance-grid article {
  min-height: 190px;
  background: var(--surface);
  padding: 28px;
}

.assurance-grid h3 {
  margin: 0 0 14px;
  font-family: var(--display);
}

.assurance-grid p {
  margin: 0;
  color: var(--muted);
}

.policy-callout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: end;
  border-top: 1px solid var(--line-strong);
  padding-top: 76px;
  padding-bottom: 100px;
}

.policy-links {
  border-top: 1px solid var(--line-strong);
}

.policy-links a {
  display: flex;
  justify-content: space-between;
  gap: 30px;
  border-bottom: 1px solid var(--line-strong);
  color: var(--ink);
  padding: 20px 0;
  text-decoration: none;
}

.policy-links span {
  font-weight: 750;
}

.policy-links small {
  color: var(--muted);
}

.policy-document {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 240px;
  column-gap: clamp(50px, 8vw, 120px);
  padding-top: 80px;
  padding-bottom: 120px;
}

.document-header {
  grid-column: 1 / -1;
  max-width: 900px;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 54px;
}

.document-header h1 {
  font-size: clamp(3rem, 6vw, 5.8rem);
}

.document-header > p:not(.eyebrow) {
  max-width: 760px;
  margin-top: 28px;
  color: var(--muted);
  font-size: 1.08rem;
}

.document-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 38px;
  margin-top: 34px;
}

.document-meta div {
  display: flex;
  gap: 12px;
}

.document-meta dt {
  color: var(--muted);
  font-size: 0.82rem;
}

.document-meta dd {
  margin: 0;
  font-weight: 700;
}

.document-toc {
  position: sticky;
  top: 24px;
  grid-column: 2;
  grid-row: 2;
  align-self: start;
  border-left: 3px solid var(--signal);
  margin-top: 64px;
  padding-left: 20px;
}

.document-toc strong,
.document-toc a {
  display: block;
}

.document-toc strong {
  margin-bottom: 14px;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
}

.document-toc a {
  color: var(--muted);
  font-size: 0.84rem;
  padding: 5px 0;
  text-decoration: none;
}

.document-body {
  grid-column: 1;
  grid-row: 2;
  max-width: 820px;
  padding-top: 30px;
}

.document-body section {
  scroll-margin-top: 20px;
  border-bottom: 1px solid var(--line);
  padding: 36px 0;
}

.document-body h2 {
  margin: 0 0 18px;
  font-family: var(--display);
  font-size: 1.42rem;
  letter-spacing: -0.02em;
}

.document-body p,
.document-body li {
  color: #314e60;
}

.document-body ul {
  padding-left: 1.25em;
}

.document-body li + li {
  margin-top: 8px;
}

.scope-table {
  margin: 24px 0;
  border-top: 1px solid var(--line-strong);
}

.scope-table [role="row"] {
  display: grid;
  grid-template-columns: 150px 130px 1fr;
  gap: 18px;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.58);
  padding: 18px 12px;
}

.scope-table span {
  color: var(--muted);
}

.support-page {
  padding-top: 86px;
  padding-bottom: 120px;
}

.support-hero {
  max-width: 920px;
}

.support-hero h1 {
  font-size: clamp(3rem, 6vw, 5.7rem);
}

.support-hero > p:last-child {
  max-width: 650px;
  margin-top: 28px;
  color: var(--muted);
  font-size: 1.1rem;
}

.support-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  margin-top: 64px;
  border: 1px solid var(--line-strong);
  background: var(--line-strong);
}

.support-grid section {
  min-height: 280px;
  background: var(--surface);
  padding: 30px;
}

.support-grid h2 {
  margin: 36px 0 14px;
  font-family: var(--display);
  font-size: 1.4rem;
}

.support-grid p {
  color: var(--muted);
}

.support-warning {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 24px;
  margin-top: 34px;
  border: 1px solid #d8aa4b;
  background: #fff4d5;
  color: #594411;
  padding: 22px;
}

.support-warning p {
  margin: 0;
}

.oauth-result {
  display: grid;
  place-items: center;
  min-height: 68vh;
  max-width: 700px;
  margin: 0 auto;
  padding: 72px 24px;
  text-align: center;
}

.oauth-result h1 {
  font-size: clamp(2.7rem, 7vw, 5rem);
}

.result-mark {
  display: grid;
  place-items: center;
  width: 72px;
  height: 72px;
  margin-bottom: 24px;
  border: 3px solid currentColor;
  border-radius: 50%;
  font-family: var(--display);
  font-size: 2rem;
  font-weight: 800;
}

.result-mark.is-success {
  color: var(--moss);
}

.result-mark.is-error {
  color: var(--danger);
}

.result-message {
  margin: 28px 0 8px;
  font-size: 1.1rem;
  font-weight: 700;
}

.result-guidance {
  color: var(--muted);
}

.site-footer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 22px 60px;
  border-top: 1px solid var(--line-strong);
  background: var(--ink);
  color: #e9f1f5;
  padding: 42px clamp(20px, 5vw, 72px);
}

.site-footer strong {
  font-family: var(--display);
}

.site-footer p {
  margin: 4px 0 0;
  color: #adc1cc;
  font-size: 0.84rem;
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.site-footer a {
  color: #e9f1f5;
  font-size: 0.84rem;
}

.footer-meta {
  grid-column: 1 / -1;
  font-family: var(--mono);
}

@media (max-width: 900px) {
  .hero,
  .policy-callout,
  .policy-document {
    grid-template-columns: 1fr;
  }

  .scope-card {
    max-width: 620px;
  }

  .route-steps {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .route-steps li:nth-child(2) {
    border-right: 0;
  }

  .policy-callout {
    align-items: start;
  }

  .document-header,
  .document-body,
  .document-toc {
    grid-column: 1;
    grid-row: auto;
  }

  .document-toc {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 5px 20px;
    border-top: 3px solid var(--signal);
    border-left: 0;
    padding: 18px 0 0;
  }

  .document-toc strong {
    grid-column: 1 / -1;
  }
}

@media (max-width: 640px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
    padding-top: 18px;
    padding-bottom: 18px;
  }

  .site-nav {
    width: 100%;
    justify-content: space-between;
  }

  .hero {
    padding-top: 58px;
  }

  .hero h1,
  .document-header h1,
  .support-hero h1 {
    letter-spacing: -0.05em;
  }

  .route-steps,
  .assurance-grid,
  .data-use-grid,
  .support-grid,
  .scope-table [role="row"],
  .support-warning,
  .site-footer {
    grid-template-columns: 1fr;
  }

  .route-steps li {
    min-height: auto;
    border-right: 0;
  }

  .route-steps li:not(:last-child)::after {
    top: auto;
    right: auto;
    bottom: -7px;
    left: 22px;
  }

  .scope-table [role="row"] {
    gap: 8px;
  }

  .site-footer nav {
    flex-direction: column;
    gap: 8px;
  }

  .footer-meta {
    grid-column: 1;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --ink: #e8f2f6;
    --muted: #abc0cb;
    --paper: #10212d;
    --surface: #162d3b;
    --line: #2d4b5c;
    --line-strong: #527183;
    --signal: #50bad3;
    --signal-dark: #8bd5e5;
    --moss: #7bc5a6;
    --danger: #f08b91;
    --button-bg: #8bd5e5;
    --button-fg: #10212d;
    --shadow: 0 18px 50px rgba(0, 0, 0, 0.28);
  }

  body {
    background:
      linear-gradient(var(--line) 1px, transparent 1px),
      linear-gradient(90deg, var(--line) 1px, transparent 1px),
      var(--paper);
    background-size: 32px 32px;
  }

  .site-header {
    background: rgba(16, 33, 45, 0.96);
  }

  code {
    border-color: #38596a;
    background: #1d3a49;
    color: #bce8f2;
  }

  .hero-purpose,
  .hero-summary,
  .document-body p,
  .document-body li {
    color: #c0d1d9;
  }

  .configuration-notice,
  .support-warning {
    background: #4b3b12;
    color: #ffe7a4;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}