/* ==========================================================================
   Yullab — tokens
   ========================================================================== */
:root {
  --bg: #F7F7FC;
  --surface: #FFFFFF;
  --surface-2: #F1F1FA;
  --ink: #14161F;
  --ink-soft: #5B5F73;
  --ink-faint: #9195A8;
  --border: #E7E7F2;

  --primary: #5B4FE8;
  --primary-ink: #4038C4;
  --primary-soft: #EEECFE;
  --accent-2: #16A672;
  --accent-2-soft: #E4F7EF;

  --shadow-sm: 0 1px 2px rgba(20, 20, 43, 0.05);
  --shadow-md: 0 8px 24px rgba(20, 20, 43, 0.07), 0 2px 6px rgba(20, 20, 43, 0.05);
  --shadow-lg: 0 20px 48px rgba(20, 20, 43, 0.12), 0 4px 12px rgba(20, 20, 43, 0.06);

  --font-sans: "IBM Plex Sans KR", "Pretendard", -apple-system, sans-serif;
  --font-display: "Space Grotesk", var(--font-sans);
  --font-mono: "JetBrains Mono", "SFMono-Regular", ui-monospace, monospace;

  --radius: 16px;
  --radius-sm: 10px;
  --radius-full: 999px;

  --container: 1180px;
  --gutter: 24px;
}

/* ==========================================================================
   Reset / base
   ========================================================================== */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, p, ol, ul { margin: 0; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; padding: 0; }
svg { display: block; }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ==========================================================================
   Scroll reveal
   ========================================================================== */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.reveal.is-visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  .reveal { transition: none; }
}

/* ==========================================================================
   Header
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(247, 247, 252, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
}

.logo-mark {
  width: 22px;
  height: 22px;
  border-radius: 7px;
  background: linear-gradient(135deg, var(--primary), var(--accent-2));
}

.nav-links {
  display: flex;
  gap: 32px;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--ink-soft);
}

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

@media (max-width: 760px) {
  .nav-links { display: none; }
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 26px;
  font-size: 0.94rem;
  font-weight: 600;
  border-radius: 10px;
  border: 1px solid transparent;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background-color 0.15s ease, border-color 0.15s ease;
}

.btn-small { padding: 9px 20px; font-size: 0.85rem; }
.btn-large { padding: 17px 32px; font-size: 1.05rem; }

.btn-solid {
  background: var(--primary);
  color: #fff;
  box-shadow: var(--shadow-sm);
}
.btn-solid:hover { background: var(--primary-ink); transform: translateY(-1px); box-shadow: var(--shadow-md); }

.btn-ghost {
  color: var(--ink-soft);
}
.btn-ghost:hover { color: var(--primary); }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  display: grid;
  grid-template-columns: 46% 54%;
  align-items: center;
  gap: 48px;
  padding: 88px var(--gutter) 96px;
  min-height: 640px;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--primary-soft);
  color: var(--primary-ink);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 8px 16px 8px 12px;
  border-radius: var(--radius-full);
  margin-bottom: 24px;
}

.pill-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-2);
  flex: none;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 4.4vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.text-gradient {
  color: var(--primary);
}

.hero-sub {
  margin-top: 24px;
  max-width: 46ch;
  color: var(--ink-soft);
  font-size: 1.08rem;
}

.hero-ctas {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 36px;
  flex-wrap: wrap;
}

/* Diagram card */
.hero-diagram-wrap,
.hero-copy { min-width: 0; }

.diagram-card {
  width: 100%;
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.diagram-card-head {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
}

.dot { width: 9px; height: 9px; border-radius: 50%; flex: none; }
.dot-red { background: #F1595C; }
.dot-yellow { background: #F4B740; }
.dot-green { background: #3FBF6F; }

.diagram-card-title {
  margin-left: 8px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-faint);
}

.proto-svg { width: 100%; max-width: 100%; height: auto; display: block; padding: 12px 6px 6px; }

.host-container {
  fill: var(--surface-2);
  stroke: var(--ink-faint);
  stroke-width: 1.5;
  stroke-dasharray: 5 5;
}

.host-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  fill: var(--ink-faint);
}

.edge { stroke: var(--border); stroke-width: 1.5; fill: none; }

.edge-label {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.04em;
  fill: var(--ink-faint);
}

.node rect {
  fill: var(--surface);
  stroke: var(--border);
  stroke-width: 1.5;
}
.node-accent rect { stroke: var(--primary); fill: var(--primary-soft); }
.node-accent-2 rect { stroke: var(--accent-2); fill: var(--accent-2-soft); }

.node-label {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 12px;
  letter-spacing: 0.03em;
  fill: var(--ink);
}

.node-caption {
  font-family: var(--font-mono);
  font-size: 11px;
  fill: var(--ink-faint);
}

.packet { fill: var(--primary); }

.diagram-caption {
  margin-top: 16px;
  font-size: 0.85rem;
  color: var(--ink-faint);
  max-width: 46ch;
}

/* ==========================================================================
   Sections
   ========================================================================== */
.section {
  padding: 96px var(--gutter);
}

.section-alt { background: var(--surface-2); }

.section-kicker {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 0.04em;
  margin-bottom: 14px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3vw, 2.3rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 52px;
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card {
  min-width: 0;
  background: var(--surface);
  border-radius: var(--radius);
  padding: 32px 28px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.card-icon-badge {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
}
.badge-a { background: var(--primary-soft); }
.badge-b { background: var(--accent-2-soft); }
.badge-c { background: #FDF0E4; }

.card-icon {
  width: 24px;
  height: 24px;
  fill: none;
  stroke-width: 1.75;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.badge-a .card-icon { stroke: var(--primary); }
.badge-b .card-icon { stroke: var(--accent-2); }
.badge-c .card-icon { stroke: #C4701F; }
.card-icon .dot { fill: currentColor; stroke: none; }
.card-icon .icon-outline { fill: var(--surface); }

.card h3 {
  font-size: 1.18rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.card p {
  color: var(--ink-soft);
  font-size: 0.96rem;
}

/* Steps */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.steps li {
  position: relative;
  min-width: 0;
  background: var(--surface);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow-sm);
}

/* connector arrow between step cards, desktop only */
.steps li:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 43px;
  right: -20px;
  width: 12px;
  height: 12px;
  border-top: 2px solid var(--border);
  border-right: 2px solid var(--border);
  transform: rotate(45deg);
}

.step-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.85rem;
  color: #fff;
  background: var(--primary);
  width: 30px;
  height: 30px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}
.steps li:nth-child(2) .step-num { background: var(--accent-2); }
.steps li:nth-child(3) .step-num { background: #C4701F; }
.steps li:nth-child(4) .step-num { background: #2E7CD6; }

.steps h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.steps p:not(.step-num) {
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.steps-note {
  margin-top: 28px;
  font-size: 0.88rem;
  color: var(--ink-faint);
}

/* Example / code */
.example-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 56px;
  align-items: center;
}

.code-card {
  min-width: 0;
  background: #14162A;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.code-card .diagram-card-head { border-bottom-color: rgba(255,255,255,0.08); }
.code-card .diagram-card-title { color: rgba(255,255,255,0.5); }

.code-block {
  margin: 0;
  padding: 22px 24px 26px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.7;
  color: #E5E6F5;
  overflow-x: auto;
}
.code-muted { color: #6C7086; }
.code-key { color: #9FB4FF; }
.code-str { color: #7DDCA6; }

/* Ecosystem logos */
.logo-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.logo-chip {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--surface);
  border-radius: var(--radius-sm);
  padding: 16px 18px;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--ink-soft);
  box-shadow: var(--shadow-sm);
}

.logo-avatar {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--surface-2);
  flex: none;
  overflow: hidden;
}

.logo-avatar img {
  width: 22px;
  height: 22px;
  object-fit: contain;
  filter: grayscale(1);
  opacity: 0.75;
  transition: filter 0.2s ease, opacity 0.2s ease;
}

.logo-chip:hover .logo-avatar img {
  filter: grayscale(0);
  opacity: 1;
}

/* Community */
.community-grid {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 64px;
  align-items: start;
}

.community-text {
  color: var(--ink-soft);
  font-size: 1.02rem;
  max-width: 52ch;
}

.tag-list {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tag-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  box-shadow: var(--shadow-sm);
}

.tag-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--primary);
  flex: none;
}

/* Contact CTA */
.section-cta { padding: 96px var(--gutter) 120px; }

.cta-card {
  min-width: 0;
  background: linear-gradient(135deg, var(--ink) 0%, #2A2550 100%);
  color: #fff;
  border-radius: 24px;
  padding: 64px 56px;
  text-align: center;
  box-shadow: var(--shadow-lg);
}
.cta-card .section-kicker { color: #B9B4F5; }
.cta-card .section-title { color: #fff; margin-bottom: 16px; }

.contact-text {
  color: rgba(255,255,255,0.72);
  font-size: 1.05rem;
  max-width: 50ch;
  margin: 0 auto 32px;
}

.cta-card .btn-solid {
  background: #fff;
  color: var(--ink);
}
.cta-card .btn-solid:hover { background: #EDEBFF; }

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background: var(--ink);
  color: rgba(255, 255, 255, 0.6);
  padding: 72px var(--gutter) 0;
}

.footer-top {
  text-align: center;
  padding-bottom: 40px;
}

.footer-logo {
  justify-content: center;
  color: #fff;
  font-size: 1.15rem;
}

.footer-tagline {
  margin: 14px auto 0;
  max-width: 42ch;
  font-size: 0.95rem;
  color: rgba(255, 255, 255, 0.55);
}

.footer-links {
  display: flex;
  gap: 64px;
  padding: 32px 24px 48px;
  border-top: 1px dashed rgba(255, 255, 255, 0.16);
}

.footer-col-title {
  color: #fff;
  font-weight: 700;
  font-size: 0.85rem;
  margin-bottom: 14px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 0.88rem;
}

.footer-col a:hover { color: #fff; }

.footer-bottom {
  padding: 24px 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.82rem;
  color: rgba(255, 255, 255, 0.4);
}

/* ==========================================================================
   Cookie banner
   ========================================================================== */
.cookie-banner {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 30;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 18px 28px;
  box-shadow: 0 -8px 24px rgba(20, 20, 43, 0.08);
}
.cookie-banner[hidden] { display: none; }

.cookie-text {
  margin: 0;
  max-width: 640px;
  font-size: 0.85rem;
  color: var(--ink-soft);
}
.cookie-text a { color: var(--primary); text-decoration: underline; }

.cookie-actions {
  display: flex;
  gap: 10px;
  flex: none;
}

.btn-cookie {
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
}
.btn-cookie-muted { background: var(--surface-2); color: var(--ink); }
.btn-cookie-solid { background: var(--primary); color: #fff; }
.btn-cookie-solid:hover { background: var(--primary-ink); }

@media (max-width: 760px) {
  .footer-links { flex-direction: column; gap: 28px; }
  .cookie-banner { padding: 16px 20px; }
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 900px) {
  .card-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .steps li::after { display: none; }
  .community-grid { grid-template-columns: 1fr; gap: 32px; }
  .example-grid { grid-template-columns: 1fr; gap: 32px; }
  .logo-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .hero {
    grid-template-columns: 1fr;
    padding-top: 56px;
    min-height: 0;
  }
  .hero-diagram-wrap { margin-top: 40px; }
  .section { padding: 64px var(--gutter); }
  .steps { grid-template-columns: 1fr; }
  .cta-card { padding: 48px 28px; }
}

/* ==========================================================================
   Notes page
   ========================================================================== */
.notes-hero {
  padding: 88px var(--gutter) 24px;
  max-width: 720px;
}

.notes-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 16px 0;
}

.notes-intro {
  color: var(--ink-soft);
  font-size: 1.05rem;
  max-width: 56ch;
}

.log-section { padding-top: 24px; }

.log {
  max-width: 720px;
  display: flex;
  flex-direction: column;
}

.log-entry {
  padding: 40px 0;
  border-top: 1px solid var(--border);
}
.log-entry:first-child { border-top: none; padding-top: 8px; }

.log-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 0.03em;
  margin-bottom: 10px;
}

.log-title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.log-body {
  color: var(--ink-soft);
  font-size: 1rem;
}

.log-body code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--surface-2);
  padding: 2px 6px;
  border-radius: 4px;
}