/* ==========================================================================
   SNOW (snsn1.com) Official Permanent Address Directory
   Design System: Black & White Monochrome DNA (--rx-bg-0: #0a0a0a ~ #ffffff)
   ========================================================================== */

:root {
  --rx-bg-0: #0a0a0a;
  --rx-bg-5: #0e0e0e;
  --rx-bg-10: #121212;
  --rx-bg-15: #181819;
  --rx-bg-20: #1c1c1e;
  --rx-bg-30: #202020;
  --rx-bg-35: #242424;
  --rx-grey-0: #f5f5f7;
  --rx-grey-10: #a1a1aa;
  --rx-grey-20: #71717a;
  --rx-grey-30: #27272a;
  --rx-brand-white: #ffffff;
  --rx-green-50: #25c06d;
  --rx-border-subtle: rgba(255, 255, 255, 0.11);
  --rx-border-strong: rgba(255, 255, 255, 0.24);
  --rx-font-sans: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, system-ui, Roboto, "Helvetica Neue", "Segoe UI", "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", sans-serif;
  --rx-font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --rx-ease: cubic-bezier(0.25, 0, 0, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  background-color: var(--rx-bg-0);
  color: var(--rx-brand-white);
  font-family: var(--rx-font-sans);
  line-height: 1.6;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  min-height: 100dvh;
  background-color: var(--rx-bg-0);
  color: var(--rx-grey-0);
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

/* Accessibility Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  z-index: 9999;
  background: var(--rx-brand-white);
  color: var(--rx-bg-0);
  padding: 8px 16px;
  border-radius: 8px;
  font-weight: 700;
  text-decoration: none;
  transition: top 0.18s var(--rx-ease);
}

.skip-link:focus {
  top: 12px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: 60px;
  background: rgba(10, 10, 10, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--rx-border-subtle);
}

.header-inner {
  max-width: 1080px;
  height: 100%;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--rx-brand-white);
}

.brand-logo {
  display: block;
  height: 24px;
  width: auto;
}

.brand-badge {
  font-family: var(--rx-font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  padding: 3px 7px;
  border-radius: 6px;
  background: var(--rx-bg-20);
  border: 1px solid var(--rx-border-subtle);
  color: var(--rx-grey-10);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-item {
  font-size: 13.5px;
  font-weight: 500;
  color: var(--rx-grey-10);
  text-decoration: none;
  transition: color 0.15s var(--rx-ease);
}

.nav-item:hover,
.nav-item:focus-visible {
  color: var(--rx-brand-white);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-pill-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 34px;
  padding: 0 11px;
  border-radius: 8px;
  background: var(--rx-bg-15);
  border: 1px solid var(--rx-border-subtle);
  color: var(--rx-grey-0);
  font-family: var(--rx-font-mono);
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.15s var(--rx-ease), background-color 0.15s var(--rx-ease);
}

.icon-pill-btn:hover {
  border-color: var(--rx-border-strong);
  background: var(--rx-bg-20);
}

.voxel-dot {
  width: 7px;
  height: 7px;
  background: var(--rx-brand-white);
  box-shadow: 2px 2px 0 rgba(255, 255, 255, 0.35);
}

.icon-pill-btn[aria-pressed="false"] .voxel-dot {
  background: var(--rx-grey-20);
  box-shadow: none;
}

.header-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 34px;
  padding: 0 13px;
  border-radius: 8px;
  background: var(--rx-brand-white);
  color: var(--rx-bg-0);
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
  transition: transform 0.15s var(--rx-ease), opacity 0.15s var(--rx-ease);
}

.header-cta:hover {
  opacity: 0.92;
  transform: translateY(-1px);
}

/* ==========================================================================
   HERO SECTION: 3D Voxel Snowfall + Monochrome Official Card
   ========================================================================== */
.hero-section {
  position: relative;
  min-height: calc(100dvh - 60px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 44px 20px 64px;
  overflow: hidden;
  border-bottom: 1px solid var(--rx-border-subtle);
}

.voxel-snow-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  pointer-events: none;
}

.hero-grid-overlay {
  position: absolute;
  inset: 0;
  z-index: 0;
  background-image:
    linear-gradient(to right, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 45%, #000 35%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 45%, #000 35%, transparent 100%);
}

.hero-vignette {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  background: radial-gradient(circle at 50% 42%, rgba(255, 255, 255, 0.04) 0%, rgba(10, 10, 10, 0.32) 68%, rgba(10, 10, 10, 0.78) 100%);
}

.hero-container {
  position: relative;
  z-index: 10;
  width: 100%;
  max-width: 760px;
  margin: 0 auto;
}

/* Breadcrumb */
.breadcrumb-nav {
  margin-bottom: 14px;
}

.breadcrumb-nav ol {
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--rx-grey-10);
  background: rgba(18, 18, 18, 0.85);
  border: 1px solid var(--rx-border-subtle);
  padding: 5px 12px;
  border-radius: 999px;
}

.breadcrumb-nav li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--rx-grey-20);
}

.breadcrumb-nav a {
  color: var(--rx-grey-0);
  text-decoration: none;
  font-weight: 600;
}

/* Central Monochrome Address Card */
.address-card {
  background: rgba(16, 16, 18, 0.86);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1px solid var(--rx-border-strong);
  border-radius: 24px;
  padding: 36px 36px 30px;
  box-shadow:
    0 24px 64px rgba(0, 0, 0, 0.72),
    inset 0 1px 0 rgba(255, 255, 255, 0.22);
}

.card-top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  padding-bottom: 24px;
  margin-bottom: 26px;
  border-bottom: 1px solid var(--rx-border-subtle);
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--rx-border-subtle);
  font-size: 12px;
  font-weight: 600;
  color: var(--rx-grey-0);
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--rx-green-50);
  box-shadow: 0 0 10px var(--rx-green-50);
  animation: pulseDot 2.2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.22); opacity: 0.72; }
}

.verified-date {
  font-family: var(--rx-font-mono);
  font-size: 12px;
  color: var(--rx-grey-10);
}

.hero-brand-lockup {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

.hero-wordmark {
  display: block;
  height: 36px;
  width: auto;
}

.hero-official-tag {
  font-family: var(--rx-font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  padding: 4px 9px;
  border-radius: 6px;
  background: var(--rx-bg-20);
  border: 1px solid var(--rx-border-subtle);
  color: var(--rx-grey-10);
}

.hero-title {
  font-size: clamp(26px, 4.2vw, 38px);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -0.025em;
  color: var(--rx-brand-white);
  margin-bottom: 16px;
}

.hero-title-sub {
  display: block;
  margin-top: 8px;
  font-size: clamp(13px, 2vw, 15px);
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--rx-grey-10);
}

.hero-lead {
  font-size: 15.5px;
  line-height: 1.72;
  color: #d4d4d8;
  margin-bottom: 26px;
}

.hero-lead strong {
  color: var(--rx-brand-white);
  font-weight: 700;
}

.inline-url-link {
  color: var(--rx-brand-white);
  font-family: var(--rx-font-mono);
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.hero-lead code {
  font-family: var(--rx-font-mono);
  font-size: 13.5px;
  padding: 2px 6px;
  border-radius: 5px;
  background: var(--rx-bg-20);
  border: 1px solid var(--rx-border-subtle);
  color: var(--rx-brand-white);
}

/* Official Domain Terminal Box */
.domain-terminal {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  padding: 16px 18px;
  border-radius: 16px;
  background: var(--rx-bg-0);
  border: 1px solid var(--rx-border-strong);
  margin-bottom: 22px;
}

.terminal-url-group {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.lock-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 9px;
  border-radius: 7px;
  background: var(--rx-bg-20);
  border: 1px solid var(--rx-border-subtle);
  font-size: 11.5px;
  font-weight: 600;
  color: var(--rx-grey-0);
}

.terminal-url {
  font-family: var(--rx-font-mono);
  font-size: clamp(20px, 3vw, 26px);
  font-weight: 700;
  color: var(--rx-brand-white);
  text-decoration: none;
  letter-spacing: 0.01em;
}

.terminal-url:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.terminal-btn-group {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  height: 44px;
  padding: 0 16px;
  border-radius: 11px;
  background: var(--rx-bg-20);
  border: 1px solid var(--rx-border-strong);
  color: var(--rx-brand-white);
  font-family: var(--rx-font-sans);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s var(--rx-ease), transform 0.15s var(--rx-ease);
}

.btn-secondary:hover {
  background: var(--rx-bg-35);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 44px;
  padding: 0 20px;
  border-radius: 11px;
  background: var(--rx-brand-white);
  color: var(--rx-bg-0);
  font-size: 14.5px;
  font-weight: 800;
  text-decoration: none;
  transition: transform 0.15s var(--rx-ease), box-shadow 0.15s var(--rx-ease);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(255, 255, 255, 0.2);
}

/* Interactive Micro-Utility Panel (Ping / DNS / Bookmark) */
.utility-panel {
  padding-top: 18px;
  border-top: 1px solid var(--rx-border-subtle);
}

.utility-tabs {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.utility-tab {
  height: 32px;
  padding: 0 12px;
  border-radius: 8px;
  background: var(--rx-bg-15);
  border: 1px solid var(--rx-border-subtle);
  color: var(--rx-grey-10);
  font-family: var(--rx-font-sans);
  font-size: 12.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s var(--rx-ease);
}

.utility-tab:hover {
  color: var(--rx-brand-white);
  border-color: var(--rx-border-strong);
}

.utility-tab.active {
  background: var(--rx-brand-white);
  color: var(--rx-bg-0);
  border-color: var(--rx-brand-white);
}

.utility-content {
  padding: 14px 16px;
  border-radius: 12px;
  background: rgba(10, 10, 10, 0.72);
  border: 1px solid var(--rx-border-subtle);
  font-size: 13px;
}

.ping-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 8px;
}

.ping-info {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.ping-label {
  color: var(--rx-grey-0);
  font-weight: 500;
}

.ping-label code,
.utility-note code,
.utility-steps code {
  font-family: var(--rx-font-mono);
  font-size: 12px;
  padding: 1px 5px;
  border-radius: 4px;
  background: var(--rx-bg-20);
  color: var(--rx-brand-white);
}

.ping-badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 9px;
  border-radius: 6px;
  background: rgba(37, 192, 109, 0.14);
  border: 1px solid rgba(37, 192, 109, 0.38);
  color: #4ade80;
  font-family: var(--rx-font-mono);
  font-size: 11.5px;
  font-weight: 600;
}

.mini-action-btn {
  height: 30px;
  padding: 0 12px;
  border-radius: 7px;
  background: var(--rx-bg-20);
  border: 1px solid var(--rx-border-strong);
  color: var(--rx-brand-white);
  font-family: var(--rx-font-sans);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s var(--rx-ease);
}

.mini-action-btn:hover {
  background: var(--rx-bg-35);
}

.utility-note {
  font-size: 12px;
  color: var(--rx-grey-10);
}

.utility-steps {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 7px;
  color: #d4d4d8;
  line-height: 1.6;
}

.utility-steps strong {
  color: var(--rx-brand-white);
}

/* 3 Core Pillar Cards */
.feature-pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-bottom: 24px;
}

.pillar-card {
  padding: 18px 18px;
  border-radius: 14px;
  background: var(--rx-bg-10);
  border: 1px solid var(--rx-border-subtle);
}

.pillar-title {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--rx-brand-white);
  margin-bottom: 6px;
}

.pillar-desc {
  font-size: 13px;
  line-height: 1.62;
  color: var(--rx-grey-10);
}

.pillar-desc code {
  font-family: var(--rx-font-mono);
  font-size: 12px;
  color: var(--rx-grey-0);
}

/* ==========================================================================
   ENTITY & FAQ SECTIONS (Slim, Authoritative, High Extractability)
   ========================================================================== */
.entity-section,
.faq-section {
  padding: 56px 20px;
  border-bottom: 1px solid var(--rx-border-subtle);
}

.section-container {
  max-width: 760px;
  margin: 0 auto;
}

.section-header {
  margin-bottom: 24px;
}

.section-eyebrow {
  display: inline-block;
  font-family: var(--rx-font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--rx-grey-10);
  margin-bottom: 6px;
}

.section-title {
  font-size: clamp(20px, 3vw, 25px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--rx-brand-white);
}

.definition-box {
  padding: 22px 24px;
  border-radius: 16px;
  background: var(--rx-bg-10);
  border: 1px solid var(--rx-border-strong);
  margin-bottom: 24px;
}

.definition-text {
  font-size: 15px;
  line-height: 1.75;
  color: var(--rx-grey-0);
}

.definition-text code {
  font-family: var(--rx-font-mono);
  font-size: 13px;
  padding: 1px 5px;
  border-radius: 4px;
  background: var(--rx-bg-20);
}

/* Specification Table */
.spec-table-wrapper {
  overflow-x: auto;
  border-radius: 14px;
  border: 1px solid var(--rx-border-subtle);
  background: var(--rx-bg-10);
}

.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
  text-align: left;
}

.spec-table caption {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}

.spec-table th,
.spec-table td {
  padding: 13px 16px;
  border-bottom: 1px solid var(--rx-border-subtle);
}

.spec-table thead th {
  background: var(--rx-bg-15);
  color: var(--rx-grey-10);
  font-weight: 600;
  font-size: 12px;
  letter-spacing: 0.02em;
}

.spec-table tbody th {
  width: 26%;
  font-weight: 600;
  color: var(--rx-grey-0);
  background: rgba(255, 255, 255, 0.015);
}

.spec-table tbody tr:last-child th,
.spec-table tbody tr:last-child td {
  border-bottom: none;
}

.spec-table a {
  color: var(--rx-brand-white);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.spec-table code {
  font-family: var(--rx-font-mono);
  font-size: 12.5px;
}

/* FAQ Grid */
.faq-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.faq-item {
  padding: 20px 22px;
  border-radius: 14px;
  background: var(--rx-bg-10);
  border: 1px solid var(--rx-border-subtle);
}

.faq-question {
  font-size: 15px;
  font-weight: 700;
  color: var(--rx-brand-white);
  margin-bottom: 8px;
  line-height: 1.4;
}

.faq-answer {
  font-size: 13.5px;
  line-height: 1.68;
  color: #d4d4d8;
}

.faq-answer strong {
  color: var(--rx-brand-white);
}

.faq-answer code {
  font-family: var(--rx-font-mono);
  font-size: 12.5px;
  padding: 1px 5px;
  border-radius: 4px;
  background: var(--rx-bg-20);
}

/* Footer */
.site-footer {
  margin-top: auto;
  padding: 28px 20px;
  background: var(--rx-bg-0);
}

.footer-inner {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.footer-copy {
  font-size: 12.5px;
  color: var(--rx-grey-10);
}

.footer-copy a {
  color: var(--rx-grey-0);
  text-decoration: none;
}

.footer-keywords {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 11.5px;
  color: var(--rx-grey-20);
}

.footer-keywords code {
  font-family: var(--rx-font-mono);
  padding: 2px 6px;
  border-radius: 4px;
  background: var(--rx-bg-10);
  border: 1px solid var(--rx-border-subtle);
  color: var(--rx-grey-10);
}

/* Responsive Breakpoints */
@media (max-width: 720px) {
  .header-nav {
    display: none;
  }

  .address-card {
    padding: 24px 20px;
    border-radius: 20px;
  }

  .domain-terminal {
    flex-direction: column;
    align-items: stretch;
  }

  .terminal-btn-group {
    width: 100%;
  }

  .btn-secondary,
  .btn-primary {
    flex: 1;
  }

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