/* ==========================================================================
   zerodoc AetherStream — website stylesheet
   Design system: docs/DESIGN_SYSTEM.md
   - 0px radius, no gradients, no shadows (none are declared anywhere below)
   - Monochrome: #000000 canvas, #0A0A0A surface, #111111 elevated,
     #222222 hairline, #444444 active border, #FFFFFF text, #888888 secondary
   - Pretendard (word-break: keep-all, letter-spacing -0.02em),
     JetBrains Mono for codes, versions, ports and other identifiers
   ========================================================================== */

:root {
  --c-canvas: #000000;
  --c-surface: #0A0A0A;
  --c-elevated: #111111;
  --c-hairline: #222222;
  --c-border-active: #444444;
  --c-text: #FFFFFF;
  --c-text-2: #888888;
  --c-text-dim: #444444;

  --font-sans: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, 'Apple SD Gothic Neo', 'Malgun Gothic', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  --gutter: 16px;
  --max-w: 1120px;
}

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

html {
  color-scheme: dark;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background: var(--c-canvas);
  color: var(--c-text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  letter-spacing: -0.02em;
  word-break: keep-all;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

a { color: inherit; }
img, svg { display: block; }

code, kbd, .mono {
  font-family: var(--font-mono);
  letter-spacing: 0;
}

code {
  font-size: 0.9em;
  background: var(--c-elevated);
  border: 1px solid var(--c-hairline);
  padding: 0 4px;
}

.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* --------------------------------------------------------------------------
   Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--c-canvas);
  border-bottom: 1px solid var(--c-hairline);
}

.nav {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 56px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-company {
  font-size: 0.7rem;
  color: var(--c-text-2);
  font-family: var(--font-mono);
  letter-spacing: 0;
}

.brand-product {
  font-weight: 700;
  font-size: 0.95rem;
}

.nav-links {
  display: flex;
  gap: 20px;
  margin-left: auto;
}

.nav-links a {
  color: var(--c-text-2);
  text-decoration: none;
  font-size: 0.875rem;
}

.nav-links a:hover,
.nav-links a:focus-visible { color: var(--c-text); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.lang-switch {
  display: flex;
  border: 1px solid var(--c-hairline);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0;
}

.lang-switch a {
  padding: 4px 8px;
  text-decoration: none;
  color: var(--c-text-2);
}

.lang-switch a[aria-current="true"] {
  background: var(--c-text);
  color: var(--c-canvas);
}

@media (max-width: 820px) {
  .nav-links { display: none; }
  .nav-actions { margin-left: auto; }
}

@media (max-width: 400px) {
  .nav { gap: 12px; }
  .nav-actions .btn-sm { display: none; } /* hero has the download button */
}

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 40px;
  padding: 8px 16px;
  border: 1px solid var(--c-text);
  background: var(--c-canvas);
  color: var(--c-text);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.12s ease, color 0.12s ease;
}

.btn:hover,
.btn:focus-visible {
  background: var(--c-text);
  color: var(--c-canvas);
}

.btn-primary {
  background: var(--c-text);
  color: var(--c-canvas);
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--c-canvas);
  color: var(--c-text);
}

.btn-sm {
  min-height: 32px;
  padding: 4px 12px;
  font-size: 0.8rem;
}

.btn-block { width: 100%; }

.btn[disabled],
.btn[aria-disabled="true"] {
  border-color: var(--c-border-active);
  background: var(--c-canvas);
  color: var(--c-text-dim);
  cursor: not-allowed;
}

:focus-visible {
  outline: 1px solid var(--c-text);
  outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   Hero
   -------------------------------------------------------------------------- */
.hero {
  padding: 72px 0 56px;
  border-bottom: 1px solid var(--c-hairline);
}

.eyebrow {
  display: inline-flex;
  gap: 8px;
  border: 1px solid var(--c-hairline);
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0;
  color: var(--c-text-2);
  margin-bottom: 24px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.15;
  font-weight: 800;
  letter-spacing: -0.03em;
  max-width: 20ch;
}

.hero .lead {
  margin-top: 20px;
  max-width: 62ch;
  color: var(--c-text-2);
  font-size: 1.05rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.hero-meta {
  margin-top: 16px;
  font-size: 0.8rem;
  color: var(--c-text-2);
}

/* --------------------------------------------------------------------------
   Notices (alpha / security warnings)
   -------------------------------------------------------------------------- */
.notice {
  border: 1px solid var(--c-text);
  background: var(--c-surface);
  padding: 20px;
  margin-top: 40px;
}

.notice-title {
  display: inline-block;
  background: var(--c-text);
  color: var(--c-canvas);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0;
  padding: 2px 8px;
  margin-bottom: 12px;
}

.notice ul {
  padding-left: 18px;
  color: var(--c-text-2);
  font-size: 0.9rem;
}

.notice li + li { margin-top: 6px; }
.notice strong { color: var(--c-text); }

.cmd {
  display: block;
  margin-top: 6px;
  padding: 8px 10px;
  background: var(--c-canvas);
  border: 1px solid var(--c-hairline);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0;
  color: var(--c-text);
  overflow-x: auto;
  white-space: pre;
}

/* --------------------------------------------------------------------------
   Sections
   -------------------------------------------------------------------------- */
.section {
  padding: 64px 0;
  border-bottom: 1px solid var(--c-hairline);
}

.section-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0;
  color: var(--c-text-2);
}

.section h2 {
  margin-top: 8px;
  font-size: clamp(1.5rem, 3vw, 2rem);
  line-height: 1.25;
  font-weight: 700;
}

.section .section-lead {
  margin-top: 12px;
  max-width: 68ch;
  color: var(--c-text-2);
}

.section-body { margin-top: 32px; }

/* --------------------------------------------------------------------------
   Status table
   -------------------------------------------------------------------------- */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--c-hairline);
}

.status-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.status-table th,
.status-table td {
  text-align: left;
  vertical-align: top;
  padding: 12px 14px;
  border-bottom: 1px solid var(--c-hairline);
}

.status-table tr:last-child td { border-bottom: 0; }

.status-table th {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0;
  color: var(--c-text-2);
  font-weight: 500;
  background: var(--c-surface);
}

.status-table td:first-child { font-weight: 600; white-space: nowrap; }
.status-table td:last-child { color: var(--c-text-2); }

@media (max-width: 640px) {
  /* Stack rows on phones: area + status on one line, detail below. */
  .status-table thead { display: none; }
  .status-table, .status-table tbody, .status-table tr { display: block; }
  .status-table tr { padding: 12px 14px; border-bottom: 1px solid var(--c-hairline); }
  .status-table tr:last-child { border-bottom: 0; }
  .status-table td { display: inline; padding: 0; border: 0; }
  .status-table td:first-child { white-space: normal; margin-right: 8px; }
  .status-table td:last-child { display: block; margin-top: 6px; }
}

.badge {
  display: inline-block;
  white-space: nowrap;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 1px 8px;
  border: 1px solid var(--c-text);
}

.badge-done { background: var(--c-text); color: var(--c-canvas); }
.badge-partial { color: var(--c-text); }
.badge-progress { color: var(--c-text); border-style: dashed; }
.badge-none { color: var(--c-text-2); border-color: var(--c-border-active); }

.footnote {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--c-text-2);
}

/* --------------------------------------------------------------------------
   Pipeline (no timing numbers until measured — docs/CLAIMS.md)
   -------------------------------------------------------------------------- */
.pipeline {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  border: 1px solid var(--c-hairline);
  list-style: none;
}

.pipeline li {
  padding: 16px;
  border-right: 1px solid var(--c-hairline);
  min-width: 0;
}

.pipeline li:last-child { border-right: 0; }

.step-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0;
  color: var(--c-text-2);
}

.step-name {
  display: block;
  margin-top: 6px;
  font-weight: 700;
  font-size: 0.95rem;
}

.step-desc {
  display: block;
  margin-top: 6px;
  font-size: 0.8rem;
  color: var(--c-text-2);
}

@media (max-width: 960px) {
  .pipeline { grid-template-columns: repeat(2, 1fr); }
  .pipeline li { border-bottom: 1px solid var(--c-hairline); }
  .pipeline li:nth-child(2n) { border-right: 0; }
  .pipeline li:nth-last-child(-n+2) { border-bottom: 0; }
}

@media (max-width: 480px) {
  .pipeline { grid-template-columns: 1fr; }
  .pipeline li { border-right: 0; border-bottom: 1px solid var(--c-hairline); }
  .pipeline li:nth-last-child(-n+2) { border-bottom: 1px solid var(--c-hairline); }
  .pipeline li:last-child { border-bottom: 0; }
}

/* --------------------------------------------------------------------------
   Card grid (security points, downloads, docs)
   -------------------------------------------------------------------------- */
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--c-hairline);
}

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

.card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 24px;
  background: var(--c-surface);
  border-right: 1px solid var(--c-hairline);
  min-width: 0;
}

.grid > .card:last-child { border-right: 0; }
.grid-2 > .card:nth-child(2n) { border-right: 0; }

.card h3 {
  font-size: 1.05rem;
  font-weight: 700;
}

.card p,
.card li {
  font-size: 0.875rem;
  color: var(--c-text-2);
}

.card ul { padding-left: 18px; }
.card li + li { margin-top: 4px; }

.card-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0;
  color: var(--c-text-2);
}

.card .btn { margin-top: auto; }

@media (max-width: 860px) {
  .grid, .grid-2 { grid-template-columns: 1fr; }
  .card { border-right: 0; border-bottom: 1px solid var(--c-hairline); }
  .grid > .card:last-child { border-bottom: 0; }
}

.doc-list {
  list-style: none;
  border: 1px solid var(--c-hairline);
}

.doc-list li { border-bottom: 1px solid var(--c-hairline); }
.doc-list li:last-child { border-bottom: 0; }

.doc-list a {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 16px;
  text-decoration: none;
}

.doc-list a:hover,
.doc-list a:focus-visible {
  background: var(--c-text);
  color: var(--c-canvas);
}

.doc-list .doc-path {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0;
  color: inherit;
  opacity: 0.7;
}

/* --------------------------------------------------------------------------
   Room code form (modal + join page)
   -------------------------------------------------------------------------- */
.code-form { display: grid; gap: 12px; }

.code-input {
  width: 100%;
  min-height: 52px;
  padding: 8px 12px;
  background: var(--c-elevated);
  border: 1px solid var(--c-border-active);
  color: var(--c-text);
  font-family: var(--font-mono);
  font-size: 1.4rem;
  letter-spacing: 0.12em;
  text-align: center;
}

.code-input:focus {
  outline: none;
  border-color: var(--c-text);
}

.form-msg {
  min-height: 1.4em;
  font-size: 0.85rem;
  color: var(--c-text-2);
}

.form-msg[data-state="error"] { color: var(--c-text); font-weight: 600; }

.steps {
  padding-left: 20px;
  color: var(--c-text-2);
  font-size: 0.9rem;
}

.steps li + li { margin-top: 6px; }
.steps strong { color: var(--c-text); }

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--gutter);
  background: #000000;
}

.modal.open { display: flex; }

.modal-card {
  position: relative;
  width: 100%;
  max-width: 480px;
  max-height: calc(100vh - 32px);
  overflow-y: auto;
  padding: 28px 24px 24px;
  background: var(--c-surface);
  border: 1px solid var(--c-text);
}

.modal-card h2 {
  font-size: 1.25rem;
  margin-top: 6px;
}

.modal-card > p {
  margin-top: 8px;
  color: var(--c-text-2);
  font-size: 0.9rem;
}

.modal-card .code-form,
.modal-card .steps { margin-top: 20px; }

.modal-close {
  position: absolute;
  top: 8px;
  right: 8px;
  width: 36px;
  height: 36px;
  border: 1px solid var(--c-hairline);
  background: var(--c-canvas);
  color: var(--c-text);
  font-size: 1.1rem;
  cursor: pointer;
}

.modal-close:hover,
.modal-close:focus-visible {
  background: var(--c-text);
  color: var(--c-canvas);
}

/* Join page */
.join-main {
  padding: 56px 0 72px;
}

.join-card {
  max-width: 560px;
  border: 1px solid var(--c-text);
  background: var(--c-surface);
  padding: 28px 24px;
}

.join-card h1 {
  font-size: 1.6rem;
  line-height: 1.3;
  margin-top: 8px;
}

.join-card p { margin-top: 10px; color: var(--c-text-2); }

.join-code {
  margin-top: 20px;
  padding: 16px;
  border: 1px solid var(--c-hairline);
  background: var(--c-canvas);
  font-family: var(--font-mono);
  font-size: 1.8rem;
  letter-spacing: 0.1em;
  text-align: center;
}

.join-card .code-form,
.join-card .steps,
.join-card .notice { margin-top: 20px; }

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.site-footer {
  padding: 40px 0 56px;
  font-size: 0.8rem;
  color: var(--c-text-2);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 24px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-links a { text-decoration: none; }
.footer-links a:hover,
.footer-links a:focus-visible { color: var(--c-text); text-decoration: underline; }

/* Bilingual pages (<html data-lang-auto>, e.g. join.html): lang.js sets
   <html lang>; the other language's blocks are hidden. */
html[lang="en"] [data-only="ko"],
html[lang="ko"] [data-only="en"] { display: none; }