/* ═══════════════════════════════════════════════
   ECHO Design System — echo.css  v1.0
   Single shared stylesheet for all ECHO pages
   ═══════════════════════════════════════════════ */

/* ─── 1. Tokens ─────────────────────────────── */
:root {
  --bg:       #0b0b0f;
  --surface:  #0f1720;
  --obsidian: #0a1018;
  --line:     #1a2330;
  --hairline: rgba(255,255,255,.06);
  --primary:  #3d84f5;
  --warn:     #f59e3d;
  --ink:      #e6eef8;
  --ink-dim:  #cbd5e1;
  --muted:    #8b9bb0;
  --dim:      #5b6878;
}

/* ─── 2. Reset ───────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }

/* ─── 3. Base ────────────────────────────────── */
body {
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100%;
}
a   { color: inherit; }
img { display: block; max-width: 100%; height: auto; }
button { cursor: pointer; font-family: inherit; }

/* ─── 4. Font ────────────────────────────────── */
@font-face {
  font-family: Inter;
  src: url(https://fonts.gstatic.com/s/inter/v20/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1ZL7.woff2) format('woff2');
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

/* ─── 5. Navigation ──────────────────────────── */
.echo-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 3rem;
  background: rgba(11,11,15,0.88);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--hairline);
  position: sticky;
  top: 0;
  z-index: 50;
}
@supports not ((backdrop-filter:blur(1px)) or (-webkit-backdrop-filter:blur(1px))) {
  .echo-header { background: rgba(11,11,15,0.97); }
}

/* Brand */
.echo-brand {
  display: flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
  color: var(--ink);
  opacity: .82;
  transition: opacity .2s;
  flex-shrink: 0;
}
.echo-brand:hover { opacity: 1; }

/* Concentric-rings mark */
.echo-mark {
  width: 20px;
  height: 20px;
  position: relative;
  flex-shrink: 0;
}
.echo-mark i {
  position: absolute;
  border: 1px solid var(--primary);
  border-radius: 50%;
  display: block;
}
.echo-mark i:nth-child(1) { inset: 7px; background: var(--primary); opacity: 1; }
.echo-mark i:nth-child(2) { inset: 3.5px; opacity: .35; }
.echo-mark i:nth-child(3) { inset: 0;     opacity: .14; }

.echo-wordmark {
  font-size: 12px;
  font-weight: 900;
  letter-spacing: .1em;
  text-transform: uppercase;
}

/* Nav links */
.echo-nav {
  display: flex;
  align-items: center;
  gap: 2.5rem;
}
.echo-nav-link {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: .2em;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  transition: color .2s;
  display: inline-flex;
  align-items: center;
  line-height: 1;
}
.echo-nav-link:hover  { color: var(--ink); }
.echo-nav-link.active { color: var(--primary); }

/* Dropdown */
.echo-nav-drop {
  position: relative;
  display: flex;
  align-items: center;
}
.echo-nav-trigger {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: .2em;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: .3rem;
  line-height: 1;
  transition: color .2s;
  user-select: none;
}
.echo-nav-trigger::after {
  content: '▾';
  font-size: 7px;
  transition: transform .2s;
}
.echo-nav-drop:hover .echo-nav-trigger         { color: var(--ink); }
.echo-nav-drop:hover .echo-nav-trigger::after  { transform: rotate(180deg); }

.echo-nav-menu {
  opacity: 0;
  visibility: hidden;
  position: absolute;
  top: calc(100% + 1rem);
  left: 50%;
  transform: translateX(-50%);
  background: rgba(14,20,29,0.98);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255,255,255,.10);
  min-width: 200px;
  box-shadow: 0 10px 40px rgba(0,0,0,.5);
  z-index: 100;
  transition: opacity .2s ease, visibility .2s ease, top .2s ease;
}
@supports not ((backdrop-filter:blur(1px)) or (-webkit-backdrop-filter:blur(1px))) {
  .echo-nav-menu { background: rgba(14,20,29,0.99); }
}
.echo-nav-drop:hover .echo-nav-menu {
  opacity: 1;
  visibility: visible;
  top: calc(100% + .5rem);
}
.echo-nav-menu a {
  display: block;
  padding: .9rem 1.5rem;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: .2em;
  font-weight: 500;
  color: var(--ink-dim);
  text-decoration: none;
  transition: background .2s, color .2s, padding-left .2s;
  border-bottom: 1px solid rgba(255,255,255,.05);
}
.echo-nav-menu a:last-child { border-bottom: none; }
.echo-nav-menu a:hover {
  background: rgba(61,132,245,.10);
  color: var(--primary);
  padding-left: 2rem;
}

/* CTA button in nav */
.echo-cta {
  background: var(--primary);
  color: #fff;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .2em;
  padding: .65rem 1.5rem;
  text-decoration: none;
  transition: filter .2s;
  flex-shrink: 0;
}
.echo-cta:hover { filter: brightness(1.1); }

/* Right side group: CTA + hamburger */
.echo-header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-shrink: 0;
}

/* Hamburger button */
.echo-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  padding: 6px 4px;
  cursor: pointer;
  flex-shrink: 0;
}
.echo-hamburger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--ink);
  transition: transform .25s ease, opacity .2s ease;
  transform-origin: center;
}
/* X state */
.echo-hamburger[aria-expanded="true"] span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.echo-hamburger[aria-expanded="true"] span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.echo-hamburger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* Full-screen mobile nav panel */
.echo-mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(11,11,15,.97);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  z-index: 48;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2.25rem;
  padding: 6rem 2rem 4rem;
  animation: mnavfade .25s ease;
}
@keyframes mnavfade { from { opacity: 0; } to { opacity: 1; } }
.echo-mobile-nav.open { display: flex; }
.echo-mobile-nav a {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: .25em;
  font-weight: 600;
  color: var(--muted);
  text-decoration: none;
  transition: color .2s;
  display: block;
  text-align: center;
}
.echo-mobile-nav a:hover  { color: var(--ink); }
.echo-mobile-nav a.active { color: var(--primary); }
.echo-mobile-nav .echo-mobile-rule {
  width: 30px;
  height: 1px;
  background: var(--line);
}
.echo-mobile-nav .echo-cta {
  margin-top: .5rem;
  font-size: 10px;
  color: #fff;
}

@media (max-width: 768px) {
  .echo-header       { padding: 1rem 1.25rem; }
  .echo-nav          { display: none; }
  .echo-hamburger    { display: flex; }
  .echo-header .echo-cta { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  .echo-mobile-nav { animation: none; }
}

/* ─── 6. Buttons ─────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--primary);
  border: 1px solid var(--primary);
  color: #fff;
  padding: 1rem 2rem;
  font-size: 9px;
  font-weight: 700;
  letter-spacing: .3em;
  text-transform: uppercase;
  cursor: pointer;
  text-decoration: none;
  font-family: inherit;
  transition: filter .25s, transform .2s;
}
.btn:hover { filter: brightness(1.12); transform: translateY(-1px); }
.btn:focus-visible { outline: 1px solid #fff; outline-offset: -4px; }

.btn.ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--muted);
}
.btn.ghost:hover {
  border-color: rgba(61,132,245,.5);
  color: var(--ink);
}

@media (prefers-reduced-motion: reduce) {
  .btn:hover { transform: none; }
}

/* ─── 7. Overlay / Panel system (game pages) ─── */
.overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(9,10,13,.82);
  backdrop-filter: blur(14px) saturate(.9);
  -webkit-backdrop-filter: blur(14px) saturate(.9);
  z-index: 10;
  padding: 20px;
  animation: ovfade .45s cubic-bezier(.25,.1,.25,1);
}
@keyframes ovfade { from { opacity: 0; } to { opacity: 1; } }

.panel {
  width: min(460px, 94vw);
  background: linear-gradient(180deg, rgba(255,255,255,.022) 0%, rgba(255,255,255,0) 120px), var(--surface);
  border: 1px solid var(--line);
  border-top: 1px solid rgba(61,132,245,.35);
  padding: 44px 44px 40px;
  animation: panelrise .55s cubic-bezier(.16,1,.3,1);
}
@keyframes panelrise {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: none; }
}
@media (prefers-reduced-motion: reduce) {
  .overlay, .panel { animation: none; }
}

.panel h1 {
  font-size: 27px;
  font-weight: 700;
  letter-spacing: -.015em;
  margin: 16px 0 8px;
}
.tagline {
  color: var(--muted);
  font-weight: 300;
  font-size: 13.5px;
  line-height: 1.75;
  margin-bottom: 30px;
}
.howto {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 13px 18px;
  margin-bottom: 30px;
  padding: 22px 0;
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}
.howto .k {
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--primary);
  padding-top: 3px;
  white-space: nowrap;
}
.howto .v {
  font-size: 12.5px;
  color: var(--muted);
  font-weight: 300;
  line-height: 1.6;
}
.modes {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.modebtn {
  background: var(--surface);
  border: none;
  color: var(--ink);
  padding: 18px 8px 15px;
  cursor: pointer;
  transition: background .25s;
  font-family: inherit;
  text-align: center;
  position: relative;
}
.modebtn::after {
  content: "";
  position: absolute;
  left: 0; right: 0; top: 0;
  height: 1px;
  background: var(--primary);
  opacity: 0;
  transition: opacity .25s;
}
.modebtn:hover                  { background: #111926; }
.modebtn:hover::after,
.modebtn:focus-visible::after   { opacity: 1; }
.modebtn:focus-visible          { outline: none; background: #111926; }
.modebtn .t {
  font-size: 16px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}
.modebtn .s {
  font-size: 8px;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--dim);
  margin-top: 6px;
}
.fineline {
  font-size: 10px;
  color: var(--dim);
  line-height: 1.7;
  margin-top: 24px;
  font-weight: 300;
}
.sumgrid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin: 28px 0;
}
.sumcell {
  background: var(--surface);
  padding: 18px 20px 15px;
}
.sumcell .n {
  font-size: 26px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  letter-spacing: -.02em;
}
.sumcell:first-child .n { color: var(--primary); }
.sumcell .l {
  font-size: 8px;
  letter-spacing: .28em;
  text-transform: uppercase;
  color: var(--dim);
  margin-top: 6px;
}
.reflect {
  font-style: italic;
  color: var(--muted);
  font-weight: 300;
  font-size: 13.5px;
  line-height: 1.75;
  border-left: 1px solid var(--primary);
  padding-left: 16px;
  margin-bottom: 30px;
}
.actions { display: flex; gap: 10px; flex-wrap: wrap; }

/* ─── 8. Typography utilities ────────────────── */
.kicker {
  font-size: 9px;
  text-transform: uppercase;
  letter-spacing: .4em;
  color: var(--primary);
  font-weight: 700;
}
.microlabel {
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: .38em;
  text-transform: uppercase;
  color: var(--muted);
}

/* ─── 9. Layout ──────────────────────────────── */
.echo-page {
  max-width: 1100px;
  margin: 0 auto;
  padding: 5rem 2rem 8rem;
}
.hidden { display: none !important; }

/* ─── 10. Social icons ───────────────────────── */
.echo-social-links {
  display: flex;
  align-items: center;
  gap: 1.1rem;
}
.echo-social-icon {
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  opacity: .8;
  transition: opacity .2s, transform .2s;
}
.echo-social-icon:hover {
  opacity: 1;
  transform: translateY(-2px);
}
.echo-social-icon svg { display: block; }

/* Keep last social icon clear of the fixed chatbot button (≈80px from right) */
footer .echo-social-links { padding-right: 5rem; }