/* ============================================================
   byte-chat landing — "Ember" design language
   Tokens mirror docs/04-design-system.md
   ============================================================ */

:root {
  /* Ember ramp */
  --ember-50:#FBF3EC; --ember-100:#F6E3D3; --ember-200:#EFC9A9;
  --ember-300:#E5A878; --ember-400:#D9834B; --ember-500:#C7642A;
  --ember-600:#A84F1D; --ember-700:#873E17; --ember-900:#47220D;

  /* Warm stone neutrals */
  --stone-0:#FFFFFF; --stone-25:#FCFBFA; --stone-50:#F7F5F2; --stone-100:#EFEBE6;
  --stone-200:#E2DCD4; --stone-300:#CCC4B9; --stone-400:#A99F92; --stone-500:#857B6E;
  --stone-600:#665E53; --stone-650:#B5AC9F; --stone-700:#4A443C; --stone-800:#322D27;
  --stone-850:#262220; --stone-900:#1C1917; --stone-950:#141210;

  /* Semantic — light */
  --bg:var(--stone-50);
  --bg-alt:#F1EAE1;
  --surface:var(--stone-0);
  --surface-2:var(--stone-100);
  --text:var(--stone-950);
  --text-2:var(--stone-600);
  --line:var(--stone-200);
  --accent:var(--ember-500);
  --accent-press:var(--ember-600);
  --accent-soft:var(--ember-100);
  --accent-ink:var(--ember-700);
  --on-accent:var(--stone-950);
  --bub-out:#F3D9BC;
  --bub-out-ink:#241A10;
  --bub-in:var(--stone-0);
  --chat-bg:#F1EAE1;
  --read:#3B82F6;
  --shadow:0 2px 8px rgba(20,18,16,.08);
  --shadow-lg:0 18px 48px -18px rgba(71,34,13,.34);

  --wrap:1120px;
  --r-sm:10px; --r:14px; --r-lg:20px; --r-xl:28px;

  --font:-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono:ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
}

:root[data-theme="dark"], :root.dark {
  --bg:var(--stone-950);
  --bg-alt:#181513;
  --surface:var(--stone-850);
  --surface-2:var(--stone-800);
  --text:#F2EEE9;
  --text-2:var(--stone-650);
  --line:var(--stone-700);
  --accent:var(--ember-300);
  --accent-press:var(--ember-400);
  --accent-soft:#3A2415;
  --accent-ink:var(--ember-300);
  --on-accent:var(--stone-950);
  --bub-out:#53341A;
  --bub-out-ink:#F5EFE8;
  --bub-in:var(--stone-850);
  --chat-bg:#131110;
  --read:#6FA8FF;
  --shadow:0 2px 10px rgba(0,0,0,.4);
  --shadow-lg:0 22px 60px -20px rgba(0,0,0,.7);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:var(--stone-950);
    --bg-alt:#181513;
    --surface:var(--stone-850);
    --surface-2:var(--stone-800);
    --text:#F2EEE9;
    --text-2:var(--stone-650);
    --line:var(--stone-700);
    --accent:var(--ember-300);
    --accent-press:var(--ember-400);
    --accent-soft:#3A2415;
    --accent-ink:var(--ember-300);
    --on-accent:var(--stone-950);
    --bub-out:#53341A;
    --bub-out-ink:#F5EFE8;
    --bub-in:var(--stone-850);
    --chat-bg:#131110;
    --read:#6FA8FF;
    --shadow:0 2px 10px rgba(0,0,0,.4);
    --shadow-lg:0 22px 60px -20px rgba(0,0,0,.7);
  }
}

/* ── reset ─────────────────────────────────────────────── */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:84px}
body{
  margin:0;background:var(--bg);color:var(--text);font-family:var(--font);
  font-size:17px;line-height:1.6;-webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img,svg{max-width:100%}
a{color:inherit}
h1,h2,h3{margin:0;line-height:1.08;letter-spacing:-.028em;font-weight:700}
p{margin:0}
ul{margin:0;padding:0;list-style:none}
:focus-visible{outline:2.5px solid var(--accent);outline-offset:3px;border-radius:6px}
@media (prefers-reduced-motion:reduce){
  *{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
  html{scroll-behavior:auto}
}

.wrap{width:100%;max-width:var(--wrap);margin-inline:auto;padding-inline:22px}
.skip{position:absolute;left:-9999px;top:0;background:var(--accent);color:var(--on-accent);padding:10px 16px;z-index:99;border-radius:0 0 10px 0}
.skip:focus{left:0}

/* ── nav ───────────────────────────────────────────────── */
.nav{
  position:sticky;top:0;z-index:50;
  background:color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter:saturate(160%) blur(14px);
  -webkit-backdrop-filter:saturate(160%) blur(14px);
  border-bottom:1px solid transparent;transition:border-color .2s, background .2s;
}
.nav.scrolled{border-bottom-color:var(--line)}
.nav-in{display:flex;align-items:center;gap:18px;height:66px}
.brand{display:flex;align-items:center;gap:9px;text-decoration:none;font-weight:700;letter-spacing:-.02em;font-size:18px}
.brand-mark{width:27px;height:27px;display:block;flex:none}
.brand-mark.sm{width:22px;height:22px}
.brand-mark svg{width:100%;height:100%;display:block}
.brand-dash{color:var(--accent)}
.nav-links{display:flex;gap:26px;margin-inline:auto;font-size:15px;font-weight:500}
.nav-links a{text-decoration:none;color:var(--text-2);transition:color .18s}
.nav-links a:hover{color:var(--text)}
.nav-right{display:flex;align-items:center;gap:10px;margin-left:auto}
.nav-links + .nav-right{margin-left:0}

.icon-btn{
  width:38px;height:38px;border-radius:11px;border:1px solid var(--line);
  background:transparent;color:var(--text-2);display:grid;place-items:center;cursor:pointer;
  transition:background .18s,color .18s,border-color .18s;flex:none;
}
.icon-btn:hover{background:var(--surface-2);color:var(--text)}
.icon-btn svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round}
.ico-moon{display:none}
:root[data-theme="dark"] .ico-sun{display:none}
:root[data-theme="dark"] .ico-moon{display:block}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]) .ico-sun{display:none}
  :root:not([data-theme="light"]) .ico-moon{display:block}
}

/* ── buttons ───────────────────────────────────────────── */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:9px;
  height:52px;padding:0 24px;border-radius:var(--r);text-decoration:none;
  font-weight:600;font-size:16px;letter-spacing:-.01em;border:1px solid transparent;
  transition:transform .15s ease, background .18s, box-shadow .2s, border-color .18s;
  white-space:nowrap;cursor:pointer;
}
.btn-sm{height:40px;padding:0 17px;font-size:14.5px;border-radius:11px}
.btn-primary{background:var(--accent);color:var(--on-accent);box-shadow:var(--shadow)}
.btn-primary:hover{background:var(--accent-press);transform:translateY(-1px)}
.btn-primary:active{transform:translateY(0)}
.btn-ghost{background:transparent;color:var(--text);border-color:var(--line)}
.btn-ghost:hover{background:var(--surface-2);transform:translateY(-1px)}
.btn-ico{width:19px;height:19px;fill:none;stroke:currentColor;stroke-width:1.9;stroke-linecap:round;stroke-linejoin:round}
.btn-ico.fill{fill:currentColor;stroke:none}

/* ── hero ──────────────────────────────────────────────── */
.hero{position:relative;padding:clamp(48px,8vw,96px) 0 clamp(64px,9vw,110px);overflow:hidden}
.glow{
  position:absolute;inset:-30% -10% auto -10%;height:760px;pointer-events:none;
  background:
    radial-gradient(48% 44% at 22% 30%, rgba(199,100,42,.20), transparent 70%),
    radial-gradient(40% 40% at 78% 18%, rgba(229,168,120,.22), transparent 72%);
  filter:blur(6px);
}
:root[data-theme="dark"] .glow{background:radial-gradient(48% 44% at 22% 30%, rgba(217,131,75,.20), transparent 70%),radial-gradient(42% 40% at 80% 16%, rgba(135,62,23,.36), transparent 72%)}
.hero-in{position:relative;display:grid;grid-template-columns:minmax(0,1.08fr) minmax(0,.92fr);gap:clamp(28px,5vw,70px);align-items:center}

.eyebrow{
  display:inline-flex;align-items:center;gap:9px;font-size:13.5px;font-weight:600;
  letter-spacing:.01em;color:var(--accent-ink);background:var(--accent-soft);
  padding:7px 14px 7px 11px;border-radius:999px;margin-bottom:22px;
}
.dot{width:7px;height:7px;border-radius:50%;background:var(--accent);box-shadow:0 0 0 0 currentColor;animation:pulse 2.6s ease-out infinite}
@keyframes pulse{0%{box-shadow:0 0 0 0 rgba(199,100,42,.5)}70%{box-shadow:0 0 0 9px rgba(199,100,42,0)}100%{box-shadow:0 0 0 0 rgba(199,100,42,0)}}

h1{font-size:clamp(38px,5.6vw,64px);letter-spacing:-.038em}
.lede{margin-top:20px;font-size:clamp(16.5px,1.45vw,19px);color:var(--text-2);max-width:31em;line-height:1.62}
.lede em{font-style:italic;color:var(--text)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:30px}
.center-row{justify-content:center}

.proof{display:flex;flex-wrap:wrap;gap:8px 10px;margin-top:30px}
.proof li{
  font-size:13px;font-weight:600;color:var(--text-2);border:1px solid var(--line);
  padding:6px 12px;border-radius:999px;background:color-mix(in srgb,var(--surface) 60%,transparent);
}

/* ── phone mock ────────────────────────────────────────── */
.hero-art{position:relative;display:grid;place-items:center;min-height:520px}
.phone{
  position:relative;z-index:2;width:min(300px,80vw);aspect-ratio:300/610;
  background:var(--stone-950);border-radius:42px;padding:9px;
  box-shadow:var(--shadow-lg), 0 0 0 1px rgba(255,255,255,.06) inset;
  transform:rotate(-1.6deg);
}
:root[data-theme="dark"] .phone{background:#2a2724}
.phone-screen{
  position:relative;height:100%;border-radius:34px;overflow:hidden;
  background:var(--chat-bg);display:flex;flex-direction:column;
}
.p-top{
  display:flex;align-items:center;gap:9px;padding:16px 14px 11px;
  background:var(--surface);border-bottom:1px solid var(--line);
}
.p-back{color:var(--accent);font-size:22px;line-height:1;margin-right:-2px}
.p-av{width:32px;height:32px;border-radius:50%;background:#A8563F;color:#fff;display:grid;place-items:center;font-size:14px;font-weight:600;flex:none}
.p-id{display:flex;flex-direction:column;line-height:1.25;min-width:0}
.p-id b{font-size:14.5px}
.p-id i{font-style:normal;font-size:11.5px;color:var(--text-2)}
.p-banner{
  background:var(--surface-2);color:var(--text-2);font-size:11px;
  padding:7px 14px;text-align:center;line-height:1.35;
}
.p-thread{flex:1;display:flex;flex-direction:column;gap:7px;padding:14px 12px;overflow:hidden}
.bub{
  max-width:78%;padding:8px 12px;font-size:13px;line-height:1.42;border-radius:16px;
  position:relative;animation:rise .5s ease-out both;
}
.bub.in{align-self:flex-start;background:var(--bub-in);color:var(--text);border-bottom-left-radius:6px;box-shadow:var(--shadow)}
.bub.out{align-self:flex-end;background:var(--bub-out);color:var(--bub-out-ink);border-bottom-right-radius:6px;padding-right:34px}
.bub.short{min-width:120px}
.bub.in:nth-child(1){animation-delay:.1s}
.bub.out:nth-child(2){animation-delay:.35s}
.bub.in:nth-child(3){animation-delay:.6s}
.bub.out:nth-child(4){animation-delay:.85s}
.bub.out:nth-child(5){animation-delay:1.1s}
@keyframes rise{from{opacity:0;transform:translateY(9px) scale(.97)}to{opacity:1;transform:none}}
.tick{position:absolute;right:10px;bottom:6px;font-size:10px;letter-spacing:-1px}
.tick-read{color:var(--read)}
.tick-sent{color:var(--text-2);opacity:.75}
.p-composer{
  display:flex;align-items:center;gap:8px;padding:10px 12px 20px;background:var(--surface);
  border-top:1px solid var(--line);
}
.p-composer span{
  flex:1;background:var(--surface-2);border-radius:18px;padding:8px 14px;
  font-size:13px;color:var(--text-2);
}
.p-send{width:32px;height:32px;border-radius:50%;background:var(--accent);flex:none;position:relative}
.p-send::after{content:"";position:absolute;inset:0;margin:auto;width:0;height:0;border-left:9px solid var(--on-accent);border-top:6px solid transparent;border-bottom:6px solid transparent;transform:translateX(2px)}

.mesh-ring{
  position:absolute;border:1px solid var(--accent);border-radius:50%;opacity:0;
  aspect-ratio:1;pointer-events:none;animation:ripple 6s ease-out infinite;
}
.r1{width:340px;animation-delay:0s}
.r2{width:340px;animation-delay:2s}
.r3{width:340px;animation-delay:4s}
@keyframes ripple{0%{transform:scale(.55);opacity:.42}100%{transform:scale(2.1);opacity:0}}

/* ── sections ──────────────────────────────────────────── */
.section{padding:clamp(62px,8vw,104px) 0}
.section.alt{background:var(--bg-alt)}
.kicker{
  font-size:12.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;
  color:var(--accent-ink);margin-bottom:14px;
}
.h2{font-size:clamp(28px,3.6vw,42px);max-width:16ch}
.h2.center{max-width:none;text-align:center}
.sub{margin-top:16px;color:var(--text-2);font-size:clamp(16px,1.3vw,18px);max-width:56ch;line-height:1.62}
.sub.center{margin-inline:auto;text-align:center}
.sub.left{max-width:44ch}

/* steps */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin-top:46px}
.step{
  position:relative;background:var(--surface);border:1px solid var(--line);
  border-radius:var(--r-lg);padding:28px 24px 26px;
  transition:transform .22s ease, box-shadow .22s ease, border-color .22s;
}
.step:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg);border-color:color-mix(in srgb,var(--accent) 34%,var(--line))}
.step-n{
  position:absolute;top:20px;right:22px;font-family:var(--mono);font-size:12px;
  color:var(--text-2);opacity:.55;letter-spacing:.05em;
}
.step-ico,.c-ico{
  width:46px;height:46px;border-radius:14px;background:var(--accent-soft);
  color:var(--accent-ink);display:grid;place-items:center;margin-bottom:18px;
}
.step-ico svg,.c-ico svg{width:23px;height:23px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.step h3,.card h3{font-size:19px;margin-bottom:9px;letter-spacing:-.02em}
.step p,.card p{color:var(--text-2);font-size:15.5px;line-height:1.6}

/* feature grid */
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin-top:46px}
.card{
  background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);
  padding:26px 24px;transition:transform .22s ease, box-shadow .22s ease, border-color .22s;
}
.card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg);border-color:color-mix(in srgb,var(--accent) 34%,var(--line))}

/* honest delivery */
.honest-in{display:grid;grid-template-columns:minmax(0,.9fr) minmax(0,1.1fr);gap:clamp(30px,5vw,64px);align-items:center}
.honest-copy .btn{margin-top:26px}
.ticks{display:flex;flex-direction:column;gap:10px}
.ticks li{
  display:grid;grid-template-columns:44px 1fr;grid-template-rows:auto auto;
  column-gap:14px;align-items:center;background:var(--surface);border:1px solid var(--line);
  border-radius:var(--r);padding:15px 18px;
}
.ticks b{font-size:15.5px;letter-spacing:-.01em}
.ticks i{grid-column:2;font-style:normal;font-size:14px;color:var(--text-2);line-height:1.45}
.t{
  grid-row:1/3;width:40px;height:40px;border-radius:11px;display:grid;place-items:center;
  font-size:15px;letter-spacing:-2px;background:var(--surface-2);color:var(--text-2);
}
.t-sent,.t-del{color:var(--text)}
.t-read{color:var(--read);background:color-mix(in srgb,var(--read) 13%,transparent)}
.t-q{color:var(--accent-ink);background:var(--accent-soft)}

/* when */
.when{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;margin-top:44px;background:var(--line);border:1px solid var(--line);border-radius:var(--r-lg);overflow:hidden}
.w-item{background:var(--bg-alt);padding:26px 24px;display:flex;flex-direction:column;gap:7px;transition:background .2s}
.w-item:hover{background:var(--surface)}
.w-item b{font-size:16.5px;letter-spacing:-.015em}
.w-item span{color:var(--text-2);font-size:15px;line-height:1.55}

/* get */
.get{padding:clamp(70px,9vw,112px) 0;background:
  radial-gradient(60% 100% at 50% 0%, color-mix(in srgb,var(--accent) 13%,transparent), transparent 72%), var(--bg);
  border-top:1px solid var(--line);border-bottom:1px solid var(--line);
}
.get-in{display:flex;flex-direction:column;align-items:center}
.fineprint{margin-top:22px;font-size:13.5px;color:var(--text-2)}

/* faq */
.faq-wrap{max-width:800px}
.faq-wrap details{
  border-bottom:1px solid var(--line);
}
.faq-wrap details:first-of-type{margin-top:38px;border-top:1px solid var(--line)}
.faq-wrap summary{
  list-style:none;cursor:pointer;padding:21px 44px 21px 0;position:relative;
  font-size:17.5px;font-weight:600;letter-spacing:-.015em;
}
.faq-wrap summary::-webkit-details-marker{display:none}
.chev{position:absolute;right:6px;top:50%;width:11px;height:11px;margin-top:-7px;border-right:2px solid var(--accent);border-bottom:2px solid var(--accent);transform:rotate(45deg);transition:transform .25s ease}
details[open] .chev{transform:rotate(-135deg);margin-top:-3px}
.faq-wrap details p{padding:0 40px 22px 0;color:var(--text-2);font-size:16px;line-height:1.65;margin-top:-4px}

/* footer */
.foot{padding:44px 0 54px;background:var(--bg)}
.foot-in{display:flex;flex-wrap:wrap;align-items:center;gap:18px 28px}
.foot-brand{display:flex;align-items:center;gap:8px;font-weight:700;letter-spacing:-.02em}
.foot-links{display:flex;gap:22px;font-size:14.5px;margin-inline:auto}
.foot-links a{color:var(--text-2);text-decoration:none;transition:color .18s}
.foot-links a:hover{color:var(--text)}
.foot-note{font-size:13.5px;color:var(--text-2)}

/* ── responsive ────────────────────────────────────────── */
@media (max-width:1000px){
  .steps,.grid,.when{grid-template-columns:repeat(2,1fr)}
  .hero-in{grid-template-columns:1fr;text-align:left}
  .hero-art{min-height:0;margin-top:20px}
  .honest-in{grid-template-columns:1fr}
  .nav-links{display:none}
  .h2{max-width:20ch}
}
@media (max-width:640px){
  body{font-size:16px}
  .br-lg{display:none}
  .steps,.grid,.when{grid-template-columns:1fr}
  .when{border-radius:var(--r)}
  .btn{width:100%}
  .cta-row{flex-direction:column;align-items:stretch}
  .foot-in{flex-direction:column;align-items:flex-start}
  .foot-links{margin-inline:0;flex-wrap:wrap}
  .phone{transform:none}
  .mesh-ring{display:none}
}