:root {
  --bg: #ffffff;
  --fg: #0e0e10;
  --muted: #6b6b72;
  --line: #e7e7ea;
  --card: #fafafa;
  --ring: rgba(14, 14, 16, 0.12);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0c0d;
    --fg: #f4f4f5;
    --muted: #9a9aa2;
    --line: #232326;
    --card: #161617;
    --ring: rgba(255, 255, 255, 0.16);
  }
}

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

html, body { height: 100%; }

body {
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--fg);
  min-height: 100vh;
  display: flex;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.shell {
  width: 100%;
  max-width: 640px;
  margin: auto;
  padding: 48px 24px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Brand */
.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  color: var(--fg);
  animation: fade-up 0.6s ease both;
}

.brand-mark { display: inline-flex; }

.brand-name {
  font-weight: 600;
  font-size: 1.1rem;
  letter-spacing: -0.01em;
}

.brand-dot { color: var(--muted); }

/* Hero */
.hero {
  margin: auto 0;
  padding: 56px 0;
}

.eyebrow {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 5px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  margin-bottom: 26px;
  animation: fade-up 0.6s 0.05s ease both;
}

.headline {
  font-size: clamp(2.2rem, 6.5vw, 3.6rem);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  animation: fade-up 0.6s 0.12s ease both;
}

.sub {
  font-size: clamp(1rem, 2.2vw, 1.1rem);
  font-weight: 400;
  color: var(--muted);
  max-width: 46ch;
  line-height: 1.65;
  margin-bottom: 34px;
  animation: fade-up 0.6s 0.2s ease both;
}

/* Form */
.signup {
  display: flex;
  gap: 8px;
  max-width: 460px;
  animation: fade-up 0.6s 0.28s ease both;
}

.signup-input {
  flex: 1;
  min-width: 0;
  padding: 14px 16px;
  font-size: 1rem;
  font-family: inherit;
  color: var(--fg);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.signup-input::placeholder { color: var(--muted); opacity: 0.7; }

.signup-input:focus {
  border-color: var(--fg);
  box-shadow: 0 0 0 3px var(--ring);
}

.signup-btn {
  padding: 14px 22px;
  font-size: 1rem;
  font-weight: 500;
  font-family: inherit;
  color: var(--bg);
  white-space: nowrap;
  background: var(--fg);
  border: 1px solid var(--fg);
  border-radius: 10px;
  cursor: pointer;
  transition: opacity 0.18s, transform 0.15s;
}

.signup-btn:hover { opacity: 0.85; }
.signup-btn:active { transform: translateY(1px); }
.signup-btn:disabled { opacity: 0.5; cursor: default; transform: none; }

.form-note {
  margin-top: 13px;
  font-size: 0.88rem;
  min-height: 1.2em;
  color: var(--muted);
  animation: fade-up 0.6s 0.32s ease both;
}

.form-note.ok { color: var(--fg); }
.form-note.err { color: #c0392b; }

@media (prefers-color-scheme: dark) {
  .form-note.err { color: #ff6b6b; }
}

/* Footer */
.foot {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.83rem;
  color: var(--muted);
  animation: fade-up 0.6s 0.4s ease both;
}

.foot a { color: var(--muted); text-decoration: none; transition: color 0.2s; }
.foot a:hover { color: var(--fg); }
.foot .dot { opacity: 0.5; }

/* Animations */
@keyframes fade-up {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 540px) {
  .signup { flex-direction: column; }
  .signup-btn { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  .brand, .eyebrow, .headline, .sub, .signup, .form-note, .foot {
    animation: none !important;
  }
}