:root {
  --bg: #ffffff;
  --soft: #f5f8fd;
  --panel: #ffffff;
  --border: #e4e9f2;
  --text: #16233f;
  --muted: #5b6473;
  --accent: #2f6fed;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.nav, footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.5rem;
  max-width: 1040px;
  margin: 0 auto;
}
.nav nav a, footer nav a { margin-left: 1.25rem; color: var(--text); }
.nav nav a:hover { color: var(--accent); text-decoration: none; }
.brand { display: inline-flex; align-items: center; font-weight: 700; font-size: 1.35rem; color: var(--text); letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
.brand:hover { text-decoration: none; }

.cta {
  background: var(--accent);
  color: #fff !important;
  padding: 0.5rem 0.95rem;
  border-radius: 8px;
}
.cta:hover { text-decoration: none; opacity: 0.92; }

main { max-width: 1040px; margin: 0 auto; padding: 1.5rem; }

.hero { padding: 3rem 0 3.5rem; text-align: center; }
.hero-logo { width: min(560px, 88%); height: auto; margin: 0 auto 1.5rem; display: block; }
.hero-sub { color: var(--muted); max-width: 640px; margin: 0 auto 2rem; font-size: 1.15rem; }

.signup-card {
  max-width: 440px;
  margin: 0 auto;
  background: var(--soft);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.6rem 1.5rem;
  text-align: left;
}
.signup-card h2 { margin: 0 0 1rem; font-size: 1.25rem; text-align: center; }
.signup-card form { display: flex; flex-direction: column; gap: 0.6rem; }
.signup-card input {
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 1rem;
  background: #fff;
  color: var(--text);
}
.signup-card input:focus { outline: 2px solid var(--accent); outline-offset: 1px; border-color: var(--accent); }
.signup-card button {
  padding: 0.75rem 1rem;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}
.signup-card button:hover { opacity: 0.94; }
.signup-card button:disabled { opacity: 0.6; cursor: default; }
.signup-msg { min-height: 1.2rem; margin: 0.6rem 0 0; font-size: 0.9rem; color: var(--muted); text-align: center; }
.signup-msg.error { color: #c0392b; }
.signup-alt { text-align: center; color: var(--muted); font-size: 0.9rem; margin: 0.75rem 0 0; }

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.1rem;
  padding: 1.5rem 0 4rem;
}
.features article {
  background: var(--panel);
  border: 1px solid var(--border);
  border-left: 4px solid var(--fc, var(--accent));
  border-radius: 12px;
  padding: 1.3rem 1.4rem;
}
.features h3 { margin-top: 0; margin-bottom: 0.4rem; }
.features p { color: var(--muted); margin-bottom: 0; }
.features code { background: var(--soft); padding: 0.05rem 0.35rem; border-radius: 5px; font-size: 0.9em; }

footer {
  border-top: 1px solid var(--border);
  color: var(--muted);
  margin-top: 2rem;
}
footer nav a { color: var(--muted); }

.doc { max-width: 720px; margin: 0 auto; padding: 2.5rem 1.5rem; }
.doc h1 { margin-top: 0; }
.doc h2 { margin-top: 2rem; }

@media (prefers-color-scheme: dark) {
  :root { --bg:#0f1115; --soft:#171a21; --panel:#171a21; --border:#262b36; --text:#e6e9ef; --muted:#8b93a4; }
  .signup-card input { background:#0f1115; }
  .hero-logo { background:#fff; border-radius:16px; padding:1rem; }
  .brand-logo { background:#fff; border-radius:8px; padding:3px 6px; }
}