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

:root {
  --bg: #0a0a0a;
  --surface: #1a1a1a;
  --border: #333333;
  --text: #ffffff;
  --text-muted: #a0a0a0;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --error: #ef4444;
  --success: #22c55e;
}

html,
body {
  height: 100%;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.hero {
  width: 100%;
  max-width: 480px;
  text-align: center;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 40px;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.brand-name {
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
}

h1 {
  font-size: clamp(28px, 6vw, 40px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.tagline {
  color: var(--text-muted);
  font-size: 16px;
  line-height: 1.6;
  margin-bottom: 36px;
}

#signup-form {
  display: flex;
  gap: 10px;
}

#email {
  flex: 1;
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  font-size: 15px;
  padding: 13px 16px;
  outline: none;
  transition: border-color 0.15s ease;
}

#email::placeholder {
  color: var(--text-muted);
}

#email:focus {
  border-color: var(--accent);
}

#submit-btn {
  background: var(--accent);
  border: none;
  border-radius: 10px;
  color: #ffffff;
  cursor: pointer;
  font-size: 15px;
  font-weight: 600;
  padding: 13px 22px;
  transition: background 0.15s ease;
  white-space: nowrap;
}

#submit-btn:hover {
  background: var(--accent-hover);
}

#submit-btn:disabled {
  opacity: 0.6;
  cursor: default;
}

#form-message {
  min-height: 22px;
  margin-top: 14px;
  font-size: 14px;
  color: var(--text-muted);
}

#form-message.error {
  color: var(--error);
}

#form-message.success {
  color: var(--success);
}

footer {
  margin-top: 64px;
  color: var(--text-muted);
  font-size: 13px;
}

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

@media (max-width: 440px) {
  #signup-form {
    flex-direction: column;
  }
}