:root {
  --navy: #0a2540;
  --sky: #f7f9fc;
  --blue: #2f80ed;
  --teal: #00c2a8;
  --lavender: #e9f0ff;
  --midnight: #06182e;
  --text: #1b2b47;
  --muted: #6b7a90;
  --border: rgba(15, 31, 59, 0.12);
  --card: #ffffff;
  --shadow-soft: 0 18px 36px rgba(10, 37, 64, 0.10);
  --shadow-hard: 0 28px 54px rgba(10, 37, 64, 0.18);
  font-size: 16px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  font-family: 'DM Sans', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text);
  background: #ffffff;
  line-height: 1.6;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover {
  color: var(--blue);
}

.container {
  width: min(800px, 92vw);
  margin: 0 auto;
  padding: 0 20px;
}

/* Hero Section */
.hero {
  padding: 80px 0 60px;
  text-align: center;
  background: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);
}

.hero h1 {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  font-weight: 700;
  color: var(--navy);
  margin: 0 0 24px;
  line-height: 1.2;
}

.hero p {
  font-size: 1.2rem;
  color: var(--muted);
  margin: 0;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* Features Section */
.features {
  padding: 80px 0;
  background: var(--sky);
}

.features h2 {
  font-size: clamp(2rem, 4vw, 2.5rem);
  font-weight: 600;
  color: var(--navy);
  text-align: center;
  margin: 0 0 50px;
}

.features-list {
  list-style: none;
  padding: 0;
  margin: 0 0 50px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.features-list li {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 16px 0;
  font-size: 1.1rem;
  color: var(--text);
  border-bottom: 1px solid rgba(15, 31, 59, 0.08);
}

.features-list li:last-child {
  border-bottom: none;
}

.features-list li::before {
  content: '✓';
  color: var(--teal);
  font-weight: 700;
  font-size: 1.2rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.features-visual {
  text-align: center;
}

.conversation-image {
  max-width: 100%;
  height: auto;
  border-radius: 16px;
  box-shadow: var(--shadow-soft);
  border: 1px solid var(--border);
}

/* Notify Section */
.notify {
  padding: 80px 0;
  background: #ffffff;
  text-align: center;
}

.notify h2 {
  font-size: clamp(2rem, 4vw, 2.5rem);
  font-weight: 600;
  color: var(--navy);
  margin: 0 0 16px;
}

.notify p {
  font-size: 1.1rem;
  color: var(--muted);
  margin: 0 0 40px;
}

.notify-form {
  max-width: 400px;
  margin: 0 auto;
}

.form-group {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
}

.form-group input {
  flex: 1;
  padding: 16px 20px;
  border: 2px solid var(--border);
  border-radius: 12px;
  font-size: 1rem;
  background: #ffffff;
  color: var(--text);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group input:focus {
  outline: none;
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(47, 128, 237, 0.1);
}

.form-group button {
  padding: 16px 32px;
  background: linear-gradient(120deg, var(--blue), #1f6fe3);
  color: #ffffff;
  border: none;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  white-space: nowrap;
}

.form-group button:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(47, 128, 237, 0.3);
}

.privacy-note {
  font-size: 0.9rem;
  color: var(--muted);
  margin: 0;
}

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

/* Mobile Responsive */
@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }
  
  .hero {
    padding: 60px 0 40px;
  }
  
  .features,
  .notify {
    padding: 60px 0;
  }
  
  .form-group {
    flex-direction: column;
    gap: 16px;
  }
  
  .form-group button {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2rem;
  }
  
  .hero p {
    font-size: 1.1rem;
  }
  
  .features-list li {
    font-size: 1rem;
  }
}