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

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", sans-serif;
  background: #0a0a0a;
  color: #ffffff;
  line-height: 1.6;
}

/* Landing Navigation */
.landing-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  padding: 20px 40px;
  background: rgba(10, 10, 10, 0.8);
  backdrop-filter: blur(20px);
  z-index: 100;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 24px;
  font-weight: 700;
  background: linear-gradient(135deg, #667eea, #764ba2);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.btn-login {
  padding: 10px 24px;
  background: transparent;
  border: 2px solid rgba(255,255,255,0.2);
  color: white;
  border-radius: 980px;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-login:hover {
  border-color: white;
  background: rgba(255,255,255,0.1);
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 140px 40px 60px;
  align-items: center;
}

.hero-content h1 {
  font-size: clamp(48px, 6vw, 80px);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: 24px;
  background: linear-gradient(135deg, #ffffff 0%, #a0a0a5 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-content p {
  font-size: clamp(20px, 3vw, 24px);
  color: #86868b;
  margin-bottom: 40px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-primary {
  padding: 16px 32px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  border: none;
  border-radius: 980px;
  color: white;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
  padding: 16px 32px;
  background: transparent;
  border: 2px solid rgba(255,255,255,0.2);
  border-radius: 980px;
  color: white;
  font-size: 17px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-secondary:hover {
  border-color: white;
}

/* Chat Mockup */
.hero-image {
  display: flex;
  justify-content: center;
  align-items: center;
}

.chat-mockup {
  width: 100%;
  max-width: 400px;
  background: rgba(29, 29, 31, 0.8);
  border-radius: 24px;
  padding: 24px;
  border: 1px solid rgba(255,255,255,0.1);
  box-shadow: 0 40px 80px rgba(0,0,0,0.4);
}

.mockup-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding-bottom: 20px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.mockup-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, #667eea, #764ba2);
}

.mockup-lines {
  flex: 1;
}

.line {
  height: 12px;
  background: rgba(255,255,255,0.1);
  border-radius: 6px;
  margin-bottom: 8px;
}

.line.short {
  width: 60%;
}

.mockup-messages {
  padding-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.message {
  height: 40px;
  border-radius: 16px;
  background: rgba(255,255,255,0.05);
}

.message.sent {
  background: linear-gradient(135deg, #667eea, #764ba2);
  align-self: flex-end;
  width: 70%;
  margin-left: auto;
}

.message.received {
  width: 80%;
}

/* Features */
.features {
  padding: 140px 40px;
  max-width: 1200px;
  margin: 0 auto;
}

.features h2 {
  font-size: clamp(36px, 5vw, 56px);
  text-align: center;
  margin-bottom: 80px;
  font-weight: 700;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
}

.feature-card {
  background: rgba(29, 29, 31, 0.6);
  border-radius: 20px;
  padding: 40px 32px;
  border: 1px solid rgba(255,255,255,0.05);
  transition: all 0.3s;
}

.feature-card:hover {
  transform: translateY(-8px);
  border-color: rgba(102, 126, 234, 0.3);
}

.feature-icon {
  font-size: 48px;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 22px;
  margin-bottom: 12px;
  font-weight: 600;
}

.feature-card p {
  color: #86868b;
  font-size: 16px;
}

/* CTA */
.cta {
  padding: 140px 40px;
  text-align: center;
  background: linear-gradient(180deg, transparent 0%, rgba(29, 29, 31, 0.5) 100%);
}

.cta h2 {
  font-size: clamp(36px, 5vw, 56px);
  margin-bottom: 16px;
  font-weight: 700;
}

.cta p {
  font-size: 20px;
  color: #86868b;
  margin-bottom: 40px;
}

/* Footer */
footer {
  padding: 40px;
  text-align: center;
  color: #86868b;
  border-top: 1px solid rgba(255,255,255,0.1);
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(10px);
  z-index: 1000;
  justify-content: center;
  align-items: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background: #1d1d1f;
  border-radius: 24px;
  padding: 40px;
  width: 100%;
  max-width: 420px;
  border: 1px solid rgba(255,255,255,0.1);
  position: relative;
  animation: modalSlide 0.3s ease;
}

@keyframes modalSlide {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  background: transparent;
  border: none;
  color: #86868b;
  font-size: 28px;
  cursor: pointer;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all 0.3s;
}

.modal-close:hover {
  background: rgba(255,255,255,0.1);
  color: white;
}

.modal-content h2 {
  font-size: 28px;
  margin-bottom: 32px;
  text-align: center;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 14px;
  color: #86868b;
  margin-bottom: 8px;
  font-weight: 500;
}

.form-group input {
  width: 100%;
  padding: 14px 18px;
  background: #0a0a0a;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 12px;
  color: white;
  font-size: 16px;
  transition: border-color 0.3s;
}

.form-group input:focus {
  outline: none;
  border-color: #667eea;
}

.btn-submit {
  width: 100%;
  padding: 16px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  border: none;
  border-radius: 12px;
  color: white;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
  margin-top: 8px;
}

.btn-submit:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

.auth-switch {
  text-align: center;
  margin-top: 24px;
  color: #86868b;
  font-size: 14px;
}

.auth-switch a {
  color: #667eea;
  text-decoration: none;
  font-weight: 500;
}

.auth-switch a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
  .hero {
    grid-template-columns: 1fr;
    padding-top: 100px;
    text-align: center;
  }

  .hero-buttons {
    justify-content: center;
  }

  .hero-image {
    order: -1;
  }

  .landing-nav {
    padding: 16px 24px;
  }

  .features, .cta {
    padding: 80px 24px;
  }
}