body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #0d1117, #1f2430);
  color: #e0e0e0;
  margin: 0;
  padding: 0;
  line-height: 1.6;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

header {
  background: #161b22;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.8);
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  flex-wrap: wrap;
  padding: 0.5rem 1rem;
}

.logo {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  user-select: none;
}

.logo1 {
  color: #275b97;
}

.logo2 {
  color: #58a6ff;
}

nav {
  display: flex;
  gap: 1.8rem;
}

nav a {
  color: #8b949e;
  text-decoration: none;
  font-weight: 600;
  transition: color 0.25s ease;
  font-size: 1rem;
}

nav a:hover,
nav a:focus {
  color: #58a6ff;
}

main.main-content {
  background: #21262d;
  margin-top: 3rem;
  padding: 2rem 3rem;
  border-radius: 12px;
  box-shadow: 0 0 15px #2384f6aa;
}

h1 {
  font-size: 2.8rem;
  font-weight: 700;
  margin-bottom: 0.3rem;
  color: #58a6ff;
}

#hero p {
  font-size: 1.2rem;
  margin-bottom: 2.5rem;
  color: #a5b8ffcc;
}

h2 {
  color: #79c0ff;
  margin-bottom: 1rem;
  border-bottom: 2px solid #2384f6;
  padding-bottom: 0.25rem;
}

ul {
  padding-left: 1.3rem;
  margin-bottom: 2rem;
  color: #adbac7;
}

form label {
  display: block;
  margin-top: 1.2rem;
  font-weight: 600;
  color: #a5b8ff;
}

form input,
form select,
form button,
form input[type="range"] {
  width: 100%;
  padding: 0.75rem;
  margin-top: 0.3rem;
  margin-bottom: 1rem;
  border-radius: 8px;
  border: none;
  font-size: 1rem;
  background: #2f363d;
  color: #e0e0e0;
  box-shadow: inset 0 0 6px #2384f6;
  transition: background 0.3s ease;
}

form input::placeholder,
form select::placeholder {
  color: #8b949e;
}

form select {
  color: #8b949e;
}

form input:focus,
form select:focus {
  outline: none;
  background: #1f2630;
  box-shadow: 0 0 12px #2384f6;
}

form button {
  background-color: #2384f6;
  color: white;
  font-weight: 700;
  cursor: pointer;
  border-radius: 10px;
  border: none;
  padding: 0.9rem 0;
  transition: background-color 0.3s ease;
}

form button:hover {
  background-color: #1c6de0;
}

#signup-message {
  font-weight: 600;
  color: #f87171;
  text-align: center;
  margin-top: 0.5rem;
}

#confidence-label {
  color: #a5b8ff;
  font-weight: 500;
}

footer {
  margin-top: 4rem;
  background: #161b22;
  padding: 1.5rem 0;
  user-select: none;
}

.footer-content {
  text-align: center;
  color: #8b949e;
  font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    align-items: flex-start;
    height: auto;
  }

  nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
    width: 100%;
    margin-top: 0.5rem;
  }

  main.main-content {
    padding: 1.5rem 1.2rem;
    margin: 1.5rem 1rem;
  }

  h1 {
    font-size: 2rem;
  }

  #hero p {
    font-size: 1rem;
  }

  .container {
    padding: 0 1rem;
  }
}