:root {
  --color-bg: linear-gradient(135deg, #dbeafe, #bae6fd, #60a5fa);
  --color-text: #111827;
  --color-heading: #0f172a;
  --color-button-bg: #0f172a;
  --color-button-hover: #2563eb;
  --color-button-text: #ffffff;
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  background: var(--color-bg);
  font-family: var(--font-sans);
  color: var(--color-text);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 1rem;
}

.container {
  background: #ffffffdd;
  max-width: 400px;
  width: 100%;
  padding: 2.5rem 2rem;
  border-radius: 1rem;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  animation: fadeInUp 1s ease forwards;
  opacity: 0;
  transform: translateY(30px);
}

h1 {
  font-size: 2.8rem;
  margin-bottom: 1.5rem;
  color: var(--color-heading);
}

form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

label {
  font-weight: 600;
  text-align: left;
  color: var(--color-heading);
  user-select: none;
}

input[type="text"],
input[type="password"] {
  padding: 0.75rem 1rem;
  font-size: 1.1rem;
  border-radius: 0.5rem;
  border: 2px solid #93c5fd;
  outline-offset: 2px;
  transition: border-color 0.3s ease;
}

input[type="text"]:focus,
input[type="password"]:focus {
  border-color: var(--color-button-hover);
  outline: none;
}

button {
  margin-top: 1rem;
  padding: 1rem;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-button-text);
  background-color: var(--color-button-bg);
  border: none;
  border-radius: 0.75rem;
  cursor: pointer;
  transition: background-color 0.3s ease, transform 0.2s ease;
}

button:hover,
button:focus {
  background-color: var(--color-button-hover);
  transform: scale(1.05);
  outline: none;
}

.register-link {
  margin-top: 1.5rem;
  font-size: 1rem;
  color: var(--color-heading);
}

.register-link a {
  color: var(--color-button-hover);
  text-decoration: none;
  font-weight: 600;
  transition: color 0.3s ease;
}

.register-link a:hover,
.register-link a:focus {
  color: var(--color-button-bg);
  outline: none;
}

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 480px) {
  .container {
    padding: 2rem 1.5rem;
  }
  h1 {
    font-size: 2.2rem;
  }
  input[type="text"],
  input[type="password"] {
    font-size: 1rem;
  }
  button {
    font-size: 1.1rem;
  }
}