* { 
  box-sizing: border-box; 
}

body {
  font-family: 'Sarabun', sans-serif;
  background: linear-gradient(135deg, #0066cc, #0052a3);
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  color: #2c3e50;
}

.signup-container {
  background: white;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.2);
  width: 100%;
  max-width: 400px;
}

.logo-section {
  text-align: center;
  margin-bottom: 32px;
}

.logo-section img {
  height: 60px;
  object-fit: contain;
}

.logo-section a {
  display: inline-block;
  transition: transform 0.25s ease;
}

.logo-section a:hover {
  transform: scale(1.05);
}

.signup-container h1 {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin: 20px 0 8px 0;
  color: #2c3e50;
}

.signup-container p {
  text-align: center;
  color: #666;
  margin: 0 0 32px 0;
  font-size: 14px;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  margin-bottom: 6px;
  font-weight: 600;
  color: #2c3e50;
  font-size: 14px;
}

.form-group input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid #d1d5db;
  border-radius: 8px;
  font-family: 'Sarabun', sans-serif;
  font-size: 14px;
  transition: all 0.25s;
}

.form-group input:focus {
  outline: none;
  border-color: #0066cc;
  box-shadow: 0 0 0 3px rgba(0,102,204,0.15);
}

.btn-signup {
  width: 100%;
  padding: 12px;
  background: #0066cc;
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  font-family: 'Sarabun', sans-serif;
  font-size: 16px;
  transition: all 0.25s;
  margin-top: 8px;
}

.btn-signup:hover {
  background: #0052a3;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3);
}

.btn-signup:disabled {
  background: #a0aec0;
  cursor: not-allowed;
  transform: none;
}

.divider {
  text-align: center;
  margin: 20px 0;
  color: #999;
  font-size: 14px;
}

.btn-login {
  width: 100%;
  padding: 12px;
  background: white;
  color: #0066cc;
  border: 2px solid #0066cc;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  font-family: 'Sarabun', sans-serif;
  font-size: 16px;
  transition: all 0.25s;
  text-decoration: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-login:hover {
  background: #f0f4f8;
  transform: translateY(-2px);
}

.btn-login:active {
  transform: scale(0.98);
}

.btn-google {
  width: 100%;
  padding: 12px;
  background: white;
  color: #757575;
  border: 1px solid #ddd;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  font-family: 'Sarabun', sans-serif;
  font-size: 16px;
  transition: all 0.25s;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.btn-google:hover {
  background: #f1f1f1;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.btn-google:disabled {
  background: #f5f5f5;
  color: #ccc;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-line {
  margin-bottom: 20px;
  width: 100%;
  padding: 12px;
  background: #00B900;
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  font-family: 'Sarabun', sans-serif;
  font-size: 16px;
  transition: all 0.25s;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.btn-line:hover {
  background: #009900;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 185, 0, 0.3);
}

.btn-line:disabled {
  background: #a0aec0;
  cursor: not-allowed;
  transform: none;
}

.error-message {
  color: #ef4444;
  font-size: 14px;
  margin-bottom: 16px;
  padding: 12px;
  background: #fee2e2;
  border-radius: 6px;
  display: none;
  border-left: 4px solid #ef4444;
  animation: slideDown 0.3s ease-out;
}

.error-message.show {
  display: block;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.back-link {
  text-align: center;
  margin-top: 16px;
}

.back-link a {
  color: #0066cc;
  text-decoration: none;
  font-weight: 600;
  font-size: 14px;
  transition: all 0.25s;
}

.back-link a:hover {
  text-decoration: underline;
  color: #0052a3;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 480px) {
  body {
    padding: 20px;
  }

  .signup-container {
    padding: 24px;
    border-radius: 8px;
  }

  .signup-container h1 {
    font-size: 24px;
  }

  .form-group {
    margin-bottom: 14px;
  }

  .form-group input {
    font-size: 16px; /* Prevents zoom on mobile */
  }

  .btn-signup,
  .btn-login {
    padding: 11px;
    font-size: 15px;
  }
}