body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  margin: 0;
  padding: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.container {
  background-color: white;
  border-radius: 12px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
  padding: 24px;
  width: 100%;
  max-width: 400px;
}

h1 {
  text-align: center;
  color: #1a1a1a;
  margin-bottom: 24px;
  font-size: 1.75rem;
}

.converter {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

select,
input,
button {
  width: 100%;
  padding: 12px;
  border: 1.5px solid #e2e8f0;
  border-radius: 8px;
  font-size: 16px;
  transition: all 0.2s ease;
}

select:hover,
input:hover {
  border-color: #cbd5e1;
}

select:focus,
input:focus {
  outline: none;
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.input-group {
  display: flex;
  gap: 12px;
}

.input-group input {
  flex: 2;
}

.input-group select {
  flex: 1.5;
}

button {
  background-color: #3b82f6;
  color: white;
  border: none;
  cursor: pointer;
  font-weight: 600;
  transition: background-color 0.2s ease;
}

button:hover {
  background-color: #2563eb;
}

button:active {
  transform: translateY(1px);
}

input[readonly] {
  background-color: #f8fafc;
  cursor: default;
}

@media (max-width: 480px) {
  .container {
    margin: 16px;
    padding: 16px;
  }

  .input-group {
    flex-direction: column;
  }

  .input-group input,
  .input-group select {
    width: 100%;
  }
}