@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600&display=swap');

body {
  font-family: 'Inter', sans-serif;
  background: linear-gradient(to bottom right, #e0e7ff, #f3f4f6);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 20px;
  color: #1f2937;
}

h1 {
  font-size: 26px;
  margin-bottom: 16px;
  color: #1e293b;
  text-align: center;
}

.container {
  background: white;
  padding: 24px;
  border-radius: 18px;
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.08);
  max-width: 400px;
  width: 100%;
  margin-bottom: 40px;
  transition: 0.3s ease;
}

.container:hover {
  transform: translateY(-2px);
}

input[type="text"],
input[type="number"] {
  width: 92%;
  padding: 12px 14px;
  font-size: 18px;
  margin-bottom: 14px;
  border: 1px solid #d1d5db;
  border-radius: 10px;
  outline: none;
  background: #f9fafb;
  transition: border 0.2s ease;
}

input:focus {
  border-color: #3b82f6;
  background: #fff;
}

.calc-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 16px;
}

button {
  background-color: #000000cc;
  color: white;
  border: none;
  padding: 14px;
  font-size: 18px;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.1s ease;
}

button:hover {
  background-color: #000000;
  transform: scale(1.02);
}

button.clear {
  grid-column: span 4;
  background-color: #ef4444;
}

button.clear:hover {
  background-color: #dc2626;
}