* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #5b8def 0%, #2ac7d4 100%);
  display: flex;
  align-items: center;
  justify-content: center;
}

.container {
  width: min(500px, calc(100% - 2rem));
  background: rgba(255, 255, 255, 0.98);
  border-radius: 24px;
  padding: 2rem;
  box-shadow: 0 25px 60px rgba(28, 58, 106, 0.16);
  text-align: center;
}

h1 {
  margin: 0 0 1rem;
  font-size: 2rem;
  color: #1f3257;
}

input[type='number'] {
  width: 100%;
  padding: 1rem 1rem;
  margin: 0.5rem 0;
  border: 1px solid #d8e2ff;
  border-radius: 16px;
  font-size: 1rem;
  color: #1d2d50;
  background: #f8fbff;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input[type='number']:focus {
  outline: none;
  border-color: #5b8def;
  box-shadow: 0 0 0 4px rgba(91, 141, 239, 0.14);
}

.buttons {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.8rem;
  margin-top: 1rem;
}

button {
  padding: 1rem;
  background: #5b8def;
  border: none;
  border-radius: 16px;
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 16px 30px rgba(25, 64, 148, 0.18);
  transition: transform 0.2s ease, background-color 0.2s ease;
}

button:hover {
  transform: translateY(-1px);
  background: #3f76f4;
}

button:active {
  transform: translateY(0);
}

#result {
  margin-top: 1.5rem;
  min-height: 1.5rem;
  font-size: 1.25rem;
  color: #1b273f;
  font-weight: 600;
}

@media (max-width: 480px) {
  .buttons {
    grid-template-columns: 1fr 1fr;
  }
}