* {
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
  margin: 0;
  padding: 0;
}

body {
  background: linear-gradient(135deg, #667eea, #764ba2);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
}

#main {
  text-align: center;
  color: #fff;
}

h1 {
  margin-bottom: 20px;
  font-size: 2.5rem;
}

.container {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 20px;
  padding: 30px 20px;
  width: 320px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

input[type="text"] {
  width: 100%;
  height: 60px;
  margin-bottom: 20px;
  font-size: 2rem;
  text-align: right;
  padding: 10px 15px;
  border: none;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
  box-shadow: inset 0 0 5px rgba(255, 255, 255, 0.1);
}

input:focus {
  outline: none;
}

.row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 15px;
}

.button {
  flex: 1;
  margin: 5px;
  font-size: 1.5rem;
  padding: 15px 0;
  border: none;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.25);
  color: #fff;
  transition: all 0.2s ease;
  cursor: pointer;
}

.button:hover {
  background: rgba(255, 255, 255, 0.4);
  transform: scale(1.05);
}

.operator {
  background-color: rgba(255, 150, 80, 0.6);
}

.operator:hover {
  background-color: rgba(255, 150, 80, 0.8);
}

.equal {
  background-color: #00c896;
  color: white;
}

.equal:hover {
  background-color: #02b489;
}

.clear {
  background-color: #ff4f5a;
}

.clear:hover {
  background-color: #e63d47;
}

@media (max-width: 400px) {
  .container {
    width: 95%;
  }

  .button {
    font-size: 1.2rem;
    padding: 12px 0;
  }

  input[type="text"] {
    font-size: 1.5rem;
  }
}