body {
  font-family: 'Segoe UI', Arial, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  margin: 0;
  padding: 20px;
  min-height: 100vh;
}

.container {
  max-width: 500px;
  margin: 20px auto;
  background: rgba(255, 255, 255, 0.95);
  border-radius: 20px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.1);
  padding: 40px 30px;
  backdrop-filter: blur(10px);
}

h1 {
  text-align: center;
  color: #2d3436;
  margin-bottom: 30px;
  font-size: 2.2rem;
  font-weight: 600;
}

.category-tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 30px;
  flex-wrap: wrap;
}

.tab-btn {
  padding: 8px 16px;
  border: none;
  border-radius: 20px;
  background: #f1f2f6;
  color: #57606f;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 500;
  font-size: 0.9rem;
}

.tab-btn.active {
  background: #5f27cd;
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(95, 39, 205, 0.3);
}

.tab-btn:hover {
  transform: translateY(-1px);
}

.converter {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 30px;
}

.input-group {
  display: flex;
  gap: 15px;
  align-items: center;
}

.arrow {
  text-align: center;
  font-size: 2rem;
  color: #5f27cd;
  font-weight: bold;
}

input[type="number"] {
  flex: 1;
  padding: 15px;
  border: 2px solid #e9ecef;
  border-radius: 12px;
  font-size: 1.1rem;
  transition: border-color 0.3s ease;
}

input[type="number"]:focus {
  border-color: #5f27cd;
  outline: none;
  box-shadow: 0 0 0 3px rgba(95, 39, 205, 0.1);
}

input[readonly] {
  background: #f8f9fa;
  color: #495057;
}

select {
  flex: 1;
  padding: 15px;
  border: 2px solid #e9ecef;
  border-radius: 12px;
  font-size: 1.1rem;
  background: white;
  cursor: pointer;
  transition: border-color 0.3s ease;
}

select:focus {
  border-color: #5f27cd;
  outline: none;
  box-shadow: 0 0 0 3px rgba(95, 39, 205, 0.1);
}

.quick-convert {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.quick-btn {
  padding: 8px 16px;
  background: linear-gradient(45deg, #ff6b6b, #ee5a24);
  color: white;
  border: none;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 0.9rem;
  font-weight: 500;
}

.quick-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(255, 107, 107, 0.3);
}

#result {
  text-align: center;
  font-size: 1.3rem;
  color: #2d3436;
  min-height: 40px;
  padding: 15px;
  background: linear-gradient(45deg, #f8f9fa, #e9ecef);
  border-radius: 12px;
  font-weight: 600;
}

@media (max-width: 600px) {
  .container {
    margin: 10px;
    padding: 30px 20px;
  }
  
  .input-group {
    flex-direction: column;
  }
  
  .converter {
    gap: 15px;
  }
  
  .arrow {
    transform: rotate(90deg);
  }
}