body {
  font-family: 'Roboto', sans-serif;
  margin: 0;
  padding: 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  color: #333;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  background-color: white;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 15px 35px rgba(0,0,0,0.1);
  backdrop-filter: blur(10px);
}

h1 {
  color: #4a90e2;
  text-align: center;
  margin-bottom: 30px;
  font-weight: 300;
}

h2 {
  color: #5a5a5a;
  border-bottom: 2px solid #4a90e2;
  padding-bottom: 10px;
}

form {
  margin-bottom: 30px;
}

label {
  display: block;
  margin-top: 15px;
  font-weight: 500;
  color: #555;
}

input, select {
  width: 100%;
  padding: 12px;
  margin-top: 5px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  box-sizing: border-box;
  transition: border-color 0.3s ease;
}

input[type="file"] {
  padding: 8px;
}

input:focus, select:focus {
  outline: none;
  border-color: #4a90e2;
}

button {
  background: linear-gradient(45deg, #4a90e2, #5cb85c);
  color: white;
  padding: 12px 20px;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  margin-top: 15px;
  font-weight: 500;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(74, 144, 226, 0.4);
}

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

.transaction {
  border: 1px solid #e0e0e0;
  padding: 20px;
  margin-bottom: 15px;
  border-radius: 10px;
  background-color: #fafafa;
  position: relative;
}

.transaction input {
  width: calc(100% - 24px);
}

.items-list {
  margin-bottom: 10px;
}

.item {
  display: flex;
  align-items: center;
  margin-bottom: 5px;
}

.item input {
  flex: 1;
  margin: 0 5px;
}

.item label {
  width: 50px;
  margin: 0;
}

.remove-item {
  background: #e74c3c;
  color: white;
  border: none;
  border-radius: 4px;
  padding: 5px 10px;
  cursor: pointer;
}

.remove-item:hover {
  background: #c0392b;
}

.remove-transaction {
  position: absolute;
  top: 10px;
  right: 10px;
  background: #e74c3c;
  color: white;
  border: none;
  border-radius: 50%;
  width: 30px;
  height: 30px;
  cursor: pointer;
  font-size: 18px;
}

.remove-transaction:hover {
  background: #c0392b;
}

#invoice-display {
  margin-top: 30px;
  padding: 30px;
  border: 1px solid #e0e0e0;
  border-radius: 10px;
  background-color: #fafafa;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

#invoice-content table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 20px;
}

#invoice-content th, #invoice-content td {
  padding: 12px;
  text-align: left;
  border-bottom: 1px solid #ddd;
}

#invoice-content th {
  background-color: #4a90e2;
  color: white;
}

#invoice-content img {
  margin: 10px 0;
  border-radius: 5px;
}

#invoice-content tr:hover {
  background-color: #f1f1f1;
}

@media (max-width: 768px) {
  body {
    padding: 10px;
  }

  .container {
    padding: 20px;
  }

  h1 {
    font-size: 24px;
  }

  h2 {
    font-size: 18px;
  }

  button {
    padding: 10px 15px;
    font-size: 14px;
  }

  input, select {
    padding: 10px;
  }

  .transaction {
    padding: 15px;
  }

  .item {
    flex-wrap: wrap;
  }

  .item label {
    width: 100%;
    margin-bottom: 5px;
  }

  .item input {
    flex: 1 1 100%;
    margin: 0;
  }

  #invoice-display {
    padding: 20px;
  }

  #invoice-content table {
    font-size: 14px;
  }

  #invoice-content th, #invoice-content td {
    padding: 8px;
  }

  #invoice-content table {
    overflow-x: auto;
    display: block;
    white-space: nowrap;
  }
}

@media print {
  body {
    background: white !important;
  }
  .container {
    display: none;
  }
  #invoice-display {
    display: block !important;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    box-shadow: none;
  }
  button {
    display: none;
  }
}