:root {
  --bg-color: #f4f6f8;
  --text-color: #333;
  --card-bg: #fff;
  --border-color: #ddd;
  --table-header: #ecf0f1;
  --button-bg: #3498db;
  --button-hover: #2980b9;
  --danger-bg: #e74c3c;
  --danger-hover: #c0392b;
}

body.dark {
  --bg-color: #1e1e1e;
  --text-color: #f1f1f1;
  --card-bg: #2c2c2c;
  --border-color: #444;
  --table-header: #333;
  --button-bg: #2980b9;
  --button-hover: #1c6ca1;
  --danger-bg: #c0392b;
  --danger-hover: #992d22;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-color);
  margin: 0;
  padding: 20px;
  color: var(--text-color);
  transition: background 0.3s, color 0.3s;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  background: var(--card-bg);
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
  transition: background 0.3s;
  position: relative;
}

h2 {
  text-align: left;
}

h3 {
  text-align: center;
}

form {
  display: flex;
  justify-content: center;
  gap: 15px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

input[type="text"],
input[type="number"] {
  padding: 10px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 16px;
  background-color: transparent;
  color: var(--text-color);
}

select {
  padding: 10px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 16px;
  background-color: transparent;
  color: var(--text-color);
}

button {
  padding: 10px 16px;
  border: none;
  border-radius: 8px;
  background-color: var(--button-bg);
  color: white;
  font-weight: bold;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

button:hover {
  background-color: var(--button-hover);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 10px;
}

th, td {
  padding: 12px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

th {
  background-color: var(--table-header);
}

canvas {
  max-width: 100%;
  margin: 30px auto;
  display: block;
}

.button-group button {
  margin: 0 5px;
  background-color: var(--danger-bg);
}

.button-group button:hover {
  background-color: var(--danger-hover);
}

.theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.theme-toggle label {
  font-size: 14px;
  color: var(--text-color);
}

.theme-toggle input[type="checkbox"] {
  transform: scale(1.3);
}

@media (max-width: 600px) {
  form {
    flex-direction: column;
    align-items: stretch;
  }
  .theme-toggle {
    top: 10px;
    right: 10px;
  }
}