:root {
  --color-primary: #007BFF;
  --color-secondary: #6C757D;
  --color-accent: #17A2B8;
  --color-neutral: #F8F9FA;
  --color-text: #212529;
  --color-background: #FFFFFF;
  --color-text-light: #FFFFFF;
  --color-success: #155724;
  --color-success-bg: #d4edda;
  --color-success-border: #c3e6cb;
  --color-danger: #721c24;
  --color-danger-bg: #f8d7da;
  --color-danger-border: #f5c6cb;
  --spacing-unit: 1rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.25rem;
  --font-size-sm: 0.875rem;
  --font-weight-normal: 400;
  --font-weight-bold: 700;
  --transition-speed: 0.3s;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  font-size: var(--font-size-base);
  color: var(--color-text);
  background-color: var(--color-background);
  margin: 0;
  padding: 0;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--spacing-unit);
  font-weight: var(--font-weight-bold);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1rem; }
h6 { font-size: 0.875rem; }

p, ul, ol {
  margin: 0 0 var(--spacing-unit);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-speed);
}

a:hover, a:focus {
  color: var(--color-accent);
  outline: none;
}

button {
  font-size: var(--font-size-base);
  padding: calc(var(--spacing-unit) / 2) var(--spacing-unit);
  color: var(--color-text-light);
  background-color: var(--color-primary);
  border: none;
  border-radius: 0.25rem;
  cursor: pointer;
  transition: background-color var(--transition-speed);
}

button:hover, button:focus {
  background-color: var(--color-accent);
  outline: none;
}

input, select, textarea {
  width: 100%;
  padding: var(--spacing-unit);
  margin-bottom: var(--spacing-unit);
  border: 1px solid var(--color-neutral);
  border-radius: 0.25rem;
  transition: border-color var(--transition-speed);
}

input:focus, select:focus, textarea:focus {
  border-color: var(--color-primary);
  outline: none;
}

.card {
  background-color: var(--color-neutral);
  padding: calc(var(--spacing-unit) * 2);
  border-radius: 0.5rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  margin-bottom: calc(var(--spacing-unit) * 2);
}

.alert {
  padding: var(--spacing-unit);
  margin-bottom: calc(var(--spacing-unit) * 2);
  border: 1px solid transparent;
  border-radius: 0.25rem;
}

.alert-success {
  color: var(--color-success);
  background-color: var(--color-success-bg);
  border-color: var(--color-success-border);
}

.alert-danger {
  color: var(--color-danger);
  background-color: var(--color-danger-bg);
  border-color: var(--color-danger-border);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: calc(var(--spacing-unit) * 2);
}

.flex {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.tooltip {
  position: relative;
  display: inline-block;
  cursor: pointer;
}

.tooltip .tooltiptext {
  visibility: hidden;
  width: 120px;
  background-color: var(--color-secondary);
  color: var(--color-text-light);
  text-align: center;
  border-radius: 0.25rem;
  padding: calc(var(--spacing-unit) / 2);
  position: absolute;
  z-index: 1;
  top: 100%;
  left: 50%;
  margin-left: -60px;
  opacity: 0;
  transition: opacity var(--transition-speed);
}

.tooltip:hover .tooltiptext, .tooltip:focus .tooltiptext {
  visibility: visible;
  opacity: 1;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition: none !important;
    animation: none !important;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-background: #2D2D2D;
    --color-text: #EAEAEA;
    --color-neutral: #3C3C3C;
  }
}

@media only screen and (max-width: 600px) {
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
  .card {
    padding: var(--spacing-unit);
  }
}

@media print {
  body {
    font-size: var(--font-size-sm);
    color: #000;
    background: none;
  }
  
  .card, .alert, button {
    box-shadow: none;
    background: none;
  }
}