/* Global variables */
:root {
  --primary-color: #3498db;
  --secondary-color: #2ecc71;
  --text-color: #2c3e50;
  --spacing-unit: 1rem;
  --border-radius: 4px;
}

/* Reset and base styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Arial', sans-serif;
  line-height: 1.6;
  color: var(--text-color);
}

/* Layout containers */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-unit);
}

/* Grid system */
.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--spacing-unit);
}

/* Flexbox components */
.flex-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Component styles */
.button {
  padding: calc(var(--spacing-unit) / 2) var(--spacing-unit);
  border-radius: var(--border-radius);
  border: none;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

.button:hover {
  opacity: 0.9;
}

.button--primary {
  background-color: var(--primary-color);
  color: white;
}

.button--secondary {
  background-color: var(--secondary-color);
  color: white;
}

/* Card component */
.card {
  border-radius: var(--border-radius);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  padding: var(--spacing-unit);
}

/* Media queries */
@media screen and (max-width: 768px) {
  .grid {
    grid-template-columns: repeat(6, 1fr);
  }
}

@media screen and (max-width: 480px) {
  .grid {
    grid-template-columns: 1fr;
  }
  
  .flex-container {
    flex-direction: column;
    gap: var(--spacing-unit);
  }
}

/* Animation keyframes */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.fade-in {
  animation: fadeIn 0.3s ease-in;
}

/* Form styles */
.form-group {
  margin-bottom: var(--spacing-unit);
}

.form-input {
  width: 100%;
  padding: calc(var(--spacing-unit) / 2);
  border: 1px solid #ddd;
  border-radius: var(--border-radius);
}

/* Navigation */
.nav {
  background-color: var(--primary-color);
  padding: var(--spacing-unit);
}

.nav__list {
  list-style: none;
  display: flex;
  gap: var(--spacing-unit);
}

.nav__link {
  color: white;
  text-decoration: none;
}

/* Utility classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }

.mt-1 { margin-top: var(--spacing-unit); }
.mb-1 { margin-bottom: var(--spacing-unit); }
.ml-1 { margin-left: var(--spacing-unit); }
.mr-1 { margin-right: var(--spacing-unit); }