/* color variables */
:root {
  --bg-color: #1a1f35;
  --text-dark: #2d3748;
  --text-medium: #4a5568;
  --text-light: #cbd5e0;
  --list-bg: #2d3748;
  --list-hover: #4a5568;
  --card-bg: #f7fafc;
  --accent: #3b82f6;
}

/* reset */
* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

/* body */
body {
  font-family: sans-serif;
  background-color: var(--bg-color);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

/* container */
.container {
  text-align: center;
  width: 100%;
  padding: 1.2rem;
}

/* heading */
h1 {
  color: var(--text-light);
  margin-bottom: 20px;
  font-size: 2rem;
  letter-spacing: 2px;
}

/* board */
.board {
  display: flex;
  justify-content: space-around;
  align-items: flex-start;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  gap: 20px;
}

/* lists */
.list {
  background-color: var(--list-bg);
  padding: 1rem;
  border-radius: 8px;
  width: 30%;
  min-height: 400px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.4);
}

.list h2 {
  color: var(--text-light);
  margin-bottom: 1rem;
  font-size: 1.5rem;
}

.list.over {
  background-color: var(--list-hover);
}

/* cards */
.card {
  background-color: var(--card-bg);
  color: var(--text-dark);
  padding: 1rem;
  margin-bottom: 10px;
  border-radius: 8px;
  cursor: grab;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:active {
  cursor: grabbing;
  transform: scale(1.05);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

/* responsive design */
@media (max-width: 768px) {
  .board {
    flex-direction: column;
    align-items: center;
  }

  .list {
    width: 80%;
    margin-bottom: 20px;
  }
}