*, *::before, *::after {
  box-sizing: border-box;
}

body {
  font-family: system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  background: #f9fafb;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  padding: 20px;
}

.heatmap-card {
  background: #ffffff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  overflow-x: auto;
}

.heatmap-card h3 {
  margin-top: 0;
  margin-bottom: 20px;
  color: #111827;
  font-size: 1.125rem;
}

.heatmap-grid {
  display: grid;
  grid-auto-flow: column;
  grid-template-rows: repeat(7, 1fr);
  gap: 4px;
}

.heat-box, .legend-box {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  background-color: #ebedf0;
}

.level-1 { background-color: #9be9a8; }
.level-2 { background-color: #40c463; }
.level-3 { background-color: #30a14e; }
.level-4 { background-color: #216e39; }

.heatmap-legend {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
  margin-top: 20px;
  font-size: 0.875rem;
  color: #6b7280;
}

const grid = document.getElementById("heatmap-grid");

for (let i = 0; i < 365; i++) {
  const box = document.createElement("div");
  box.className = "heat-box";
  
  const randomValue = Math.random();
  
  if (randomValue > 0.9) {
    box.classList.add("level-4");
  } else if (randomValue > 0.7) {
    box.classList.add("level-3");
  } else if (randomValue > 0.4) {
    box.classList.add("level-2");
  } else if (randomValue > 0.2) {
    box.classList.add("level-1");
  }
  
  grid.appendChild(box);
}