* {
    margin: 0;
    padding: 0;
}
body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f8f9fb;
  color: #333;
}

header {
  padding: 60px 20px;
  text-align: center;
  background: #4f46e5;
  color: white;
}

header h1 {
  margin-bottom: 10px;
}

.actions {
  margin-top: 20px;
}

.btn, button, #fileInput, select {
  padding: 12px 20px;
  text-decoration: none;
  border-radius: 6px;
  margin: 5px;
  display: inline-block;
}

.primary {
  background: white;
  color: #4f46e5;
  font-weight: bold;
}

.secondary {
  border: 2px solid white;
  color: white;
}

section {
  padding: 40px 20px;
  max-width: 1000px;
  margin: auto;
}

.table-container {
  max-height: 250px;
  overflow: auto;
  border: 1px solid #ccc;
  background: white;
}

table {
  border-collapse: collapse;
  width: 100%;
}

th, td {
  border: 1px solid #ddd;
  padding: 6px;
  font-size: 14px;
}

td {
  min-width: 80px;
}

.controls {
  margin: 15px 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

canvas {
  width: 100% !important;
  height: auto !important;
  background: white;
  margin-top: 15px;
}

.chart-wrapper {
  width: 100%;
  max-width: 900px;
  margin: 20px auto;
  aspect-ratio: 16 / 9;   /* 👈 key */
}


footer {
  text-align: center;
  padding: 20px;
  background: #eee;
  margin-top: 40px;
}


/* ---------- MOBILE TWEAKS ---------- */
@media (max-width: 768px) {

  header {
    padding: 40px 15px;
  }

  header h1 {
    font-size: 28px;
  }

  header p {
    font-size: 16px;
  }

  .actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
  }

  .btn {
    width: 90%;
    text-align: center;
  }

  section {
    padding: 25px 15px;
  }

  /* Table handling */
  .table-container {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  table {
    min-width: 600px; /* important */
    font-size: 13px;
  }

  th, td {
    padding: 6px;
    white-space: nowrap;
  }

  /* Controls stack */
  .controls {
    flex-direction: column;
  }

  .controls select,
  .controls button {
    width: 100%;
    font-size: 16px;
    padding: 10px;
  }

  /* Chart */
  canvas {
    height: 260px !important;
  }

  #download {
    width: 100%;
    padding: 12px;
    font-size: 16px;
  }
}