html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
  width: 100%;
  overflow-x: hidden;
  background: #111;
  color: #fff;
  font-family: 'Helvetica Neue', sans-serif;
  text-align: center;
  box-sizing: border-box;
  min-width: 340px;
  -webkit-text-size-adjust: 100%;
}

@media screen and (max-width: 440px) {
  h2 {
    font-size: 18px;
  }

  #marathon-estimate {
    font-size: 16px;
  }
}

.card {
  background: #222;
  padding: 30px;
  border-radius: 20px;
  box-shadow: 0 0 10px #0f0;
  width: 90%;
  max-width: 600px;
  margin: 20px auto;
  box-sizing: border-box;
}

textarea,
input,
select {
  width: 98%;
  padding: 10px;
  font-size: 1.1em;
  margin: 10px auto;
  border-radius: 10px;
  border: none;
  display: block;
  box-sizing: border-box;
}

button {
  width: 98%;
  padding: 10px;
  font-size: 1.1em;
  margin: 10px auto;
  border-radius: 10px;
  border: none;
  display: block;
  background: #0f0;
  color: #000;
  cursor: pointer;
  box-sizing: border-box;
}

.accordion-section {
  margin-top: 2em;
}

.accordion-box {
  background-color: #333;
  padding: 15px;
  border-radius: 12px;
  box-shadow: inset 0 0 5px #555;
  width: 100%;
  box-sizing: border-box;
}

.accordion-toggle {
  background-color: #111;
  color: #0f0;
  border: none;
  padding: 10px 15px;
  font-size: 1em;
  cursor: pointer;
  width: 100%;
  text-align: left;
  box-sizing: border-box;
}

.accordion-content {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.5s ease;
  width: 100%;
  box-sizing: border-box;
}

.accordion-content.open {
  max-height: 1000px;
}

.canvas-container {
  width: 100%;
  max-width: 100%;
  box-sizing: border-box;
  margin-top: 20px;
}

canvas {
  width: 100% !important;
  height: auto !important;
  background-color: #000;
  border-radius: 10px;
  box-sizing: border-box;
}

@media screen and (max-width: 480px) {
  .card {
    padding: 20px;
  }

  textarea,
  input,
  select,
  button {
    font-size: 1em;
    padding: 8px;
  }

  .accordion-toggle {
    font-size: 0.95em;
    padding: 8px 12px;
  }
}

footer {
  position: sticky;
  top: 100%;
  text-align: center;
  padding: 1.5rem;
  font-size: 20px;
}

footer a {
  color: #ccc;
  transition: 0.3s;
  font-family: Arial, sans-serif;
}

footer a:hover {
  opacity: 0.7;
}