.main-layout {
  display: grid;
  grid-template-columns: minmax(260px, calc(50vw - 24px)) minmax(420px, calc(50vw - 24px));
  align-items: flex-start;
  gap: 24px;
  box-sizing: border-box;
  margin: 0 auto;
  padding: 0 32px 0 12px;
}
.main-controls {
  min-width: 260px;
  width: 100%;
  max-width: none;
  text-align: center;
  align-self: flex-start;
  position: sticky;
  top: 16px;
  padding: 0 12px;
  box-sizing: border-box;
}
.howto-box {
  background:#ffffff;
  flex: 2 1 420px;
  min-width: 0;
  border: 1px solid #ccc;
  border-radius: 8px;
  padding: 12px 64px;
  margin: 0;
  text-align: left;
  max-width: 960px;
}

.howto-box h2 {
  margin-top: 0;
  text-align: center;
}

body > h2 {
  margin-bottom: 2em;
}

p.warning {
  color: red;
}
p.error {
  color: red;
  font-weight: bold;
}
#status.warning,
#status.error {
  color: red;
  font-weight: bold;
  white-space: pre-line;
}
#status.warning,
#status.error {
  color: red;
  font-weight: bold;
}
label.radio {
  display: inline;
}
input:invalid {
  color: red;
}
body {
  text-align: center;
  max-width: none;
}
#configForm {
  text-align: center;
}
#configForm p {
  text-align: center;
}
#firmwareList {
  text-align: center;
}
#firmwareList ul {
  list-style: none;
  padding: 0;
  margin: 0 auto;
  display: inline-block;
  text-align: center;
}
#firmwareList li {
  margin: 0;
}
button {
  margin: 5px;
  background: #0046AF;
  color: #ffffff;
  border: 1px solid #003a8c;
  border-radius: 6px;
  padding: 0.7em 1.2em;
  cursor: pointer;
  transition: background-color 150ms ease, transform 150ms ease, border-color 150ms ease;
}

button:hover,
button:focus-visible {
  background: #002053;
  border-color: #002f70;
}

button:active {
  background: #002f70;
}

/* Driver install callout (Windows only) */
.driver-install {
  position: relative;
  display: inline-block;
  color: #0b5fff;
  cursor: help;
  line-height: 1.6;
  text-decoration: none;
}
.driver-install:hover,
.driver-install:focus-within {
  outline: 2px solid #0b5fff;
  outline-offset: 2px;
  border-radius: 6px;
}
.driver-install__tooltip {
  position: absolute;
  left: 50%;
  top: 100%;
  transform: translateX(-50%);
  width: min(520px, 92vw);
  text-align: left;
  padding: 10px 12px;
  background: #ffffff;
  color: #1b1b1b;
  border: 1px solid rgba(0, 0, 0, 0.14);
  border-radius: 10px;
  box-shadow: 0 18px 50px rgba(0, 0, 0, 0.18);
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 140ms ease, transform 140ms ease, visibility 140ms ease;
}
.driver-install:hover .driver-install__tooltip,
.driver-install:focus-within .driver-install__tooltip,
.driver-install__tooltip:hover {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
  pointer-events: auto;
}
.driver-install__tooltip b {
  display: inline-block;
  margin-bottom: 6px;
}
.driver-install__tooltip ol {
  margin: 6px 0 0 18px;
}
.driver-install__tooltip li {
  margin: 2px 0;
}

@media (max-width: 920px) {
  .main-layout {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
  }

  .main-controls,
  .howto-box {
    width: 100%;
    max-width: 100%;
  }

  .main-controls {
    position: static;
    top: auto;
  }
}