.difference-card {
  position: relative;
  background: var(--white);
  color: var(--ink);
  border-color: var(--ink);
}

.difference-card::before {
  content: "";
  position: absolute;
  inset: -1px -1px auto;
  height: 4px;
  background: linear-gradient(90deg, var(--body), var(--warm), var(--accent));
}

.intro h1 {
  max-width: 760px;
  font-size: clamp(2.4rem, 4.4vw, 4rem);
  line-height: .96;
  letter-spacing: -.055em;
}

.difference-card .section-heading {
  margin-bottom: 28px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.difference-inputs label > div,
.primary-result,
.result-grid,
.result-item {
  border-color: var(--line);
}

.primary-result button,
.result-item > button {
  background: var(--paper);
  color: var(--ink);
  border-color: var(--line);
}

.lambda-label {
  display: flex !important;
  align-items: baseline;
  gap: 7px;
}

.lambda-label i {
  display: inline;
  margin: 0;
  font: italic .9rem Georgia, serif;
  letter-spacing: 0;
  text-transform: none;
  white-space: nowrap;
}

.lambda-label sub {
  font-size: .7em;
}

.physics-note {
  color: var(--body);
  opacity: 1;
}

.physics-note .note-label {
  display: inline-block;
  margin-right: 10px;
  padding: 0 !important;
  background: transparent !important;
  color: var(--accent);
  font-size: .66rem;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.inline-equation {
  font: italic .9rem Georgia, serif;
  color: var(--ink);
  white-space: nowrap;
}

.inline-equation sub {
  font-size: .7em;
}

@media (max-width: 850px) {
  .result-item:nth-child(3n) {
    border-right-color: var(--line);
  }
}

@media (max-width: 620px) {
  .intro h1 {
    font-size: clamp(2.2rem, 9vw, 3rem);
  }

  .difference-card .section-heading {
    margin-bottom: 22px;
    padding-bottom: 18px;
  }

  .result-item,
  .result-item:nth-child(3n) {
    border-bottom-color: var(--line);
  }
}