.converter-shell { padding-bottom: 54px; }

.converter-heading {
  display: grid;
  grid-template-columns: 1fr .8fr;
  align-items: end;
  gap: 48px;
  padding: 42px 0 34px;
}

.converter-heading h1 { font-size: clamp(2.35rem, 4vw, 3.6rem); }
.converter-heading > p { max-width: 400px; margin: 0 0 4px; color: var(--muted); font-size: .94rem; line-height: 1.55; }

.converter-panel {
  padding: clamp(20px, 3.5vw, 36px);
  border: 1px solid var(--line);
  background: rgba(13, 25, 35, .88);
  box-shadow: 0 28px 80px rgba(0, 0, 0, .28);
}

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.field { display: grid; gap: 10px; min-width: 0; }
.field > span { color: var(--muted); font-size: .66rem; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }

select, input, output {
  width: 100%;
  border: 0;
  border-bottom: 1px solid rgba(255, 255, 255, .2);
  border-radius: 0;
  color: var(--text);
  background: transparent;
  font: inherit;
}

select { padding: 10px 34px 10px 0; cursor: pointer; color-scheme: dark; }
select option { color: var(--text); background: #0d1923; }
input { min-height: 54px; padding: 6px 0; font-size: clamp(1.75rem, 3.5vw, 2.7rem); font-weight: 650; letter-spacing: -.035em; outline: none; }
input:focus, select:focus { border-color: var(--accent); outline: none; }
input[aria-invalid="true"] { border-color: #ff6e6e; }
output { display: flex; align-items: center; min-height: 54px; padding: 6px 0; overflow-wrap: anywhere; color: var(--accent); font-size: clamp(1.75rem, 3.5vw, 2.7rem); font-weight: 650; letter-spacing: -.035em; }

.category-field { max-width: 330px; margin-bottom: 32px; }
.category-field select { font-size: 1rem; font-weight: 700; }
.conversion-grid { display: grid; grid-template-columns: minmax(0, 1fr) 42px minmax(0, 1fr); align-items: center; gap: clamp(14px, 2.5vw, 28px); }
.unit-side { display: grid; gap: 20px; min-width: 0; }
.unit-field select { font-size: .92rem; }

.swap {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--accent);
  background: #071018;
  font-size: 1.2rem;
  cursor: pointer;
  transition: transform .2s, border-color .2s;
}
.swap:hover { border-color: var(--accent); transform: rotate(180deg); }
.swap:focus-visible, .copy-button:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

.converter-footer { display: flex; justify-content: space-between; align-items: center; gap: 18px; margin-top: 26px; padding-top: 18px; border-top: 1px solid var(--line); }
.hint { margin: 0; color: var(--muted); font-size: .85rem; }
.copy-button { padding: 8px 12px; border: 1px solid var(--line); color: var(--text); background: transparent; font: inherit; font-size: .82rem; cursor: pointer; }
.copy-button:hover { border-color: var(--accent); }
.equivalence { min-height: 1.5em; margin: 20px 0 0; color: #c5d1d7; font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: .8rem; text-align: center; }
.precision-note { display: flex; gap: 20px; max-width: 610px; margin: 24px 0 0 auto; color: var(--muted); font-size: .76rem; line-height: 1.5; }
.precision-note span { color: var(--accent); font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.precision-note p { margin: 0; }

@media (max-width: 760px) {
  .converter-heading { grid-template-columns: 1fr; gap: 18px; padding: 36px 0 28px; }
  .conversion-grid { grid-template-columns: 1fr; }
  .swap { justify-self: center; transform: rotate(90deg); }
  .swap:hover { transform: rotate(270deg); }
  .category-field { max-width: none; margin-bottom: 40px; }
  .converter-footer { align-items: flex-start; flex-direction: column; }
  .copy-button { width: 100%; }
  .precision-note { flex-direction: column; gap: 8px; }
}