:root {
  --bg: #111318;
  --card: #1a1d24;
  --card-soft: #20242d;
  --text: #f3f4f6;
  --muted: #a8b0bf;
  --border: #343a46;
  --accent: #7dd3fc;
  --accent-strong: #38bdf8;
  --danger: #f87171;
  --radius: 1rem;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top, #1f2937 0, transparent 32rem),
    var(--bg);
  color: var(--text);
}

.app-shell {
  width: min(100% - 2rem, 760px);
  margin: 0 auto;
  padding: 3rem 0;
}

.card {
  background: color-mix(in srgb, var(--card) 94%, black);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(1.25rem, 3vw, 2rem);
  box-shadow: 0 1.5rem 4rem rgba(0, 0, 0, 0.35);
}

.card + .card {
  margin-top: 1.25rem;
}

.app-header {
  margin-bottom: 1.5rem;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0.5rem;
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  line-height: 1.1;
}

h2 {
  margin-bottom: 1rem;
  font-size: 1.25rem;
}

.app-header p,
.muted {
  color: var(--muted);
}

.form-grid,
.converter-grid {
  display: grid;
  gap: 1rem;
}

.field {
  display: grid;
  gap: 0.4rem;
}

label {
  color: var(--muted);
  font-size: 0.95rem;
}

input,
select,
button {
  font: inherit;
}

input,
select {
  width: 100%;
  color: var(--text);
  background: var(--card-soft);
  border: 1px solid var(--border);
  border-radius: 0.7rem;
  padding: 0.8rem 0.9rem;
}

input:focus,
select:focus,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.inline-control,
.speed-control,
.number-control {
  display: grid;
  gap: 0.5rem;
}
.inline-control {
  grid-template-columns: minmax(0, 1fr) auto;
}

.speed-control {
  grid-template-columns: auto minmax(0, 1fr) auto auto;
  align-items: center;
}

.number-control {
  grid-template-columns: auto auto minmax(0, 1fr) auto auto;
  align-items: center;
}

.number-control-with-unit {
  grid-template-columns: auto auto minmax(0, 1fr) auto auto auto;
}

.adjust-button,
.calculate-button {
  border: 0;
  cursor: pointer;
  color: #061018;
  background: var(--accent);
  font-weight: 700;
}

.adjust-button {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 999px;
  font-size: 1.4rem;
  line-height: 1;
}

.adjust-large {
  width: 3.25rem;
  font-size: 1rem;
}

.adjust-button:hover,
.calculate-button:hover {
  background: var(--accent-strong);
}

.calculate-button {
  margin-top: 0.5rem;
  min-height: 3rem;
  border-radius: 0.8rem;
}

.result {
  margin-top: 1.5rem;
  padding: 1rem;
  background: var(--card-soft);
  border: 1px solid var(--border);
  border-radius: 0.8rem;
}

.result-grid {
  display: grid;
  gap: 0.6rem;
}

.result-row {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  padding-bottom: 0.6rem;
}

.result-row:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.result-label {
  color: var(--muted);
}

.result-value {
  text-align: right;
  font-weight: 700;
}

.error {
  color: var(--danger);
  font-weight: 700;
}

@media (max-width: 560px) {
  .speed-control {
    grid-template-columns: auto minmax(0, 1fr) auto;
  }

  .speed-control select {
    grid-column: 1 / -1;
  }

  .inline-control {
    grid-template-columns: 1fr;
  }

  .result-row {
    display: grid;
  }

  .result-value {
    text-align: left;
  }

    .number-control,
    .number-control-with-unit {
      grid-template-columns: auto auto minmax(0, 1fr) auto auto;
    }

    .number-control-with-unit select {
      grid-column: 1 / -1;
    }
}