:root {
  color-scheme: light dark;
  --bg: #f6f7f9;
  --card: #ffffff;
  --text: #15171a;
  --muted: #68707d;
  --line: #d9dee7;
  --accent: #2563eb;
  --danger: #dc2626;
  --soft: rgba(21, 23, 26, .06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --card: #171a21;
    --text: #f2f4f8;
    --muted: #9aa3b2;
    --line: #2a3040;
    --accent: #60a5fa;
    --danger: #f87171;
    --soft: rgba(242, 244, 248, .08);
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  background:
    radial-gradient(circle at top left, color-mix(in srgb, var(--accent) 22%, transparent), transparent 32rem),
    var(--bg);
  color: var(--text);
  font: 15px/1.55 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

main {
  width: min(800px, 100%);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: 26px;
  box-shadow: 0 18px 60px rgba(0, 0, 0, .12);
}

h1 {
  margin: 0 0 6px;
  font-size: clamp(24px, 4vw, 34px);
  letter-spacing: -.04em;
}

p {
  margin: 0;
  color: var(--muted);
}

header {
  margin-bottom: 22px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

@media (max-width: 700px) {
  .grid {
    grid-template-columns: 1fr;
  }
}

.span2 {
  grid-column: 1 / -1;
}

label,
legend {
  display: block;
  font-weight: 700;
  margin-bottom: 6px;
}

fieldset {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  margin: 0;
}

fieldset legend {
  padding: 0 6px;
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px 12px;
  background: transparent;
  color: var(--text);
  font: inherit;
  outline: none;
}

input:focus,
select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 20%, transparent);
}

.checks {
  display: grid;
  gap: 9px;
}

.checks label {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-weight: 500;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

button {
  border: 0;
  border-radius: 999px;
  padding: 11px 17px;
  color: white;
  background: var(--accent);
  font: inherit;
  font-weight: 800;
  cursor: pointer;
}

button.secondary {
  color: var(--text);
  background: var(--soft);
}

button:hover {
  filter: brightness(1.05);
}

button:active {
  transform: translateY(1px);
}

.result {
  margin-top: 18px;
  display: grid;
  gap: 10px;
}

.row {
  display: grid;
  grid-template-columns: 110px 1fr auto;
  gap: 10px;
  align-items: center;
}

@media (max-width: 620px) {
  .row {
    grid-template-columns: 1fr;
  }
}

.out {
  overflow-wrap: anywhere;
  border: 1px dashed var(--line);
  border-radius: 12px;
  padding: 10px 12px;
  background: var(--soft);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.hint {
  min-height: 22px;
  margin-top: 12px;
  font-size: 13px;
}

.error {
  color: var(--danger);
  font-weight: 800;
}

footer {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

footer p {
  font-size: 13px;
}