@import url('https://fonts.googleapis.com/css2?family=Sour+Gummy:wght@400;600;700&display=swap');

:root {
  --bg: #fafafa;
  --card: #ffffff;
  --text: #0b0b0b;
  --muted: rgba(11, 11, 11, 0.58);
  --line: rgba(11, 11, 11, 0.12);
  --accent: #58ff72;
  --accent-dim: #1a6b28;
  --shadow: 0 1px 3px rgba(11, 11, 11, 0.06);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100dvh;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  font-size: clamp(15px, 0.35vw + 14px, 16px);
  line-height: 1.45;
}

a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:hover {
  opacity: 0.88;
}

.shell {
  max-width: 720px;
  margin: 0 auto;
  padding: clamp(16px, 4vw, 28px) clamp(14px, 3vw, 20px) 40px;
}

.top {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: clamp(18px, 3vw, 26px);
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
}

.brand {
  font-family: 'Sour Gummy', system-ui, sans-serif;
  font-weight: 700;
  font-size: clamp(1.2rem, 2.5vw, 1.45rem);
  letter-spacing: 0.02em;
}

.brand span {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  margin-right: 8px;
  vertical-align: middle;
  box-shadow: 0 0 0 1px rgba(26, 107, 40, 0.25);
}

.back {
  font-size: 0.9rem;
  color: var(--muted);
}

h1 {
  font-family: 'Sour Gummy', system-ui, sans-serif;
  font-weight: 600;
  font-size: clamp(1.05rem, 2vw, 1.2rem);
  margin: 0 0 6px;
  letter-spacing: 0.02em;
}

.lead {
  margin: 0 0 20px;
  color: var(--muted);
  font-size: 0.92rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: clamp(16px, 3vw, 22px);
  box-shadow: var(--shadow);
  margin-bottom: 16px;
}

.grid {
  display: grid;
  gap: 16px;
}

@media (min-width: 560px) {
  .grid-2 {
    grid-template-columns: 1fr 1fr;
  }
}

label {
  display: block;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--muted);
  margin-bottom: 6px;
}

input[type='text'],
input[type='number'] {
  width: 100%;
  padding: 12px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  font: inherit;
  font-size: 1rem;
  font-variant-numeric: tabular-nums;
  background: #fff;
  color: var(--text);
}

input:focus {
  outline: 2px solid rgba(88, 255, 114, 0.45);
  outline-offset: 1px;
  border-color: rgba(26, 107, 40, 0.35);
}

.hint {
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 6px;
}

.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.presets button {
  border: 1px solid var(--line);
  background: #fff;
  padding: 8px 12px;
  border-radius: 999px;
  font: inherit;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  color: var(--text);
}

.presets button:hover {
  border-color: rgba(11, 11, 11, 0.28);
}

.presets button.is-on {
  border-color: var(--accent-dim);
  background: rgba(88, 255, 114, 0.14);
}

.results {
  display: grid;
  gap: 12px;
}

@media (min-width: 480px) {
  .results {
    grid-template-columns: repeat(3, 1fr);
  }
}

.result-box {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 12px;
  text-align: center;
  background: rgba(255, 255, 255, 0.9);
}

.result-box strong {
  display: block;
  font-family: 'Sour Gummy', system-ui, sans-serif;
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 8px;
}

.result-box .val {
  font-size: clamp(1.05rem, 2.8vw, 1.25rem);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.result-box.highlight .val {
  color: var(--accent-dim);
}

.note {
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.5;
  margin-top: 18px;
}