:root {
  color-scheme: light;
  --ink: #17253a;
  --muted: #6c7788;
  --paper: #f7f3eb;
  --card: rgba(255, 255, 255, 0.92);
  --accent: #f05d3d;
  --accent-dark: #c9442b;
  --teal: #1a8075;
  --line: #d9d7d1;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 15%, rgba(240, 93, 61, 0.16), transparent 28rem),
    radial-gradient(circle at 90% 88%, rgba(26, 128, 117, 0.17), transparent 30rem),
    var(--paper);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.32;
  background-image: linear-gradient(rgba(23, 37, 58, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(23, 37, 58, 0.045) 1px, transparent 1px);
  background-size: 28px 28px;
}

.page-shell {
  position: relative;
  width: min(1180px, calc(100% - 40px));
  min-height: 100vh;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 0.78fr 1.22fr;
  gap: clamp(36px, 7vw, 96px);
  align-items: center;
  padding: 56px 0;
}

.eyebrow {
  display: inline-block;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.22em;
  border-bottom: 2px solid currentColor;
  padding-bottom: 7px;
}

h1 {
  margin: 24px 0 20px;
  font-family: Georgia, "Noto Serif SC", serif;
  font-size: clamp(2.8rem, 5.5vw, 5.3rem);
  line-height: 0.98;
  letter-spacing: -0.055em;
}

h1 span { color: var(--teal); }
.intro > p { max-width: 35rem; color: var(--muted); font-size: 1.05rem; line-height: 1.8; }

.rule-pills { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 28px; }
.rule-pills span { border: 1px solid rgba(23, 37, 58, 0.18); border-radius: 999px; padding: 8px 13px; font-size: 0.82rem; font-weight: 700; }

.calculator {
  background: var(--card);
  border: 1px solid rgba(23, 37, 58, 0.1);
  border-radius: 26px;
  box-shadow: 0 28px 80px rgba(23, 37, 58, 0.14);
  padding: clamp(24px, 4vw, 44px);
  backdrop-filter: blur(14px);
}

.section-heading, .section-heading > div { display: flex; align-items: center; gap: 12px; }
.section-heading { justify-content: space-between; margin-bottom: 22px; }
.step { color: var(--accent); font-size: 0.75rem; font-weight: 900; letter-spacing: 0.1em; }
h2 { margin: 0; font-size: 1rem; letter-spacing: 0.02em; }
.hint { color: var(--muted); font-size: 0.78rem; }

.pattern-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 9px; }
.pattern-option { position: relative; cursor: pointer; }
.pattern-option input { position: absolute; opacity: 0; pointer-events: none; }
.pattern-option span {
  display: grid;
  place-items: center;
  min-height: 48px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  font-size: 0.94rem;
  font-weight: 750;
  transition: 160ms ease;
}
.pattern-option:hover span { border-color: var(--teal); transform: translateY(-1px); }
.pattern-option input:focus-visible + span { outline: 3px solid rgba(26, 128, 117, 0.23); }
.pattern-option input:checked + span { color: white; border-color: var(--ink); background: var(--ink); box-shadow: 0 8px 18px rgba(23, 37, 58, 0.2); }

.target-block { margin-top: 34px; }
.target-block label { display: block; font-size: 0.9rem; font-weight: 800; margin-bottom: 12px; }
.input-row { display: grid; grid-template-columns: auto 1fr auto; align-items: stretch; gap: 10px; }
.equals { display: grid; place-items: center; color: var(--teal); font-family: Georgia, serif; font-size: 2rem; padding-right: 2px; }
input[type="number"] { width: 100%; min-width: 0; border: 1px solid var(--line); border-radius: 13px; padding: 13px 15px; color: var(--ink); background: white; font: inherit; font-size: 1.1rem; }
input[type="number"]:focus { outline: 3px solid rgba(26, 128, 117, 0.17); border-color: var(--teal); }
button { border: 0; border-radius: 13px; padding: 0 20px; color: white; background: var(--accent); font: inherit; font-weight: 800; cursor: pointer; transition: 160ms ease; }
button:hover { background: var(--accent-dark); transform: translateY(-1px); }

.result { position: relative; margin-top: 24px; border-radius: 16px; padding: 20px 22px; background: #e9f4f1; border-left: 4px solid var(--teal); }
.result-label { display: block; color: var(--muted); font-size: 0.76rem; font-weight: 800; letter-spacing: 0.08em; }
.result strong { display: block; margin-top: 7px; color: var(--teal); font-family: Georgia, "Noto Serif SC", serif; font-size: clamp(1.65rem, 4vw, 2.45rem); }
.result[data-state="empty"], .result[data-state="error"] { background: #fff1ed; border-color: var(--accent); }
.result[data-state="empty"] strong, .result[data-state="error"] strong { color: var(--accent-dark); font-size: 1.15rem; }
.copy-button { position: absolute; right: 16px; top: 16px; color: var(--teal); background: transparent; border: 1px solid rgba(26, 128, 117, 0.28); padding: 7px 10px; font-size: 0.74rem; }
.copy-button:hover { color: white; background: var(--teal); }

@media (max-width: 850px) {
  .page-shell { grid-template-columns: 1fr; gap: 32px; padding: 42px 0; }
  .intro { text-align: center; }
  .intro > p { margin-inline: auto; }
  .rule-pills { justify-content: center; }
  h1 { font-size: clamp(2.8rem, 12vw, 4.8rem); }
}

@media (max-width: 540px) {
  .page-shell { width: min(100% - 22px, 1180px); padding: 28px 0; }
  .calculator { border-radius: 20px; padding: 20px 16px; }
  .pattern-grid { grid-template-columns: repeat(2, 1fr); }
  .input-row { grid-template-columns: auto 1fr; }
  .input-row button { grid-column: 1 / -1; min-height: 50px; }
}