:root {
  color-scheme: light;
  --ink: #20312b;
  --muted: #68776f;
  --paper: #f4f0e8;
  --card: #fffdf8;
  --green: #315c4b;
  --green-dark: #244639;
  --clay: #b76445;
  --line: #ddd7ca;
  --soft: #e8efe9;
  --warning: #946c21;
  font-family: "Noto Sans TC", "Microsoft JhengHei", system-ui, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 0%, rgba(183, 100, 69, .12), transparent 30rem),
    var(--paper);
}

button, input { font: inherit; }
button { cursor: pointer; }

.hero {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  padding: calc(1.5rem + env(safe-area-inset-top)) max(1.25rem, calc((100vw - 760px) / 2)) 1.5rem;
  color: white;
  background: var(--green);
}

.hero h1 { margin: .1rem 0 .35rem; font-size: clamp(1.75rem, 7vw, 2.5rem); }
.hero p { margin: 0; opacity: .84; line-height: 1.6; }
.eyebrow { font-size: .72rem; letter-spacing: .18em; font-weight: 800; }

main {
  width: min(100% - 1.5rem, 760px);
  margin: 1rem auto 3rem;
}

.card {
  margin-bottom: 1rem;
  padding: 1.15rem;
  border: 1px solid rgba(49, 92, 75, .1);
  border-radius: 20px;
  background: var(--card);
  box-shadow: 0 8px 28px rgba(51, 53, 43, .07);
}

.section-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  margin-bottom: .5rem;
}

.section-heading > div:first-child { display: flex; align-items: center; gap: .65rem; }
h2 { margin: 0; font-size: 1.12rem; }
.step { color: var(--clay); font-size: .72rem; font-weight: 900; letter-spacing: .08em; }
.hint { margin: .25rem 0 1rem; color: var(--muted); font-size: .86rem; line-height: 1.55; }

.presets { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: .35rem; }
.presets button, .material-actions button, .ghost {
  padding: .45rem .65rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--green);
  background: white;
  font-size: .76rem;
  font-weight: 700;
}

.ghost { color: white; border-color: rgba(255,255,255,.45); background: transparent; }

.oxide-groups { display: grid; gap: 1rem; }
.oxide-group h3 {
  margin: 0 0 .55rem;
  color: var(--muted);
  font-size: .78rem;
  letter-spacing: .08em;
}

.oxide-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: .55rem;
}

.oxide-field {
  position: relative;
  display: block;
}

.oxide-field span {
  position: absolute;
  top: .38rem;
  left: .65rem;
  color: var(--muted);
  font-size: .68rem;
}

.oxide-field input {
  width: 100%;
  padding: 1.25rem .6rem .45rem;
  border: 1px solid var(--line);
  border-radius: 11px;
  color: var(--ink);
  background: #fff;
  font-variant-numeric: tabular-nums;
}

.oxide-field input:focus {
  outline: 2px solid rgba(49, 92, 75, .23);
  border-color: var(--green);
}

.flux-total, .total-row {
  display: flex;
  justify-content: space-between;
  margin-top: .9rem;
  padding: .75rem .9rem;
  border-radius: 12px;
  background: var(--soft);
}

.flux-total strong.warning { color: var(--warning); }
.text-button { padding: .25rem; border: 0; color: var(--green); background: none; font-weight: 800; }
.material-panel { overflow: hidden; transition: max-height .25s ease; }
.material-panel.collapsed { max-height: 0; }
.material-panel:not(.collapsed) { max-height: 1800px; }
.material-actions { display: flex; gap: .4rem; margin: .6rem 0 .8rem; }

.material-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .45rem;
}

.material-choice {
  display: flex;
  align-items: center;
  gap: .55rem;
  min-height: 48px;
  padding: .55rem .65rem;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: #fff;
}

.material-choice input { width: 18px; height: 18px; accent-color: var(--green); }
.material-choice span { font-size: .88rem; }
.material-choice small { display: block; color: var(--muted); font-size: .67rem; }

.calculate {
  position: sticky;
  bottom: calc(.75rem + env(safe-area-inset-bottom));
  z-index: 3;
  width: 100%;
  margin: .15rem 0 1rem;
  padding: 1rem;
  border: 0;
  border-radius: 16px;
  color: white;
  background: var(--clay);
  box-shadow: 0 9px 24px rgba(122, 61, 39, .25);
  font-weight: 900;
}

.recipe-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: .75rem;
  align-items: center;
  padding: .8rem 0;
  border-bottom: 1px solid var(--line);
}

.recipe-row:last-child { border-bottom: 0; }
.recipe-name { font-weight: 800; }
.recipe-formula { margin-top: .2rem; color: var(--muted); font-size: .72rem; }
.recipe-weight { color: var(--green); font-size: 1.08rem; font-weight: 900; font-variant-numeric: tabular-nums; }
.badge { padding: .35rem .6rem; border-radius: 999px; background: var(--soft); color: var(--green); font-size: .75rem; font-weight: 900; }
.badge.medium { color: var(--warning); background: #f7ecd4; }
.badge.low { color: #9a3f37; background: #f7dfdc; }

.notice {
  margin: .75rem 0;
  padding: .75rem;
  border-radius: 11px;
  color: var(--muted);
  background: #f7f4ed;
  font-size: .82rem;
  line-height: 1.5;
}

details { margin-top: 1rem; }
summary { color: var(--green); cursor: pointer; font-weight: 800; }
.comparison { margin-top: .7rem; overflow-x: auto; }
.comparison table { width: 100%; border-collapse: collapse; font-size: .78rem; }
.comparison th, .comparison td { padding: .48rem; border-bottom: 1px solid var(--line); text-align: right; }
.comparison th:first-child, .comparison td:first-child { text-align: left; }
.comparison .high-error { color: #a24539; font-weight: 800; }
.note-card p { margin: .55rem 0 0; color: var(--muted); font-size: .84rem; line-height: 1.65; }

footer {
  padding: 0 1rem calc(2rem + env(safe-area-inset-bottom));
  color: var(--muted);
  text-align: center;
  font-size: .72rem;
}

.hidden { display: none !important; }

@media (max-width: 560px) {
  .hero { padding-left: 1.25rem; padding-right: 1.25rem; }
  .section-heading { align-items: flex-start; }
  .section-heading:not(.result-card .section-heading) { flex-direction: column; }
  .presets { justify-content: flex-start; }
  .oxide-grid { grid-template-columns: repeat(2, 1fr); }
  .material-list { grid-template-columns: 1fr; }
}