:root {
  --bg: #f4f6fb;
  --bg-grad-1: #eef2fb;
  --bg-grad-2: #f7f4fb;
  --card: #ffffff;
  --card-border: #e4e8f0;
  --text: #1a2233;
  --text-soft: #5a6472;
  --text-faint: #8a93a3;
  --primary: #4f6cf7;
  --primary-soft: #eef1fe;
  --input-bg: #f8fafc;
  --input-border: #d7dde8;
  --shadow: 0 10px 30px rgba(30, 45, 90, 0.08);
  --protein: #4f6cf7;
  --carbs: #f0a13c;
  --fat: #e9647b;
  --error: #d64545;
  --radius: 14px;
}

:root[data-theme="dark"],
html.dark {
  --bg: #0e1220;
  --bg-grad-1: #10152a;
  --bg-grad-2: #171226;
  --card: #171c2e;
  --card-border: #262c40;
  --text: #eef1f8;
  --text-soft: #a8b0c2;
  --text-faint: #737d92;
  --primary: #7d93ff;
  --primary-soft: #1e2540;
  --input-bg: #1a2036;
  --input-border: #333a52;
  --shadow: 0 12px 34px rgba(0, 0, 0, 0.4);
  --protein: #7d93ff;
  --carbs: #f0b45f;
  --fat: #f07f92;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1220;
    --bg-grad-1: #10152a;
    --bg-grad-2: #171226;
    --card: #171c2e;
    --card-border: #262c40;
    --text: #eef1f8;
    --text-soft: #a8b0c2;
    --text-faint: #737d92;
    --primary: #7d93ff;
    --primary-soft: #1e2540;
    --input-bg: #1a2036;
    --input-border: #333a52;
    --shadow: 0 12px 34px rgba(0, 0, 0, 0.4);
    --protein: #7d93ff;
    --carbs: #f0b45f;
    --fat: #f07f92;
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: linear-gradient(150deg, var(--bg-grad-1), var(--bg-grad-2));
  background-attachment: fixed;
  min-height: 100vh;
  line-height: 1.55;
}

/* ---------- Header ---------- */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1000px;
  margin: 0 auto;
  padding: 18px 20px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; }
.logo { color: var(--primary); font-size: 1.4rem; line-height: 1; }
.brand-name { letter-spacing: -0.01em; }

.theme-toggle {
  width: 40px; height: 40px;
  border-radius: 50%;
  border: 1px solid var(--card-border);
  background: var(--card);
  color: var(--text);
  cursor: pointer;
  font-size: 1.05rem;
  display: grid; place-items: center;
  transition: transform 0.15s ease, background 0.2s ease;
}
.theme-toggle:hover { transform: rotate(15deg); }

/* ---------- Layout ---------- */
.container { max-width: 1000px; margin: 0 auto; padding: 8px 20px 40px; }

.intro { text-align: center; margin: 10px 0 28px; }
.intro h1 { font-size: clamp(1.7rem, 4vw, 2.4rem); margin: 0 0 12px; letter-spacing: -0.02em; }
.lede { color: var(--text-soft); max-width: 640px; margin: 0 auto; font-size: 1.02rem; }

.layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  align-items: start;
}
@media (max-width: 760px) {
  .layout { grid-template-columns: 1fr; }
}

.card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px;
}

/* ---------- Form ---------- */
.unit-toggle {
  display: inline-flex;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 10px;
  padding: 3px;
  margin-bottom: 18px;
}
.unit-btn {
  border: none; background: transparent; cursor: pointer;
  padding: 7px 18px; border-radius: 8px;
  font-size: 0.9rem; font-weight: 600; color: var(--text-soft);
  transition: all 0.18s ease;
}
.unit-btn.active { background: var(--primary); color: #fff; }

.field { margin-bottom: 16px; }
.field > label {
  display: block; font-size: 0.85rem; font-weight: 600;
  margin-bottom: 7px; color: var(--text);
}
.unit-hint { color: var(--text-faint); font-weight: 400; font-size: 0.8rem; }

input[type="number"], select {
  width: 100%;
  padding: 11px 12px;
  border: 1px solid var(--input-border);
  border-radius: 10px;
  background: var(--input-bg);
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
input[type="number"]:focus, select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}
select { appearance: none; -webkit-appearance: none; cursor: pointer;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'><path d='M2 4l4 4 4-4' stroke='%238a93a3' stroke-width='1.6' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 34px;
}

.dual { display: flex; gap: 10px; }
.dual-item { position: relative; flex: 1; display: flex; align-items: center; gap: 6px; }
.dual-item input { flex: 1; }
.dual-item .unit-hint { white-space: nowrap; }

/* Segmented radio */
.seg {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--input-border);
  border-radius: 10px;
  overflow: hidden;
}
.seg-3 { grid-template-columns: 1fr 1fr 1fr; }
.seg input { position: absolute; opacity: 0; pointer-events: none; }
.seg label {
  text-align: center;
  padding: 10px 6px;
  cursor: pointer;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-soft);
  background: var(--input-bg);
  border-left: 1px solid var(--input-border);
  transition: all 0.15s ease;
}
.seg label:first-of-type { border-left: none; }
.seg input:checked + label { background: var(--primary); color: #fff; }

.goal-note { font-size: 0.82rem; color: var(--text-faint); margin: 9px 2px 0; }

.error { color: var(--error); font-size: 0.87rem; margin: 6px 0 0; min-height: 1em; }

.hidden { display: none !important; }

/* ---------- Results ---------- */
.result-card { display: flex; flex-direction: column; }
.result-top {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 6px;
}
.stat {
  background: var(--input-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 14px;
}
.stat.highlight {
  grid-column: 1 / -1;
  background: var(--primary-soft);
  border-color: var(--primary);
}
.stat-label { display: block; font-size: 0.78rem; color: var(--text-soft); font-weight: 600; margin-bottom: 6px; }
.stat-value { font-size: 1.7rem; font-weight: 700; letter-spacing: -0.02em; }
.stat-value small { font-size: 0.72rem; font-weight: 500; color: var(--text-faint); margin-left: 5px; }
.stat.highlight .stat-value { color: var(--primary); }

.macros-title { font-size: 1rem; margin: 20px 0 12px; }
.macros { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; }
.macro {
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 13px 11px;
  text-align: center;
  background: var(--input-bg);
}
.macro-head { font-size: 0.82rem; font-weight: 600; color: var(--text-soft); display: flex; align-items: center; justify-content: center; gap: 6px; }
.dot { width: 9px; height: 9px; border-radius: 50%; display: inline-block; }
.macro-protein .dot { background: var(--protein); }
.macro-carbs .dot { background: var(--carbs); }
.macro-fat .dot { background: var(--fat); }
.macro-grams { font-size: 1.4rem; font-weight: 700; margin: 6px 0 3px; letter-spacing: -0.02em; }
.macro-cal { font-size: 0.75rem; color: var(--text-faint); }

.macro-bar {
  display: flex;
  height: 12px;
  border-radius: 8px;
  overflow: hidden;
  margin-top: 16px;
  background: var(--input-bg);
}
.macro-bar span { display: block; height: 100%; transition: width 0.3s ease; }
.bar-protein { background: var(--protein); }
.bar-carbs { background: var(--carbs); }
.bar-fat { background: var(--fat); }

.result-hint { font-size: 0.8rem; color: var(--text-faint); margin: 16px 0 0; }

/* ---------- Prose / FAQ ---------- */
.prose { margin-top: 40px; max-width: 760px; }
.prose h2 { font-size: 1.35rem; margin: 30px 0 12px; letter-spacing: -0.01em; }
.prose p { color: var(--text-soft); }
.formula-list { list-style: none; padding: 0; margin: 14px 0; }
.formula-list li {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 12px 14px;
  margin-bottom: 8px;
  font-size: 0.92rem;
  font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  color: var(--text);
}

.faq details {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 4px 16px;
  margin-bottom: 10px;
}
.faq summary {
  cursor: pointer;
  font-weight: 600;
  padding: 12px 0;
  list-style: none;
  position: relative;
  padding-right: 26px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute; right: 2px; top: 10px;
  font-size: 1.3rem; color: var(--primary); font-weight: 400;
  transition: transform 0.2s ease;
}
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { margin: 0 0 14px; font-size: 0.94rem; }

.disclaimer {
  font-size: 0.85rem;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-left: 3px solid var(--carbs);
  border-radius: 8px;
  padding: 12px 15px;
  margin-top: 24px;
}

/* ---------- Footer ---------- */
.site-footer {
  text-align: center;
  padding: 26px 20px 34px;
  color: var(--text-faint);
  font-size: 0.88rem;
}
.site-footer a { color: var(--primary); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }