:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1e222b;
  --fg: #e6e8ec;
  --muted: #8a93a6;
  --accent: #9ae6b4;
  --border: #272b35;
  --error: #ff6b6b;

  --cat-under: #7cc4ff;
  --cat-severe-under: #c5a3ff;
  --cat-normal: #9ae6b4;
  --cat-over: #f5c26b;
  --cat-obese1: #f5c26b;
  --cat-obese2: #ff9ec7;
  --cat-obese3: #ff6b6b;
  --cat-obese4: #ff6b6b;
}

* { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-size: 15px;
  line-height: 1.6;
}

header {
  padding: 24px 32px 8px;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
}
header h1 { margin: 0; font-size: 22px; }
header #subtitle {
  grid-column: 1 / 2;
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 14px;
}
.lang-switch {
  grid-column: 2 / 3;
  grid-row: 1 / 3;
  display: flex;
  align-items: center;
  gap: 6px;
}

main {
  padding: 28px 32px 48px;
  max-width: 640px;
  margin: 0 auto;
}

.input-section {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px 24px;
  margin-bottom: 20px;
}

.field { margin-bottom: 14px; }
.field:last-child { margin-bottom: 0; }

label {
  display: block;
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
  margin-bottom: 4px;
}

input[type="number"] {
  width: 100%;
  padding: 12px 16px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--fg);
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 20px;
}
input[type="number"]:focus { outline: none; border-color: var(--accent); }

select {
  padding: 8px 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--fg);
  font-size: 13px;
}

.error {
  margin-top: 10px;
  color: var(--error);
  font-size: 13px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}

.result {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px 28px;
}

.hero { text-align: center; margin-bottom: 24px; }
.hero-label {
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.hero-value {
  font-size: 72px;
  color: var(--accent);
  font-weight: 700;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  line-height: 1;
  margin-top: 4px;
}

.meta-rows {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.meta-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 10px 0;
  border-top: 1px dashed var(--border);
}
.meta-label {
  color: var(--muted);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.meta-value {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 16px;
  color: var(--fg);
}
.category-value {
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", sans-serif;
  font-size: 16px;
  font-weight: 600;
}
.cat-under { color: var(--cat-under); }
.cat-severe-under { color: var(--cat-severe-under); }
.cat-normal { color: var(--cat-normal); }
.cat-over { color: var(--cat-over); }
.cat-obese1 { color: var(--cat-obese1); }
.cat-obese2 { color: var(--cat-obese2); }
.cat-obese3 { color: var(--cat-obese3); }
.cat-obese4 { color: var(--cat-obese4); }

footer {
  padding: 24px 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 12px;
  text-align: center;
}