:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --border: #e2e8f0;
  --accent: #b4233c;
  --accent-weak: #fde4e8;
  --error: #b91c1c;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --surface: #111a2b;
    --text: #e2e8f0;
    --muted: #94a3b8;
    --border: #23314a;
    --accent: #fb7185;
    --accent-weak: #3b1520;
    --error: #f87171;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.65;
  font-size: 16px;
}
a { color: var(--accent); }
.wrap { max-width: 860px; margin: 0 auto; padding: 0 16px; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 8px; top: 8px; background: var(--surface); padding: 8px; z-index: 10; }

.site-header { background: var(--surface); border-bottom: 1px solid var(--border); }
.site-header .wrap { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 20px; padding-top: 10px; padding-bottom: 10px; }
.logo { font-weight: 800; font-size: 1.25rem; text-decoration: none; color: var(--text); }
.site-header nav { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: 0.9rem; }
.site-header nav a { text-decoration: none; color: var(--muted); }
.site-header nav a:hover { color: var(--accent); }

main { padding-top: 16px; padding-bottom: 48px; }
.breadcrumb { font-size: 0.85rem; color: var(--muted); margin: 0 0 8px; }
.breadcrumb a { color: var(--muted); }
h1 { font-size: 1.6rem; line-height: 1.35; margin: 8px 0 8px; }
h2 { font-size: 1.25rem; margin: 2em 0 0.6em; padding-bottom: 4px; border-bottom: 2px solid var(--accent-weak); }
h3 { font-size: 1.05rem; margin: 1.5em 0 0.4em; }
.lead { color: var(--muted); margin-top: 0; }
.updated { font-size: 0.8rem; color: var(--muted); }

.tool {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin: 16px 0 24px;
}
.tool-form { display: grid; gap: 12px; }
.tool-form label { display: grid; gap: 4px; font-weight: 600; font-size: 0.95rem; }
.tool-form label.check { display: flex; align-items: center; gap: 6px; font-weight: 400; }
.tool-form fieldset { border: 1px solid var(--border); border-radius: 8px; padding: 8px 12px 12px; margin: 0; }
.tool-form legend { font-weight: 600; font-size: 0.95rem; padding: 0 4px; }
.tool-form .inline, .tool-form fieldset.inline { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.tool-form .inline label { display: flex; align-items: center; gap: 6px; }
input, select, textarea, button {
  font: inherit;
  color: inherit;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  min-height: 44px;
  max-width: 100%;
}
input[type="checkbox"] { min-height: auto; width: 18px; height: 18px; }
fieldset.inline input[type="number"], fieldset.inline input[type="text"] { width: 8em; }
textarea { width: 100%; resize: vertical; }
input:focus, select:focus, textarea:focus, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
button { background: var(--accent); color: #fff; border: none; cursor: pointer; font-weight: 600; justify-self: start; }
button.secondary { background: transparent; color: var(--accent); border: 1px solid var(--accent); }
@media (prefers-color-scheme: dark) { button { color: #0b1220; } button.secondary { color: var(--accent); } }

.percent-grid p { margin: 0; display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.percent-grid input { width: 7.5em; }
.percent-grid output { font-weight: 700; font-size: 1.1rem; min-width: 4em; color: var(--accent); }

.result { margin-top: 16px; }
.result:empty { display: none; }
.result .big { font-size: 1.5rem; margin: 0 0 8px; }
.result .big strong { font-size: 2.2rem; color: var(--accent); }
.result-list { margin: 0; display: grid; gap: 0; }
.result-list > div { display: grid; grid-template-columns: minmax(8em, 38%) 1fr; gap: 12px; padding: 8px 0; border-top: 1px solid var(--border); }
.result-list dt { color: var(--muted); font-size: 0.9rem; }
.result-list dd { margin: 0; overflow-wrap: anywhere; }
@media (max-width: 520px) { .result-list > div { grid-template-columns: 1fr; gap: 0; } }
.hint { color: var(--muted); margin: 0; }
.error { color: var(--error); }
.tag { display: inline-block; font-size: 0.75rem; background: var(--accent-weak); color: var(--text); border-radius: 999px; padding: 0 8px; }
details { margin-top: 12px; }
summary { cursor: pointer; color: var(--accent); }

.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.data-table { border-collapse: collapse; width: 100%; font-size: 0.92rem; }
.data-table caption { text-align: left; color: var(--muted); font-size: 0.85rem; padding-bottom: 4px; }
.data-table th, .data-table td { border-bottom: 1px solid var(--border); padding: 6px 8px; text-align: left; white-space: nowrap; }
.data-table th { background: var(--accent-weak); }
.data-table tr.muted td { color: var(--muted); }

.faq dt { font-weight: 700; margin-top: 12px; }
.faq dt::before { content: "Q: "; color: var(--accent); }
.faq dd { margin: 4px 0 0; }
.faq dd::before { content: "A: "; font-weight: 700; color: var(--muted); }

.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; padding: 0; list-style: none; }
.cards a { display: block; height: 100%; background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 12px 14px; text-decoration: none; color: var(--text); }
.cards a:hover { border-color: var(--accent); }
.cards strong { display: block; color: var(--accent); }
.cards span { font-size: 0.85rem; color: var(--muted); }

.site-footer { border-top: 1px solid var(--border); background: var(--surface); padding: 20px 0; font-size: 0.85rem; color: var(--muted); }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 4px 16px; }
.small { font-size: 0.8rem; }

/* file tools */
.drop-zone { border: 2px dashed var(--border); border-radius: 12px; padding: 16px; background: var(--surface); }
.drop-zone.dragging { border-color: var(--accent); }
.drop-zone input[type="file"] { min-height: auto; padding: 8px 0; border: none; background: transparent; }
.file-list { margin: 0; padding: 0; list-style: none; display: grid; gap: 6px; }
.file-list:empty { display: none; }
.file-list li { display: flex; justify-content: space-between; align-items: center; gap: 8px; padding: 6px 10px; border: 1px solid var(--border); border-radius: 8px; }
.file-list .file-name { overflow-wrap: anywhere; }
.file-list .file-actions { display: flex; gap: 4px; flex-shrink: 0; }
.file-list .file-actions button { min-height: 32px; padding: 2px 10px; }
.file-list button:disabled { opacity: 0.35; cursor: default; }
button:disabled { opacity: 0.5; cursor: default; }
.downloads { display: grid; gap: 6px; }
a.download { display: inline-block; padding: 8px 14px; border: 1px solid var(--accent); border-radius: 8px; font-weight: 600; text-decoration: none; }
.note:empty { display: none; }
code { background: var(--surface); border: 1px solid var(--border); border-radius: 4px; padding: 0 4px; }
input[type="radio"] { min-height: auto; width: 18px; height: 18px; }
/* long English option labels must not push the form wider than the screen */
.tool-form, .tool-form label, .tool-form fieldset { min-width: 0; }
.tool-form label > select, .tool-form label > input:not([type="checkbox"]):not([type="radio"]) { width: 100%; }